Clinical Review Abstract
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Survival benefit associated with the number of chemotherapy/biologic treatment lines in 5,129 elderly metastatic colon cancer patients.
Gastrointestinal (Colorectal) Cancer
2013 ASCO Annual Meeting
J Clin Oncol 31, 2013 (suppl; abstr e14524)
Author(s): Nader Hanna, Zhiyuan Zheng, Corinne Woods, Ebere Onukwugha, Kaloyan A. Bikov, Brian S. Seal, C. Daniel Mullins; University of Maryland, Department of Surgery, Division of General and Oncologic Surgery, Baltimore, MD; University of Maryland, Department of Pharmaceutical Health Services Research, Baltimore, MD; University of Maryland Baltimore School of Pharmacy, Pharmaceutical Health Services Research Department, Baltimore, MD; University of Maryland School of Pharmacy, Baltimore, MD; School of Pharmacy, University of Maryland, Baltimore, MD; Bayer HealthCare Pharmaceuticals, Wayne, NJ
Background: Metastatic colon cancer (mCC) patients often receive multiple lines of chemotherapy/biologics treatment to improve survival, yet the "real world" benefits and risks of multiple treatment lines have not been fully examined. Methods: The National Cancer Institute’s SEER-Medicare data was analyzed to determine the association between the number of treatment lines and 5-year survival in mCC patients. Patients were at least 66 years old, diagnosed with mCC in 2003-2007 and followed until death or 12/31/09. Only patients who survived at least 3 months from diagnosis were included. Cox proportional hazards regression was used along with inverse probability weighting method to adjust for the probability of receiving treatment. Results: Of 5,129 elderly Medicare mCC patients, the 5-year survival rate was 12.9% (n=664). Each incremental treatment was significantly associated with an increase in the average five-year survival by 5.4 months, 7.2 months and 2.7 months for 1st-line, 2nd-line and subsequent treatments, respectively. Significant variables associated with increased mean survival times were receipt of 1st-line, 2nd-line or subsequent treatment compared to no treatment (hazard ratio HR=0.58, 0.36 and 0.32, respectively, p<.01); resection/ablation of liver metastases (HR=0.80, p<.01) and primary site surgery (HR=0.52, p<.01). Significant variables associated with lower survival times were poorly-graded tumor (HR=1.53, p<.01), Charlson Comorbidity Index score of at least 3 compared to 0 (HR=1.15, p=.016), female (HR=1.07, p=.043) and age (in 10-year increments, HR=1.06, p=.011). Conclusions: Among elderly Medicare mCC patients who survived at least 3 months from diagnosis, receipt of 1st-line, 2nd-line and subsequent treatments was associated with incremental increases in the average survival time. However, this may reflect physician treatment patterns in healthier patients who are more likely to receive treatment. Additional factors that significantly increased survival time were primary site surgery (by 5.5 months), resection/ablation of liver metastases (by 1.9 months) and a tumor not poorly-graded (by 3.6 months).
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