Predictive Factors of the Use of Systemic Therapy in Stage IV Colorectal Cancer: Who Gets Chemotherapy?

Abstract

Background: Chemotherapy improves survival in patients with stage IV colorectal cancer (CRC). Although in a clinical trial setting, strict eligibility criteria are used for chemotherapy, little is known about the use of chemotherapy in the general population. The study aims to assess clinicopathological variables that correlate with the use of chemotherapy in patients with stage IV CRC.

Methods: A retrospective cohort study involving patients with stage IV CRC, diagnosed between 1992 and 2005, in the province of Saskatchewan was carried out. A logistic regression analysis was performed to assess the correlation of various clinicopathological factors with the use of chemotherapy.

Results: A total of 1,237 eligible patients were identified. Their median age was 70 years (range: 22-98) and the male:female ratio was 1.3:1. 23.8% had an ECOG performance status (PS) of ≥2 and 61.8% of the patients had a comorbid illness. 46.8% of the patients received chemotherapy. The multivariate logistic regression analysis revealed that an age of <65 years [odds ratio (OR) 3.82, 95% CI: 2.59-5.63], metastasectomy (OR 3.60, 95% CI: 1.82-7.10), normal albumin (OR 3.26, 95% CI: 2.44-4.36), no comorbid illness (OR 2.87, 95% CI: 1.34-6.16), ECOG PS of <2 (OR 2.72, 95% CI: 1.94-3.82), normal blood urea nitrogen (OR 2.24, 95% CI: 1.40-3.59), palliative radiation (OR 2.03, 95% CI: 1.38-2.99), primary tumor resection (OR 2.00, 95% CI: 1.47-2.73), and the time period (OR 1.85, 95% CI: 1.41-2.42) were significantly correlated with the use of chemotherapy.

Conclusions: The use of chemotherapy appears to be increasing in stage IV CRC. Patients treated with curative intention or who underwent primary tumor resection were more likely to receive chemotherapy. Despite a known benefit of chemotherapy in elderly patients, a differential use of chemotherapy was noted in this population.