Frequency of unplanned surgical intervention in patients with stage IV colorectal cancer receiving palliative chemotherapy: An analysis of SEER-Medicare.

Abstract

640 Background: Patients (pts) with synchronous stage IV colorectal cancer commonly begin palliative chemotherapy while the primary tumor remains. Single institution series report low rates of surgical intervention, but this has not been examined nationally. The present study utilizes a large national dataset to examine the natural history of unplanned surgical intervention in stage IV colorectal cancer pts on palliative chemotherapy. Methods: SEER-Medicare was queried for pts with metastatic colorectal cancer (1998-2009) who underwent resection or diversion (ICD9 procedure/CPT). The cohort was separated into 3 groups: elective (surgery on admission without urgent/emergent flag), urgent (surgery not on day of admission but within hospitalization or with urgent flag) and emergent (emergent flag). Pts who underwent any procedure for curative intent (elective colorectal surgery, liver directed therapy or surgery for pulmonary metastases) at any time were excluded. Demographics, tumor grade and comorbidities were analyzed for effect on intervention rate. Time to event for either urgent or emergent surgical intervention or censorship by death, were measured. Conditional analyses were performed to determine the risk of surgical intervention at 6 months, 1 and 2 years post diagnosis. Results: 3,992 pts met inclusion criteria. Median age=73; 53% male. White 79%, black 11% and other 10%. The overall intervention rate was 6%; 35% emergent, 65% urgent. At 42 months, 90% of the pts had died. The probability of requiring unplanned surgery between 6-12 months was 2.5%; 12-24 months=1.9%, and >24 months=0.8%. Charlson comorbidity score of 1 was a significant predictor of surgical intervention (HR 1.64 [1.24, 2.19]). Sex, age and race had no influence on the likelihood of surgical intervention. Conclusions: This study represents a large series of stage IV colorectal cancer pts and the frequency of unplanned surgery in pts receiving palliative chemotherapy. Pts treated with palliative chemotherapy are unlikely to require urgent or emergent surgery, and therefore prophylactic surgery to reduce the risk of perforation or obstruction should not be routinely performed.