Toxicities and clinical outcome of adjuvant dysphagia optimized versus standard intensity-modulated radiotherapy for post-operative oral cavity cancers: A prospective comparative study.

BACKGROUND

We prospectively assessed acute and late toxicity in post-operative oral cavity squamous cell carcinoma (PO-OCSCC) treated with adjuvant dysphagia optimized intensity-modulated radiotherapy (Do-IMRT) versus standard IMRT (S-IMRT).

MATERIAL AND

METHODS

Fifty-six patients of PO-SCC without indications of concurrent chemotherapy were alternatively allocated to adjuvant Do-IMRT (n = 28) versus S-IMRT (n = 28) arms. High- and low-risk planning target volume received 60 and 54 Gy, respectively, in 30 fractions over 6 weeks. Dysphagia aspiration-related structures (DARS) were contoured in both arms. While dosimetric constraints were given in Do-IMRT arm, doses to DARS were only observed without dose constraints in S-IMRT arm. Acute and late toxicity were assessed by common terminology criteria for adverse events (CTCAE) v5.0 and RTOG criteria, respectively.

RESULTS

The primary site of disease was buccal mucosa (64% vs. 53%) and oral tongue (21% vs. 32%), in Do-IMRT and S-IMRT, respectively. The mean doses to DARS was significantly less with Do-IMRT (all p < 0.001) as compared to S-IMRT. Median follow-up was 24.2 months. Grade ≥2 oral pain was less in the Do-IMRT arm (50% vs. 78.6%, p = 0.05). Grade ≥2 late dysphagia at 2 years were significantly less in Do-IMRT arm (0% vs. 17.9%, p = 0.016). Two-year locoregional control was 89.2% in Do-IMRT and 78.5% in S-IMRT (p = 0.261).

CONCLUSION

DARS can be spared in PO-OCSCC patients treated with Do-IMRT without compromising coverage of the target volumes. Limiting doses to DARS leads to lesser acute and late toxicity without compromising locoregional control.