Immediate risk of non-cancer deaths after a cancer diagnosis

BACKGROUND: Receiving a cancer diagnosis may trigger immediate fatal non-cancer health outcomes in addition to dying of cancer itself. We aim to investigate the full pattern of non-cancer deaths in patients within a year of a cancer diagnosis. METHODS: Patients diagnosed with cancer between 1990 and 2016 were identified from the SEER program. Standardized mortality ratios (SMRs) were calculated to characterize the relative risks of non-cancer deaths compared with the general population. RESULTS: Among 7,366,229 patients, 241,575 non-cancer deaths (15.9%) were recorded in the first year following a cancer diagnosis. The relative risk of non-cancer deaths was 2.34-fold (95% confidence interval (CI): 2.33-2.35) that of the general population. The majority of non-cancer deaths were caused by cardiovascular diseases (21.8%), followed by infectious diseases (7.2%). Significant elevations in mortality risks were observed for nearly all non-cancer causes, particularly in infectious diseases (SMR: 5.08; 95% CI: 5.03-5.13). Patients with liver cancer (SMR: 12.29; 95% CI: 12.06-12.53) were at the highest risk of early non-cancer deaths. The risks of non-cancer deaths were highest within the first month after diagnosis, and decreased rapidly thereafter. CONCLUSIONS: Risks of non-cancer deaths vary by the types of causes and anatomic sites of cancer. Our data underscore the importance of close observation and early multidisciplinary care for noncancer conditions in patients who have recently received a cancer diagnosis.