Outcomes of Oral Cavity Squamous Cell Carcinoma Patients Under the Age of 40: A Propensity Score Matched Analysis

Abstract

Conflicting evidence exists regarding prognosis in younger patients with oral cavity squamous cell carcinoma (OSCC) compared to older counterparts. We compared the outcomes of OSCC patients <40 year-old (yo) to those between 40-70 yo treated at our institution. All OSCC treated between 2005 and 2017 were reviewed. Clinical characteristics and outcomes of a younger cohort (age <40 yo) were compared to the all the older (40-70 yo) patients, and then to a 1:1 matched propensity score matched older cohort. The cohorts were matched including: gender, ECOG performance status (PS), pT- and pN-categories, primary tumor subsite (oral tongue vs other subsites), resection margin status, and presence of extranodal extension (ENE). The primary endpoint was 5-yr overall survival (OS, measured by Kaplan-Meier method), and secondary endpoints were 5-yr locoregional failure (LRF, analyzed by competing risk method), and disease-free survival (DFS, evaluated by Kaplan-Meier method). A total of 57 patients were identified in the younger (< 40) cohort which had a median follow up of 4.3 (0.1-13.6) years, and 441 in the older (40-70) cohort who had a median follow up of 2.7 (0.2-9.4) years. Among the younger (< 40 yo) cohort: median age was 33 yo, 24 (42%) females, 35 (61%) non-smokers, and 25 (44%) non-drinkers; bilateral and ipsilateral neck dissection was performed in 12 (21%) and in 30 (53%), respectively. Postoperative radiation therapy was given in 23 (40%), and concurrent chemotherapy in 15 (26%). Before applying the propensity score matching, a comparison of the younger cohort (n=57) and entire older cohort (n=441) showed that younger patients, had better ECOG PS (PS 0-1 98% vs 94%, p=0.022), less smoking history (37% vs 67% p=<0.01), had more oral tongue primary tumor site (81% vs 46%, p<0.001), fewer pT3-4 (18% vs 45%, p<0.001), less frequent pN+ (42% vs 65%, p<0.001), and less pENE+ (17% vs 34%, p=0.01), a similar proportion received chemotherapy (28% v 26%, p=0.76). The young patients had better 5 year OS (82% [95% CI 71%-93%] vs (66% [60-71%] p=0.008), better 5 year DFS (66% [54%-81%] vs 54% [49%-60%] p=0.031), and less LRF (26% [16%-43%]) vs 31% [27%-37%] p=0.18). Following propensity score matching (50 patients in each matched cohort); there was no significant difference between the younger and older cohort in 5-yr OS (81% [70%-94%] vs. 71% [59%-85%], p=0.18), 5-yr DFS (63% [49%-80%] vs. 64% [52%-79%], p=0.49), and 5-yr LRF (28% [17%-47 %] vs. 32% [21%-48%], p=0.29). OSCC patients under 40 yo have better ECOG PS and pathologic features compared to the 40-70 yo counterparts. With propensity score matching, younger and older cohorts have comparable survival and tumor control. The clinical impression of poor outcomes for patients aged less than 40yrs may represent recall bias.