CAN CANCER BE PREVENTED

Padmasree, Prof Kakarla Subba Rao
Director\Chancellor, Nizam's Institute of Medical Sciences Hyderabad.

"Can Cancer be prevented?" is the common question asked by most of the educated as well as some of the lay people. Cancer as the term suggests is a malignant condition that clutches the organ involved, like a "crab". It also spreads locally as well as to any organ in the body through the lymphatic or blood stream. It can also involve the neighboring structures. The dictum that' prevention is better than cure' certainly applies to cancer also. Since the introduction of latest technology in radiotherapy and surgical therapy and with the latest cancericidal drugs available, the cure rate has increased in the last decade to 42-45% as compared with earlier rate of 20%. It is true that 80 % of these cancers are preventable, provided proper precautions are taken and appropriate measures are instituted.

PREVENTION: Multiple factors play role in the causation and progress of cancer. Certain cancers are inherited and some are familial. With the advanced research in genetics, oncogenes for certain cancers are being identified. It is important that if there is a familliar history of cancer, one should take precautions apart from obtaining genetic counseling.

Certain benign conditions may exist in the body that may transform into cancer. Examples include inflammatory colitis either Crohn's or ulcerative, peptic is in a Barrette's type of Esophagus, which are prone to malignancy. An undecided testis is also prone for development of cancer. Certain polyps of gastrointestinal tract may also have a tendency to become cancerous. In multiple endocrine neoplasm (MEA) syndromes the incidence of cancer development is known. A simple Exotosis or an Enchondroma of the bone may develop into Chondrosarcoma. As a general rule, radical prophylactics and radical surgery is indicated particularly when they are multiple and when there is a history of hereditary occurrence.

Certain percentage of patients suffering from Hepatitis-B may develop Hepatocellular Carcinoma. Similarly in women, Cervical Cancer is attributed to human Papilloma virus infection. Helicobacter pylori is linked with cancer of the stomach. Human T- cell lymph tropic type Epstein Barr virus is associated with certain lymphomas. If the infections are recognized earlier and treated well, there is every likelihood of preventing the development of cancer.

Dietetic factors do also contribute to development of cancer. It is common knowledge that abundant dietary fiber prevents colonic cancers. Green vegetables, carrots and certain fruits contain anti-carcinogens like carotenoids. Similarly, phyto- oestrogens, organoselenium, phenolic and organosulfur compounds which are found in fresh fruits, vegetables and grains can inhibit carcinogens. Cereals, vegetables, fruits and legumes may have a preventive effect on cancer by diluting the concentration of carcinogens in gastrointestinal tract. Fried and burnt foods should be avoided. Consumption of animal fat is associated with development and spread of prostatic cancer. With reference to consumption of fats, there are good fats and bad fats, saturated and unsaturated fats. Unsaturated fats are definitely better for health. However, limiting fat intake is essential in preventing Cardiovascular diseases also. Literature is replete with instances that obese people may develop cancer of the breast and colon.

Use of tobacco products definitely are attributed to the development of cancer. Smoking cigarettes, chuttas and beedis have the greatest risk factor and is attributed to 30 % of the cancer deaths. Passive smokers are much more prone to lung cancer than actual smokers. Similarly usage of Pan masala, pan parag and chewing of tobacco containing products also cause oral, pharyngeal and other cancers. Smoking is also attributed to the development of cancer of the bladder; kidney, nasopharynx, stomach, pancreas, etc.lt does not matter whether one smokes filtered or non-filtered cigarettes, the proneness to the incidence of lung cancer is the same. King size cigarettes contain more tar and hence are more dangerous Besides smoke, pollution in the atmosphere and quality of air that we breathe also contribute to the development of cancer of the lung and other organs. Tar, asbestos and other pollutants in the air also contribute to the high incidence of cancer.

Ionizing radiations such as back ground radiation, radiation produced by medical diagnostics and therapeutics, radiation produced from certain industries are to some extent responsible for the development of cancer. In fair skinned people, excessive exposure to the sun may cause cancer. Hence, preventive measures should be taken by filtering the ultra violet rays.

Physicians who deal with X-rays, Alpha radiations, Beta radiations and Gamma radiations are also at risk of developing blood cancer.

In women, Cervical Cancers are common, especially in India. They could be prevented by screening for early infections. Awareness of cancer and prevention by adopting hygienic methods should be focused upon. In medicine 'treating the cause is cure' is the dictum and so also taking care of the causative factors in prevention are most important.

Apart from the principles of prevention and methods adopted enunciated above, certain medications will have an effect in preventing some cancers. These are called chemo preventive agents. These include synthetic compounds of Vit-A and retinoids. The mechanism of prevention of epithelial oral cancer by these drugs is well studied. However, enough proof is not evident yet.

Aspirin has been found to reduce the incidence of polyposis and prevent angiogenesis. It has the well known advantage of prevention of clotting in blood vessels. Literature is abundant in confirming that 'strokes' and 'heart attacks' can be reduced by routine intake of small doses of Aspirin.

Hormonal therapy in the prevention of endometrial, ovarian, breast and prostatic cancers is well known and should be individual based and should be taken only on the advice of medical specialists.

In conclusion, I should emphasize that preventive factors in cancer so exist and the individual awareness and regulation of one's own life style are important. While these factors playa role in prevention of certain cancers, periodic screening for cancerous conditions is mandatory in the risk groups. Advice from the medical experts is essential in preventing certain other cancers. The role of these preventive strategies is enormous. Individuals, communities, physicians and health planners should come up with a policy of prevention of cancer and thus reduce the morbidity and mortality resulting from cancer.