Outcomes of Patients with Oral Cavity Squamous Cell Carcinomas Treated with Adjuvant IMRT with Perineural Invasion.
Int J Radiat Oncol Biol Phys 2023;
117:e569-e570. [PMID:
37785737 DOI:
10.1016/j.ijrobp.2023.06.1898]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S)
Patients with advanced oral cavity squamous cell carcinoma (OCSCC) have high rates of recurrence and dismal outcomes. Treatment consists of definitive surgery followed by risk-adapted adjuvant radiation therapy based on pathologic review. Perineural invasion (PNI) is thought to be an intermediate risk factor, leading to clinical uncertainty as to adjuvant therapy in the setting of PNI. We performed a single institution retrospective review of patients with OCSCC treated with adjuvant radiation with or without PNI and examined relapse-free survival (RFS) and overall survival (OS).
MATERIALS/METHODS
We performed a single-institutional retrospective review of patients with OCSCC treated with adjuvant IMRT +/- chemotherapy after surgical resection from July 2002- August 2021 using our institution's Head and Neck SPORE database. Time to recurrence or death was calculated from end of RT. OCSCC within 5 years of RT was considered a recurrence, beyond this timeframe any OCSCC was considered a new primary. Univariate analysis of predictors for RFS and OS were performed using the Kaplan-Meier method with log-rank test. Factors significant on univariable analysis were entered into parsimonious cox multivariable analysis using forward selection methodology. A p-value <0.05 was considered significant in both analyses.
RESULTS
In total, 494 patients with OCSCC were identified that received surgery and adjuvant IMRT. In this cohort, 48.8% of patients had pT4 tumors, 62.2% of patients had nodal involvement, and 40.3% of patients had extranodal extension. PNI was present in 63.6% of patients (n = 314). With regards to tumor subsite, 40.9% originated from the oral tongue, 21.5% originated from the gums, 18% originated from the floor of mouth, and 19.6% from the other sites. Median age was 59 years, and median adjuvant RT dose was 63 Gy (Interquartile range [IQR]) 60-66 Gy). The majority of patient received platinum-based chemotherapy (51.8%), and 44.1% of patients did not receive adjuvant chemotherapy. The 3-year RFS and OS with a median follow-up of 32 months (IQR 12-69 months) is presented in Table 1. On univariable analysis for OS, T stage (p = 0.003), N stage (p<0.001), PNI (p = 0.005), extranodal extension (ENE) (p<0.001), margin status (p = 0.038), and chemotherapy (p<0.001) were significant. On multivariable analysis, T stage (p<0.001), N stage (p = 0.010), PNI (p = 0.017), and ENE (p = 0.007) remained significant. Similar results were seen in the RFS analysis.
CONCLUSION
In this large single institution study, PNI was a significant and independent negative predictive factor for RFS and OS in patients with OCSCC that had received definitive surgery followed by adjuvant IMRT. To our knowledge this is the largest study of its kind, and these findings can help guide clinical decision making for these patients.
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