Winning Abstract - 5. Outcome of prostate brachytherapy in men with intermediate risk disease-results of Oncura multi-institutional database

You can read the winning abstract lower down this page or click here.

1.  Early UK results of real-time dynamic prostate brachytherapy for the management of low and intermediate risk prostate cancer

Hidekazu Yamamoto, Guy's Hospital, Department of Urology

Peter Acher, Guy's Hospital, Department of Urology

John Withington, Guy's Hospital, Department of Urology

Steven Morris, Guy's Hospital, Department of Oncology

Janette E. Nichol, Guy's Hospital, Department of Urology

Rick Popert, Guy's Hospital, Department of Urology

Aims/Introduction:

Our institution offers prostate brachytherapy as a day case procedure which combines treatment planning, seed implantation and post-implantation dosimetry verification into a single hospital episode.  Following our initial report on the first UK series of real-time dynamic prostate brachytherapy (RTDPB) (Acher et al. BJUI; 99:1066-71), we report on the biochemical relapse-free survival (BRFS) and intervention rates in our 2003-7 cohort.  Furthermore, we evaluate the roles of intra- and post-operative CT dosimetry in the prediction of BRFS.

Materials/Methods:

221 patients aged 64 ±8 yrs with low (55%) or intermediate D’Amico risk prostate cancer received RTDPB between 2003-7. Median follow-up was 42 months (range 12-72).  Prostate volumes ranged from 14-91cm3 (mean 40cm3).  All patients were implanted with iodine-125 as a monotherapy at a prescribed dose of 145Gy.  Image capture, outlining, treatment planning and dose optimisation were conducted using the Variseed software.  Post-operative CT dosimetry was also conducted as per American Brachytherapy Society guidelines (mean 44 days post op).  PSA measurements were conducted at 3,6,9,12 months and every 6 months thereafter.

Results

Overall, 11 patients (5%) experienced biochemical failure (nadir+2).  1 patient died from metastatic prostate cancer.  6 patients (3%) had recurrence confirmed histologically and underwent salvage prostatectomy or hormone treatment.  Kaplan-Meier survival analysis showed the overall BRFS rate to be 94% at 72 months, with a non-significant difference between low (95.6%) and intermediate (92.1%) risk groups (p=0.46).  Neither intra-operative nor post-operative dosimetry measurements (D90 and V100) showed any significant difference between those with and without biochemical failure.  Complications included urethral stricture (1/221), proctitis (2/221) and bowel incontinence (1/221)

Conclusion:

Our data highlight the efficacy of RTDPB in the treatment of patients with low / intermediate risk prostate cancer.  Our results compare favourably to other larger brachytherapy series.  Post-operative dosimetry did not appear to provide any additional benefit over intra-operative dosimetry alone.

Return to top of page.

2.  Evaluating and improving prostate seed implant techniques: Pre-operative volume study and treatment planning vs intra-operative planning: the Edinburgh Cancer Centre experience.

Dr William Keough, Ph.D., Acting Head of Brachytherapy Service, Edinburgh Cancer Centre                          

Dr Duncan McLaren, MD. Consultant Clinical Oncologist,  Edinburgh Cancer Centre

Dr John Brush, M.D., Consultant Radiologist, Edinburgh Cancer Centre 

Mr Terry Kehoe, M.S., Director of Oncology Physics, Edinburgh Cancer Centre

Tiffany West, Clinical Technologist, Edinburgh Cancer Centre

Mr John Ross, Intra-op Strand Loading Technician, Edinburgh Cancer Centre

Aims/Introduction:

We are presenting a comparison of implant results using different techniques for Prostate Seed Brachytherapy.  These techniques include pre-operative volume studies and treatment planning using uniformly spaced stranded seeds, and two intra-operative techniques using uniformly spaced stranded seeds.   

Comparing the post implant dosimetry results with the implant techniques identified above has provided the data to evaluate processes and procedures that are currently being used to improve post implant dosimetry results. 

Materials/Methods:

Ct scan post implant dosimetry are used to compare V100, V150, V200, and D90 data for patients treated using pre-operative volume studies (n=46) and two intra-operative techniques (n=55).  The first intra-operative technique involves single needle ultrasound tracking with deposition of the seed strand.  The second intra-operative technique involves the insertion of approximately 5-6 needles in one plane of the prostate followed by the deposition of the strands in that plane.

Results

The results in Table 1 indicate better V100 and D90 coverage with Intra-operative plane by plane deposition when compared to both pre-operative volume studies and intra-operative single needle ultrasound tracking and deposition of seeds.

Table 1

Conclusion:

1. Intra-operative ultrasound tracking of each needle increases movement and deformation of the prostate.  This resulted in reduced D90 and V100 values. 

2.  Preliminary results for the Intra-operative plane by plane deposition technique reduced the amount of ultrasound probe movement which subsequently decreases prostate deformation.  This has produced an improvement on our D90 and V100 values.

3.  The reduction in Intra-operative compared to Pre-operative D90 and V100 values may be a result of reduction in treatment planning time in theatre.     

4.  Other treatment techniques will be discussed which could improve results and reduce theatre time

Return to top of page.

3.  Long term survival and toxicity outcomes following LDR prostate brachytherapy

Mr Amr M Emara, Royal Surrey County Hospital, St Luke's Cancer Centre, Guildford

Mr Ather M Abdelbaky, Royal Surrey County Hospital, St Luke's Cancer Centre, Guildford

Dr Jenny Nobes, Royal Surrey County Hospital, St Luke's Cancer Centre, Guildford

Dr Robert W Laing, Royal Surrey County Hospital, St Luke's Cancer Centre, Guildford

Professor Stephen E M Langley, Royal Surrey County Hospital, St Luke's Cancer Centre, Guildford

Aims/Introduction:

To monitor and evaluate the long term survival and side effects for patients treated by LDR prostate brachytherapy (BXT).

Materials/Methods: 

To date we have treated more than 1400 patients with BXT for early prostate cancer in our centre.  We reported the biochemical failure (Houston +2) in 743 patients treated with a minimum 3 years follow up.

A questionnaire including standard scoring systems for urinary, erectile and bowel function (IPSS, IIEF 5 and QLQ-C30/ PR25 respectively) was sent to 226 patients who successfully crossed the 5 years mark up-to 10 years of follow up, we received reply back from 174 (77%) patients.

Results 

PSA survival was 93%, and stratified as 94 %, 92 % and 90 % for low, intermediate and high risk patients respectively. 

Long-term toxicity: mean IPSS score increased from 6.3 to 8.1 at follow up (p<0.05). Of the patients with mild symptoms pre-BXT (IPSS 0-7), 64% remained in this group at follow up, 31% developed moderate symptoms (IPSS 8-19), and 5% developed severe symptoms (IPSS 20-35). And for the patients who had initially presented with moderate IPSS; 28% improved to mild symptoms on post-BXT follow up, while 61%, remained with moderate symptoms, and 1% developed severe symptoms.  77%, 21% and 2%, respectively, reported good, acceptable or poor quality of life secondary to urinary symptoms on the long term.

63% of patients potent (IIEF >13) pre-BXT remained potent at (5-10 yr) follow up.  At follow up, 52% and 45% of patients, respectively, had normal or mild bowel function (QLQ-C30/PR25= 4, 5-8).  3% of patients reported moderate symptoms (QLQ-C30/PR25= 9-16).

Conclusion:

This study demonstrates excellent clinical outcomes with low morbidity on the long term for post-BXT patients up to 10 years of follow up.

Return to top of page.

4.  Is it possible to give greater than 145Gy to the prostate margin without compromising on toxicity?

Hyde KJ, Berkshire Cancer Centre, Royal Berkshire Hospital, UK

Dallas NL, Berkshire Cancer Centre, Royal Berkshire Hospital, UK

Doggart AJ, Berkshire Cancer Centre, Royal Berkshire Hospital, UK

Malone PR, Harold Hopkins Department of Urology, Royal Berkshire Hospital, UK

Jones A, Harold Hopkins Department of Urology, Royal Berkshire Hospital, UK

Rogers PB, Berkshire Cancer Centre, Royal Berkshire Hospital, UK

Aims/Introduction:

A post-implant D90 of at least 140Gy to the prostate provides optimal biochemical control of prostate cancer1. A dose-response relationship in prostate cancer is well documented. EORTC 2007 guidelines advise on dosimetry parameters but no consensus dose exists for real-time brachytherapy. We define a real-time intraoperative D90 to the prostate and margin to achieve a minimum post-implant D90 of 140Gy.

Materials/Methods:

256 patients with early prostate cancer were treated with iodine-125 brachytherapy using the real-time technique between November 2003 and October 2009. Patients with intermediate risk disease (T1-2, Gleason 7, PSA 10-20) also received six months of anti-androgens. The intended dose was 160Gy to the margin, defined as the prostate with a three dimensional volume expansion by 3 mm, constrained to 0 mm posteriorly and cranially. CT post-implant dosimetry was performed for 249 patients after four weeks.

Results

The mean prostate D90 was 189Gy intraoperatively (163-215Gy) and 179Gy post-implant (138-222Gy). 99% of patients received a minimum post-implant prostate D90 of 140Gy.

Our mean D90 to the margin was 163Gy intraoperatively (126-203Gy) and 151Gy post-implant (116-185Gy). The mean prostate V100 was 98.2% intraoperatively (91.0-100%) and 94.3% post-implant (74.4-99.8%). The mean prostate V150 was 51.8% intraoperatively (22.1-72.0%) and 55.0% post-implant (28.4-85.0%).

The mean urethral D10 was 140.0% post-implant (94.5-232.0%). The mean rectal V100 was 0.93 cc post-implant (0-3.84 cc).

Of 220 patients followed for more than a year, 3 relapsed. Recatheterisation occurred in 1.8% of patients and urethral strictures in 1.4%. No rectovesical fistulae occurred; rectal bleeding occurred in 5.5%. 

Conclusion:

We recommend a real-time prescription of 189Gy to the prostate to provide a margin dose of 160Gy. This achieves a minimum post-implant prostate D90 of 140Gy and low rates of biochemical relapse and toxicity. 

References:

1. Stock RG et al. Int J Radiat Oncol Biol Phys 1998; 41: 101-8

Return to top of page.

***Winning Abstract***

5.  Outcome of prostate brachytherapy in men with intermediate risk disease-results of Oncura multi-institutional database

A.Tran, Christie NHS Trust, Manchester
P.Hoskin, Mount Vernon Hospital, Northwood, Middlesex, UK

D.Bottomley, St. James's Institute of Oncology, Leeds teaching Hospitals NHS Trust

P.Mandall, Christie NHS Trust, Manchester

R. Swindell, Christie NHS Trust, Manchester

J.Wylie, Christie NHS Trust, Manchester

Aims/Introduction:

The optimal treatment for patients with intermediate risk disease remains unclear and practise varies amongst centres.  We report the outcome for large cohort of intermediate patients treated predominantly with LDR brachytherapy monotherapy in a multi-institutional U.K. practice.

Materiasl/Methods:

 692 men diagnosed with intermediate risk prostate adenocarcinoma between 2000-2007 and treated with Iodine-125 brachytherapy at Leeds, Mount Vernon and Christie were identified from the Oncura sponsored multi-institutional database which contains data on over 2000 patients. Intermediate risk was defined by the D’Amico classification. Biochemical failure was defined using both the ASTRO (3 rises past nadir) and Phoenix (nadir plus 2) definitions after excluding benign PSA bounces. Kaplan-Meier methods were used to estimate biochemical relapse-free survival (BRFS).  A univariate analysis was performed to assess the significance of additional hormones, external beam radiotherapy (EBRT), Gleason score 4+3 vs 3+4, PSA 10-20, T2b disease, pre or post implant dosimetry variables on BRFS.

Results

All patients had only one of the following risk factors (450 Gleason 7, 189 PSA 10-20 and 53 T2b). The median age was 64 years (range 48-82) with a median follow up of 44 months. Hormone therapy was administered in 163 patients for a median of 158 days (range 63-792) and was predominately given prior to implant. External beam radiotherapy (EBRT) was delivered to 28 patients. Median pre-implant doses (range) were: D90 184.3Gy (120.4-197.2), V150 60Gy (45.5-82.4), V200 20.1Gy (11.5-37.2). 293 cases had post implant dosimetry with median values of: D90 134Gy (73.2-199.3), V150 48.4Gy (18.1-85.3), V200 19.5Gy (7.0-57.7). The 3 and 5 year BRFS defined by ASTRO were 94.5% and 91.8% and by Phoenix definitions 92.7% and 86.0%, respectively. On univariate analysis the only predictor of inferior outcome was PSA 10-20.  All other analysed variables were non-significant.

Conclusion:

With a median follow up of 3.6 years our results show good biochemical control rates in this large group with intermediate risk disease. Brachytherapy monotherapy appears a justifiable treatment in this cohort and there was no demonstrable benefit achieved through additional EBRT or hormones.  Longer term outcome analysis is planned.

Return to top of page.

6.  Prostate Seed Brachytherapy - Can Ultrasound be used in Post Implant Dosimetry Analysis?

Christopher Walker, University College Hospital, Galway

Anysja Zuchora, University College Hospital, Galway

Frank Sullivan, University College Hospital, Galway

Margaret Moore, University College Hospital, Galway

Aims/Introduction:

AAPM recommendations (Nath et al. Med Phys. 2009 Nov;36(11):5310-22) state that post implant dosimetry of I-125 prostate seed brachytherapy be performed via CT guidance 30 ± 7 days after the procedure. This study attempts to determine whether TRUS based post-implant dosimetry parameters, determined on the day of the case, can be considered statistically equivalent to those acquired from a CT scan taken after 30 days.

Materials/Methods:

A retrospective study was performed, visually marking seeds on post-implant TRUS images for 43 patients using Varians Variseed™ software. Dosimetric parameters of D90, V100, and V150 for the prostate were determined for both TRUS and CT. A Paired Students T-Test and a Wilcoxon Paired Sample test were used to determine whether parameters based on these modalities could be considered statistically equivalent. Reproducibility tests were also carried out on the precision of the Variseed seed-finding software.

Results

Analysis showed that TRUS and CT D90 and V100 values could be considered statistically equivalent based on a significance level of 0.05, but V150 could not. For one patient, 100 iterations of the seed finder software on a post-implant CT image set yielded an average prostate D90 of (169.9 ± 2.2)Gy and V100 of (93.5 ± 0.7)%.

Conclusion:

The dosimetry parameters of D90 and V100 taken from a post-implant TRUS can be considered statistically equivalent to day-30 CT, however the V150 value cannot. This method has merit especially when natural gland motion occurs during the implant process or if artificial hips are present. The use of multiple iterations of the seed-finder on CT images is also suggested.

Return to top of page.

7.  The role of MR fusion in post implant dosimetry after I-125 permanent seed prostate brachytherapy.

Joe Berresford, Christie NHS Trust, Manchester

Sarah Barton, Christie NHS Trust, Manchester

Bernadette Carrington, Christie NHS Trust, Manchester

John Logue, Christie NHS Trust, Manchester

Tony Elliott, Christie NHS Trust, Manchester

James Wylie, Christie NHS Trust, Manchester

Aims/Introduction:

The aim of this investigation was to compare the outcomes of CT and CT/MR fusion based post implant dosimetry in permanent prostate brachytherapy.

Materials/Methods:

Five patients who underwent I-125 prostate brachytherapy at The Christie were entered into a study to evaluate efficacy of CT compared with CT/MR fusion based post implant dosimetry. Alongside their 30 day CT scan patients were imaged in a MR scanner on the same day. The two datasets were fused together using Varian’s Variseed (v.8) software and seed localisation was performed using the CT images. The patient plans were then copied to allow four members of staff with varied prostate brachytherapy experience to independently contour the prostates on both datasets. The CT datasets were contoured first to ensure a fair comparison.

The two imaging modalities were compared by assessing the CT and MR generated volumes. The effect of differences in volume on several dosimetric quantifiers was then assessed.

Results

The average prostate volume across all contours generated using CT (36.6 cc) was found to be within 2% of that produced using the MR images (37.2 cc). The volume difference corresponded to a 6% drop in the overall average D90 from 156.8 Gy with CT to 147.0 Gy using MR. However, variation in the contoured volumes was high across all patients on both CT and MR.

Conclusion:

Whilst the fusion process is relatively simple, the high variation in contoured volumes produced during this study show the difficulties involved in providing an accurate post implant dosimetry service.   In this small study MR fusion failed to demonstrate any advantage over traditional CT based post implant dosimetry.

Return to top of page.

8.  Investigating the efficacy of using 0.35T MR images to assess the urethral dose from I-125 seed implants at 30 days.

David Inchley, Mount Vernon Hospital, Northwood, Middlesex, UK.

Clare Anderson, Mount Vernon Hospital, Northwood, Middlesex, UK.

Gerry Lowe, Mount Vernon Hospital, Northwood, Middlesex, UK.

Peter J Hoskin, Mount Vernon Hospital, Northwood, Middlesex, UK.

Aims/Introduction:

The current I-125 seed post planning protocol at Mount Vernon hospital involves performing a CT scan 30 days after implantation. This is then used to identify the number and position of seeds within the patient. The prostate and rectal contours are delineated by the clinician and the dose distribution is calculated. At MVH we do not delineate the urethral position in our post plan images as the patient is not catheterized and aerated gel is not used for this procedure.

The aim of this investigation is to assess the efficacy of using 0.35T MR images to identify the urethral position on the post plan CT images and therefore assess the dose received by the urethra.

Materials/Methods:

Immediately following the 30 day CT scan, five patients were scanned on our 0.35T Siemens Magnetom C! open bore MRI scanner. The post plan dosimetry was then performed using the Variseed 8.0.1 treatment planning system (Varian Medical Systems) to find the seeds and the CT and MR images were fused using Brachyvision 8.1. Once the images were fused, the MR images were used to delineate the urethra and the dose was calculated from the seed positions defined on the CT images.

Results

To date we have scanned five patients with both CT and MR on day 30 post implant. This has allowed determination of urethral dose and demonstrates that the principle does work. It has however raised many issues about the technique which will be discussed. The Brachyvision software uses pixel by pixel matching with a mutual information algorithm, which will tend to match the bony anatomy. Is this the best way to match the images? Has the prostate moved during the short time between scans due to bladder filling/emptying? Which image set do we base the critical structure contouring on? We can’t see the seeds on the MR images but the critical structures are much more easily defined on the MR. What is the dosimetric correlation between images acquired at the time of implant to those acquired at day 30?

Conclusion:

This investigation has demonstrated that using 0.35T MR images to define the urethral position in 30 day CT post plan images is in principle an effective way of assessing the dose to the prostatic urethra. It has however raises may more interesting issues which must be considered if the technique is to be employed clinically.

Return to top of page.

9.  Low Dose Rate (LDR) prostate brachytherapy with I125 seeds biochemical Progression Free Survival (bPFS) and associated risk factors - The Northampton Experience.

Dr Jamie Mills, Specialist Registrar Clinical Oncology, Northampton General Hospital

Dr Philip Camilleri, Consultant Oncologist, Northampton General Hospital

Mr Roger Kunkler, Consultant Urologist, Northampton General Hospital

Ms Sally Mora, Urology Specialist Nurse, Northampton General Hospital

Dr Christine Elwell, Consultant Oncologist, Northampton General Hospital

Aims/Introduction:

To assess biochemical progression free survival and associated possible risk factors after permanent I125 prostate brachytherapy.

Materials/Methods:

Data on 190 patients treated with permanent prostate brachytherapy  between 2002 and 2008 and completing at least one year follow up were evaluated. All patients had prostate cancer T1c-T2c N0 M0 , gleason <=7, PSA <19, and were treated with I125 seeds to a prescription dose of 160 Gy.  Patients were classified into: risk groups with 114- low, 60- medium and 16- high risk as well as according to prostate volume, and intra-operative and  post-operative D90.  All patients were followed up 3 monthly in the first year, and 6 monthly thereafter. The median follow up was 30 months (range 12-60 ) and mean age was 63 years. Biochemical relapse was defined as PSA nadir + 2ng/L.

Results

A total of 9 patients relapsed giving an overall bPFS of 95.3%.  The mean time to relapse was 30.3 months.  The 1,2,3,4 and 5 year bPFS were 100%, 97.37%, 96.32%, 95.3%, and 95.3% respectively.  High and medium risk disease were the only significant risk factors for bPFS with 25% (4/16) high risk patients and 5% (3/60) medium risk patients relapsing compared to 1.7% (2/114) low risk patients (p<0.0001).  Comparing relapsers to non-relapsers there was no significant difference in prostate volume (33cm3 vs 31 cm3),  intra-operative D90 (189Gy vs 191Gy) or  post operative D90 (171 Gy vs 169 Gy).   22% (2/9) of relapsers received hormones at any point before relapse vs. 13.3%(24/181) of non relapsers,  (p=0.450).

Conclusion:

These  data  show encouraging rates of bPFS in low/intermediate risk groups.  High risk men should be warned of the significant risk of failure in spite of treatment for their prostate cancer.  Prostate volume, hormone use, and intra-operative or post-operative D90 do not predict bPFS at this point in time.

Return to top of page.

10.  Retrospective review of the first one hundred patients treated with LDR 125 I brachytherapy for early prostate cancer at the Plymouth Oncology Centre.

Dr John McGrane, Specialist Registrar Clinical Oncology, Plymouth Oncology Centre, Derriford Hospital

Dr Sarah Pascoe, Consultant Clinical Oncologist, Plymouth Oncology Centre, Derriford Hospital

Dr Francis Daniel, Consultant Clinical Oncologist, Plymouth Oncology Centre, Derriford Hospital

Mr Salvo Natale, Associate Specialist in Urology, Derriford Hospital

Simon Legge, Radiation Technician, Plymouth Oncology Centre, Derriford Hospital

Savvas Rizkalla, Physicist, Plymouth Oncology Centre, Derriford Hospital

Aims/Introduction:

To review rates of biochemical relapse-free survival, bounce effect and side effects in the first one hundred patients treated with LDR 125 I prostate brachytherapy for early prostate cancer.

Materials/Methods:

The records of one hundred consecutive patients treated with  LDR 125 I prostate brachytherapy from 2nd November 2006 to 10th November 2009 at the Plymouth Oncology Centre were retrospectively reviewed. Evidence of biochemical relapse-free survival (bRFS), bounce effect, immediate treatment complications and treatment-related side effects were assessed. Two definitions of biochemical failure (bF) were used American Society for Therapeutic Radiology and Oncology (ASTRO) definition of three sequential PSA rises (bF3) and the Phoenix definition of PSA nadir + 2 (bFn+2). Patients required sufficient PSA testing and follow-up time to be analysed for bRFS.

Results

At a median follow-up of 21 months 85 patients were deemed eligible for bFRS analysis. All patients are alive but two patients developed metastatic disease. The rate of bRFS using the bF3 definition was 96.5% and using the bFn+2 definition was 92.9%. Two cases fulfilled bFn+2 but were subsequently shown to be bounce effect. The mean times for development of bF were 18 months (bF3) and 21 months (bFn+2).

A clear bounce effect was seen in 17.9% of patients of which all had continued bRFS. Only one case of post brachytherapy urinary retention occurred with no major peri-operative complications. New erectile dysfunction was reported in 16 patients and only 3 patients developed new lower urinary tract symptoms that persisted for 12 months or more post brachytherapy.

Conclusion:

Using appropriate selection criteria LDR 125 I prostate brachytherapy currently shows favourable rates of biochemical relapse-free progression and low side-effect rates at the Plymouth Oncology Centre.

Return to top of page.

11.  Salvage LDR brachytherapy for local failure after initial external beam radiotherapy for prostate cancer. Initial experience at Guys Hospital.

Sarkodie T, Guy's and St Thomas's Hospital, London

Acher P, Guy's and St Thomas's Hospital, London

Yamamoto H, Guy's and St Thomas's Hospital, London

Popert R, Guy's and St Thomas's Hospital, London

Beaney R, Guy's and St Thomas's Hospital, London

Morris S, Guy's and St Thomas's Hospital, London 

Aims/Introduction:

To describe our initial experience of salvage brachytherapy for local failure after radical external beam radiotherapy for Prostate cancer.

Materials/Methods:

Two patients who received radical external beam radiotherapy in 1999 and 2002 were diagnosed with biopsy confirmed local failure in 2008 and 2009 respectively. They had both received 64Gy in 32 fractions using a three field conformal plan. Both patients had biochemical failure according to the Phoenix criteria and then underwent assessment with MRI and trans-perineal template biopsies, which confirmed recurrence. They were counseled on salvage options and their Prostate size, lower urinary tract symptoms and flow rate determined. Both patients underwent flexible sigmoidoscopy to exclude signs of rectal late radiation damage by an experienced rectal surgeon. 

Results

Both patients were treated with our day case dynamic dose feedback intra operative planning technique at a prescribed dose of 120Gy to the prostate with Iodine 125 seeds. The intra-operative dosimetry for patient 1 was prostate D90 139.2Gy, Urethra V140 5%, Rectum V100 0cc, and for patient 2 was prostate D90 130.8Gy, Urethra V140 0%, Rectum V100 0cc. The post implant dosimetry showed a D90 of 145.2Gy and 121Gy respectively. Both patients tolerated the procedure well with no acute grade 3 or 4 urinary or GI toxicity and remain well at 6 months and 12 months follow up respectively.

Conclusion:

Our initial experience shows salvage brachytherapy is well tolerated and an option for our patients to consider for treatment of local failure after external beam radiotherapy. 

Return to top of page.

12.  What impact would the use of 125I Oncoseed model 9011 source instead of 6711 have on dosimetry and visibility for permanent prostate brachytherapy?

Gemma Roberts, Trainee medical physicist, St. James's Institute of Oncology, Leeds Teaching Hospitals NHS Trust

Bashar Al Qaisieh, Radiotherapy physicist, St. James's Institute of Oncology, Leeds Teaching Hospitals NHS Trust

Peter Bownes, Head of brachytherapy physics, St. James's Institute of Oncology, Leeds Teaching Hospitals NHS Trust

Aims/Introduction:

The 125I source currently used for prostate brachytherapy at St. James’s Institute of Oncology is the Oncura Oncoseed model 6711 (RapidStrand).  A new, thinner seed is available (model 9011 - ThinSeed).  This would be implanted using narrower needles (20G instead of 18G), potentially reducing oedema and keeping the dose distribution closer to that planned.  The aim of this study is to assess how the new source would affect treatment planning and imaging.  

Materials/Methods:

To investigate dosimetry, sample plans using 0.458U RapidStrand seeds were anonymised and the seeds replaced with ThinSeed sources.  The dosimetry data for the 9011 source was taken from Rivard (Med. Phys. 36(2) 2009) and into the VariSeed v8.0 planning system.  The plans were compared using dose-volume indices.  The source strength was adjusted until the dose indices closely matched the original plans.  The patients were re-planned using ThinSeeds and compared to the original plans in terms of dosimetry, number of seeds and needles and planning difficulty.  To investigate visibility, images of dummy seeds of both types were taken using ultrasound, fluoroscopy, CT and MRI and were analysed visually and by taking line profiles and distance measurements.

Results

The ideal source strength to be used with ThinSeed seeds is 0.488U.  Applying the current 0.458U source strength used with RapidStrand requires extra seeds and needles, potentially increasing cost and trauma.  The closest available strength, 0.496U, gives acceptable clinical plans with no change in the number of needles required.  The visibility of both seed types was acceptable on ultrasound, fluoroscopy and CT.  The thinner seeds have reduced artefacts and better resolution on CT.  Further study into MR visibility for post treatment dosimetry is required.

Conclusions:

Model 9011 0.496U ThinSeeds could replace 0.458U 6711 RapidStrand seeds with no major changes in treatment planning.  Use of ThinSeeds may improve seed identification for CT post treatment dosimetry.

Return to top of page.

13.  Prostate cancer treated with Permanent Seed Implantation- the East Scotland Experience

Alastair Law, Edinburgh Cancer Centre, Western General Hospital, Edinburgh

Gill Kerr, Edinburgh Cancer Centre, Western General Hospital, Edinburgh

Grahame Howard, Edinburgh Cancer Centre, Western General Hospital, Edinburgh

Tiffany West, Edinburgh Cancer Centre, Western General Hospital, Edinburgh

Terry Kehoe, Edinburgh Cancer Centre, Western General Hospital, Edinburgh

John Brush, Edinburgh Cancer Centre, Western General Hospital, Edinburgh

Duncan Mclaren, Edinburgh Cancer Centre, Western General Hospital, Edinburgh

Aims/Introduction:

Introduction We report the outcome, in terms of PSA relapse to 5 years and complication rates, for the first 150 patients treated at the Edinburgh Cancer Centre (the referral centre for south east Scotland) with LDR brachytherapy for early stage prostate cancer.

Material/Methods:

The case records of the patients were reviewed and the following variables were recorded - PSA at presentation, Gleason score and T stage.  PSA results, complication rates and erectile function were recorded post treatment with a minimum follow up of three years. PSA failure was defined as a sustained rise above the nadir of more than 2 ng/ml (Houston definition).

The patients were divided into risk groups on the basis of their initial PSA and Gleason score- low risk having PSA<10 and Gleason <6, high risk having PSA>10 and Gleason >7 and intermediate risk having one of the factors raised.

Results:

In the good prognostic group (n=82) the PSA relapse rate was 6.2%  (95%CI 0.9-11.5%), in the intermediate group (n=52) 18.5% (7.5-29.6) and in the poor (15) 41.8% (16.1-67.5). The complication rate is low with 8/150 (5%) patients needing temporary catheterisation and 8/150 (5%) needing intervention for stricture. There have been 21 PSA failures and 4/11 deaths were due to disease.  Two local failures were confirmed one on biopsy, one on salvage prostatectomy (but in seminal vesicles only)

34 % had none, or mild to moderate erectile dysfunction assessed on IIEF.

Conclusion:

The results of the first 150 patients treated with brachytherapy in Edinburgh show high rates of local control, particularly in low risk group (94% at 5 years). The complication risk of urinary retention and catheterisation is also acceptable. The higher risk groups may benefit in the future from HDR brachytherapy in combination with external beam radiotherapy. 

Return to top of page.

14.  Determining shift in the prostate base position during single fraction intra-operative HDR delivery.

Naomi Morrissey, Christie NHS Trust, Manchester

Sarah Barton, Christie NHS Trust, Manchester

Laura Lane, Christie NHS Trust, Manchester

Cathy Taylor, Christie NHS Trust, Manchester

John Logue, Christie NHS Trust, Manchester

James Wylie, Christie NHS Trust, Manchester

Aim/Introduction:

Intra-operative high dose rate (HDR) prostate brachytherapy techniques involve an initial planning study done prior to needle insertion followed by re-localising the prostate base position once all needles have been inserted.  Marked cranial base movement can occur during needle insertion.  This study aimed to quantify this movement and explore possible manoeuvres to limit the change in base position between pre-planning and final plan.

Materials/Methods:

A fiducial marker was placed at the base under ultrasound guidance and prior to needle insertion.  Subsequent radiographs taken before and during different stages of the HDR process identified movement of the fiducial marker relative to the superior edge of the symphysis pubis.

There were two arms of the investigation.  First to assess the degree of prostate base movement when all needles were inserted into the prostate after the initial planning process. The second to assess whether inserting 4 treatment needles to stabilise the prostate prior to the planning process would reduce the subsequent cranial movement with the remaining needles.

Results

64 patients were identified, 12 where stabilisation needles were not used and 52 where the prostate was stabilised prior to the planning study.

In cases where stabilisation needles were not used the median cranial base displacement was 1.7 cm (range 0.6-3.4cm).  Inserting 4 stabilisation needles prior to planning resulted in a median cranial shift of 1.0 cm (range 0.3-2.1 cm).  Insertion of the remaining catheters resulted in a further median shift of 1.1 cm (range 0-4 cm). 

Conclusion:

There is significant displacement of the base cranially during needle insertion, which must be accounted for when inserting needles.  Placing 4 needles prior to the planning process can reduce but does not eliminate any subsequent cranial movement.  On-going analysis is planned to examine changes in apical position and overall prostate length as a result of catheter insertion. 

Return to top of page.

15.  Outcome of prostate brachytherapy in men with Gleason score 8 treated with I-125 brachytherapy alone - results of Oncura multi-institutional database

A.Tran, Christie NHS Trust, Manchester
P.Hoskin, Mount Vernon Hospital, Northwood, Middlesex, UK

D.Bottomley, St. James's Institute of Oncology, Leeds Teaching Hospitals NHS Trust

P.Mandall, Christie NHS Trust, Manchester

R. Swindell, Christie NHS Trust, Manchester

J.Wylie, Christie NHS Trust, Manchester

Aim/Introduction:

Monotherapy with low dose rate permanent seed implant brachytherapy is rarely used in patients with high risk disease. We report the outcome of patients diagnosed with Gleason 8 disease that have been treated with LDR permanent seed implant brachytherapy in a multi-institutional series.

Materials/Methods:

Patients diagnosed with Gleason 8 prostate adenocarcinoma and treated with LDR brachytherapy at Leeds, Mount Vernon and Christie Hospitals between 2000-2007 were identified from the Oncura sponsored national database. Patients who received additional external beam radiotherapy were excluded from analysis. Biochemical failure was defined using Phoenix criteria (nadir+2).

Results

 21 patients were analysed. The median age was 67 (range 48-75). All had organ confined disease; 16 were staged as T1c, 4 T2a and 1 T2b. 8 had hormones pre-implant with 5 receiving LHRHa, 1 anti-androgen and 2 complete androgen blockade. Data was not complete in the total duration of hormone therapy. The median PSA prior to implant was 7.3 (range 1.1-16.8).  The median follow-up was 32 months (range 4.3- 66.5). Six of the 8 patients that received hormones remain biochemically controlled and the remaining 2 patients relapsed and died from disease. Eleven of 13 patients that did not have hormones are relapse free at last follow up.

Conclusion:

Our preliminary data suggest that brachytherapy monotherapy may be a viable treatment option in selected patients with Gleason 8 disease. Biochemical control was achieved in 81% of patients with a median follow up of 32 months.  Longer term outcome analysis is needed to confirm whether these patients remain biochemically controlled.