ESTRO 2024 - Abstract Book

S1257

Clinical - Head & neck

ESTRO 2024

The median RT duration was 44 days (IQR: 41-47 days). Elective contralateral nodal irradiation was done in 63 patients (37 Tongue, 23 Buccoalveolar). Concurrent chemotherapy was administered in 60 (41.9%) patients. The median follow-up of surviving patients was 20 months (IQR: 10-32). The 2-year Locoregional Control, Disease-Free Survival, and Overall Survival (Figure) were 73.9% (95% CI: 64.9-82.9), 64.8 (95% CI: 55.4-74.2), and 74.3% (95% CI: 64.7-83.9) respectively. Overall there were 44 (30.8%) recurrences, of which 32 (22.4%) were locoregional failures, 21 (14.7%) distant failures, and 7 (4.9%) combination of locoregional and distant failures (Table). There were 3 contralateral nodal failures in the elective nodal regions (2 tongue cancer patients in elective RT volume and one retromolar trigone patient irradiated unilaterally). Factors significant for inferior disease-free survival on the univariate analysis included higher pT stage (p=0.05), higher pN stage (p=0.001), ENE (p<0.001), Perineural invasion (p=0.001) and higher grade (p=0.01). Flap-related complications after RT completion were seen in 8 patients (4 dehiscence, 2 necrosis, and 2 infections), all of which could be managed conservatively. RTOG Acute ≥ grade 3 dermatitis, mucositis, and dysphagia were seen in 4 (2.8%), 7 (4.9%), and 38 (26.6%) patients, respectively. RTOG Late ≥ grade 3 subcutaneous fibrosis, xerostomia, and dysphagia were seen in 2 (1.4%), 5 (3.5%), and 5 (3.5%) patients, respectively.

Conclusion:

The locoregional failure rates, survival outcomes, and toxicity rates were comparable to outcomes of adjuvant conventional RT and IMRT in OCSCC in literarture. The entire flap need not be intentionally covered in the target volume in adjuvant IMRT with a pedicled flap. The incidence of contralateral nodal failure remains low in well lateralized bucco-alveolar complex tumors. Elective contralateral nodal irradiation should be considered only for those with a heavy nodal burden at ipsilateral level Ib, in tumors crossing the midline or in tumors having high propensity for contralateral lymph nodal involvement.