ESTRO 2024 - Abstract Book

S1328

Clinical - Head & neck

ESTRO 2024

Rajiv Gandhi Cancer Institute and Research Centre, Radiation Oncology, New Delhi, India

Purpose/Objective:

Several studies have shown anterior commissure involvement to be a poor prognostic factor in patients with early glottic cancer (EGC). However, literature on impact of posterior commissure (PC) involvement on treatment outcome is sparse, owing to its less frequent occurrence in EGC. PC as an epicenter of tumour and as primary site of tumour is even more uncommon. If PC is found to be involved in EGC it tends to extend posteriorly eventually involving vocal process. Occasionally arytenoid cartilage’s internal surface also gets involved. The aim of current study is to determine prognostic impact of PC involvement in EGC treated with radical radiotherapy (RT).

Material/Methods:

It was a retrospective study in which newly diagnosed 234 patients with EGC (clinical T1 or T2 without nodal involvement) were included. They were divided into two groups, one group with 31 patients with PC involved and another group with remaining 203 patients with no PC involvement. Data was collected from the patient’s charts for comparison between baseline patients and disease related characteristics between the two groups. Patients were either treated with two-dimenstional RT or intensity modulated RT to a radical dose with conventional fractionation. The end points for this study were loco-regional control (LRC) and overall survival (OS). LRC and OS were computed with Kaplan-Meier curve with log-rank test for comparison between the two groups. Univariate analysis and Multivariate Cox proportional hazards regression analysis was performed to estimate the impact of known relevant prognostic factors on LRC and OS.

Results:

Patients and disease related characteristics were comparable between the two groups. The median follow up of PC involvement group was 62.52 months and 55.12 months in PC uninvolved group. Median LRC in PC uninvolved group had not reached till the time of analysis. Median LRC in PC involved group was 121.20 months (95% confidence interval [CI] 58.34 – 148.55). This difference in LRC was statistically non-significant (p = 0.208). Median OS in PC uninvolved group was had not reached till the time of analysis. Median OS for PC involved group was 151.07 months (95% confidence interval [CI] 51.05 – 177.43). This difference in OS was statistically non-significant (p = 0.388). Univariate analysis showed no impact of PC involvement on LRC or OS as shown in Table below.

Loco-regional control

Overall survival

Overall survival

Univariate analysis

Univariate analysis

Multivariate analysis

HR (95% CI);

p

Factors

Groups

HR (95% CI);

p value

HR (95% CI); p value

value

0.788 (0.112 – 1.232); p value = 0.532 (1.187 – 4.256); p value = 0.039 2.244

1.298 (0.729 – 1.019); p value 0.211

Continuous

Age (in years)

3.142 (1.109 – 5.650); p value = 0.021

2.109 (1.439 – 6.502); p value = 0.009

Gender

Male