Surgical margin assessment after neoadjuvant chemotherapy plus nimotuzumab in locally advanced oral squamous cell carcinoma

Background: The surgical safety margin of the oral squamous cell carcinoma (OSCC) is not clear. We investigate the effect of nimotuzumab (N) combined with nab-paclitaxel, cisplatin, and fluorouracil (APF) neoadjuvant chemotherapy on the surgical margin. Methods: This was a single-center retrospective study, included 18 to 75 ages diagnosed newly histologically confirmed OSCC patients at the Fourth Hospital of Hebei Medical University between September 2019 and December 2021. Patients were divided into neoadjuvant chemotherapy and surgery group (G1 group, N + APF), chemotherapy and surgery group (G2 group, APF alone), and surgery group (G3 group). Tissue samples of the tumor core zone (P0), adjacent (P1, 3-5 mm from tumor), distal adjacent (P2, 7-10 mm from tumor), and surgical margin (P3, 15 mm from tumor) were collected. The main indicators of pathological evaluation were pathologic complete response (pCR) and major pathologic response (MPR). Chi-square or Fisher test was used for the pathological response rate of qualitative data, and t test or analysis of variance (ANOVA) was used for protein expression changes of quantitative data. A threshold value of p < 0.05 indicated statistical significance. Results: In the G1 (n = 15) and G2 (n = 20) groups, various degrees of degeneration and necrosis were observed in the tumor retraction area. Nine cases of MPR and four cases of pCR in the G1 group; eight cases of MPR and three cases of pCR in the G2 group. The expressions of p53, eIF4E, and EGFR in the samples of the three groups decreased from P0 to P2 ( p < 0.05). In the molecular tumor shrinkage area, the expression levels of p53, eIF4E, and EGFR in the shrinkage zone were lower than those in the negative margin. Conclusion: There is no significant statistical difference between APF plus nimotuzumab or APF alone in the pathological remission rate. The surgical margin was defined to 1.5 cm clinical margin after tumor regression.