The risk of malignancies in patients receiving hematopoietic stem cell transplantation: a systematic review and meta-analysis

Introduction Hematopoietic stem cell transplantation (HSCT) is widely used in the treatment of malignant and non-malignant diseases. Due to advances in the number of survivors of this treatment, the number of survivors is increasing, but the late complications of this therapeutic approach such as secondary cancers have been long term and have not been fully controlled. Methods The present meta-analysis study was performed by considering English-language articles in the databases including Web of Science, Scopus and PubMed. This meta-analysis included cohort studies that reported an incidence of cancer following stem cell transplantation (SCT). Random/fixed effect size meta-analyses were used to standardize the incidence ratio for different cancers. Results 22 studies that evaluated patients receiving SCT (n = 270,063) were included in the study. The study found 9233 cases of cancer after transplantation. Meta-analysis showed that the risk of cancer after SCT was SIR = 1.66 (95% CI 1.47-1.86). The most common cancers observed in SCT recipients were bone tissue, head and neck cancers, and melanoma, with SIRs of 10.04 (3.48-16.61), 6.35 (4.76-7.93) and 3.52 (2.65-4.39), respectively. Conclusion The meta-analysis findings showed that the risk of secondary cancers after HSCT was significantly increased in most types of cancers. Consequently, diagnostic tests for common cancers should be included in the screening program of these patients for the prevention and early detection of high-risk cancers.