Sarah Hiddleston

Collected data can help pinpoint what action is needed to improve survival rates

CHENNAI: Fewer people in India are surviving cancer than currently acknowledged, a new study undertaken by the Cancer Institute, Adyar has revealed. The finding implies that national prevention, diagnosis and treatment drives may not be as effective as previously thought. But the data collected could help pinpoint what action is needed to improve survival rates, and therefore highlight the need for more such studies to be undertaken in cancer registries across the country.

R.Swaminathan, R. Rama and V. Shanta, whose research paper was published this week in the Bulletin of the World Health Organisation, show that relying on methods used in the West to track cancer survival rates results in a bias in favour of survival. The 10 most common cancers and all tobacco-related cancers registered at the Cancer Institute in Chennai from 1990-99 (followed through to 2001) were matched with statistics on all deaths held by Chennai Corporation and unmatched diagnoses then followed up through telephone enquiries and house visits.

The results show that in countries such as India, where mortality registration systems are deficient and the identity particulars of deceased individuals are often inaccurate, these “active follow up” methods give a truer picture.

“Conventional survival analysis in the West presumes that whoever is not reported dead is alive. But there, they have good health information systems. If we apply that in India, our research in Chennai shows that we will be overestimating the 5-year survival rate by anywhere between 22 and 47 per cent,” Dr. Swaminathan, Chief Biostatistician, Adyar Cancer Institute told The Hindu.

Silver lining

But the silver lining is the opportunity data like this presents to tackle the disease at its weakest points and plan for the future. “If we know survival rates we can better predict the future cancer burden, which is useful for public health planning,” he said.

If the data on the survival rate of breast cancer patients beyond 5 years is as low as 44 per cent, compared with 54 per cent of those with cervix cancer, this may be because radiation treatment is available in four government hospitals, whereas breast cancer treatment is prolonged, uses various methods and may be managed by multiple people. Matching the figures for both cancers with Western survival rates that range from 70-80 per cent highlighted the need to invest in early screening, he said.

“Proper reporting is essential for us to see results,” said Balu David, Director of Tamil Nadu’s Regional Cancer Centre in Kancheepuram, who estimated that around 10 per cent of those who had been diagnosed or treated at the hospital could not be contacted.

The Cancer Institute is one of only six out of 20 registries that have undertaken survival studies. “Any cancer survival study in India should have an active follow up mechanism,” Dr. Swaminathan said.

“This is only a metropolitan study. Rural registries are sparse and the survival rate may be lower in rural areas.”