Opinion - Op-Ed   

Vaccination option for cervical cancer

The focus that The Hindu provided recently, through an editorial and an editorial page article, on cervical cancer has drawn the attention of governments and the public to a scourge that India, and other countries of the world, face. It is all the more relevant as the disease is very common among middle-aged women belonging to the poorer sections of the community who shoulder several family and social responsibilities.

As early as in 1970, the value of the Papanicolaou test (Pap smear) in reducing mortality from cervical cancer was known to health professionals: what is now the standard test for cervical cancer involves a brushing of the cervix that is analysed to detect any aberrant cell growth. But they were unable to make it universal because of the scarcity of trained laboratory technicians, laboratories and, above all, the lack of a well-managed health department. Such facilities are essential to organise screening camps, locate those at risk and treat any malignant and pre-malignant conditions which are relatively few and far between. The treatment is time-consuming and expensive. Some of the smaller European and Scandinavian countries have successfully implemented Pap smear programmes for cervical cancer control thanks to the availability of efficient health care systems and to the fact that their population sizes are small. In a country like the U.K., the Pap smear programme was a disaster initially.

Doing Pap smears repeatedly in a population is an extremely expensive proposition and entails a heavy workload. Studies by Tony Miller and others to find out the optimum frequency, age group and number of Pap smears to be done during a woman’s lifetime to detect the disease in a curable stage and in a cost-effective manner, have shown that one smear done between the age of 35 and 45 will reduce the mortality level by two-thirds. If repeated again after five years it will reduce the mortality rate by more than 90 per cent. This gives an excellent reason for countries like India to do a Pap smear for every woman at the age of 40. This will bring down the chances of a woman’s death due to cervical cancer by 70 per cent. A second Pap smear at the age of 45 or 50 years will eliminate the possibility of dying of cervical cancer almost completely. In the metropolitan cities, and in States such as Kerala, Tamil Nadu and Maharashtra, where pathology laboratories are aplenty, this can be done easily if only people are made aware of its value and if local gynaecologists would cooperate.

As one could make out easily, the principle behind the studies done in Usmanabad in Maharashtra jointly by the International Agency for Research on Cancer (IARC) and the Tata Memorial Hospital (R. Sankaranarayanan et al. “HPV Screening for Cervical Cancer in Rural India,” 2009, New England Journal of Medicine, April 2, Volume 360, Page 1385-1394) was the same as that was behind earlier Pap smear studies. A study based on viral DNA tests done in a well-defined population between the age of 35 and 59 followed by treatment with maximum coverage should naturally emphasise the same findings as in earlier Pap smear studies, which showed protection for two-thirds of the women.

The major difference between the two studies is that the test used by Dr. Sankaranarayanan was more reliable and there was no subjectivity. Unfortunately, as a second viral DNA test is not contemplated in the IARC-TMH study, the maximum impact of the programme (90 per cent mortality reduction with two Pap smears) could not be demonstrated. But if the test can be made more affordable, we may be able to cover a huge population and detect many pre-cancers and cancers.

The expenses do not stop with the test. As in a Pap smear programme, mobilising the health system to conduct the tests, inviting women to undergo them, and delivering the results to them, are all labour-intensive in a DNA test programme also. The provision of treatment will impose a further financial strain on governments. Also, the management of pre-malignant conditions could mandate the deployment of trained nurses and paramedical personnel if not doctors.

One significant development that has occurred in the last 10 years with respect to cervical cancer control is the development of a vaccine for the control of infection caused by HPV (human papilloma virus) strains 16 & 18, which cause 90 per cent of the cases. The vaccine has to be administered to adolescents between the age of 9 and 12 and before the first sexual union. It produces excellent immunity, almost 100 times more than the natural immunity produced by the body to such infections. The immunity from the vaccine lasts for such a length of time as a woman would need.

HPV 16 & 18 infection starts soon after the first sexual congress. In 90 per cent of the women it subsides automatically, while 10 per cent carry on with the infection because of poor natural immunity and repeated infection as in the case of sexually active women. Such persistent infection leads to pre-cancer and in a small subgroup to cancer. Persistent infections are avoided by enhanced immunity achieved through HPV vaccination.

Preliminary studies have demonstrated that 70 per cent of the deaths can be avoided by such vaccination. Comprehensive and new-technology vaccines offering 100 per cent protection are likely to be introduced soon and these will ensure protection for all from cervical cancer death in the near future.

The major advantage of the vaccine is the fact that time-consuming and expensive tests and post-test treatments could be avoided. The vaccination programme will be successful if the surveillance is fool-proof. There is no need for the health service to launch labour-intensive universal deployment of trained health personnel to get women in for the tests and for community level follow-up.

Now that it is clear from early studies that 70 per cent of the cases can be prevented by the use of currently available vaccines and that the new-technology vaccines have the potential to prevent 90 per cent of the deaths caused by cervical cancer (which are approximately 75,000 in India annually) and that all these could be achieved without any major modification or addition to the health service management systems, why should we not accept a pragmatic vaccine mode without wasting time on laborious and costly experimentation with the Pap smear or the viral DNA test, knowing well that we will not be able to implement them with the present health resources? Hepatocellular carcinoma (liver cancer) is another form of cancer caused by a virus infection (Hepatitis B), which was endemic in China and some South-East Asian countries. It was controlled to a large extent by means of HPV vaccination. Why not adopt the same approach in the case of cervical cancer?

(Dr. M. Krishnan Nair is the founder-director of the Regional Cancer Centre, Thiruvananthapuram. He is an adviser to the Director General of the World Health Organisation and the American Cancer Society University.)

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