Effects of transplantation-related immunosuppression on co-existent neuroendocrine tumours

BACKGROUND: Here we detail our experience of managing patients found to have a neuroendocrine neoplasm (NEN) whilst on immunosuppression for a transplanted organ. AIM: We aimed to quantify the behaviour of NENs under solid-organ transplant-related immunosuppression. DESIGN: This was an observational, retrospective case series. METHODS: Ten patients were identified from a prospectively kept database. Three were excluded. RESULTS: Four patients received a liver, two a kidney, and one a heart transplant. All but one received calcineurin-based immunosuppression. NENs were found in five patients post-transplant: one had surgery for transverse colonic neuroendocrine carcinoma NEC (pT4N1M0, Ki67 60%), was cancer-free after four years; one had cold biopsy of duodenal NEN (pT1N0M0, Ki67 2%), cancer-free at four months; one 7 mm pancreatic NEN (pT1N0M0), untreated and stable for seven years; one small-bowel NEN with mesenteric metastasis (pTxNxM1), alive four years after diagnosis; and one untreated small-bowel NEN with mesenteric metastasis, stable at 1 year after liver transplantation. Two NENs were discovered pre-transplant, one pancreatic NEN (pT1N0M0, Ki67 5%), remains untreated and stable at three years. One gastric NEN (type 3, pT1bN0M0, Ki67 2%) remains stable without treatment for two years. CONCLUSIONS: NENs demonstrate indolent behaviour in the presence of transplant-related immunosuppression.