Purpose: To provide an analysis of conditional survival (CS) in rectal cancer patients. Cancer survival is typically reported in terms of survival from time of diagnosis. CS can provide improved prognostic information for patients surviving a given period after diagnosis.
Methods: Data from 36,321 rectal cancer patients diagnosed between 1988 and 1998 were analyzed using the Surveillance, Epidemiology, and End Results (SEER 17) database. Observed 5-year CS rates according to disease stage, age, sex, and race were calculated using the life-table method.
Results: As survival from diagnosis increased from 0 to 5 years, the 5-year observed CS changed from 73% to 74% for stage I disease, 56% to 66% for stage II, 47% to 65% for stage III, and 6% to 48% for stage IV. Patients aged 65 years and over at diagnosis had lower CS than those under 65 years, both at diagnosis (45% vs. 61%) and at 5 years from diagnosis (59% vs. 81%). Men had slightly lower 5-year survival than women, both at diagnosis (50% vs. 53%) and after 5 years (68% vs. 71%). Black patients had slightly lower survival than white patients for nearly all time points and stages.
Conclusion: For rectal cancer patients who survive a given period of time after diagnosis, the largest increases in CS are in patients with advanced stage disease and for those under 65 years of age. CS can provide more accurate prognostic information for rectal cancer patients who survive a given period after diagnosis.