What Is Cancer, and Can I Avoid It?

Cancer is a group of diseases characterized by the uncontrolled growth and spread of abnormal cells – genetic errors – that can result in poor health or even death if not treated.

More than a third of all Americans will get some form of cancer in their lifetimes. Cancer cells have been described as immortal because, unlike normal cells, they don’t age and die, but instead can continue to multiply without end. Metastatic cancer happens when cancerous cells disperse into surrounding tissues or even travel to other parts of the body through the blood or lymph systems. Cancer kills by growing and spreading into key organs, nerves, or blood vessels and interfering with and impairing their function.

What Causes Cancer?

Although the causes of development are not completely understood, numerous factors are known to increase risk, including tobacco use, excess body weight, inherited or inherent genetic mutations. These risk factors may act simultaneously or in sequence to initiate and/or promote cancer growth.

How Is Cancer Treated?

The most common treatments are surgery, chemotherapy, and radiation. Other options include targeted therapy, immunotherapy, laser, hormonal therapy, and others.

Surgery is a common treatment for many types. During the operation, the surgeon takes out the mass of cancerous cells (tumor) and some of the nearby tissue.

Chemotherapy refers to drugs used to kill cancer cells. The drugs may be given by mouth or into a blood vessel via an IV.

Radiation therapy uses x-rays, particles, or radioactive seeds to kill cancer cells. These cells grow and divide faster than normal cells in the body. Because radiation is most harmful to quickly growing cells, radiation therapy damages cancer cells more than normal cells.

Can Cancer Be Prevented?

A substantial proportion of cancers could be prevented, including all cancers caused by tobacco use and other unhealthy behaviors.

Excluding non-melanoma skin cancer, at least 42% of newly diagnosed cancers in the US – about 805,600 cases in 2022 – are potentially avoidable, including the 19% of cancers caused by smoking and at least 18% caused by a combination of excess body weight, alcohol consumption, poor nutrition, and physical inactivity.

Many of the more than 5 million skin cancers diagnosed annually could be prevented by protecting skin from excessive sun exposure and not using indoor tanning devices.

Screening can help prevent colorectal and cervical cancers by detecting and removing precancers in the colon, rectum, and uterine cervix. Screening is known to reduce mortality for cancers of the breast, colon, rectum, cervix, lung, and prostate.

How Many People Will Get Cancer This Year?

About 2 million new cases are expected to be diagnosed in the US in 2022. Approximately 600,000 deaths are expected in the US in 2022. Cancer is the second most common cause of death in the US, exceeded only by heart disease.

Invasive female breast cancer incidence rates have been increasing by about 0.5% per year since the mid-2000s. The disruption of health services due to COVID resulted in millions of people who missed or postponed appointments for screening or follow-up of abnormal results or new symptoms, as well as patients already diagnosed who experienced treatment delays and/or modifications. The consequences of this interruption in care will become evident in statistics over the next several years to come.

Who Is at Risk of Developing Cancer?

Everyone is at risk, although the likelihood increases greatly with age. About 80% of the people diagnosed in the US are 55 years of age or older and 57% are 65 or older. In the US, an estimated 40 out of 100 men and 39 out of 100 women will develop it during their lifetime. Certain behaviors and other modifiable factors also increase risk, such as smoking, having excess body weight, drinking alcohol, and eating an unhealthy diet.

How Much Progress Has Been Made Against Cancer?

Substantial progress has been made in recent decades. The overall age-adjusted death rate rose during most of the 20th century, peaking in 1991, mainly because of the smoking epidemic. As of 2019, the rate had dropped 32% – mostly because of reductions in smoking and advances in early detection and treatment for lung, colorectal, breast, and prostate cancer. Early diagnosis reduces the risk of death and increases treatment options. Mammography is a low-dose x-ray procedure used to detect breast cancer before it becomes symptomatic.

Colorectal cancer has generally declined since the mid-1980s in adults 50 and older, but increased by 1.5% per year in younger individuals, a trend that began in the mid-1990s for unknown reasons.

Research is attempting to identify ways to turn telomerase off, making cancer cells mortal. This could be delivered through engineered viruses, or even an immunization.

There Is Hope.

If every cell has some chance of becoming cancerous, large, long-lived organisms, like humans, should have an increased risk of developing cancer compared to small, short-lived organisms. But that’s not always true.

Animals, like elephants, with 1,000 times more cells than humans do not exhibit an increased risk, suggesting that natural mechanisms can suppress cancer 1,000 times more effectively than is done in human cells. The lack of correlation between body size and risk is known as Peto’s Paradox, named after epidemiologist Richard Peto. This shows that theoretically, more can be discovered and done to prevent it.

What Percentage of People Survive?

Cancer survival is typically described in terms of relative survival, which is a measure of life expectancy among patients compared to that among the general population of the same age, race, and sex. Survival rates vary widely, and generally depend on a number of factors including the type, age at diagnosis, gender, race, and general health.

More recently, many of the most commonly diagnosed cancers have ten-year survival rates of 50% or more. In 2022, 69% of survivors have lived 5+ years since their diagnosis; 47% of survivors have lived 10+ years since their diagnosis; and 18% of survivors have lived 20+ years since their diagnosis. Improvements in survival reflect advances in treatment, as well as earlier diagnosis for some cancers.

What Are The Signs and Symptoms?

It depends on the type. Generally, being aware of changes in your body (such as a new mole or lump under the skin) and bringing these to the attention of a healthcare professional can also result in the earlier detection.

Signs and symptoms of various types of cancer can include blood in the urine, pain or lumps in various places you didn’t notice before, changes in your bathroom habits, fatigue, nausea, coughing blood, unexplained weight loss, fever, and anemia.

Unfortunately, with some cancers including liver, lung, prostate, pancreatic, colorectal and breast cancer, symptoms may not appear until the disease is advanced. This is why regular proactive screening is so important.

What Can I Do To Help Avoid Cancer?

In 2020, the American Cancer Society released new diet and physical activity guidelines for reducing risk. These guidelines include community action recommendations because of the strong influence of the environment on individual diet and activity choices.

Aside from avoiding tobacco use, maintaining a healthy body weight, being physically active, consuming a healthful diet, and avoiding or limiting alcohol intake are the most effective strategies for reducing the risk of cancer. An estimated 18% of cases and 16% of deaths are attributable to the combined effects of excess body weight, alcohol consumption, physical inactivity, and an unhealthy diet.

A healthy eating pattern includes:

Foods that are high in nutrients in amounts that help achieve and maintain a healthy body weight
A variety of vegetables – dark green, red, and orange, fiber-rich legumes (beans and peas), and others
Fruits, especially whole fruits with a variety of colors
Whole grains

Healthy eating does not include:

Red and processed meats
Sugar-sweetened beverages
Highly processed foods and refined grain products

According to the ACS, it is best not to drink alcohol. People who do choose to drink alcohol should limit their consumption to no more than 1 drink per day for women and 2 drinks per day for men.

An estimated 5% of cancers in men and 11% in women are attributed to excess body weight, associated with an increased risk of developing several types of cancer: uterine, esophagus, liver, stomach, kidney, meningioma, multiple myeloma, pancreas, colorectum, gallbladder, ovary, female breast (postmenopausal), and thyroid. There is some evidence that excess body weight may also increase the risk for cancers of the mouth, pharynx, larynx, and male breast, as well as fatal prostate cancer and non-Hodgkin lymphoma.

Evidence is growing about the adverse health consequences of cumulative exposure to excess body fat over the life course as a result of excessive weight that begins during childhood.