This past week was tough for me emotionally, but far, far tougher for some of my patients. I diagnosed a number of new cancer cases. What are the current trends for this terrible disease?
The American Cancer Society estimates that 1,700,000 new cases of cancer will be diagnosed in the United States during 2015. That is equal to about one-half of 1% of the population (1 in 200). Some 600,000 people this year will die. Thankfully, great work is being done in the field, and treatment expenditures for cancer patients keep climbing. They were $125 billion in 2010, and will likely hit $156 billion by the year 2020.
What causes cancer? More often then not, the root cause is never identified! Why one person may contract cancer from a particular exposure, and another does not, is also unclear. Cancer starts with one single cell that goes “bad.” A cell may transform to a malignant cancer as a result of an interaction between genetic factors and one of these three groups of carcinogens:
•physical carcinogens, such as ultraviolet and ionizing radiation
•chemical carcinogens, such as asbestos, tobacco smoke, aflatoxin (a food contaminant), and arsenic (a drinking water contaminant)
•biological carcinogens, such as infections from certain viruses, bacteria or parasites.
The most common cancers diagnosed in the United States this year, in the following order, will be breast, lung, prostate, colorectal, bladder, melanoma of the skin, non-Hodgkin lymphoma, thyroid, kidney and renal, endometrial, leukemia, and pancreatic. The frequency of cancers varies by gender. Among men, the most common sites are lung, prostate, colorectal, stomach, and liver. Among women, the most common sites are breast, colorectal, lung, cervix, and stomach.
Cancer deaths are higher among men (208 deaths per 100,000 men, compared to 145 deaths per 100,000 women). About 40% of men and women will be diagnosed with cancer at some point in their lifetime. Note, however, that this figure includes simple skin cancers that are easily treated.
The most meaningful indicator of progress against cancer is a change in mortality (the death rate). The incidence of a cancer is also an important statistic, but incidence may reflect a new technology or test that is better at detection, or an actual rise in that cancer due to more people being exposed to risk factors. For example, many more prostate cancer cases are now being detected by the PSA blood test. However, a large number of these cases will never actually lead to illness or to death. The incidence of prostate cancer rises due to increased detection, but the actual mortality does not.
Overall, cancer mortality in this country has been dropping since the early 1990s. However, not all cancer death rates have gone down. Declining smoking rates have pushed down the number of cases, but an aging and increasingly obese population has led to an upward trend in new cases and mortality. Cancers with rising rates include HPV-related cancers of the cervix and esophagus; melanoma of the skin; and thyroid, pancreatic, liver, and kidney cancer.
What can we do to minimize our own cancer risk? One third of cancer deaths are likely due to a handful of behavioral, lifestyle, and dietary risks:
•Tobacco use: Smoking is the leading risk factor for cancer, causing around 20% of global cancer deaths and 70% of global lung cancer deaths
•Exposure to indoor radon gas, and household use of solid fuels like wood and charcoal: Radon gas is the second leading cause of lung cancer, causing 20,000 lung cancers per year. It is found in homes built on top of uranium, and is odorless. Testing can detect its presence in a home.
•Eating a diet low in fruit and vegetables
•Lack of physical activity
•Excessive alcohol use
•Sexual behavior leading to HPV infection
•Infection by hepatitis B
•Too much sun exposure
•Exposure to urban air pollution
My message today is simple: Live your life. Love your life. Minimize your own odds of getting cancer, as well as other diseases, by making wise and healthful choices every day.