Cancer is the second most common cause of death after cardiovascular disease in the USA. A quarter of all deaths or 550,000 deaths are due to cancer despite having the best treatment available in the world. According to the National Cancer Society, there are 11.1 million Americans with a history of cancer. That number will reach 20 million by year 2030. Approximately 13% (or 7.5 million) of the world’s death are attributed to cancer every year. This will reach 12 million by 2030 according to WHO (World Health Organisation). Obviously our goal of early detection through screening will increase the effectiveness of treatment immensely.
The three most common causes of cancer in males are prostate, lung, colon-rectal cancer; while in females they are breast, lung, and colon-rectal cancer. Less than 25% of world cancer population is genetically predisposed to cancer. Approximately 80% of cancer cases are caused by environmental factors like smoking, pollutants and carcinogens.
Most of the cancer screening recommendations are common among American Cancer Society (ACS), US Prevention Services Task Force (USPSTF) and National Institute of Health.
PROSTATE CANCER
PSA (prostate specific antigen) is recommended for all men above 50 years of age. But according to June 2011 issue of Time Magazine on Screening Dilemma, this screening is considered to be of marginal benefit. If 1000 men aged 55 to 70 underwent annual PSA testing for 10 years then it would save only one life. There will be 150 to 200 false alarms requiring biopsy and 30-100 will be over diagnosed and receive unnecessary radical prostatectomy or radiation.
LUNG CANCER
There is no routine cancer screening for lung cancer. After using chest x-ray as a screening test for several decades it was discovered that screened patient had higher mortality rate than those who were not screened. There are some recent anecdotal reports of using CAT scans or MRI of the chest for high risk patients but it has not been recommended yet.
COLON-RECTAL CANCER
Every 50 years or older individual is recommended to have colon cancer screening with annual faecal occult blood test or colonoscopy every 10 years if it is found to be normal. One advantage of colonoscopy is that the doctor can not only look for cancer but remove any suspicions polyp or benign cancer as well as performing biopsy at the same time. The USPSTF says that colonoscopy, sigmoidoscopy and faecal blood test can all be effective.
BREAST CANCER
Mammogram is recommended for all women at 50 years of age unless they are at high risk of breast cancer. In a high risk case screening starts at 40 years of age. High risk women include those having family members with breast cancer, being a likely carrier of BRCA mutation or exposure to radiation to chest for Hodgkin’s disease. Women should undergo clinical breast exam started every three years between ages 20 to 39 years then every year after age 40.
CERVICAL CANCER
A Pap smear is started three years after starting intercourse or by age 21 years then every year through age 29. For women age 30 or more, it is every 2-3 years. They can stop screening at 70 years if there have been three negative tests in the last 10 years. It can also be stopped in women who have hysterectomy for benign lesion. Since cervical cancer is caused by the Papilloma Virus, vaccine against it is available now.
ENDOMETRIAL CANCER
Women who are at average or increased risk due to history of unopposed estrogen therapy, tamoxifen therapy, late menopause, nulliparity, infertility, or obesity, diabetes, and hypertension need to have screening or biopsy.
CONCLUSION
Cancer screening is an important part of our daily medical care. While it may be every patient’s right, there is medical legal implementations for physicians. The WHO principles of cancer prevention include limiting tobacco use, watching your weight, eating fruit and vegetables, physical fitness and avoiding pollution and indoor smoking. It is believed that 30% of the world cancer cases can be avoided. Cancer screening is extremely important for early detection and prompt treatment especially when the numbers of cancer cases are rising rapidly.
[Anis Ansari, MD is Board Certified in Internal Medicine and Nephrology Practising as Medical Associate, Clinton, Iowa, USA]