Significance of delayed primary excision in localized nonmetastatic adult head and neck rhabdomyosarcoma

Adult rhabdomyosarcoma (RMS) is a highly aggressive tumor. Multidisciplinary treatment is important. However, the role of surgery is controversial. The purpose of this study was to reveal the role of a delayed primary excision (DPE) after induction chemotherapy (IC) in localized nonmetastatic adult head and neck RMS. We retrospectively reviewed 24 adult head and neck RMS. Treatment was classified into the following two groups: the DPE group, who received IC followed by surgery, postoperative radiotherapy, and adjuvant chemotherapy (17 patients); the chemoradiotherapy (CRT) group, who received IC followed by chemoradiotherapy (seven patients). We analyzed the efficacy of IC, local control rate (LCR), and overall survival (OS). In the DPE group, 10 patients (59%) underwent complete surgical resection. In the evaluation of the surgical specimens, 14 patients (82%) had residual viable tumors after IC. The response to IC was significantly associated with the 3‐year LCR (CR/PR vs. SD/PD: 100% vs. 33%, P = 0.0014). In patients with good response to chemotherapy, the DPE group had a significantly better 3‐year LCR compared with that of the CRT group (DPE group vs. CRT group, 100% vs. 44%, P = 0.018). However, the treatment modalities were not associated with OS (DPE group vs. CRT group, 65% vs. 57%: P = 0.98). The recurrence patterns differed according to treatments, and distant metastases were more frequent in the DPE group. DPE may impact local control of localized nonmetastatic adult head and neck RMS. Poor response to IC is a risk factor for local recurrence.