Oral Cancer in India: Learning from Different Populations

Oral cancer is a heterogeneous group of cancers arising from different parts of the oral cavity, with different predisposing factors, prevalence, and treatment outcomes. It is the sixth most common cancer reported globally with an annual incidence of over 300,000 cases, of which 62% arise in developing countries.

There is a significant difference in the incidence of oral cancer in different regions of the world. The age-adjusted rates of oral cancer vary from over 20 per 100,000 population in India, to 10 per 100,000 in the U.S., and less than 2 per 100,000 in the Middle East (1).

In comparison with the U.S. population, where oral cavity cancer represents only about 3% of malignancies, it accounts for over 30% of all cancers in India. The variation in incidence and pattern of oral cancer is due to regional differences in the prevalence of risk factors. But as oral cancer has well-defined risk factors, these may be modified – giving real hope for primary prevention.

Impact of Smokeless Tobacco

Tobacco use and alcohol are known risk factors for cancers of the oral cavity. In India 57% of all men and 11% of women between 15-49 years of age use some form of tobacco.

Besides smoking, use of smokeless tobacco is widely prevalent. The use of Betel quid (pan) - consisting of pieces of areca nut, processed or unprocessed tobacco, aqueous calcium hydroxide (slaked lime) and some spices wrapped in the leaf of piper betel vine leaf - is very common and is accepted socially and culturally in many parts of India. Additionally, gutka, zarda, kharra, mawa and khainni are all dry mixtures of lime, areca nut flakes and powdered tobacco custom mixed by vendors. In recent years, commercially available sachets of premixed areca nut, lime, catechu, condiments with or without powdered tobacco have become very popular, particularly among younger Indians. Typically, the pan or gutka is kept in the cheek and chewed or sucked for 10-15 minutes, with some users keeping it in overnight.

Acquisition of the tobacco habit typically occurs early in life through imitation of a family member or peers. Various studies carried out across the country report that at least a third of school students less than 15 years of age have used one form or another of tobacco. However, with improved public health education, the prevalence of these risk factors is decreasing around the globe, including in India (2). An analysis of oral cancer incidence from 1990 to 2005 in Chennai, India has revealed the benefit of such public health interventions, demonstrating a significant parallel reduction in oral cancer incidence. A comparison of oral cancer incidence in India and the U.S. has shown a similar downward trend in both countries. However, the reduction is much more dramatic in India, where there is a much higher prevalence of oral cancer.

Recently, a trend has been observed towards increased incidence of oral cancer among young adults. This increase in incidence is only observed in patients with tongue cancer. In an analysis of 482 consecutive patients presenting with head and neck cancer to a tertiary care cancer center in India, 135 out of the 286 (47%) oral cavity cancer patients did not have any known risk habits (tobacco or alcohol use) (unpublished data).

The Need for Screening

Despite the fact that the oral cavity is accessible for visual examination, and that oral cancers and premalignant lesions have well-defined clinical diagnostic features, oral cancers are typically detected in their advanced stages. In fact, in India, 60-80% of patients present with advanced disease as compared to 40% in developed countries. Consistent with patients presenting for medical care with more advanced disease in India compared with developed countries, overall survival is also reduced. Early detection would not only improve the cure rate, but it would also lower the cost and morbidity associated with treatment.

It is imperative that cost-effective oral cancer screening and awareness initiatives be introduced in high-risk populations such as those found in India. Several large population-based oral cancer screening programs have been carried out, either as opportunistic screenings or as population-wide screenings. Although these studies have confirmed the effectiveness of screening to detect oral cancer and pre-cancerous lesions, only recently has a study from India demonstrated that oral cancer screening by trained health workers can lower mortality of the disease - especially in individuals with a history of tobacco use (3). In this randomized, controlled trial of almost 192,000 people, carried out over an eight-year period, there was a significant reduction in mortality in the intervention arm (29.9 cases per 100,000) versus the control arm (45.4 cases per 100,000), due to detection of oral cancer at an early stage.

A cost-effectiveness analysis revealed that an oral cancer visual inspection by trained health workers can be carried out for under U.S. $6 per person. The incremental cost per life-year saved was U.S. $835 for the all-screened population and U.S. $156 in the high-risk population (individuals with a tobacco habit) (4).

Our group has investigated the effectiveness of mouth self-examination to further reduce the cost of the screening and to increase awareness in a high-risk fishing community in coastal India. In this study involving 30,530 participants, one round of health education - including a brochure containing information about mouth-self-examination distributed by local health workers - identified 28 early stage oral premalignant and malignant lesions. Moreover, this simple and cost-effective strategy had a significant impact on the awareness of oral cancer in the broader community.

Looking Forward

With a goal of early detection and quality care to cancer patients, the Mazumdar-Shaw Cancer Center (MSCC) of Narayana Hrudayalaya Medical City, (a large cancer center with 1,400 beds, structurally and operationally designed to facilitate multidisciplinary care integrated with community oncology) recently initiated its service in India. The financial backbone of this program is a "microeconomic health care insurance scheme," wherein farmers contribute about U.S. $3 per year, entitling the family to essential health care. The scheme - conceived by the founder of Narayana Hrudayalaya Health Care Service, Dr. Devi Shetty - is supported by state government. MSCC is committed to the early detection of highly prevalent cancers, and in collaboration with Rajiv Gandhi University of Health Sciences (RGUHS), an 'onco-net' program has been initiated in different dental and medical colleges affiliated with RGUHS and district hospitals through a telemedicine network.

MSCC will coordinate the activity of the 'onco-net', and also has a mandate to train the next generation of physicians in the field of oncology. The focus of the oral oncology research program at MSCC is early detection and prevention, providing tangible benefits to oral cancer patients and the community at large.

There is still much to be done. Oral cancer remains a major health problem in India, and only dedicated, sustained efforts towards early detection and prevention will reduce the burden of this disease.

REFERENCES:

1. Sankaranarayan R, Masuyer E, Swaminathan R, Ferley J, Whelan S; Head and neck cancer: a global perspective on epidemiology and prognosis. Anticancer Res 18:4779-86, 1998
2. Elango JK, Gangadharan P, Sumithra S, Kuriakose MA: Trends of head and neck cancers in urban and rural India. Asian Pac J Cancer Prev 7:108-12, 2006
3. Sankaranarayanan R, Ramadas K, Thomas G, Muwonge R, Thara S, Mathew B, Rajan B. Effect of screening on oral cancer mortality in Kerala, India: a cluster-randomised control trial; Trivandrum Oral Cancer Screening Study Group. Lancet 365:1927-33, 2005
4. Subramanian S, Sankaranarayanan R, Bapat B, Somnathan T, Thomas G Mathew B, Vinoda J, Ramdas K. Cost-effectiveness of oral cancer screening: results from a cluster randomized controlled trial in India. Bull World Health Organ 87:200-206, 2009