"Tobacco consumption can sometimes cause submucous fibrosis, where the jaw muscles get fibrosed and the person can't work the jaw muscles properly. The individual has to take liquids. This is the pre-cancerous stage," Lalir Kumar told IANS.
Ten percent of such cases develop into full-blown oral cancer, where even surgery can't help, he added.
"The mucus membranes on the insides of both cheeks get affected by cancer; so there is no scope for surgery. How does one replace them? It is very difficult," said Kumar.
Oral cancer cases are seen largely in southern India, especially Kerala, where chewing betel nut or supari is common.