Cause of Death among Long-Term Cancer Survivors: The NANDE Study

Survival information for Japanese patients with cancer is based only on survival status and the cause of death among these patients remains unclear. In this study, Osaka Cancer Registry data (1985-2014) and vital statistics data (1985-2016) were linked to create a database, permitting the extraction of data on the causes of death. In total, 522,566 subjects diagnosed with cancer between 1995 and 2011 were analyzed. Follow-up for vital status was conducted 5 and 10 years after cancer diagnosis. To evaluate the three causes of death (index cancer, non-index cancer, and non-cancer death), cause-specific hazard and cumulative incidence functions were estimated using a life table and Gray's methods. The number of deaths owing to any of the causes in the observation period (median: 3.51 years, mean: 4.90 years) was 394,146. The 5- and 10-year cancer-specific survival rate was 48.56% and 39.92%, respectively. Immediately after cancer onset, the hazard of index cancer death was high. The proportion of non-index cancer deaths was high in patients with mouth and pharynx cancers. The hazard of index cancer death remained constant for breast and liver cancers. In prostate, breast, and laryngeal cancers with good prognosis, the hazard of non-index cancer and non-cancer death constantly increased.