Variation in Radiotherapy Referral and Treatment for High-risk Pathological Features after Radical Prostatectomy:...

Guidelines recommend the discussion of adjuvant radiotherapy post-prostatectomy for prostate cancer patients with high-risk pathology to consider all of their treatment options. We determine whether patterns of radiotherapy referral and treatment post-prostatectomy reflect guideline-based use in a contemporary prostatectomy cohort.

Electronic treatment records were linked to Ontario's cancer registry. Multivariable regression was used to evaluate clinical and health systems factors associated with referral and the use of adjuvant radiotherapy within 6 months post-prostatectomy.

Among 2663 patients treated with prostatectomy between 1 January 2012 and 30 November 2012, 1261 (47%) were found to have adverse pathology and 492 were referred to radiation oncology ≤6 months post-prostatectomy, of whom 51% received adjuvant radiotherapy. Multivariable analysis showed that patients were more likely to be referred to radiation oncology from a low-volume surgical facility (≤50 versus >50 radical prostatectomy cases, odds ratio 2.50 [1.80-3.48]), if they lived farther from a radiotherapy centre (>50 km versus <10 km, odds ratio 1.73 [1.22-2.46]), if they were seen by radiation oncology preoperatively (odds ratio 1.95 [1.51-2.52]), or if they had adverse pathology: high T-category (pT3b/T4 versus pT2, odds ratio 17.87 [12.14-26.30]; pT3a versus pT2, odds ratio 5.24 [3.95-6.97]), positive margins (non-apex positive versus negative, odds ratio 4.20 [3.19-5.53]; apex only positive versus negative, odds ratio 2.60 [1.71-3.94]) and high Gleason score (8-10 versus ≤6, odds ratio 11.32 [5.37-23.84]; 7 versus ≤6, odds ratio 4.18 [2.16-8.10]). Wide geographic variation in radiotherapy referral rates persisted (range 6-66%; P < 0.0001). After radiotherapy referral, only high T-category (pT3b/T4 versus pT2, odds ratio 5.37 [3.01-9.60]; pT3a versus pT2, odds ratio 2.72 [1.59-4.65]) and non-apex positive margins (odds ratio 2.81 [1.86-4.23]) remained significantly predictive of treatment.

Variations in referral for a discussion of radiotherapy post-prostatectomy are not mainly explained by patient characteristics. After seeing radiation oncology, treatment decisions correlated most strongly with pathological findings. Understanding the reasons for the tremendous non-clinical variations in care is needed to ensure access to potentially curative radiotherapy post-prostatectomy for high-risk prostate cancer patients.