The biological approach to the radiotherapy of the oral cancers of South India.

Two-thirds of all cancers in South India are squamous cell carcinomas, of which 78% to 93% are late cases requiring radiotherapy. Oral cancers, which constitute the majority of these, provided an excellent clinical model for studies in radiotherapeutic biology. Their characteristics made them ideally suited for our clinical trials. The paper reviews the special biology of these lesions, the factors involved in their radiation non-response, the therapeutic postulations that suggested themselves, the implementation of these therapeutic protocols and the mixed story of failure and success that has marked the two decades of these studies. It discovers the fact that radiation response is not just a factor of tumor extent but involves several biological subtleties in both tumor and its host environment. It also discusses possible future approaches to bridge a gap of about 30% failure in these lesions, especially in the context of a poor economy.