ESTRO 2024 - Abstract Book

S1413

Clinical - Head & neck

ESTRO 2024

Purpose/Objective:

The aim of the study is to analyze the effectiveness of adjuvant radiotherapy (RT) or radio-chemotherapy (RCHT) in patients with squamous cell carcinoma (SCC) of the oral tongue (OTC) after primary surgery. Prognostic factors influencing the effectiveness of this treatment has been also identified.

Material/Methods:

Between 2002 and 2018 in the National Research Institute of Oncology in Gliwice (Poland) 174 patients with SCC of OTC were treated surgically with adjuvant RT alone (72%) or combined with chemotherapy (28%). Median age of the patients was 57 years (range 29-88) and majority of patients (72%) had smoked. Distribution of pathological stage of disease was as follows: pI - 14%, pII – 12%, pIII - 34% and pIV - 40%. Neck lymph nodes were involved by cancer (pN+) in 52% of patients and between them 43% had extracapsular cancer extension (pECE+). Probabilities of overall survival (OS), local control (LC), nodal control (NC) were estimated by Kaplan-Meier method and were compared by log-rank test. Multivariate analysis was used to evaluate the impact of clinical and treatment parameters on treatment outcomes.

Results:

The 5-year overall survival (OS), locoregional control (LRC) and metastasis-free survival (MFS) rates were: 58%, 80% and 84%, respectively. The 5-year LRC was significantly higher for women (88% vs 77%, p=0.03). Surgical radicality plays a crucial role in LRC rates - among patients with R0 resection compared to those with R1 resection, 5-year LRC was 85% vs 66% p=0,009, and for free surgical margins above 5mm compared to involved, 92% vs 74%, p=0,01. According to pathological staging 5-year LRC was 92% for stages pI-II and 80% for stages pIII-pIV (p=0,03). Among the histopathological features, the most significant factors that worsen prognosis were the lymph nodes involvement (5-year LRC 73% vs 88%, p=0,007) and the presence of neuroinvasion (5-year LRC 61% vs 85%, p=0,006). Median radiotherapy treatment time (RTT) was 47 days and for the patients with RTT <=45 days 5-year LRC was 88% while for RTT >45 days – 71% (p=0,005). The multivariate analysis showed that neuroinvasion was the only independent prognostic factor of shorter LRC (p=0,03).

Conclusion:

That retrospective study is based on the experiences of oral tongue cancer combined treatment realized in one institution over the past 17 years. It is clear that such a long time has allowed many diagnostic and treatment approaches tried to achieve the best solutions. The obtained results confirm that the histopathological features of SCC, especially neuroinvasion, and the duration of radio-oncological treatment have a significant impact on prognosis. Extending duration of combined treatment negatively affects locoregional control.

Keywords: oral tongue cancer, radiotherapy, neuroinvasion