KEY POINTS
- This single-institution retrospective series included 34 oral cavity squamous cell carcinoma patients undergoing surgery with immediate free-flap reconstruction followed by postoperative RT or chemoradiotherapy between 2018 and 2024.
- Instead of intentionally irradiating the entire reconstructed flap, the high-risk CTV concentrated on the native tissue–flap junction plus a 10-mm isotropic margin, modified for anatomical barriers. High-risk PTV received 60–66 Gy in 30–33 fractions, while low-risk PTV received 50 Gy in 25 fractions.
- After a median 44 months of follow-up, only 3 patients (8.8%) developed local recurrence: two were in-field and one marginal. No recurrence occurred within the free flap itself; two local failures involved the native tissue–flap junction.
- Three-year locoregional relapse-free survival, DFS and OS were 87.0%, 74.8% and 81.4%, respectively. Among five patients with any locoregional failure, four had pN2 disease and three had close margins.
- Despite the flap-sparing strategy, the reconstructed tissue still received substantial incidental dose: median flap mean dose was 52.5 Gy and median maximum dose 62.9 Gy, reflecting its proximity to postoperative target volumes.
- Acute grade ≥2 oral mucositis occurred in 50.0%, dysphagia in 29.4%, dermatitis in 14.7% and xerostomia in 8.8%. Three patients developed grade 3 mucositis; late grade 3 events included two cases of osteoradionecrosis and two cases of dysphagia requiring long-term rehabilitation/tube feeding.
- Importantly, no flap necrosis, dehiscence or infection was reported. The authors nevertheless caution against routine flap omission when residual disease, tumor extension into the flap interface, multifocal positive/close margins or uncertain operative anatomy create higher intraflap risk.
CLINICAL TAKEAWAY
These data support the concept that postoperative oral cavity CTVs may often be centered on the high-risk native tissue–flap interface rather than automatically covering the entire flap. But with only 34 patients and no controlled comparison, flap sparing should remain anatomy- and risk-adapted rather than becoming a blanket contouring rule.