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Prevention of Cancer – 12 – Immunity, Physical activity

Prevention of Cancer PART – 12

(All the articles published in past are available at

Question:  In last part, we discussed additional aspects related to Hygiene and how it can prevent several cancers. 1. Hepatitis B and C are risk factors for liver cancer, lymphoma. Role of other viruses like EBV, HHV8. 2. Role of H.pylori bacteria in stomach lymphoma. 3. Points related to personal hygiene. Covering eating and preparing food; menstrual, sexual, peripartum hygiene; newborn hygiene; daily bath; cleaning mouth after food.

From the last two parts, it is very clear that personal hygiene from newborn to elderly, at every phase of life, and both at home and outside is a very important part of being healthy. For prevention of cancer, as well as many other diseases. In part 10, you used term “immune surveillance”. Can you elaborate?

Ans: Yes, we mentioned this while discussing HIV. HIV infection reduces immunity, and this predisposes a person to over 20 different types of cancers. Patients who have low immunity from other reasons, also have higher risk of various cancers. For example, those post transplant, who are on immune suppression medicines.

So, we do know that immunity has some role in cancer prevention. Our immune cells, such as T lymphocytes have the ability to identify cancer cells in our body, and remove them. We all form cancer cells in our body during the process of producing so many cells. But the quality control systems of body remove these occasional bad cells. For some reasons, this does not happen efficiently in some people. T cells and other cells do not clear these bad cells in some people, and these bad cells then go on to make more cells resulting in cancer. We don’t exactly know why?

Even on treatment side, we have medicines based on this knowledge of T cells clearing cancer cells. Latest class of medicines in cancer field is Immunotherapy (check point inhibitors e.g. pembrolizumab, nivolumab). These medicines renew ability of T cells to identify cancer cells. Once T cells identify cancer cells, they clear them from body. These medicines are active in a large number of cancers, over 10 types of cancers, most notably cancers of lung, melanoma, head and neck, bladder, rectum, colon, Hodgkin lymphoma, and others. And more research is ongoing.

Que: Does this mean that if our immunity is good, we will not get cancer?

Ans: Well, it is not that simple. Immunity is a broad concept, and there are many components of immunity. We have no good measurements for all components of immunity, for example even for T cell dysfunction. But broadly we can say that yes maintaining good immunity in general is part of cancer prevention. And once again, good immunity can be maintained by good lifestyle – i.e. healthy Aahar, Vihar, Vichar. So, no short cuts here i.e. taking some “supplement to boost immunity” or one food item for immunity, is not going to work. Holistic healthy behavior is the only way to maintain good immunity.

Que: Thank you for that point. Many people talk about immunity, but as of now it is not something we can define clearly and measure. And yes, so many supplements promise to boost immunity. Many of my patients are taking these in the hope of a good health, spending so much money.

Ans: But the worst part is people often disregard other aspects and rely mainly on supplements. That false sense of security is more dangerous than supplements itself. For example, people are so heavily focused on what to eat. They forget the importance of How to Eat, and How to Digest well. Three pillars of good health are Aahar, Vihar, Vichar. We have covered Vihar partially earlier i.e. night shift and risk of cancer. But this is a broad area, primarily covering physical activity and rest.

There is a growing understanding of role of physical activity in maintaining good health. Multiple studies have also shown that it is also linked to cancer prevention.

Que: That means regular exercise is important. How many hours or minutes of minimum exercise is required?

Ans: Good news is that Physical Activity is not same as exercise. Exercise is part of physical activity, but there are other forms of physical activity. Means even if you don’t go for formal exercise, but you are physically active, then you derive health benefits. For example, if a person is active most of the day managing children home etc. Or a person walks to work, takes stairs in place of elevator, is not sitting most of the day, or participates in some sport etc, that is also good physical activity. Activities of daily chores basically also qualify for important physical activity. One should incorporate this in daily life. Formal exercise is difficult for most people to be doing regularly. If you can, it is good. But the lesson is that there are many alternate ways. In fact, studies have shown that even weekend bouts of physical activity are almost equally as good as exercise five times a week. Med Sci Sports Exerc. 2019 Jan; 51(1): 35–40. Eric J Shiroma et al. This study showed that even 10 minutes bout of moderate intensity physical activity once or twice a week also provided significant benefit against all cause mortality i.e. death from all causes. So, if you play some sport only on weekend or walk/jog/cycling only on weekend, it is still worth doing.

Another very important study showed value of exercise in young age, during school and college days. In adolescence. Sarah J. Nechuta et al. Cancer Epidemiol Biomarkers Prev. 2015 August ; 24(8): 1270–1276. In a study of almost 75,000 women, conclusion was: Adolescent exercise participation, independent of adult exercise, was associated with reduced risk of cancer, cardiovascular disease, and all-cause mortality. November 16, 2022 Dr Chirag A. Shah; M.D. Oncology/Hematology (USA), 9998084001.

Diplomate American Board of Oncology and Hematology. Ahmedabad.

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