Proton Therapy for Major Salivary Gland Cancer: Clinical Outcomes

Abstract

Purpose To report clinical outcomes in terms of disease control and toxicity in patients with major salivary gland cancers (SGCs) treated with proton beam therapy. Materials and Methods Clinical and dosimetric characteristics of patients with SGCs treated from August 2011 to February 2020 on an observational, prospective, single-institution protocol were abstracted. Local control and overall survival were calculated by the Kaplan-Meier method. During radiation, weekly assessments of toxicity were obtained, and for patients with ≥ 90 days of follow-up, late toxicity was assessed. Results Seventy-two patients were identified. Median age was 54 years (range, 23-87 years). Sixty-three patients (88%) received postoperative therapy, and nine patients (12%) were treated definitively. Twenty-six patients (36%) received concurrent chemotherapy. Nine patients (12%) had received prior radiation. All (99%) but one patient received unilateral treatment with a median dose of 64 GyRBE (relative biological effectiveness) (interquartile range [IQR], 60-66), and 53 patients (74%) received intensity-modulated proton therapy with either single-field or multifield optimization. The median follow-up time was 30 months. Two-year local control and overall survival rates were 96% (95% confidence interval [CI] 85%-99%) and 89% (95% CI 76%-95%], respectively. 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. Conclusion Proton beam therapy 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.

Use of Chamomile Infusion to Mitigate Radiotherapy-Induced Dry Desquamation in Head and Neck Cancer Patients

“…Although the radiotherapy techniques have been advancing with the objective of minimizing adverse effects, such as Intensity-Modulated Radiotherapy (IMRT) and proton beam therapy, patients with head and neck cancer are at a higher risk of developing severe RD as they have the skin very close to the target volumes. 20 …”

“…Although the radiotherapy techniques have been advancing with the objective of minimizing adverse effects, such as Intensity-Modulated Radiotherapy (IMRT) and proton beam therapy, patients with head and neck cancer are at a higher risk of developing severe RD as they have the skin very close to the target volumes. 20 The presence of moist desquamation considered a severe RD grade causes suffering to the patient, as it is accompanied by symptoms such as pain and discomfort, in addition to increasing the risk of infection. 21 After the occurrence of any RD skin change, the skin exposed to ionizing radiation tends to evolve to moist desquamation without the use of interventions for its management.…”

A narrative review of intensity-modulated proton therapy for head and neck cancer

“…Hanania et al identified 72 MSGT patients-53 (74%) of whom were treated with IMPT-and reported the 2-year LC and OS rates of 96% and 89%, respectively. The most common toxicity grade-3 was radiation dermatitis (21%), with no late-grade ≥3 adverse events were observed (50).…”

The evolving landscape of salivary gland tumors

“…More recently, proton therapy has been used in the treatment of SGCs, although with a predominate focus of reducing toxicity of treatment. Single‐institution reports describe minimal toxicity associated with proton therapy in both the definitive and adjuvant settings and very promising locoregional control 66,67 . Proton therapy may be specifically beneficial in patients who have either extensively locally invasive tumors or perineural invasion involving the skull base, which may be in close proximity to critical normal structures, such as the brainstem, optic nerves, or temporal lobe.…”

“…Single-institution reports describe minimal toxicity associated with proton therapy in both the definitive and adjuvant settings and very promising locoregional control. 66,67 Proton therapy may be specifically beneficial in patients who have either extensively locally invasive tumors or perineural invasion involving the skull base, which may be in close proximity to critical normal structures, such as the brainstem, optic nerves, or temporal lobe. However, no prospective evidence exists to support the use of proton therapy in this setting.…”