Post-operative conformal radiotherapy on prostate cancer after radical prostatectomy. Results and dose constraint on bladder volume

Abstract

14647 Background: To report on the results of post-operative conformal radiotherapy (3DCRT) on patients submitted to radical prostatectomy with high risk of biochemical failure or with biochemical failure. Methods: From July 1998 to December 2001, 40 patients with high risk of biochemical failure (T3 stage or positive margins) or with biochemical failure (PSA ≥ 0.2 ng/ml) after radical prostatectomy were submitted to 3DCRT on a single institution and were analyzed retrospectively. The median age was 65 years (52–74). The median pre-3DCRT PSA was 1.3 ng/ml (0–8.98). Twenty eight patients were submitted to pelvic 3DCRT. The median radiation dose on prostate region was 77 Gy (68.4–81). Biochemical failure was considered after 3 consecutive PSA increasing or the beginning of androgen suppression therapy for any reason after 3DCRT. Results: The median follow-up was 56.1 months (19.7–84.6). The 5-year actuarial biochemical progression-free survival was 84.5%. Six (15%) patients had biochemical failure and 4 (10%) distant metastases. The 5-year actuarial biochemical progression-free survival was 94.9% with pre-3DCRT PSA ≤1.5 ng/ml and 69.9% when >1.5 ng/ml (p = 0.0215). Two patients had rectal bleeding grade 2. Nine patients had urinary toxicity grade 2–3. The 5-year actuarial free from urinary toxicity grade 2–3 was 72.9%. Age >65 years and radiation dose >65 Gy on 30% of bladder volume resulted on more late urinary toxicity grade 2–3 (p = 0.0410 and p = 0.0177, respectively). Conclusions: 3DCRT was effective for biochemical control on patients with high risk of biochemical failure or with biochemical failure after radical prostatectomy. Patients with pre-3DCRT PSA ≤1.5 ng/ml have more biochemical control. It was suggested to restrict radiation dose ≤65 Gy on 30% of bladder volume to minimize late grade 2–3 urinary toxicity. More cautious on patients >65 years submitted to post-operative irradiation are required. No significant financial relationships to disclose.