157285-173

Outcomes of perioperative systemic therapy (ST) in patients with R0 resection of metastatic colorectal cancer (mCRC).

Category: 
Cancers of the Colon, Rectum, and Anus
Session Type and Session Title: 
Poster Session C: Cancers of the Colon, Rectum, and Anus
Abstract Number: 

496

Poster Board Number: 
Poster Session C Board #A9
Citation: 
J Clin Oncol 34, 2016 (suppl 4S; abstr 496)
Author(s): 
Richard M. Lee-Ying, Daniel John Renouf, Howard John Lim, Caroline Speers, Winson Y. Cheung; University of Calgary Tom Baker Cancer Centre, Calgary, AB, Canada; BC Cancer Agency, Vancouver, BC, Canada

Abstract Disclosures

Abstract: 

Background: Adjuvant fluoropyrimidine (FP) +/- oxaliplatin (OX) ST improves overall survival (OS) following curative resection of stage II or III CRC, while other regimens do not. Utility of pseudo-adjuvant ST in mCRC patients who achieved R0 resection of their metastases remains controversial. We aim to describe population-based outcomes based on choice of ST. Methods: Patients diagnosed with mCRC from 2003 to 2010 and referred to any 1 of 5 cancer centers in British Columbia, Canada were reviewed. We categorized patients who underwent a successful R0 resection of their metastases into 3 groups based on receipt of peri-operative ST: 1) FP alone; 2) OX-based; and 3) non-standard or no ST. We compared OS using multivariate Cox regression models that adjusted for potential confounders. Results: We identified and reviewed 1,641 patients with mCRC among whom 225 achieved R0 resection of their metastases. In this cohort, median age was 63 years (Interquartile range (IQR) 55-70), 118 (52%) were men, 196 (87%) reported ECOG 0/1, 149 (66%) had a colonic primary, and 103 (46%) presented with de novo metastatic disease. The site of metastatic resection was hepatic in 144 (64%), pulmonary in 34 (15%), locoregional in 11(5%), and other in 36 (16%). A total of 122 (54%) received standard ST. Regimens included 28 (12%) FP alone, 94 (42%) OX-based, 25 (11%) irinotecan and 38 (17%) including bevacizumab. The median duration of ST was 10 cycles (IQR 7-12), with 56% and 44% delivered pre- and post-operatively, respectively. In multivariate analyses, liver or lung involvement (HR 0.60, 95% CI 0.40-0.88, p=0.01) predicted for improved OS when compared to metastases affecting other organs or sites. Receipt of OX-based ST was the only regimen associated with better OS, while the rest were not (Table). Conclusions: Findings from this population-based cohort of mCRC suggest that use of a defined course of OX-based ST for pseudo-adjuvant intent around the time of R0 resection of liver or lung metastases is correlated with improved OS.

Hazard ratios (HR) for OS by ST.

STHR (95% CI)p
FP0.67 (0.39-1.15)0.15
OX0.69 (0.47-0.99)0.045
Bevacizumab1.20 (0.75-1.95)0.45
Irinotecan1.14 (0.72-1.79)0.57
None1.36 (0.95-1.96)0.097