ESTRO meets Asia 2024 - Abstract Book

S187

Interdisciplinary – Head & neck

ESTRO meets Asia 2024

Purpose/Objective:

The standard treatment for oral cavity squamous cell carcinoma(SCC) is surgery +/-adjuvant radiotherapy(RT) or chemo radiotherapy(CTRT). Several factors in postoperative-histopathology reports(HPR) predict prognosis and risk of recurrence. We evaluated correlation of extent of Extranodal Extension(ENE) (microscopic≤2mm, major ENE>2mm) and perineural invasion(PNI) (intratumoral, extratumoral) with overall survival(OS) and disease-free survival(DFS) and type of progression (loco regional vs distant) in post-operative oral cavity SCC patients.

Material/Methods:

Patients of histopathologically-proven OCCs receiving adjuvant RT or CTRT at MPMMCC-HBCH between January 2019-July 2022. Overall survival (OS) was calculated from the date of surgery until the date of death from any cause. DFS was evaluated from the date of surgery until the date of disease progression (locoregional, distant, or both) or death. Survival rates were estimated using the Kaplan-Meier method, and the log-rank test was used to compare survival outcomes. Univariate and multivariate analysis was performed to correlate the pathological risk factors in post-operative histopathology with survival outcomes. All reported P values are 2-sided, and P ≤ .05 will be considered significant for all analyses. The analysis was performed using SPSS version-25.0 518 patients (stage I-16, II-16, III-109, IVa-213, IVb-116) were retrospectively analysied. (median age-49 years; range-23-84 and male: female 9:1). 182 had Ca oral tongue, followed by buccal-mucosa (53), alveolus (63), retromolar-trigone (14), hard palate (5) and floor of mouth (1). Volumetric-modulated arc therapy(VMAT) was used in 340 and 3-dimensional Conformal RT(3DCRT)-178, with median-dose 60Gy/30# at 2Gy/#. 106-ENE+ve (79 microscopic, 27-major) and 176-PNI+ve (147-intratumoral, 29-extratumoral). Disease progressed in 180/518 (118 locoregional, 62-distant), 303-locoregionally-controlled, 24-lost to follow-up after RT and 10-didn’t complete RT. Median follow-up period-17 months. Overall median DFS-39 months (range-33.4-44.5) and 2-year OS-96%(median OS not reached). DFS without (or non-applicable) ENE-40.8 months(range-36.7-44.8), ENE≤2mm-13.1 months(range-9.7-16.5), ENE>2mm-10.4 months(range-7.7-13) p<.001; without PNI-42.7 months(range-36-50), intratumoral-33.8 months(range-18.8-48.8), extratumoral-21.7 months(range-15.5-27.9) p-.024. 2-year OS without (or non-applicable) ENE-95%, ENE≤2mm-72%, ENE>2mm-76%, p-<.001; without PNI-90%, intratumoral-88%, extratumoral-95%, p-.47. p value for DFS and OS with ENE≤2mm vs >2mm-.96 and .99; for intra vs extratumoral PNI-.43 and .57 respectively. No significant correlation was found between extent of ENE and PNI with type of progression- locoregional or distant. Results:

Conclusion:

ENE and PNI have significant implication on survival outcomes and recurrence, but their extent is not associated with any worsening of survival outcomes or the type of progression.

Keywords: Adjuvant radiotherapy, perineural invasion, ENE

References:

1.Cheng HS, Liu SA, Lin JC. Survival outcome and prognostic factor analyses in early tongue cancer patients treated with surgery alone. Ther Radiol Oncol [Internet]. 2020 Jun 30 [cited 2023 Oct 29];4(0). Available from: https://tro.amegroups.org/article/view/5990