Multi-institutional analysis of synchronous prostate and rectosigmoid cancers.
Jacobs, C; Trotter, J; Palta, M; Wu, Y; Willett, C; Lee, WR; Czito, BG
Published in: Journal of Clinical Oncology
33 Background: Synchronous prostate cancer (PC) and rectosigmoid (RS) cancer (RSC) is a challenging clinical situation. Methods: A retrospective review of Duke University and Durham VA charts was performed for men with adenocarcinomas of the prostate and RS colon from 1988-2017. Synchronous presentation was defined as symptoms, diagnosis (dx), or treatment (tx) of PC/RSC within 12 months. The primary endpoint was overall survival (OS), calculated from latest dx date. Univariate and multivariate (MVA) Cox regression was performed using STATA 15.1. Results: Among 31,883 men with PC identified, 330 (1%) also had RSC. 54 (16%) were considered synchronous (median age 67, IQR 62-72). PC was more commonly the first dx (59%), and 15 (28%) underwent prostatectomy (n=13) or radiotherapy (RT, n=2) before a dx of synchronous RSC. 26%, 57%, and 17% had stage I, II-III, and IV RSC, respectively. Prostatectomy, LAR, APR, and combined surgery for both PC/RSC was performed in 17 (31%), 24 (44%), 10 (19%), and 2 (4%) men, respectively. 35 (65%) received RT with median RS dose of 50.4 Gy (IQR 50.4-54 Gy) and prostate boost to 66 Gy (IQR 61-72 Gy). 34 (63%) received 5-FU based chemotherapy, 23 (43%) received ADT, and 9 (17%) received no PC-specific tx. After a median follow up of 43 (IQR 21-93) months, there were 34 deaths: 18 (53%) due to RSC, 2 (6%) due to PC, 3 (9%) due to grade 5 toxicity, 7 (21%) due to another malignancy, and 4 (12%) due to unknown cause without recurrence. Grade 5 toxicities resulted from sequential hepatectomy/LAR, combined prostatectomy/APR, and myocardial infarction while on ADT. Crude late grade ≥3 toxicities include 9 (17%) GI and 6 (11%) GU. Two anastomotic leaks <2.3 years after LAR occurred in men who received neoadjuvant prostate RT boost of 70.6-76.4 Gy. Stages II-III (HR 4.3, p=0.02) and IV (HR 16, p<0.01) for RSC but only stage IV (HR 31, p<0.01) for PC were significantly associated with OS on MVA. Among 30 men with stage II-III RSC and non-metastatic PC, 5-FU based chemotherapy (HR 0.34, p=0.04) but no PC-specific tx was significantly associated with OS on MVA. Conclusions: Synchronous RSC is a greater contributor to mortality than PC. Men aged ≥50 with localized PC should undergo colorectal cancer screening prior to tx to evaluate for synchronous RSC.
