Head and neck cancer.

Background Patients with head-and-neck cancers who are free of disease after local therapy remain at high risk for both recurrent and second primary tumors Retinoids have proved efficacious in the treatment of premalignant oral lesions and are promising agents for the prevention of epithelial carcinogenesis Methods We prospectively studied 103 patients who were disease-free after primary treatment for squamous-cell cancers of the larynx, pharynx, or oral cavity After completion of surgery or radiotherapy (or both), these patients were randomly assigned to receive either isotretinoin (13-cis-retinoic acid) (50 to 100 mg per square meter of body-surface area per day) or placebo, to be taken daily for 12 months Results There were no significant differences between the two groups in the number of local, regional, or distant recurrences of the primary cancers However, the isotretinoin group had significantly fewer second primary tumors After a median follow-up of 32 months, only 2 patients (4

https://www.nejm.org/doi/pdf/10.1056/NEJM199009203231205

Prevention of second primary tumors with isotretinoin in squamous-cell carcinoma of the head and neck.

Most head and neck cancers are derived from the mucosal epithelium in the oral cavity, pharynx and larynx and are known collectively as head and neck squamous cell carcinoma (HNSCC). Oral cavity and larynx cancers are generally associated with tobacco consumption, alcohol abuse or both, whereas pharynx cancers are increasingly attributed to infection with human papillomavirus (HPV), primarily HPV-16. Thus, HNSCC can be separated into HPV-negative and HPV-positive HNSCC. Despite evidence of histological progression from cellular atypia through various degrees of dysplasia, ultimately leading to invasive HNSCC, most patients are diagnosed with late-stage HNSCC without a clinically evident antecedent pre-malignant lesion. Traditional staging of HNSCC using the tumour–node–metastasis system has been supplemented by the 2017 AJCC/UICC staging system, which incorporates additional information relevant to HPV-positive disease. Treatment is generally multimodal, consisting of surgery followed by chemoradiotherapy (CRT) for oral cavity cancers and primary CRT for pharynx and larynx cancers. The EGFR monoclonal antibody cetuximab is generally used in combination with radiation in HPV-negative HNSCC where comorbidities prevent the use of cytotoxic chemotherapy. The FDA approved the immune checkpoint inhibitors pembrolizumab and nivolumab for treatment of recurrent or metastatic HNSCC and pembrolizumab as primary treatment for unresectable disease. Elucidation of the molecular genetic landscape of HNSCC over the past decade has revealed new opportunities for therapeutic intervention. Ongoing efforts aim to integrate our understanding of HNSCC biology and immunobiology to identify predictive biomarkers that will enable delivery of the most effective, least-toxic therapies. Head and neck squamous cell carcinomas (HNSCCs) originate from the mucosal epithelium in the oral cavity, pharynx and larynx and are commonly associated with viral infection and tobacco use. This Primer provides an overview of the epidemiology, pathogenesis and treatment of HNSCCs of different aetiologies and the effects of the cancer and its treatment on patient quality of life.

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Head and neck squamous cell carcinoma

Chemoprevention is the use of pharmacologic or natural agents that inhibit the development of invasive cancer either by blocking the DNA damage that initiates carcinogenesis or by arresting or reversing the progression of premalignant cells in which such damage has already occurred. Recent advances in our understanding of the mechanisms of carcinogenesis have led to the synthesis of new drugs that can inhibit tumor development in experimental animals by selective action on specific molecular targets, such as the estrogen, androgen, and retinoid receptors or inducible cyclooxygenase. Several of these agents (including tamoxifen, 13-cis-retinoic acid, retinyl palmitate, and an acyclic retinoid) are clinically effective in preventing the development of cancer, particularly in patients who are at high risk for developing second primary tumors after surgical removal of the initial tumor.

https://science.sciencemag.org/content/sci/278/5340/1073.full.pdf

Recent advances in chemoprevention of cancer.

Retinoids have a reputation for being both detrimental and beneficial: they are teratogens, but they also have tumour-suppressive capacity. Cell biology and genetics have significantly improved our understanding of the mechanisms that underlie the anti-proliferative action of retinoids. Recent elucidation of the pathways that are activated by retinoids will help us to exploit the beneficial aspects of this powerful class of compounds for cancer therapy and prevention.

The promise of retinoids to fight against cancer

13-cis-Retinoic acid has been reported to be effective in treating oral leukoplakia. We randomly assigned 44 patients with this disease to receive 13-cis-retinoic acid (24 patients) or placebo (20), 1 to 2 mg per kilogram of body weight per day for three months, and followed them for six months. There were major decreases in the size of the lesions in 67 percent (16 patients) of those given the drug and in 10 percent (2 patients) of those given placebo (P = 0.0002); dysplasia was reversed in 54 percent (13 patients) of the drug group and in 10 percent (2 patients) of the placebo group (P = 0.01). The clinical response to the drug correlated with the histologic response in 56 percent (9 of 16) of the patients evaluated. Relapse occurred in 9 of 16 patients two to three months after treatment ended. The toxic effects of the drug were acceptable in all but two patients. Cheilitis, facial erythema, and dryness and peeling of the skin were common; conjunctivitis and hypertriglyceridemia also occurred. All adverse reactions could be reversed by reducing the dose or temporarily discontinuing the drug. We conclude that 13-cis-retinoic acid, even in short-term use, appears to be an effective treatment for oral leukoplakia and has an acceptable level of toxicity.

R Bell

Papers

13-cis-retinoic acid in the treatment of oral leukoplakia.