20-year landmark study by Indian scientists demonstrate Clinical Breast Examination as a preferred screening method
Mumbai: A 20-year landmark study by Tata Memorial Hospital(TMC) in Mumbai has proved that clinical breast examination is a woman friendly and cost-effective alternative to mammography to check for breast cancer. Dr.Rajendra Badwe, Director TMC, a co-author on the study said, “If implemented as a breast screening method in India, CBE would save 15,000 deaths from breast cancer each year, and 40,000 lives globally in low and middle income countries (LMICs). All this at a fraction of screening cost, thereby reducing stress on the overburdened healthcare systems.” Dr. Badwe was speaking at a press conference held at TMC, Mumbai to discuss the findings of the study.
Breast cancer is the most common cancer among women globally and in India. The incidence of breast cancer is increasing in all countries of the world, but particularly so in low and middle income countries (LMICs). In Mumbai, the incidence of breast cancer has risen by nearly 40% between 1992 and 2016 and breast cancer has become the leading cause of death from cancer in India.
Breast cancers in LMICs are frequently detected in advanced stages, and consequently, more than half the global deaths from breast cancer occur in these countries. Mammography is the standard screening technique for early detection of breast cancer which is widely used in the Western world. Although intuitively appealing, self-breast examination has not been found to be effective in reducing mortality from breast cancer. The study by TMC establishes Clinical Breast Examination as an effective technique which suits LMICs as it is highly affordable in comparison to mammography.
As part of the study, 75,360 women in the screening arm were offered four rounds of CBE conducted by trained female primary health workers and cancer awareness information every two years, followed by five rounds of active surveillance by way of home visits every two years. Another 76,178 women in the control arm received one round of cancer awareness followed by eight rounds of active surveillance every two years. Participants in both arms were eligible for free diagnostic evaluation and treatment at the Tata Memorial Hospital.
Breast cancer was detected at an earlier age in the screening arm than in the control arm (55 v 57 years), with a significant reduction in the proportion of women with more advanced stage (III or IV) disease (37% v 47%) – known as down-staging. The results of the study showed a 30% reduction in mortality due to breast cancer in women aged 50 years and above. This degree of mortality reduction is similar to that from mammography. Although this study did not find benefit in women below age of 50 years, it did find 34% reduction of mortality in these women provided they regularly attended all four rounds of screening.
The use of mammography for screening for breast cancer requires expensive machinery, highly trained radiologists and radiographers and a high level of quality control. In India the cost of a digital mammography machine is approximately Rs. 3 crores, and each examination cost around Rs. 2000. Clearly India cannot afford mass screening by mammography for all its women. CBE on the other hand, is low-cost, technically simple, woman-friendly and a touch-sensitive procedure, without the discomfort of compression or the hazard of radiation.
A highlight of the study is the involvement of primary health care workers whose academic qualification was matriculation. Dr. Vani Parmar, Surgeon, TMC trained the first batch of health workers for performing the CBE procedure. Dr Gauravi Mishra, Professor of Preventive Oncology, is a Co-investigator on the study and has been associated with the trial since its early years and refers to it as her lifetime research project. “It has been a herculean task according to Dr. Mishra. It involved tracing 150,000 participants scattered in different areas of Mumbai, meticulously maintaining their records, counselling them to attend for screening and keeping surveillance over two decades. With the research reaching its culmination, it is immensely gratifying to see the findings being translated into evidence based guidelines and strengthen the national cancer control policies in India and other LMICs.”
Although the impact of this intervention will be strongly felt and perceived in developing countries with scarce resources, its importance in high resource countries cannot be ignored, with mammography being susceptible to over-diagnosis and overtreatment. It is estimated that nearly 30 percent of breast cancers are unnecessarily detected and treated with use of mammography.
The Mumbai study is clearly a stimulus for more research to help mitigate the problems of over-detection and overtreatment. Some studies further indicate that about 15-35% of women are non-compliant to mammography, due to certain factors like physical discomfort, fear of procedure and delay in receiving results. CBE could easily serve as a more acceptable, humane and quick screening intervention.
The study spanning over twenty years was conducted by a team of researchers, led by Dr Indraneel Mittra, Surgeon, Tata Memorial Centre. He conceived a randomized trial to investigate the efficacy of CBE in reducing death rates from breast cancer in the early 1990s. Following a successful pilot study, he obtained a major research grant from the US National Cancer Institute for a 15 year study. The present randomised trial was initiated in 1998 which comprised of 151,538 women aged 35-64 from 20 clusters in the city of Mumbai.