External Beam Radiation Therapy Followed By Interstitial Radiotherapy With Iridium-192 For Solitary Bladder Tumours: Results Of 111 Treated Patients

Main Category: Prostate / Prostate Cancer
Also Included In: Urology / Nephrology;  Cancer / Oncology
Article Date: 19 Sep 2008 - 8:00 PDT

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UroToday.com - Radical cystectomy is the standard treatment in patients with muscle-invasive bladder cancer without metastases. Organ preservation in invasive bladder cancer can only be achieved in carefully selected patients, without compromising survival and should result in an adequate bladder capacity to be a good alternative to cystectomy. Various bladder sparing strategies have been reported. Our brachytherapy-based bladder-preserving treatment protocol for solitary T1-T2 bladder cancer (≤ 5 cm), results in a 73% 10-year disease-specific survival rate and preserves the bladder in 89%, in carefully selected patients. These results particularly justify the use of this modality when radical cystectomy is not an option i.e. in patients who refuse radical cystectomy or who are poor candidates for major surgical procedures.

The procedure started with a macroscopically complete resection of the bladder tumour followed by External Beam Radiation Therapy (EBRT) to prevent scar metastases. A dose of 2820 cGy in 12 fractions over 3 weeks was applied, using two parallel opposed fields covering the true pelvis. A few days after the completion of EBRT, surgery was performed through a 10-15 cm lower abdominal incision. The lymph nodes in both iliac fossae were palpated and dissected in case of induration/enlargement. In order to place the nylon tubes for after-loading IRT, the bladder was opened away from the tumour site and 2-5 nylon tubes were placed through the bladder wall at a distance of approximately 1-2 cm from the tumour location. Partial cystectomy was considered, as part of the protocol, if the site was located away from the bladder floor and the ureteral orifices, with a minimal margin of 2 cm of normal tissue. Five patients clinically staged as T2 tumours, were found to have a T3 tumour in their partial cystectomy specimen and were still included in this analysis.

Lymph node dissection was not performed routinely because of the previously reported risk of lymphatic fluid leaks alongside the after-loading tubes; this would have been a reason for treatment discontinuation. The value of extended lymph node dissection during radical cystectomy as noted in a few single institution reports has not been explored in bladder sparing strategies. It has been stated that an extended lymph node dissection may provide a survival advantage in both node-positive and node-negative tumours, without increasing morbidity and mortality. We currently advocate a pelvic lymph node dissection in all patients, to improve the staging process and survival.

[Neo]adjuvant chemotherapy as part of bladder sparing protocols is controversial. It has been established that chemotherapy in conjunction with cystectomy, radiotherapy or the combination, results in a modest 5% improvement in OS. Patients in our treatment protocol were highly selected (the vast majority had T2-tumors), often refused a cystectomy and were considered poor surgical candidates.

In such patients, the decision to use chemotherapy or not, has to be individualized and a thorough weighing of the risks (toxicity) and benefits.

Due to varying selection criteria, it is difficult to compare results of different bladder-sparing curative treatment protocols. In our series, the inclusion of 5 T3 patients and the inclusion of 4 N+ patients and the fact that no formal lymph node dissection has been performed on a routine basis will have had a negative impact on survival rates. On the other hand, in comparison with most radical cystectomy series, we have a positive patient selection. For instance, our series does not include patients with CIS, all tumours are solitary and the size is ≤5 cm. Therefore, it is important to emphasize that our inclusion criteria are also prognostic factors. This is also the case in other bladder preservation series and therefore, only randomized controlled trials can determine which strategy is best.

Written by Ilze E.W. van Onna, MD, as part of Beyond the Abstract on UroToday.com

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