To investigate demographic, clinical and treatment-related factors associated with receipt of adjuvant chemotherapy for stage III (node positive) colon cancer in NSW, Australia. We also estimate the proportion of people who were medically fit and could potentially have received adjuvant chemotherapy but did not.
This is a population-based retrospective cohort study using linked NSW Cancer Registry, NSW Clinical Cancer Registry (node positive), NSW Admitted Patient Data Collection, Medicare Benefits Schedule and Pharmaceutical Benefits Schedule data. People aged ≥15 years diagnosed with stage III (node positive) colon cancer from 2008 to 2012 were identified and included in the study if they underwent surgery with curative intent within 6 months of diagnosis. A multilevel multivariable logistic regression model was used to examine factors associated with adjuvant chemotherapy within 6 months from surgery after adjusting for key demographic and clinical factors.
Of the 2,169 people who underwent surgery, 70% (1,514) received adjuvant chemotherapy. Adjuvant chemotherapy use was higher in people <70 years (89%) than in older people ≥70 years (54%). After adjustment, receipt of adjuvant chemotherapy was significantly less likely with older age, not having a current partner, higher Charlson comorbidity score, higher American Society of Anaesthesiologists (ASA) Physical Status score, an emergency resection, and admission to intensive care after surgery. Amongst medically fit people defined as having a Charlson score of 0 and ASA score of 1 or 2, 17% did not receive adjuvant chemotherapy.
Although adjuvant chemotherapy is recommended for medically fit stage III colon cancer people, we observed that 30% of people overall and 17% of those who were medically fit with no observed comorbidities and good physical status did not receive chemotherapy. Further investigation is needed to better understand reasons behind the under-utilisation of adjuvant chemotherapy.