Influence of bone invasion on outcomes after marginal mandibulectomy in squamous cell carcinoma of the oral cavity.

INTRODUCTION: Marginal mandibulectomy (MM) is indicated for oral cavity squamous cell carcinomas (OCSCC) that abut or minimally erode the mandible without gross invasion. Successful implementation of MM is predicated on accurate patient selection and appropriate adjuvant treatment based on well-known host and tumor characteristics. The incidence of microscopically diagnosed bone involvement in MM specimens and its implications on outcomes have however not been reported in large contemporary series. PURPOSE: To report the incidence of bone involvement and analyze its influence on oncologic outcomes in selected patients who underwent MM in treatment of OCSCC. METHOD: A retrospective cohort study was performed on a consecutive series of previously untreated patients requiring MM, at a tertiary care cancer center, between 1985 and 2012 (n = 326). The median age was 64 years and 59% were male. The majority of patients (67%) had a primary tumor of the floor of the mouth or lower alveolus, 80% were clinically staged T1-2, and 31% were clinically N+. Postoperative radiation (PORT) was used in 27% and chemoradiation (POCTRT) in 8% of patients who had microscopic bone invasion. The median follow up period was 55 months and endpoints of interest were local and regional recurrence free (LRFS and RRFS) and disease specific (DSS) survival. RESULTS: Microscopic bone invasion was present in 15% of patients (n = 49). Among these, cortical invasion was present in 32, medullary in 13, and it was not specified in 4. Eight patients had microscopic positive bone margins. Positive bone margins were associated with medullary bone involvement (p < 0.001), floor of mouth and buccal mucosa primary site (p = 0.03), and positive soft tissue margins (p = 0.06). LRFS and DSS were similar in patients without versus with bone invasion (62.8% vs 79.7% and 76.2% vs 66% respectively, p = NS). LRFS were similar in patients with microscopic positive versus negative bone margins, as long as postoperative adjuvant treatment was administered. CONCLUSION: Microscopic bone involvement does not adversely influence outcomes but medullary bone involvement does confer a higher risk of positive bone margins. MM and appropriate adjuvant treatment is an effective strategy for treatment of OCSCC in selected patients with primary tumors adherent to or in proximity to the mandible.

Impact of elective neck dissection on the outcome of oral squamous cell carcinomas arising in the maxillary alveolus and hard palate.

BACKGROUND: Whether elective lymph neck dissection (ELND) is associated with improved survival in oral squamous cell carcinomas (SCC) of the maxillary alveolus/hard palate is not known. METHODS: One hundred ninety-nine patients presenting de novo and receiving treatment for clinically node negative SCC of the maxillary alveolus/hard palate at 2 cancer centers between 1985 and 2011 were analyzed. RESULTS: Forty-two patients (21%) received ELND. Occult nodal metastases were present in 29% of the dissected necks. The ELND group had more T3 to T4 status tumors (62% vs 34%; p < .001) and positive-margin resections (59% vs 38%; p = .019). Patients undergoing ELND experienced lower rates of neck recurrence (6% vs 21%; p = .031), superior 5-year recurrence-free survival (68% vs 45%; p = .026), and overall survival (86% vs 62%; p = .043). ELND was associated with a 2-fold decrease in risk of recurrence in multivariable analysis. CONCLUSION: ELND was associated with lower rates of recurrence and improved survival in SCC of the maxillary alveolus/hard palate. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1688-E1694, 2016.

A novel tumor: specimen index for assessing adequacy of resection in early stage oral tongue cancer.

PURPOSE: Surgical margin status frequently affects decisions regarding adjuvant treatment; however, reporting and interpretation of surgical margins is subject to considerable subjectivity because of many factors including the adequacy of resection. We developed a novel measure of the adequacy of surgical resection, the tumor: specimen index (TSI), and tested its utility at predicting clinical outcomes in a retrospective cohort study. PATIENTS AND METHODS: An institutional database was queried to identify previously untreated patients with T1 and T2 oral tongue cancer who underwent surgery during 1985-2009 (n=433). The TSI, a geometric mean representing the percentage of the surgical specimen that is occupied by the tumor in average single dimension, was calculated from the largest measured lengths, widths, and heights of the tumor in relation to the entire surgical specimen. Multivariate analyses of locoregional recurrence-free probability (LRRFP) and disease-specific survival (DSS) were performed with commonly accepted prognosticators in addition to TSI and surgical margins status. RESULTS: The mean TSI was 41 (range 11-90; SD 14). Surgical margin status was associated with TSI; margins were negative in 84% of patients with TSI<45 and in 63% of patients with TSI⩾45 (p<0.001). TSI⩾45 was associated with worse LRRFP (57% vs. 76%, p<0.001) and worse DSS (68% vs. 85%, p<0.001). In a multivariate analysis that did not include TSI, surgical margin status independently predicted LRRFP (p=0.014) but not DSS. When TSI was included, only TSI, and not surgical margin status, was an independent predictor of both LRRFP (p=0.002) and DSS (p=0.011). CONCLUSION: The tumor: specimen index is an easily-calculated metric for estimating the adequacy of 3-dimensional resection in T1 and T2 oral tongue cancer that independently predicts oncologic outcomes.

Pathologically determined tumor volume vs pathologic T stage in the prediction of outcome after surgical treatment of oropharyngeal squamous cell carcinoma.

IMPORTANCE: Traditional prognostic models for squamous cell carcinoma of the head and neck are based on the TNM staging system. However, there is growing evidence that tumor volume (TV) may be a more accurate predictor of outcome. OBJECTIVE: To determine whether pathologic TV (pTV) in patients with oropharyngeal squamous cell carcinoma treated surgically is a more significant predictor of outcome compared with pathologic tumor (pT) stage. DESIGN, SETTING, AND PARTICIPANTS: Review of patients whose treatment was managed between January 1, 1985, and December 2005 at a US tertiary referral cancer center. The participants included 159 patients who had undergone primary surgery for oropharyngeal squamous cell carcinoma and had 3 dimensions reported on histopathologic testing. MAIN OUTCOMES AND MEASURES: The pTV was calculated as the product of the 3 dimensions expressed in cubic centimeters. For comparison of pT stage with pTV in outcome prediction, concordance indexes were generated using the bootstrap method (n = 1000) to quantify the predictive accuracy of recurrence and survival outcomes. Concordance indexes were then compared and a significant difference was considered when P < .05. RESULTS: The median age of the patients was 59 years (range, 22-84 years) and 106 were male (67%). Sites of the tumors were base of the tongue (86 patients [54%]), tonsil (48 [30%]), soft palate (24 [15%]), and posterior pharyngeal wall (1 [1%]). The median follow-up time was 64 months (range, 1-272 months). The median tumor volume was 6.8 cm3 (range, 0.1-162.5 cm³). Pathologic TV was a significant predictor of disease-specific mortality. Unlike pT stage, pTV was a significant predictor of local recurrence, regional recurrence, and distant recurrence. Comparison of concordance indexes showed that pTV was a significantly better predictor of disease-specific mortality, local recurrence, and distant recurrence (all P < .05). CONCLUSIONS AND RELEVANCE: Pathologic TV outperforms pT stage in the prediction of outcome following surgical treatment of oropharyngeal cancer. Tumor volume should be considered in the design of prospective surgical trials.