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Objectives: While the NCCN guidelines maintain that T4b oral cavity squamous cell carcinoma (OCSCC) should undergo either non-surgical treatments or clinical trials, promising outcomes of T4b OCSCC having surgical excision have been reported. We analyzed and compared the clinical outcomes of Taiwanese patients with pT4a and pT4b OCSCC who had undergone surgical treatment.Methods: From 2011 to 2017, a total of 4031 and 355 patients with first primary pT4a and pT4b OCSCC were identified. A propensity score (PS)-matched analysis of patients (n = 351 each) for pT4a and pT4b tumors was also performed.Results: The 5-year disease-specific and overall survival (DSS/OS) rates were more favorable in patients with pT4a than in those with pT4b OCSCC (64%/55%, p < 0.0001; 55%/43%, p < 0.0001, respectively). Compared with pT4a, those with pT4b tumors had a higher burden of the following risk factors: buccal/retromolar/hard palate subsite, male sex, depth ≥ 10 mm, and positive margins. Before PS matching, multivariable analyses revealed that pT4b tumors (versus pT4a) were an adverse prognosticator for both 5-year DSS and OS (hazard ratios: 1.32 and 1.39, respectively). However, in the PS-matched cohort, no significant differences in 5-year DSS and OS rates were observed between pT4a and pT4b OCSCC (57%/56%, p = 0.4024; 48%/44%, p = 0.1807, respectively) CONCLUSIONS: No significant outcome differences were evident between pT4b and pT4a OCSCC after PS matching. The most plausible hypothesis for the observed survival difference between T4a and T4b tumors is that it was driven by positive margins. We suggest that T4b OCSCC should undergo initial surgical excision if adequate resection is possible. [ABSTRACT FROM AUTHOR]

Purpose: The evidence for adjuvant therapy of oral cavity squamous cell carcinoma (OCSCC) in National Comprehensive Cancer Network (NCCN) guidelines is derived from patients with head and neck cancer. Here, we examined whether adjuvant therapy should be guided by a detailed analysis of pathologic risk factors in patients with pure OCSCC.Methods and Materials: Between 2004 and 2016, we retrospectively reviewed 1200 consecutive patients with OCSCC who underwent radical surgery and neck dissection in the Chang-Gung Memorial Hospital (CGMH). Patients were divided into 3 prognostic groups. High-risk patients were those with extranodal extension (ENE) and/or positive margins (ENE/margins+, n = 267). Intermediate-risk patients were further divided into 3 subgroups: (1) patients in whom adjuvant therapy was indicated according to the CGMH but not the NCCN guidelines (NCCN[-]/CGMH[+], n = 14); (2) patients in whom adjuvant therapy was indicated by the NCCN but not the CGMH guidelines (NCCN[+]/CGMH[-], n = 160); and (3) patients in whom adjuvant therapy was indicated according to both guidelines (NCCN[+]/CGMH[+], n = 411). Low-risk patients were those for whom adjuvant therapy was not suggested in light of either guideline (NCCN[-]/CGMH[-], n = 348).Results: According to NCCN guidelines, postoperative adjuvant therapy was indicated in 69.8% of the participants. However, only 57.7% of patients were in need of adjuvant therapy by CGMH guidelines. The following 5-year outcomes were observed in the NCCN(-)/CGMH(-), NCCN(-)/CGMH(+), NCCN(+)/CGMH(-), NCCN(+)/CGMH(+), and ENE/margins+ subgroups: locoregional control, 88%/70%/83%/79%/68%, P < .001 (NCCN[+]/CGMH[-] vs NCCN[+]/CGMH[+], P = .576); distant metastases, 2%/7%/2%/9%/36%, P < .001 (NCCN[+]/CGMH[-] vs NCCN[+]/CGMH[+], P = .003); disease-specific survival, 97%/86%/94%/84%/56%, P < .001 (NCCN[+]/CGMH[-] vs NCCN[+]/CGMH[+], P < .001); and overall survival, 92%/86%/87%/68%/42%, P < .001 (NCCN[+]/CGMH[-] vs NCCN[+]/CGMH[+], P < .001), respectively.Conclusions: Patients in the NCCN(+)/CGMH(-) subgroup, 28% (160/571[160 + 411]) of NCCN intermediate-risk patients, had more favorable 5-year disease-specific and overall survival (94% and 87%) than the NCCN(+)/CGMH(+) subgroup. The former are unlikely to derive clinical benefits from NCCN guidelines. The 70% adjuvant therapy rate required by NCCN guidelines after radical surgery might be too high, ultimately leaving room for improvement. [ABSTRACT FROM AUTHOR]