Increasing age-related survival gap among patients with colorectal cancer: a population-based retrospective study.

ABSTRACT

BACKGROUND: Survival for patients with colorectal cancer (CRC) has improved over the past decades. However, it is unclear whether older patients have benefited to the same extent as younger patients. METHODS: The Surveillance, Epidemiology, and End Results (SEER) 9 registries database was queried for CRC patients from 1975 to 2009. We presented yearly data for survival with overlying loess-smoothing lines across all age groups. Another cohort was created using the SEER 18 registries database for patients diagnosed with CRC from 1973 to 2014. Yearly data for surgery-performed rate, stage proportion, and multivariate hazard ratio were performed with overlying smoothing lines across all age groups. RESULTS: In the analysis SEER 9, 5-year cause-specific survival (CSS) of patients aged ≤ 54, 55-64, and 65-74 years showed robust increase since 1975; however, the survival of patients aged 75-84 years remained low despite modest improvement, and patients aged 85 or older even showed no survival gains since 1990. In the analysis of SEER 18, there has been a steady increase in the survival of patients aged ≤ 54, 55-64, 65-74, and 75-84 years as time period advanced; however, of CRC patients aged ≥ 85 years, the survival curves of period 1990-1999 and 2000-2012 could not be distinguished from each other presented with negligibly a small gap from the curve of 1980-1989. CONCLUSIONS: The strong interaction between age and year of diagnosis implies that older patients have benefited less over time than younger patients, especially for patients aged ≥ 85 years.