OBJECTIVETo investigate the clinical features and response to therapies in multiple myeloma (MM) patients with del (17p).

METHODSA total of 122 newly diagnosed MM patients hospitalized in the Department of Hematology of Peking University Third Hospital between October 2012 and September 2016 were analyzed retrospectively. The fluorescent in situ hybridization(FISH) and G-binding staining were used for detection of cytogenetic abnormalities. These MM patients with del (17p) were divided into non-bortezomib chemotherapy (VAD or CHOP) group and bortezomib chemotherapy (PAD or PCD) group. Response criteria was according to IMWG criteria, including complete remission (CR), very good partial remission (VGPR), partial remission (PR), stable disease (SD), overall response rate (ORR) was defined as CR+VGPR+PR. The Kaplan-Meier method was used to evaluate overall survival (OS) and progressive free survival (PFS).

RESULTSCytogenetic abnormalities were detected in 60 patients, and the frequency of del(17p) was 10.7% (13 of the 122 patients). For the 13 MM patients with del(17p), median age was 59 years old, male vs female ratio was 8:5, 7 patients were found to have soft tissue plasmacytoma at the time of diagnosis, and IgG accounted for 61.5% (8/13). The frequency of coexisting other cytogenetic abnormalities was 53.8% (7/13); del(13q14) (D13S319 and/or RB1) accounted for 30.8%(4/13), and gain (1q21) 23.1%(3/13), 13 patients were able to be evaluated for the response, ORR were 33.3%(2/6) vs 100.0%(7/7), VGPR 0% vs 57.1%, PR 33.3% vs 42.9%, PD 50.0% vs 0% in non-bortezomib chemotherapy and bortezomib groups, respectively (P=0.042). 4 patients received 50 Gy radiotherapy for soft tissue plasmacytoma, no responses were observed. With a median follow up of 14(2.0-40)months, median PFS and OS time were 6(95% CI0.9-11.1) months and 21(95% CI9.0-33.0) months, respectively. Median OS in bortezomib groups was significant longer than that in the non-bortezomib groups, not reachable vs 10.8(95%CI3.4-16.6) months (P=0.017).

CONCLUSIONMM with del(17p) shows high frequency of soft tissue plasmacytoma, and high prevalence of coexisting gain(1q21) and del(13q14). These patients are not sensitive to non-bortezomib chemotherapy or radiotherapy, and has a poor survival. Bortezomib are able to improve the outcome of these MM patients.