Quantifying the Immense Burden of OPMDS and of Oral Cancer in South Asia: Time for Action

Abstract

Background: Cancer of head and neck is sixth most common malignancy worldwide https://www.ncbi.nlm.nih.gov/pubmed/27245686 . ∼90% are squamous cell carcinomas [HNSCC]. Of H&N sites, mouth is most common [∼300,373 cases pa, cf oropharynx ∼142,387; larynx ∼156,877; nasopharynx 86,691]. Across south Asia, cancer of lip & mouth [oral cancer: OSCC] is a serious public health problem. In many, it is the most common cancer among men, 5th/6th in women, second overall. Five year survival rates are < 50%. Treatment is devastating. It is difficult to get authorities and public to recognize the problem: this is not a “glamorous” cancer. Yet we know the major causes so most disease is preventable. In south Asia, the major causes are tobacco - mostly chewed, areca [erroneously called betel] nut, mostly as component of betel quid, and heavy alcohol use in a background of diets lacking adequate antioxidant vitamins/minerals. To this is added the global epidemic of human papillomavirus [HPV]-driven nonkeratinising squamous epithelial head/neck cancer, particularly in lymphoid tissues of Waldyer's ring. Though data vary by country, high-risk [hr]HPVs are likely associated with up to 30% of OSCC too. We need detailed local information, especially as hrHPV-driven SCC respond well to radio/chemotherapy. Next-generation molecular methods are now examining roles for fungi and bacterial consortia. Across Asia, most OSCC arise from long-standing changes in oral mucosa: oral potentially malignant disorders [OPMD]. Leukoplakia is commonest, though with lowest risk. Risk is greater in red or mixed red/white lesions. Oral submucous fibrosis is prevalent and devastating. It has a high rate of malignant transformation and causes immense suffering: burning mouth, taste disturbances and severe sclerosis of soft tissues resulting in restricted mouth opening. The major etiology is areca nut. There is genetic and inherited propensity: very young children encouraged to chew areca can be seriously affected. There are no truly successful treatments, be it surgery to relieve trismus, physiotherapy to improve mouth opening and dietary supplements with numerous antioxidants, most commonly curcumin. Strategy: Primary prevention is possible. Improve diet; no tobacco; no areca nut [we need a WHO Framework Convention on areca]: to nip in the bud a serious epidemic of HPV-related cancers, sexual hygiene and widespread vaccination of girls - in my opinion also of boys. Public education is key. Legal controls on tobacco, areca & alcohol are needed - a tremendous challenge especially for areca, given the ancient cultural importance of this masticatory in myriad forms. It is time for effective action. Outcomes: In India and Sri Lanka we have made great progress with public awareness and with regulations on advertising and sale of smokeless tobacco and some areca products. Southeast Asia lags behind. HPV vaccination requires greater uptake across the region. What was learned: Both top-down and bottom-up approaches are needed.