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.
The Surveillance, Epidemiology, and End Results (SEER) 9 registries database was queried for patients diagnosed with colorectal cancer from 1975 to 2009. Patients were categorized by age as being ≤54, 55-64, 65-74, 75-84, and ≥85 years. 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. Survival analyses for the periods of 1973-1979, 1980-1989, 1990-1999, and 2000-2012 were conducted. Yearly data for surgery-performed rate and stage proportion were performed with overlying loess smoothing lines across all age groups.
In the analysis of the SEER 9 registries database, 5-year CSS of patients aged ≤54, 55-64 and 65-74 years showed robust increase since 1975; however, survival of patients aged 75-84 years remained low despite of modest improvement, and patients aged 85 or older even showed no survival gains since 1990. Same trend exists after stratifying the disease as localized, regional and distant. In the analysis of the SEER 18 registries database, 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 and older, the survival curves of period 1990-1999 and 2000-2012 couldn’t be distinguished from each other and presented with a negligibly small gap from the survival curve of 1980-1989.
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. Further studies are needed to determine the cause for these trends and identify potential strategies.
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