AHNS Series: Do you know your guidelines?Principles of radiation therapy for head and neck cancer: A review of the National Comprehensive Cancer Network guidelines.

This article is a continuation of the "Do You Know Your Guidelines" series, an initiative of the American Head and Neck Society's Education Committee to increase awareness of current best practices pertaining to head and neck cancer. The National Comprehensive Cancer Network guidelines for radiotherapy in the treatment for head and neck cancers are reviewed here in a systematic fashion according to site and stage. These guidelines outline indications for primary and adjuvant treatment, as well as general principles of radiotherapy. © 2016 Wiley Periodicals, Inc. Head Neck 38: 987-992, 2016.

External-beam radiotherapy for differentiated thyroid cancer locoregional control: A statement of the American Head and Neck Society.

The use of external-beam radiotherapy (EBRT) in differentiated thyroid cancer (DTC) is debated because of a lack of prospective clinical data, but recent retrospective studies have reported benefits in selected patients. The Endocrine Surgery Committee of the American Head and Neck Society provides 4 recommendations regarding EBRT for locoregional control in DTC, based on review of literature and expert opinion of the authors. (1) EBRT is recommended for patients with gross residual or unresectable locoregional disease, except for patients <45 years old with limited gross disease that is radioactive iodine (RAI)-avid. (2) EBRT should not be routinely used as adjuvant therapy after complete resection of gross disease. (3) After complete resection, EBRT may be considered in select patients >45 years old with high likelihood of microscopic residual disease and low likelihood of responding to RAI. (4) Cervical lymph node involvement alone should not be an indication for adjuvant EBRT.

Phosphorus-32, a clinically available drug, inhibits cancer growth by inducing DNA double-strand breakage.

Radioisotopes that emit electrons (beta particles), such as radioiodine, can effectively kill target cells, including cancer cells. Aqueous 32P[PO4] is a pure beta-emitter that has been used for several decades to treat non-malignant human myeloproliferative diseases. 32P[PO4] was directly compared to a more powerful pure beta-emitter, the clinically important 90Y isotope. In vitro, 32P[PO4] was more effective at killing cells than was the more powerful isotope 90Y (P ≤ 0.001) and also caused substantially more double-stranded DNA breaks than did 90Y. In vivo, a single low-dose intravenous dose of aqueous elemental 32P significantly inhibited tumor growth in the syngeneic murine cancer model (P ≤ 0.001). This effect is exerted by direct incorporation into nascent DNA chains, resulting in double-stranded breakage, a unique mechanism not duplicatable by other, more powerful electron-emitting radioisotopes. 32P[PO4] should be considered for human clinical trials as a potential novel anti-cancer drug.