Childhood cancer survivors are at an increased risk for developing an intestinal obstruction requiring surgery (IOS) 5 or more years after the initial cancer diagnosis, according to a study based on data from the Childhood Cancer Survivor Study.
The risk was greater among those who had a pelvic or abdominal tumor and had been exposed to pelvic or abdominal radiotherapy, reported the authors, who pointed out that no study has “rigorously” investigated the incidence of intestinal obstruction in childhood cancer survivors. The study appeared online in the Journal of Clinical Oncology (2015 Aug 10 doi: 10.1200/JCO.2015.61.5070).
The subjects in the study had been diagnosed with cancer before age 21 years between 1970 and 1986 and were followed longitudinally in the CCSS. The sample included 12,316 childhood cancer survivors who had survived at least 5 years from the time they were diagnosed with cancer and 4,023 of their siblings.
The cumulative incidence of “late” IOS (occurring at least 5 years after the cancer diagnosis) was 5.8% among those who had an abdominopelvic tumor and 1% among those who had other types of cancer, compared with 0.3% among siblings, who served as controls in the study. After adjusting for year of diagnosis, age at diagnosis, cancer type, radiotherapy, surgery, and other confounding factors, the risk of late IOS was significantly increased among those who had an abdominopelvic tumor (3.6 times greater) and those who had received abdominal/pelvic radiotherapy (2.4 times greater). Mortality was also almost twofold higher among those who developed late IOS when adjusted for the same factors, but there was no association with chemotherapy, cyclophosphamide equivalent dose, or platinum agent score and late IOS.
“The risk of IOS extends for decades beyond cancer diagnosis, implying the need for long-term vigilance, especially among survivors with abdominal or pelvic tumors and survivors who have undergone treatment with abdominal or pelvic surgery or radiotherapy,” concluded lead author Dr. Arin Madenci of Boston Children’s Hospital and his coauthors.
“Widespread awareness of the signs and symptoms of IOS will facilitate timely presentation and effective management of this complication. Although prevention of IOS is not currently possible, education of survivors of cancer, their families, and their health care providers is critical,” they added.
The study was supported by grants from the National Cancer Institute and Cancer Center Support (Centers of Research Excellence) and by the American Lebanese Syrian Associated Charities. Dr. Madenci and nine other authors had no disclosures. The remaining three authors had disclosures that included receiving honoraria, travel, and expenses from Sandoz, holding stock or other ownership in Pfizer and Novartis, serving as a consultant or advisor to United Therapeutics, and having an immediate family member with stock or other ownership in several pharmaceutical companies.