Background: Although colorectal adenomas serve as prime target for colorectal cancer (CRC) surveillance in other high-risk groups, data on adenoma risk after childhood cancer are lacking. We evaluated the risk of histologically confirmed colorectal adenomas among childhood cancer survivors. A secondary aim was to assess CRC risk. Methods: The DCOG-LATER cohort study includes five-year Dutch childhood cancer survivors and a sibling comparison group (n=883). Colorectal tumors were identified from the population-based Dutch Pathology Registry (PALGA).We calculated cumulative incidences of adenomas/CRCs for survivors and siblings. For adenomas, multivariable Cox regression models were used to evaluate potential risk factors. All statistical tests were two-sided. Results: Among 5843 five-year survivors (median follow-up = 24.9 years), 78 individuals developed an adenoma. Cumulative incidence by age 45 years was 3.6% (95% confidence interval [CI] = 2.2% to 5.6%) after abdominopelvic radiotherapy (AP-RT; 49 cases) vs 2.0% (95% CI=1.3% to 2.8%) among survivors without AP-RT (28 cases; Pdifference = .07) and vs 1.0% (95% CI=0.3% to 2.6%) among siblings (6 cases) (Pdifference = .03). Factors associated with adenoma risk were AP-RT (hazard ratio [HR] = 2.12, 95% CI=1.24 to 3.60), total body irradiation (TBI; HR=10.55, 95% CI=5.20 to 21.42), cisplatin (HR=2.13; 95% CI=0.74 to 6.07 for <480 mg/m2; HR=3.85, 95% CI=1.45 to 10.26 for 480 mg/m2; Ptrend = .62), a hepatoblastoma diagnosis (HR=27.12, 95% CI=8.80 to 83.58), and family history of early-onset CRC (HR=20.46, 95% CI=8.10 to 51.70). Procarbazine was statistically significantly associated among survivors without AP-RT/TBI (HR=2.71, 95% CI=1.28 to 5.74). Thirteen CRCs occurred. Conclusion: We provide evidence for excess risk of colorectal adenomas and CRCs among childhood cancer survivors. Adenoma risk factors include AP-RT, TBI, cisplatin, and procarbazine. Hepatoblastoma (familial adenomatous polyposisassociated) and family history of early-onset CRC were confirmed as strong risk factors. A full benefit-vs-harm evaluation of CRC screening among high-risk childhood cancer survivors warrants consideration.

Additional Metadata
Persistent URL dx.doi.org/10.1093/jnci/djx266, hdl.handle.net/1765/114506
Journal National Cancer Institute. Journal (Print)
Citation
Teepen, J.C. (Jop C.), Kok, J.L. (Judith L.), van Leeuwen, F.E, Tissing, W.J.E, Dolsma, W.V. (Wil V.), Van Der Pal, H.J. (Helena J.), … Ronckers, C.M. (2018). Colorectal adenomas and cancers after childhood cancer treatment: A DCOG-LATER record linkage study. National Cancer Institute. Journal (Print), 110(7), 758–767. doi:10.1093/jnci/djx266