India's first childhood cancer survivor registry suggests 94.5% overall survival rate: Study

New Delhi: India's first registry of childhood cancer survivors shows a 94.5 per cent rate of five-year overall survival and nearly 90 per cent event-free survival, according to a study published in The Lancet Regional Health Southeast Asia journal.

The Indian Childhood Cancer Survivorship (C2S) study, initiated in 2016, is among the world's first registry from a resource-limited setting, researchers said.

The team, including researchers from the All India Institute of Medical Sciences (AIIMS) and Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, looked at 5,419 children diagnosed with cancer before turning age 18 and in remission post-treatment from 20 centres across the country. Survival data was available for 5,140 participants.

Acute leukaemia was found to be the most common diagnosis (40.9 per cent), while common therapeutic strategies included chemotherapy for 94.7 per cent of the participants, surgery for 30 per cent and radiotherapy for 26.3 per cent.

"The 5-year overall survival (OS) and event-free survival (EFS) rates for the entire cohort were 94.5 per cent and 89.9 per cent, respectively," the authors wrote.

A five-year overall survival rate is the percentage of patients who are alive five years after their initial diagnosis or start of treatment, whereas event-free survival rate is the number of patients who remain free of certain complications after their primary treatment for cancer ends.

For 2,266 of the survivors who were followed up for at least two years post-treatment, the five-year overall survival rate was found to be 98.2 per cent and event-free survival rate 95.7 per cent.

The authors said the C2S cohort can serve as a model for similar resource-limited settings, and also highlights a collaboration across public and private sector institutions from all four regions of the country -- east, west, north, and south.

Further, the study can help inform policy-relevant research with respect to childhood cancer survivorship, the team said.

The researchers said late effects are likely to appear months or years after the completion of cancer treatment, with one-third to one half of childhood cancer survivors estimated to experience a long-term or late effect of therapy -- up to one-half of which could be life-threatening.

However, data on the prevalence of late effects in childhood cancer survivors from low and middle-income countries, including India, are limited, they said.

"The C2S study represents the first structured attempt to build a nationwide childhood cancer survivors' cohort in India," the authors wrote.

The cohort "paves the way towards addressing the evidence gap on childhood cancer survivorship in lower income and middle-income countries -- providing a means to explore long-term outcomes, treatment exposures, and late effects in the Indian context," they said.