Pre- and post-prostatectomy variables associated with pelvic post-operative radiotherapy in prostate cancer patients: a national registry-based study

Abstract

Background: In patients with prostate cancer (PCa), the lack of clear guidelines on the use of radiotherapy after radical prostatectomy (RP) invites unwanted variation of this treatment. We describe the hazard ratios and probabilities related to the use of post-RP radiotherapy.

Material and methods: Data were collected from the Cancer Registry of Norway and nine radiotherapy units. All patients were diagnosed with a non-metastatic PCa from January 2004 through June 2011. Adjuvant radiotherapy was defined as pelvic radiotherapy initiated <5 months after RP at a PSA <0.2 ng/ml. All other pelvic radiotherapy series were categorized as salvage radiotherapy, and, combined with adjuvant radiotherapy they were termed post-RP radiotherapy.

Results: Of 6840 prostatectomized patients, 1170 (17%) had undergone post-RP radiotherapy, mainly as salvage radiotherapy. The number of adjuvant radiotherapy series almost tripled from 2009. Based on pre-prostatectomy variables (PSA, Gleason score, and clinical risk group) and findings in the prostatectomy specimens (status of resection margins, pathological tumor category and Gleason’s score), the probability of post-RP radiotherapy ranged respectively from 14% to 73%, and from 4% to 83%.

Conclusions: In our study, post-RP radiotherapy was applied in approximately one in six patients. Based on the combination of PCa-specific variables routinely available at the time of diagnosis, a patient’s probability of post-RP radiotherapy can be determined before decision of primary treatment strategy, followed by probability determination based on histopathological variables emerging from the prostatectomy specimen.