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Long-Term Outcomes Following Radiotherapy for Pediatric Salivary Gland Tumors
Etzer M Augustin1, Daniel J Indelicato1, Julie A Bradley1
1Department of Radiation Oncology, University of Florida College of Medicine, Jacksonville, Florida, USA.
Insights
Proton therapy (PT) for pediatric salivary gland tumors, using lower doses and smaller margins, achieved excellent survival (96%) and local control (94%) with limited toxicity.
Area of Science:
- Pediatric Oncology
- Radiation Oncology
- Head and Neck Surgery
Background:
- Pediatric salivary gland tumors require specialized treatment to minimize long-term effects on developing anatomy.
- Institutional guidelines advocate for reduced radiation doses, smaller margins, and proton therapy (PT) for pediatric patients.
- This study evaluates the outcomes of this conservative pediatric management approach.
Purpose of the Study:
- To report the outcomes of a pediatric management strategy for salivary gland tumors.
- To assess the efficacy and toxicity of proton therapy in children with salivary gland tumors.
- To evaluate the impact of conservative neck management and moderate-dose PT on disease control and patient safety.
Main Methods:
- Retrospective review of 31 pediatric patients treated with PT between 2006 and 2023.
- Common histologies included mucoepidermoid carcinoma, acinic cell carcinoma, and adenoid cystic carcinoma.
- Treatment involved proton therapy with specific planning target volumes (GTV, CTV1, CTV2) and dose regimens, alongside selective neck dissections in select cases.
Main Results:
- Median follow-up of 7.5 years demonstrated high overall survival (96%) and local control (94%).
- No nodal recurrences were observed.
- Acute toxicities were generally mild (mucositis, dermatitis); late toxicities primarily affected the auditory system (hearing loss, otitis media, osteonecrosis).
Conclusions:
- Conservative neck management combined with moderate-dose proton therapy to reduced volumes yields excellent long-term disease control in pediatric salivary gland tumors.
- This approach results in limited toxicity, preserving quality of life for young patients.
- The findings support the institutional guidelines for pediatric salivary gland tumor treatment.
Background:
In contrast to adult salivary gland tumors, our institutional guidelines utilize lower radiation doses, smaller target margins, and proton therapy (PT) to minimize radiation to children's developing skull base anatomy. Herein, we report outcomes of our pediatric management approach.
Procedures:
We identified 31 pediatric patients with salivary gland tumors treated with PT at our institution between 2006 and 2023. Most common histologies were mucoepidermoid carcinoma (n = 14), acinic cell carcinoma (n = 5), and adenoid cystic carcinoma (n = 5). Eight patients with radiographic lymphadenopathy underwent neck dissection prior to presentation, with selective dissections involving <4 nodal levels in 7/8 cases. The gross tumor volume (GTV) encompassed the residual tumor and tumor bed. Clinical target volume (CTV1), defined as GTV + 1 cm margin, received 50.4 Gy. Prophylactic nodal irradiation was administered to three patients. CTV2 equaled the GTV and was treated to a median total dose of 64.8 Gy (range, 61.2-70.8). Toxicity was assessed with CTCAE Version 5.0.
Results:
Median follow-up was 7.5 years (range, 1.2-15). Overall survival (OS) was 96%, and local control was 94%. There were no nodal recurrences. Acute toxicities were limited to mucositis requiring opioids and transient Grade 3 dermatitis. The most serious late toxicity involved the auditory system, including three patients requiring hearing aids, one with chronic otitis media, one with osteonecrosis of the mastoid, and one with external canal stenosis. There was neither Grade 4 toxicity nor second malignancy.
Conclusions:
Conservative neck management and moderate-dose PT delivered to smaller volumes resulted in excellent long-term disease control and limited toxicity in children with common salivary gland tumors.
