Approximately 34–86% of neoplasms of the salivary glands are located in the parotid gland and parotidectomy is the first-line treatment for parotid gland tumors. Frey syndrome and cosmetic deformity are common complications experienced by patients following parotidectomy and the sternocleidomastoid muscle flap (SCMF) is used to prevent them. Numerous studies have been performed to examine the effectiveness of the SCMF for the prevention of cosmetic deformity and Frey syndrome, however, they provide contradictory results and possess small sample sizes with consequently low statistical power. In order to evaluate the effectiveness of the SCMF for the prevention of Frey syndrome and cosmetic deformity following parotidectomy, we performed a systematic review and meta-analysis based on published randomized controlled trials (RCTs), which were identified using PubMed and CNKI databases, and references of studies up to August 2012 were included. Using these criteria, we yielded 11 RCTs. Following an independent assessment of the methodological quality of these studies and the extraction of data, a systematic review and meta-analysis was conducted. The results of the meta-analysis demonstrated that there was a significant trend towards a lower risk of objective incidence [67%; risk ratio (RR), 0.33; 95% confidence interval (CI), 0.16–0.67; P<0.01] and subjective incidence (66%; RR, 0.34; 95% CI, 0.16–0.75; P= 0.01) of Frey syndrome in the SCMF group. The sensitivity analysis also indicated that this result was significant. Due to the considerable variation between the included studies, a meta-analysis was not applicable to assess cosmetic deformity. Two RCTs demonstrated that the difference between the SCMF and no SCMF group was not statistically significant, while the other seven RCTs detected a statistically significant difference between the two groups. Publication bias was detected. In conclusion, based on currently available evidence, the use of the SCMF is benefical for the prevention of Frey syndrome, however, whether it is also benefical for cosmetic deformity remains inconclusive.

223 Background: Definitive or palliative chemoradiation therapy has been employed in the management of esophageal squamous cell carcinoma (ESCC). Immune checkpoint inhibitor has improved outcomes in metastatic stage IV pts. Here we report the addition of KN046, a PD-L1/CTLA-4 bispecific antibody, to concurrent chemoradiation (CRT) therapy to determine the safety and efficacy of this approach (ChiCTR2000031544). Methods: Pts with recurrent or metastatic ESCC, not been treated by CRT or other systemic treatment within 6 months, were recruited and received palliative CRT consisting of cisplatin (75 mg/m2 IV Q3W for 4~6 cycles), paclitaxel (135~175 mg/m2 IV Q3W for 4-6 cycles) and radiation (SBRT or conventional and dose are determined at the investigator’s discretion according to institutional standard). KN046 at ascending doses of 1, 3 and 5 mg/kg Q3W was added within 7-14 days after the completion of radiation therapy (RT) and concurrently with chemotherapy, followed by KN046 Q2W maintenance. Dose limiting toxicities (DLTs) were assessed for the first treatment cycle of KN046. Anti-tumor activity was assessed according to RECIST 1.1 every 6 weeks within the first year, and every 12 weeks thereafter. Results: As of June 30, 2020, 18 subjects were enrolled and received KN046 treatment (1mg/kg, n = 3; 3mg/kg, n = 11; 5mg/kg, n = 4). The median KN046 exposure was 11.5 weeks. No DLT was reported. 3 (16.7%) subjects experienced Grade 3, KN046 related adverse events (1 Grade 3 pneumonitis and 2 Grade 3 colitis recovered after steroid and antibiotic Tx). For 18 evaluable subjects, the disease control rate and objective response rate were 94.4% and 44.4%, respectively. DOR and PFS were not matured yet as of cutoff date. At 3 mg/kg, objective response was observed in 5 out of 9 subjects (55.6%) with measurable disease and disease control rate was 100%; 7/9 (77.8%) subjects experienced further tumor reduction after initiation of KN046 treatment. It is worth to note that, 2 subjects at 3mg/kg achieved complete response after receiving KN046 treatment. Conclusions: The addition of KN046 to CRT was well tolerated and showed promising efficacy signal in recurrent or metastatic ESCC. This pilot study enables further investigation of a new treatment modality of KN046 with CRT in this detrimental disease with poor prognosis. Clinical trial information: 2000031544.