Poor tumor differentiation is an independent adverse prognostic variable in patients with locally advanced oral cavity cancer--Comparison with pathological risk factors according to the NCCN guidelines.

METHODS: We sought to compare the prognostic impact of tumor differentiation with respect to adverse risk factors (RFs) identified by the National Comprehensive Cancer Network (NCCN) guidelines--including extranodal extension (ENE), positive/close margins, perineural invasion, lymphatic invasion, and vascular invasion--in patients with locally advanced oral cavity squamous cell carcinoma (OCSCC). RESULTS: Between 1996 and 2018, 1179 consecutive patients with first primary pT3-4 OCSCC were included. A three-level grading system was adopted--in which the final classification was assigned according to the most prevalent tumor grade. We identified 382/669/128 patients with well/moderately/poorly differentiated tumors, respectively. Compared with well/moderately differentiated tumors, poorly differentiated OCSCC had a higher prevalence of the following variables: female sex (4%/6%/11%), ENE, (14%/36%/61%), positive margins (0.5%/2%/4%), close margins (10%/14%/22%), perineural invasion (22%/50%/63%), lymphatic invasion (2%/9%/17%), vascular invasion (1%/4%/10%), and adjuvant therapy (64%/80%/87%). The 5-year rates of patients with well/moderately/poorly differentiated OCSCC were as follows: local control (LC, 85%/82%/84%, p = 0.439), neck control (NC, 91%/83%/70%, p < 0.001), distant metastases (DM, 6%/18%/40%, p < 0.001), disease-free survival (DFS, 78%/63%/46%, p < 0.001), disease-specific survival (DSS, 85%/71%/49%, p < 0.001), and overall survival (OS, 68%/55%/39%, p < 0.001). Multivariable analysis identified the following variables as independent prognosticators for 5-year outcomes: ENE (LC/NC/DM/DFS/DSS/OS), poorly differentiated tumors (NC/DM/DFS/DSS/OS), positive margins (LC/DFS), lymphatic invasion (DFS/DSS/OS), perineural invasion (DM), and age ≥65 years (OS). CONCLUSIONS: In addition to ENE, poor tumor differentiation was identified as the second most relevant adverse RF for patients with pT3-4 OCSCC. We suggest that the NCCN guidelines should include poor tumor differentiation as an adverse RF to refine and tailor clinical management.

Precision Adjuvant Therapy Based on Detailed Pathologic Risk Factors for Resected Oral Cavity Squamous Cell Carcinoma: Long-Term Outcome Comparison of CGMH and NCCN Guidelines.

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.

Clinical Outcomes of Taiwanese Patients with cT4 Oral Cavity Squamous Cell Carcinoma: Toward the Identification of the Optimal Initial Treatment Approach for cT4b Patients.

BACKGROUND: The National Comprehensive Cancer Network guidelines recommend that patients with oral cavity squamous cell carcinoma (OSCC) and cT4b disease should be either included in clinical trials or treated with a nonsurgical approach. However, surgery may be feasible in selected patients with adequate safety margins. Using the nationwide Taiwanese Cancer Registry Database, we examined the prognosis of cT4b OSCC patients in relation to their treatment approach. METHODS: Of the 18,910 patients with previously untreated first primary OSCC identified between 2004 and 2010, 492 (2.6 %) had cT4b tumors. Of them, 327 (66 %) received initial treatment with surgery, whereas 165 (34 %) were initially treated with a nonsurgical approach. Of the latter group, 78 patients subsequently underwent surgery. A 5-year disease-specific survival (DSS) ≥45 % was considered as a favorable outcome. RESULTS: Better 5-year DSS and overall survival (OS) rates were observed in cT4b patients initially treated with surgery (vs. nonsurgery; DSS, 51 vs. 38 %; OS, 43 vs. 27 %, respectively, p < 0.001). Of the participants initially treated with surgery, patients with cN0-2 disease had better 5-year survival rates (DSS: cN0, 59 %; cN1, 53 %; cN2, 46 %; OS: cN0, 49 %; cN1, 50 %; cN2, 37 %) than those with cN3 disease (DSS: 0 %; OS: 0 %). Among cT4b patients who initially received a nonsurgical treatment, subjects who subsequently underwent surgery showed better outcomes. CONCLUSIONS: Primary surgery is performed in approximately two-thirds of cT4b OSCC patients, with cN0-2 cases showing a good prognosis. Patients who initially received a nonsurgical approach can subsequently be treated with surgery and achieve favorable outcomes.

Identification of a high-risk group among patients with oral cavity squamous cell carcinoma and pT1-2N0 disease.

PURPOSE: In the American Joint Committee on Cancer 2010 classification system, pT1-2N0 oral cavity squamous cell carcinoma (OSCC) is considered an early-stage cancer treatable with surgery alone (National Comprehensive Cancer Network 2010 guidelines). Our aim was to evaluate the feasibility of surgery alone for pT1-2N0 OSCC patients. METHODS AND MATERIALS: Among 1279 previously untreated OSCC patients referred to our hospital between January 1996 and May 2008, we identified 457 consecutive patients with pT1-2N0 disease. All had radical tumor excision with neck dissection. A total of 387 patients showing pathologic margins greater than 4 mm and treated by surgery alone were included in the final analysis. All were followed up for at least 24 months after surgery or until death. The 5-year rates of control, distant metastasis, and survival were the main outcome measures. RESULTS: The 5-year rates in the entire group of pT1-2N0 patients were as follows: local control, 91%; neck control, 92%; distant metastases, 1%; disease-free survival, 85%; disease-specific survival, 93%; and overall survival, 84%. Multivariate analysis identified poor differentiation and pathologic tumor depth of 4 mm or greater as independent risk factors for neck control, disease-free survival, and disease-specific survival. A scoring system using poor differentiation and tumor depth was formulated to define distinct prognostic groups. The presence of both poorly differentiated tumors and a tumor depth of 4 mm or greater resulted in significantly poorer 5-year neck control (p < 0.0001), disease-free (p < 0.0001), disease-specific (p < 0.0001), and overall survival (p = 0.0046) rates. CONCLUSION: The combination of poor differentiation and pathologic tumor depth of 4 mm or greater identified a subset of pT1-2N0 OSCC patients with poor outcome, who may have clinical benefit from postoperative adjuvant radiotherapy.