Proton therapy for head and neck carcinoma

Proton therapy for head and neck carcinoma

Proton therapy for head and neck carcinoma

Proton particles do not deposit exit dose, which allows proton therapy to spare normal tissues distal to the tumor target. This is particularly useful for treating head and neck tumors because of the anatomic constraints encountered in nearly all cancers in this region.

Studies comparing proton versus photon therapy have reported significantly lower rates of acute > grade 2 dysphagia, dysgeusia, mucositis and nausea favoring proton therapy. Additionally, proton therapy resulted in prevention of weight loss, lower opioid use, and less gastrostomy tube dependence.

Benefits of proton therapy for head and neck cancers

Proton therapy enables the delivery of aggressive local therapy. Proton therapy for paranasal sinus tumors reported improved local control and survival. A recent meta-analysis also reported that proton therapy was superior to IMRT in both disease-free survival (72% vs. 50% at 5 years) and tumor control (81% vs. 64%).
The dosimetric advantage unique to proton therapy translates into toxicity reduction. Studies comparing proton versus photon therapy have reported significantly lower rates of acute > grade 2 dysphagia, dysgeusia, mucositis
and nausea favoring proton therapy. Additionally, proton therapy resulted in prevention of weight loss, lower opioid use, and less gastrostomy tube dependence.

For recurrent head and neck cancer requiring reirradiation, proton therapy is able to maximize a focused dose of radiation to the tumor while minimizing dose to
surrounding tissues which results in a minimal acute toxicity profile, even in patients who have received multiple prior courses of radiotherapy. Proton therapy is ideally suited for recurrent patients who are at risk of serious complications due to the high cumulative doses to critical structures.

Reference to ongoing studies

There are three phase II and III studies registered with Clinicaltrials.gov. MD Anderson Cancer Center leads a phase II/III randomized trial comparing IMPT and IMRT for oropharyngeal cancer. This study will enroll 360 patients. The primary measure sets the rates and severity of late grade 3-5 toxicity between the two modalities.

MGH leads a phase II study to investigate if proton therapy results in equivalent or improved local control rate with similar or lower toxicity compared to IMRT in treating locally advanced sinonasal malignancy. With 90 patients to enroll, the trial will measure primarily local control at 2 years, and the secondary endpoints including vision preservation, Quality of Life (QoL) and neurocognitive function at 5 years.

The Technische Universität Dresden is conducting a study looking into proton re-irradiation for patients with head and neck cancer in a previously (> 50 Gy) irradiated field. The trial will measure late toxicity as the primary endpoint, as
well as survival and QoL as the secondary endpoints.

The expert's perspective
Dr. Alexander Lin is the Chief of the Head and Neck Cancer Radiotherapy Section and the Medical Director of the Roberts Proton Therapy Center. He addresses challenges specific to standard head and neck radiation, and cites specific scenarios in which proton therapy may be beneficial. “The head and neck region contains many vital organs that perform critical everyday functions.Often, these organs are located very close to areas that require treatment with radiotherapy.

For many patients who are cured, they live long-term with the after effects of treatment, often with a negative impact on functions such as speech, swallowing, and general quality of life. For other patients, there are limitations on how much radiation can be safely delivered, limiting the odds of obtaining a cure. It is here that proton therapy has tremendous potential. By reducing normal tissue exposure to radiation, proton therapy can minimize longterm toxicity, ensuring excellent post-treatment quality of life. For cancers that are untreatable with standard techniques, proton therapy can potentially deliver the higher doses of radiation needed to obtain cure while maintaining patient safety.” 

 

Useful documents, white papers and publications

Learn more about the benefits of proton therapy  and find the latest studies in this IBA white paper.

IBA White paper: Treating head and neck carcinoma with proton therapy

General overview of the current practice, opportunities and challenges in head and neck carcinoma treatment