Surendra Shastri
Professor & Head
Department of Preventive Oncology
Tata Memorial Hospital
India
AsianScientist (Apr. 13, 2016) – Once thought of as a disease of the developed world, cancer is now making its impact felt across the developing world as well. In India, where limited resources have to be stretched to meet the needs of over 1.2 billion people, there are 2.5 million people estimated to be living with the disease.
What developing nations need, says Professor Surendra Shastri of the Tata Memorial Hospital in India, are affordable, accessible interventions. Shastri, who also heads the World Health Organization’s Collaborating Center for Cancer Prevention, Screening and Early Detection, has been actively involved in developing such interventions for oral, cervical and breast cancers, some of the deadliest cancers in India.
Apart from his work as co-founder of the Advocacy Forum for Tobacco Control and director of the Smokefree Mumbai Campaign, Shastri has developed a highly effective and low cost screening method for cervical cancer based on vinegar. The results of the 12-year study involving over 150,000 women showed that the screen could help reduce cancer deaths by 31 percent, all at the cost of just 30 Rupees per test.
Asian Scientist Magazine caught up with Shastri at War on Cancer Health Care Forum held in Singapore on March 17, 2016.
1. What percentage of India’s overall health burden is due to cancer and which are the top cancers India has to deal with?
A decade ago, cancer was the 10th most common cause of mortality in India but now it is the 5th most common fatality. The top causes of death in India are cardiac disease and infectious diseases like tuberculosis. Although cancer is not at the top, as it is in Western countries, it is moving fast.
Among males, lung, esophageal, oral and stomach cancer are the top cancers. For females, the top cancer today is breast cancer. About five years back, cervical cancer was number one and breast cancer was ranked number two. After that, we have esophageal, colorectal and ovarian cancer, in that order.
2. What would you say is India’s main challenge when it comes to dealing with cancer?
The main challenge is that there’s not enough government initiative to control cancer. It is not perceived as a priority; infectious diseases are the top priority instead. Although there is funding set aside, there is not as much as might be required.
Secondly, because of the fact that most cancer patients in India will eventually die, the average person on the street has great fear about cancer so they do not want to go to the hospitals for cancer screening. Since the common mindset is that they will die from cancer anyway, they don’t see the need for cancer screening.
We need more awareness and health promotion to help people understand that cancer is like any other disease—diabetes, cardiac conditions and so on—which can be treated if diagnosed early. A normal life can continue with early diagnosis and treatment from time to time.
3. One way to get more people screened is to lower the cost of screening, something which you have shown to be possible for cervical cancer with the visual inspection with acetic acid (VIA) test. Could you tell us more about how the test works?
The primary healthcare worker is supposed to insert a speculum and observe the cervix of the uterus with good light source, which is normally done as part of a routine reproductive health checkup. Once she’s done that, then she takes freshly prepared 4% acetic acid—better known as vinegar—and applies it generously to the cervix with a simple cotton swab. Cells which are pre-cancerous have larger nuclei and proteins, so the application of acetic acid coagulates the proteins and within a minute, those areas which have higher nuclearity will look like thick white patches on the cervix.
If the white patches are nearer to what we call as the endocervix, the area where the cervix has got a hole and enters the uterus, then the patient is deemed acetic acid positive. Only women with a positive acetic acid test will need to be referred for further biopsy.
The sensitivity of this test is about 70-72 percent and the specificity is about 84 percent. In contrast, even under the best quality control situations, the sensitivity of Pap smears is not more than 70 percent while the specificity is 90-95 percent. So the VIA test compares very closely with Pap smear in its attributes as a screening test. In terms of cost, it cost me 30 Indian Rupees for one screen, which is about half a US dollar. The average cost of Pap smear in India would be 700 Rupees—20 times the costs of the acetic acid test.
4. You studied the impact of vinegar testing for cervical cancer in over 150,000 women. What were the conclusions of your study?
We had originally planned the study for 16 years but at 12 years our data safety monitoring committee asked us to stop the trial as they thought the data looked good. So by the 12th year, we were able to analyze the data and show a clear 31 percent mortality reduction. This is after four rounds of screening at 24 month intervals with vinegar which means that if primary healthcare workers do four screenings during the entire lifetime of the woman between 35 and 64 years, then there’s no need for them to go on screening.
Extrapolating the data, we showed that if we do the test for the entire country, we would be able to prevent 20,000 to 70,000 cancer deaths a year. And if the test is adopted by other low to middle income countries, we will prevent about 78,000 cancer deaths annually. The test is a great benefit to countries which either cannot afford Pap smears or who don’t have the logistics to perform Pap smears.
5. Are there plans to roll out a VIA screening program in India?
At present, the government of India has taken up VIA screening as part of the non-communicable diseases program. As a pilot, the primary healthcare workers in six districts of every state in India have been trained to provide the vinegar test. In about six months or so, we will do actual screening and this pilot program will go on for about two years. If it is seen to succeed at the program level, then it will be scaled up to the state level and the national level.
6. When it comes to a screening program at such a large scale, what are the risks of over-diagnosis?
I think the whole concept of screening has to be understood clearly. Screening will always lead to a certain number of false positives, patients who unnecessarily go for invasive diagnostic procedures. Some of them might even have to undergo treatment which was never required. So screening always has the issue of over diagnosis and treatment which is causing harm.
The VIA screen is a visual test. In contrast, for mammography or a radiological mammography, there is a possibility that you discover something in situ which will never grow into an invasive cancer. But when you do a physical examination, you are looking for a lump. If there is a lump, we do needle aspiration cytology to prove whether the growth is malignant or not. So the chances of over-diagnosis with these kinds of physical techniques (breast cancer examination, VIA) is very low and we have shown that as part of our publication. We have to balance between the benefits and harms from the public health standpoint.
When we come to lung cancer screening, it’s hopeless. There will be too much over diagnosis in Asian or South Asian countries where lung diseases such as tuberculosis are very prevalent. If you do screening with low dose CT scans for lung, you will find almost 90 out of 100 persons will have some lesions, and they will be all false positives. It will be doing more harm than good. Similarly for prostate cancer, there is absolutely no evidence that screening is beneficial.
So screening is not something we can do for all cancers. It has to be clearly proven that by screening, we are able to diagnose very accurately, and we have good treatment modalities. Otherwise we should not do screening because it will be causing more harm.
7. What breakthroughs in cancer diagnosis or treatment do you hope to see in the next 10 years?
There is a lot of genetic work that is going on, searching for molecular markers etc, but what I would be more interested in seeing is an intervention that can be provided by a primary healthcare worker at the village level. Only then you will have universal access. For low to middle income countries it is important to weigh the benefits and the harms, making affordability is a very important issue.
Something which is already there right now but needs to be moving very fast into the population is the nonavalent cervical cancer vaccine. Although herpes simplex virus [a causative agent of cervical cancer] strains 16 and 18 are considered the most common, there might be more strains in circulation in Asia.
It is possible for countries in the region, which have a large capacity for developing low cost medicines and vaccines, to have indigenous vaccine development. I know for one in India, and for sure in China, that it is already happening. So if we are able to have affordable vaccines in the near future, I think that will be the largest breakthrough for eradicating cervical cancer from our region.
This article is from a monthly series called Asia’s Scientific Trailblazers. Click here to read other articles in the series.
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Copyright: Asian Scientist Magazine.
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