A Study to Evaluate the Efficacy of Purely Accelerated 6 Fraction-per-Week Radiotherapy in Post-Operative Oral Cavity Squamous Cell Carcinoma

Purpose/Objective(s)

To determine the efficacy of pure modestly accelerated fractionated radiotherapy (PM-ART) in postoperative setting in patients of squamous cell carcinoma of oral cavity (OCSCC) in terms of Locoregional control (LRC), Overall survival (OS), and Disease-free survival (DFS).

Materials/Methods

40 post-operative OCSCC patients with one or more high risk features (pT3 or higher, close margins, DOI >10 mm, lymphovascular invasion, perineural invasion, >1 node positive, extra capsular extension) were treated between May 2015 and July 2016 with adjuvant PM-ART alone (60Gy in 30 fractions @ 2Gy per fraction; 6 fractions per week, over 5 weeks by three-dimensional conformal technique on a linear accelerator). Primary endpoint of the present study was to evaluate the efficacy of PM-ART and secondary endpoint was late toxicity assessment.

Results

40 patients were followed up till July 2021 of which four were lost to follow up. At a Median follow up of 45.5 months (range 4-70 months), 3-year LRC was 75%. Out of 40 patients, 17 patients had expired at the time of analysis of which 3 deaths occurred due to other competing causes after the completion of RT. DFS rate at 3 years was 64.8% and median DFS was 64.2 months; 3-year OS rate was 59%, and median OS was not yet reached. 23 patients were available for evaluation of late toxicity at the time of analysis. Xerostomia and subcutaneous fibrosis were the main late toxicities observed as follows – xerostomia grade 2 in 2 patients (9%), grade 1 in 11 patients (48%), subcutaneous fibrosis grade 2 was seen in 2 patients (9%), and grade 1 in 12 patients (52%). There was no grade 3 or higher late toxicities recorded.

Conclusion

Intensification of treatment by using PM-ART (6 fractions per week) was found to have good locoregional control rates and survival outcomes with acceptable late toxicities and needs to be evaluated in the context of randomized controlled trials to validate the findings.