These researchers examined the inter-relationships between comorbidity, receipt of treatment, ethnicity and cancer survival among a cohort of patients with liver and stomach cancers in New Zealand. New Zealand Cancer Registry data identified 269 Māori patients diagnosed with stomach and liver cancers, who were compared with a randomly selected group of 255 non-Māori patients. By 2 years post-diagnosis, over 70% of patients had died. As comorbidity burden increased among those with Stage I–III disease, it was increasingly less likely that the patient would receive curative surgery (e.g., C3 Index score 6 vs 0, adjusted odds ratio [OR] 0.32; 95% CI, 0.13 to 0.78) and the risk of mortality increased (e.g., C3 Index score 6 vs 0, adjusted all-cause hazards ratio [HR] 1.44; 95% CI, 0.93 to 2.23). Receipt of curative surgery reduced this excess mortality, in some cases substantially; the extent to which this occurred varied by level of comorbidity. Māori patients had somewhat higher levels of comorbidity (34% in highest comorbidity category compared with 23% for non-Māori) and poorer survival that could not be explained by age, sex, site, stage, comorbidity or receipt of curative surgery (adjusted cancer-specific HR 1.36; 95% CI, 0.97 to 1.90; adjusted all-cause HR 1.33; 95% CI, 0.97 to 1.82). Access to healthcare factors accounted for 25–36% of this survival difference.
