Cautionary tale of active surveillance in intermediate-risk patients: Overall and cause-specific survival in the Sunnybrook experience.
163 Background: To document the long-term outcomes of intermediate risk (IR) prostate cancer patients managed on active surveillance (AS) protocol in a single institute. Methods: Patients(pts) with PSA >10ng/ml or Gleason score 7 or clinical stage T2b/2c were identified from a prospectively collected database of 945 patients managed on AS between 1995 and 2013. Intervention was offered to those pts with a PSA doubling time of < 3 years, Gleason score or clinical progression.Overall survival (OS), cause-specific survival (CSS) for IR and low risk (LR) pts were analyzed as well as metastasis free survival (MFS) and treatment-free survival (TFS) for IR pts. Results: 237 (23.9%) pts had IR disease, with a median follow up of 6.9 years (IQR 3.89, 10.85) .708 pts had LR cancer with a median follow up of 6.4 years (IQR 3.76, 9.03). 61.2% of the IR cohort was older than 70 years. 86 IR pts (36.3%) received treatment (mainly radiation). The median treatment free interval for IR pts was 12.3 years (range 10.1 - 19.8). 33 IR patients developed biochemical failure and 17 developed metastatic disease [11 IR pts(4.6%) and 6 LR pts(0.8%)].The 10 and 15year OS was 68.4% and 50.3% for IR pts;83.6% and 68.8% for LR pts (p value <0.0001).Similarly 10 and 15 year CSS was 95.5% and 88.5% for IR ; 98.2% and 96.3% for LR pts (p value=0.006).The hazard ratio for IR pts versus LR pts was 2.08 for OS and 3.75 for CSS.IR pts had 3.75 times higher chance of dying from prostate cancer when compared to LR pts (Table). 10 year MFS and TFS were 92.1% (87.4-97.1%) and 58.5% (51.6-66.4%) in the IR cohort. Survival outcomes did not vary according to the year of patient enrollment. Conclusions: AS for intermediate risk prostate has significantly lower OS and CSS compared to low risk patients and therefore extreme caution should be exercised if it were to be implemented in intermediate risk patients. [Table: see text]