Prognostic factors of adjuvant chemotherapy discontinuation among stage III colon cancer patients: A survey of medical oncologists and a systematic review and meta-analysis

Abstract

Background: Factors that are prognostic of early discontinuation of adjuvant chemotherapy among stage III colon cancer patients have yet to be described. To address this gap, a survey of medical oncologists and a systematic review and meta-analysis were conducted.

Methods: A survey was distributed in March 2019 to medical oncologists who treat colon cancer within Alberta, Canada. Clinicians were asked to rank the prognostic importance of a set of variables using a Likert scale and agreement was quantified using a weighted Cohen's kappa. In addition, we systematically searched four databases up to July 2019. Meta-analyses were conducted using a random-effects model.

Results: Of the 25 clinicians who were sent the survey, 14 responded. Overall, there was no agreement regarding which variables were prognostic of early discontinuation (weighted Cohen's kappa = 0.12; 95% CI = 0.05-0.18). From an initial 3927 articles, 18 investigations were identified for inclusion in our review. Based upon evidence from both the survey and the systematic review, the following four variables were identified as being prognostic of early discontinuation: (a) comorbidity (OR_{2+ vs 0} = 1.53; 95% CI = 1.30-1.79); (b) performance status (OR_{ECOG 2+ vs 0-1} = 1.33; 95%CI = 1.07-1.65); (c) T stage (OR_{T4 vs T1-2} = 1.57; 95% CI = 0.99-2.50); and (d) chemotherapy regimen (estimates not pooled due to heterogeneity). In addition to these factors, there was some suggestion that age, marital status/social support, muscle mass, N stage, and tumor grade had prognostic value.

Conclusions: Current evidence is heterogeneous and limited. Additional research is needed to confirm our findings and to explore additional prognostic factors.

Keywords: adherence; adjuvant chemotherapy; colorectal neoplasms; completion; discontinuation.