For adult survivors of childhood cancer, knowledge about the long-term risk of intestinal obstruction from surgery, chemotherapy, and radiotherapy is limited.
Intestinal obstruction requiring surgery (IOS) occurring 5 or more years after cancer diagnosis was evaluated in 12,316 5-year survivors in the Childhood Cancer Survivor Study (2,002 with and 10,314 without abdominopelvic tumors) and 4,023 sibling participants. Cumulative incidence of IOS was calculated with second malignant neoplasm, late recurrence, and death as competing risks. Using piecewise exponential models, we assessed the associations of clinical and demographic factors with rate of IOS.
Late IOS was reported by 165 survivors (median age at IOS, 19 years; range, 5 to 50 years; median time from diagnosis to IOS, 13 years) and 14 siblings. The cumulative incidence of late IOS at 35 years was 5.8% (95% CI, 4.4% to 7.3%) among survivors with abdominopelvic tumors, 1.0% (95% CI, 0.7% to 1.4%) among those without abdominopelvic tumors, and 0.3% (95% CI, 0.1% to 0.5%) among siblings. Among survivors, abdominopelvic tumor (adjusted rate ratio [ARR], 3.6; 95% CI, 1.9 to 6.8; P < .001) and abdominal/pelvic radiotherapy within 5 years of cancer diagnosis (ARR, 2.4; 95% CI, 1.6 to 3.7; P < .001) increased the rate of late IOS, adjusting for diagnosis year; sex; race/ethnicity; age at diagnosis; age during follow-up (as natural cubic spline); cancer type; and chemotherapy, radiotherapy, and surgery within 5 years of cancer diagnosis. Developing late IOS increased subsequent mortality among survivors (ARR, 1.8; 95% CI, 1.1 to 2.9; P = .016), adjusting for the same factors.
The long-term risk of IOS and its association with subsequent mortality underscore the need to promote awareness of this complication among patients and providers.