Stage-specific conditional survival among young versus older adults with colorectal cancer in the United States, 2004-2010.

Abstract

257 Background: Conditional survival (CS) is a relevant prognostic measure for cancer survivors and physicians and may be particularly important for young adult patients with CRC (colorectal cancer), whose incidence is rising. We sought to compare CS among young versus older adults with CRC. Methods: Patients diagnosed with colon or rectal adenocarcinoma between 2004-2010 were identified from the Surveillance, Epidemiology and End Results (SEER) registry. Overall survival (OS) and cancer-specific survival (CSS) were estimated, along with smoothed yearly hazards of death due to CRC, other causes and any cause, stratified by age at diagnosis ( < 50 vs. >50 years). Stage-specific conditional 5-year OS and 5-year CSS given that patients had already survived 1, 2, 3, 4 or 5 years after diagnosis was calculated, also stratified by age. Results: Among 161,859 patients with median follow-up of 54 months, 35,411 (21.9%) were aged < 50 years. Both OS and CSS were superior among younger adult as compared to older adult patients (p < 0.001). For older adults with rectal cancer, hazards of death due to non-cancer causes exceeded that of rectal and colon cancer approximately 6 and 4.5 years after diagnosis, respectively. Among younger adults, hazard of death from cancer remained greater than death from other causes throughout the entire study interval. Patients experienced improved conditional survival over time with greater improvement seen for more advanced stages. However, young adults had less CS improvement over time than older adults. For example, the 5-year overall and CSS for Stage IV colon cancer improved from 7.4% to 52.4%% (OS) and 15.1% to 78.5% (CSS) 0 to 5 years after diagnosis for older adults. In contrast, for younger adults, the 5-year overall and CSS for Stage IV colon cancer improved from 15.6% to 57% (OS) and 19.3% to 68.4% (CSS). Conclusions: Prognosis for CRC improves over time for all patients, although the increase in survival appears to be less for younger than older adults. Up to 10 years after diagnosis, the primary cause of death in younger adults with CRC remains their incident cancer.