Importance: Survivors of blood or marrow transplant (BMT) are at increased risk of subsequent malignant neoplasms (SMNs). Cancers of the gastrointestinal (GI) system are of special interest because their clinical behavior is often aggressive, necessitating early detection by increasing awareness of high-risk populations.
Objective: To describe the risk of SMNs in the GI tract after BMT.
Design, setting, and participants: A cohort study of 6710 individuals who lived at least 2 years after BMT performed between January 1, 1974, and December 31, 2014, at City of Hope, University of Minnesota, or University of Alabama at Birmingham. End of follow-up was March 23, 2020. Data analysis was performed between September 1, 2022, and September 30, 2022.
Exposures: Demographic and clinical factors; therapeutic exposures before or as part of BMT.
Main outcomes and measures: Development of SMNs in the GI tract after BMT. Participants self-reported SMNs in the GI tract; these were confirmed with pathology reports, medical records, or both. For deceased patients, death records were used. Standardized incidence ratios determined excess risk of SMNs in the GI tract compared with that of the general population. Fine-Gray proportional subdistribution hazard models assessed the association between risk factors and SMNs in the GI tract.
Results: The cohort of 6710 individuals included 3444 (51.3%) autologous and 3266 (48.7%) allogeneic BMT recipients. A total of 3917 individuals (58.4%) were male, and the median age at BMT was 46 years (range, 0-78 years). After 62 479 person-years of follow-up, 148 patients developed SMNs in the GI tract. The standardized incidence ratios for developing specific SMNs ranged from 2.1 for colorectal cancer (95% CI, 1.6-2.8; P < .001) to 7.8 for esophageal cancer (95% CI, 5.0-11.6; P < .001). Exposure to cytarabine for conditioning (subdistribution hazard ratio [SHR], 3.1; 95% CI, 1.5-6.6) was associated with subsequent colorectal cancer. Compared with autologous BMT recipients, allogeneic BMT recipients with chronic graft-vs-host disease were at increased risk for esophageal cancer (SHR, 9.9; 95% CI, 3.2-30.5). Conditioning with etoposide (SHR, 2.0; 95% CI, 1.1-3.5) and pre-BMT anthracycline exposure (SHR, 5.4; 95% CI, 1.3-23.4) were associated with an increased risk of liver cancer compared with no exposure to the respective agents.
Conclusions and relevance: The findings of this cohort study are relevant for oncologists and nononcologists who care for the growing number of survivors of transplant. Awareness of subgroups of survivors of BMT at high risk for specific types of SMNs in the GI tract may influence recommendations regarding modifiable risk factors, as well as individualized screening.