Nasopharyngeal carcinoma in the Northeastern states of India

Abstract

Nasopharyngeal cancer (NPC) is a rare disease in most parts of the world, except for Southeast Asia, some parts of North Africa and the Arctic. It is mostly seen in people of Chinese origin. In India, NPC is also rare, except for the Hill States of Northeast India, particularly Nagaland, Manipur, and Mizoram. The striking feature of NPC in Northeast India is that the incidence ranges over the complete spectrum from the lowest (as 0.5/100 000 to 2.0/100 000 among Caucasoid) to the highest (as about 20/100 000 among Cantonese/Zhongshan dialect Chinese). The age-adjusted rate of NPC in Kohima district of Nagaland State is 19.4/100 000, which is among the highest recorded rates. By contrast, in Assam, one of the so-called Hill States but not itself a hilly state, NPC is much less common. The Northeastern region is distinguished by a preponderance of the Tibeto-Burman languages and by variable mongoloid features among peoples of the region. The nature of the migratory populations who are presumed to be bearers of the mongoloid risk is unknown, but these NPC occurrence features provide an outstanding opportunity for NPC risk investigation, such as that of the hypothesis of Wee et al. for westward displacement of Chinese aborigines following the last glacial maximum.

Figure 1.. District-wise distribution of age-adjusted incidence rates of nasopharyngeal cancer (NPC) in males in different districts of India registered in 2002 in the Population-Based Cancer Registries (PBCRs) of the National Cancer Registry Programme of Indian Council of Medical Research. The figure was downloaded from the website of the National Cancer Registry Programme of Indian Council of Medical Research with publication permission. The rates are reported as per 100 000 population.

Figure 2.. Age-adjusted incidence rates of NPC in males registered between 2004 and 2005 in all PBCRs. The data are from the PBCRs of National Cancer Registry Programme of Indian Council of Medical Research. Only 2 PBCRs, Mizoram and Sikkim PBCRs, cover an entire state. At the time of publication of the PBCR report of National Cancer Registry of ICMR, the data from new PBCRs are not available. The rates are reported as per 100 000 population. The Northeastern states of India (excluding Assam state) have higher incidence of NPC than the rest states of India.

Figure 3.. Age-adjusted incidence rates of NPC in males registered in 2002 in some PBCRs. The data are from the PBCRs of National Cancer Registry Programme of Indian Council of Medical Research. The rates are reported as per 100 000 population. The Northeastern states of India (excluding Assam state) have higher incidence of NPC than the rest states of India.