A study by the MD Anderson group reported clinical outcomes of 72 patients with major salivary gland cancers (SGCs) treated by PBT. Sixty-three patients (88%) received postoperative therapy, and nine patients (12%) were treated definitively. All (99%) but one patient received unilateral treatment with a median dose of 64 GyRBE. With a median follow-up time of 30 months, this study reported the two-year local control and overall survival rates were 96% and 89%.
Radiation dermatitis was the predominant grade-3 toxicity (seen in 21% [n = 15] of the patients), and grade ≥ 2 mucositis was rare (14%; n = 10 patients). No late-grade ≥ 3 toxicities were reported. The authors concluded that PBT for treatment of major SGCs manifests in low rates of acute mucosal toxicity. In addition, the current data suggest a high rate of local control and minimal late toxicity.