BI07 Outcomes of oral squamous cell carcinoma following haematopoietic stem cell transplantation

Abstract

Abstract Haematopoietic stem cell transplant (HSCT) recipients are at increased risk of malignancies, including cancers of the oral cavity, with a reported observed-to-expected ratio of 10.7, accounting for 14% of all solid tumours following HSCT. We report 10 cases of oral squamous cell carcinoma (SCC; 2016–2022) in HSCT recipients from a single tertiary centre [nine men and one woman; median age at diagnosis 52 years (range 27–66)]. Thirty per cent were ex-smokers and 10% current smokers. Prior to HSCT, 50% had reduced intensity conditioning, 40% had myeloablative conditioning and 10% had both. Eighty per cent were recipients of sibling allografts and 20% were recipients from matched unrelated donors. Ninety per cent had a history of chronic graft-versus-host disease (GVHD), with affected sites including the mouth (n = 6), skin (n = 6), eyes (n = 5), lungs (n = 4), kidneys (n = 3) and liver (n = 1). Forty per cent had active severe manifestations of oral GVHD. Treatments used for oral GVHD included topical immunosuppression (n = 5), oral immunosuppression (n = 6) and extracorporeal photopheresis (ECP; n = 2). Median latency from HSCT to oral SCC diagnosis was 10 years (range 4–22). At the time of SCC diagnosis, 20% were not taking immunosuppressants, 20% were being treated with topical corticosteroids and 50% with oral immunosuppression, and one patient was recently treated with ECP. Examination findings at SCC diagnosis included induration, ulceration, tenderness, bleeding, hyperkeratosis, speckling and lymphadenopathy (n = 1). Fifty per cent were asymptomatic. In 40% of cases, a previous biopsy showed hyperplastic or dysplastic changes. The commonest sites of SCC were the tongue (n = 4) and buccal mucosa (n = 3). The disease stage (TNM) at presentation ranged from T1N0M0 to T4N2M0. Sixty per cent of cases were T3 or T4 and 40% had nodal involvement. Management included radical surgical resection in 90% of cases; 10% received adjuvant radiotherapy and 10% chemoradiotherapy. One patient with an SCC on the lower lip underwent resection using Mohs micrographic surgery. Median duration of follow-up for the cohort was 0.8 years (range 0.4–5.7) with a 50% mortality rate. In our cohort, median survival following oral SCC diagnosis was 0.8 years (range 0.4–5.0) and SCC-specific mortality was 30% (n = 3). We report the largest UK case series, to the best of our knowledge, of oral SCC post-HSCT. The data show a long latency from HSCT to the onset of oral SCC, highlighting the importance of regular, active oral surveillance by haematologists, dermatologists, oral specialists and dentists. This follow-up is recommended irrespective of the severity of GVHD and length of iatrogenic immunosuppression. Intensive surveillance is indicated in groups at higher risk with a history of chronic oral GVHD.