High incidence of oral squamous cell carcinoma independent of HPV infection after allogeneic hematopoietic SCT in Taiwan

Hematopoietic SCT (HSCT) is a well-recognized therapeutic procedure to prolong life and cure patients with life-threatening hematological malignancies; however, the risk of developing secondary carcinoma may increase in long-term survivors. The objective of this study was to determine the incidence and risk factors for secondary squamous carcinoma after HSCT. Between 1984 and 2004, 170 allogeneic HSCT recipients aged >15 years, who had survived for >5 years were enrolled. Demographic data and the characteristics of secondary carcinoma were collected and analyzed for the determination of the incidence and risk of developing secondary carcinoma. Eight patients developed secondary carcinoma, including five oral squamous cell carcinomas, one esophageal, one gastric and one ovarian carcinoma, but no cutaneous carcinomas were detected at a median follow-up of 14.1 years (range, 5.1-23.3 years) after HSCT. The accrual 10-year cumulative incidence of secondary carcinoma was 2.89%. In univariate and multivariate analyses, chronic GVHD and age >40 years at the time of HSCT were both significant risk factors independently associated with the development of secondary carcinoma. Thus, the occurrence of secondary carcinoma is one of the late complications in patients undergoing HSCT. Oral squamous cell carcinoma was more common in our patients after HSCT, indicating the need for lifelong surveillance of the oral cavity. Moreover, because of the relatively long latency in developing secondary carcinoma, extended follow-up is required for a thorough understanding of the incidence and characteristics of secondary carcinoma after HSCT.