L Zhou¹, CL Cui², B Lian², L Si², ZH Chi², XN Sheng², LL Mao², X Wang², BX Tang², XQ Yan², J Guo²

¹Department of Renal Cancer and Melanoma,China Peking University School of Oncology, Beijing Cancer Hospital, Beijing. ²China Peking University School of Oncology,Beijing Cancer Hospital, Beijing.

Objective：Mucosalmelanoma (MM) is the second common subtype in Asians with a percentage of 22-25%; but there have been few epidemiologic studies. So we performed are trospective analysis of MM about its clinical presentation, gene mutation, systemic therapy (tx) and prognosis. Method：Using institutional databases, we identified patients (pts) with MM who were treated in Chinese melanoma centers between 2006-2014 with basic demographics andclinical outcomes. Result：463MM pts were included. Median age at diagnosis 56 years (range, 17-86); 61%female; primary site：149anal-rectal, 125 genitourinary, 174 head/neck, 15 others. Mutation (mut) status：14.1%(45/319) KIT mut; 9.7% (31/319) BRAF mut; 10.3% (33/319) NRAS mut. Stage I-II/III/IV at referring – 36%/17%/47%, M1a/b/c – 17%/18%/65%. The median overall survival (mOS) was 28.0 mo (95% CI 25.1-30.9 mo). Multivariate analysis showed that clinical stage and LDH level were significant prognostic factorsfor OS. The application of adjuvant therapy and LDH level were significant prognostic factors for disease free survival. For 293 pts who developed stage IV, mOS was 14.0 mo, for M1a, M1b, M1c, 20.2, 16.0, 11.1 mo respectively (P=.004). In 1st-line setting, the objective response rate (RR), disease control rate (DCR) and median progress free time (PFS) was 11.8%, 54.8%, and 3.1 mo (95% CI 2.6-3.8 mo), most of the pts using dacarbazine/temozolomide, cisplatin plus rhEndostatin had RR, DCR and PFS,12.3%, 64.6%, and 4.5 mo respectively. In 2nd-line setting, paclitaxel pluscarboplatin was common regimen, RR, DCR and PFS was 8.3% 61.1% and 3.3 mo (95%CI 2.0-4.4 mo). The mPFS of 3rd-line tx (including Abraxane, investigation altargeted drugs, etc) was 1.3 mo without complete regression and partial regression. 8/20 pts harboring c-kit mutation used imatinib, 3/8 pts had SD fora median PFS of 6.7 mo. 5/15 pts harboring BRAF mutation used vemurafenib, 3/7pxs got response, mPFS cannot be evaluated. Conclusion：The prognosis for MM is still poor, clinical stage has its significance for OS. Forpts with stage IV, the efficacy of systemic tx includes chemotherapy and targeted therapy is modest. Further investigation into the biology and treatment of MM is needed.

KeyWords：melanoma