Proton Therapy: How It Is Beneficial For Nasopharyngeal Cancer

Medically reviewed by Dr Johann Tang, Senior Consultant Radiation Oncologist

Nasopharyngeal cancer, or nose cancer, occurs in the cells lining the area behind the nose and just above the back of the throat. It is one of the more common cancers in Singapore, with around 300 new cases diagnosed yearly. Nasopharyngeal cancer treatment options often include a multimodality approach involving radiation therapy and systemic chemotherapy.

Nasopharyngeal cancer presents a unique treatment challenge for radiation oncologists. This is because the tumours typically involve complex anatomic structures near critical organ systems like the brainstem, temporal lobes, oral cavity, mandible, and optic structures. Moreover, radiation therapy is not without toxicity and may carry side effects for the patient. 

Given the critical organs present in these areas, more conformal and precise treatment delivery may be more beneficial. The unique properties of proton therapy make it suitable for treating tumours in anatomically complex areas, such as nasopharyngeal cancer, enabling disease control while showing promise for acute and chronic toxicity reduction.

How Proton Therapy Is Used To Treat Nasopharyngeal Cancer

Proton therapy is often recommended to treat tumours that have not spread and are near vital parts of the body, like nasopharynx cancer. Compared to conventional radiation treatment, protons possess unique properties that enable oncologists to better deliver the radiation doses to the tumor whilst avoiding the normal surrounding tissue organs, thus sparing more of the surrounding healthy tissue. 

Learn More: Is Proton Therapy Safer Than Traditional Radiotherapy?

Case Study 1

A phase 2 trial conducted using a combined proton and photon approach in 23 patients with locally advanced nasopharyngeal cancer reported no local or regional relapse at a median follow-up of 28 months, with only two patients developing distant metastases.

Meanwhile, two-year disease-free survival (DFS) and overall survival (OS) rates were 90% and 100%, respectively, with no grade 4 or 5 toxicities. The most common grade 3 or higher toxicities reported were weight loss and hearing loss (38% and 29% of patients, respectively), with no reports of grade 3 xerostomia.

Case Study 2

In a case-match control study conducted by Holliday et al. regarding intensity-modulated proton therapy and intensity-modulated photon therapy, the findings reported a lower NG-tube placement frequency with proton therapy than radiation therapy – 20% compared to 65% – which could be due to the lower mean radiation dose delivered to the oral cavity.

Case Study 3

A retrospective study of patients treated with proton therapy versus radiation therapy for nasopharyngeal, nasal cavity, or paranasal sinus cancers overseen by McDonald and colleagues found that patients require lower opioid use to manage pain after treatment, as well as a lower NG-tube dependence rate.

Based on the current findings on the use of proton beam therapy for nasopharyngeal cancer, there may be evidence to suggest that proton therapy is more feasible and safe in reducing the side effects of radiation therapy while maintaining local tumour control. 

If you are interested in learning more about proton therapy and its suitability in treating nasopharyngeal cancer, do not hesitate to consult Dr Johann Tang. As a radiation oncologist in Singapore for over two decades, Dr Tang has experience treating nasopharyngeal cancer patients with traditional radiation therapy and proton therapy.