Risk factor and Prevention of Cancer:

The old saying, “An ounce of prevention is better than a pound of cure”, holds true not only for infectious diseases but also for cancer.

Why cancer prevention is important?

Most cancers are lifestyle-related risk factors. In India, tobacco-related cancers account for 48% of the total cancer cases and cervical cancers form the bulk (36%) of cancers in females.

Primary Prevention

Primary prevention refers to a reduced or to eliminate exposure to carcinogens.

Primary prevention includes:

• Compulsory education about tobacco related cancers, unhealthy sexual habits and cancer preventive diet.

Modifiable cancer risk factors:

• Tobacco causes cancers at many sites. Alcohol consumption is associated with oral, oesophageal and other cancers;
• Obesity associated with increased risk of colon, breast and other cancers.
• Balanced mixed diet can prevent several cancers.

Chemoprevention

This includes the use of natural or synthetic substances to reduce the risk of developing cancer or its recurrence.

Eg: Selective oestrogen receptor modulators (tamoxifen), NSAIDs, (COX-2 inhibitors) for colon cancer, Retinoids (cis-retinoic acid) for primary cancers of the head and neck and Finasteride, an alpha-reductase inhibitor that can lower the risk of prostate cancer. Vaccines are used to prevent infection by oncogenic agents against hepatitis B for cancers of liver and Human papillomavirus (HPV) vaccine for prevention of Cervical Cancer.Genetic testing with BRCA1, 2 has lead to prophylactic oophorectomy and mastectomy for Breast & Ovarian Cancer, prophylactic colectomy in adenomatous polyposis gene mutation.

Diet and Cancer

Diet is one of the aetiological factors in carcinogenesis. Epidemiological studies (study done by Doll and Peto) have shown that 35% of cancers are associated with diet.

Fat present in red meat modifies DNA synthesis, alters the microflora and induces the production of oestrogens, associated with breast and colon cancers.

Micronutrients and cancer

Micronutrients – vitamins and minerals, non-nutrients such as proteins (legumes), monoterpenes (citrus fruits), polyphenoles (tea and spices) and allium (onion and garlic) have protective effects and prevent cancer. They act through metabolic, antioxidant, differentiation and immune modulation.

Dietary recommendations

• Increased intake of vegetables and fruits (minimum of five servings per day)
• Intake of 55% carbohydrates, <30% fats and 20-30g of fibre
• Avoidance of salt-cured and smoked food
• Limitation of alcohol.

Secondary prevention includes screening programmes.

Recommendations for the early detection in asymptomatic persons

Screening programmes are:

• Opportunistic, in which the population seeks medical professionals.
• Organized, in which medical professionals approach the public.