The management of head and neck tumors with high technology radiation therapy

Abstract

Squamous cell carcinoma is responsible for 90% of the head and neck cancers affecting over 600,000 people worldwide. Radiation therapy, surgery and chemotherapy are the most important treatment modalities in head and neck squamous cell carcinoma. The aim of this review is to summarize the recent innovations in head and neck radiation therapy, which intends to appreciate the cutting-edge intensity-modulated radiation therapy strategies to mitigate long-term toxicities and evaluate promising technologies in the field as adaptive treatment, dose painting and proton therapy.

Keywords:

• Head and neck cancer
• quality of life
• radiation therapy
• toxicity
• treatment

Key issues

• Intensity-modulated radiation therapy (IMRT) in head and neck neoplasm implies intensity variation of the beam, which promotes a tight isodose to irregular structure shape. As a result of this conformity, assuring immobilization and localization is essential.

• IMRT has proved to be noninferior when compared to conformal external beam radiation in oncological end points in head and neck neoplasms.

• Quality of life (QoL) is a major oncological end point in head and neck cancer. Dysphagia may play a more important role than xerostomia on QoL.

• Sparing pharynx constrictors and glottis-supraglottic larynx might play an important role in reducing swallowing toxicity rates and consequently improving QoL.

• Xerostomia can lead to several other symptoms and toxicities besides oral discomfort, such as sleep disturbance, speech difficulty, dysphagia, increased risk of caries and infection. Attention must be paid because IMRT and parotids dose restriction allow greater salivary flow recovery, reduced patient-reported xerostomia and improved QoL.

• Submandibular sparing could aggregate further improvement to parotid sparing strategy in salivary preservation.

• Voice and speech are mostly affected in the first 2 months after chemoradiation, but majorly returns to baseline after 12 months. Radiation dose to the glottis appears to be an independent predictor for voice quality and speech impairment.

• Dose painting relates to steering an extra boost to sites of expected higher radioresistance as pointed out by functional imaging.

• Adaptive planning radiation therapy (ART) refers to the generation of a new adapted plan that accounts for structures shift along radiation therapy and aims to improve target coverage and reduce unnecessary OAR dose. Adaptive planning radiation therapy appears to add further benefit to IMRT in OAR spare; however, more robust data are needed.

• Proton therapy presents a distinct pattern of dose distribution by releasing a great part of energy at a certain depth. Proton therapy may be superior in sparing OAR when compared to photon IMRT, however, lacks solid prospective clinical data.

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.