Michael Douglas: Stress caused my cancer.

Michael Douglas told the Mirror, UK that he believes that stress played a significant role in his getting cancer: “This type of cancer can be brought on by alcohol and tobacco abuse and by a certain type of sexually transmitted reason, but I look at it as stress. I’ve had a pretty stressful year on a number of fronts, some of which were public and some of which weren’t.” This past year, Douglas’ son Cameron was sentenced to prison for five years for methamphetamine trafficking.

Douglas also told the Mirror: “I’ve always worked hard and played hard and I’m sure I’ll be cleaning up my act in the future. But I’m still looking forward to a good glass of wine when I get my taste buds back… My plans are to lick this cancer but it will probably take four or five months. I’ve always prided myself on putting as much as I possibly can into everything I do and I’m going to beat this.”

Douglas did show up for the New York premier of his latest movie, Wall Street: Greed Never Sleeps on Monday , but did not give any interviews.

Douglas is not the first celebrity we have covered who consider stress to be a factor in their getting cancer. Click here to see our story on Kyle Minogue.

So what do the experts say about stress and cancer?

According to the National Cancer Institute, psychological stress affects the body in many ways. Although a direct relationship between psychological stress and the development of cancer has not been scientifically proven, researchers have suggested that psychological factors may affect cancer progression (increase in tumor size or spread of cancer in the body) in patients who have the disease.

The complex relationship between physical and psychological health is not well understood. Scientists know that psychological stress can affect the immune system, the body’s defense against infection and disease (including cancer); however, it is not yet known whether stress increases a person’s susceptibility to disease.

Psychological stress refers to the emotional and physiological reactions experienced when an individual confronts a situation in which the demands go beyond their coping resources. Examples of stressful situations are marital problems, death of a loved one, abuse, health problems, and financial crises.The body responds to stress by releasing stress hormones, such as epinephrine (also called adrenaline) and cortisol (also called hydrocortisone). The body produces these stress hormones to help a person react to a situation with more speed and strength. Stress hormones increase blood pressure, heart rate, and blood sugar levels. Small amounts of stress are believed to be beneficial, but chronic high levels of stress are thought to be harmful. Chronic stress can increase the risk of obesity, heart disease, depression, and various other illnesses. Stress also can lead to unhealthy behaviors, such as overeating, smoking, or abusing drugs or alcohol, that may affect cancer risk.

Studies done over the past 30 years that examined the relationship between psychological factors, including stress, and cancer risk have conflicting results. Although the results of some studies have indicated a link between various psychological factors and an increased risk of developing cancer, a direct cause-and-effect relationship has not been proven.

Some studies have indicated an indirect relationship between stress and certain types of virus-related tumors. Evidence from both animal and human studies suggests that chronic stress weakens a person’s immune system, which in turn may affect the incidence of virus-associated cancers, such as Kaposi sarcoma and some lymphomas.

More recent research with animal models suggests that the body’s neuroendocrine response (release of hormones into the blood in response to stimulation of the nervous system) can directly alter important processes in cells that help protect against the formation of cancer, such as DNA repair and the regulation of cell growth.

Study results are inconsistent because it is difficult to separate stress from other physical or emotional factors when examining cancer risk. For example, certain behaviors, such as smoking and using alcohol, and biological factors, such as growing older, becoming overweight, and having a family history of cancer, are common risk factors for cancer. Researchers may have difficulty controlling the presence of these factors in the study group or separating the effects of stress from the effects of these other factors. In some cases, the number of people in the study, length of follow-up, or analysis used is insufficient to rule out the role of chance. Also, studies may not always take into account that cancer is not a homogeneous (uniform in nature) disease.

In people who have cancer, studies have indicated that stress can affect tumor growth and spread, but the precise biological mechanisms underlying these effects are not well understood. Scientists have suggested that the effects of stress on the immune system may in turn affect the growth of some tumors. However, recent research using animal models indicates that the body’s release of stress hormones can affect cancer cell functions directly.

A review of studies that evaluated psychological factors and outcome in cancer patients suggests an association between certain psychological factors, such as feeling helpless or suppressing negative emotions, and the growth or spread of cancer, although this relationship was not consistently seen in all studies. In general, stronger relationships have been found between psychological factors and cancer growth and spread than between psychological factors and cancer development.