Why the Disadvantaged Are More Likely to Die of Cancer

NEW YORK—The disadvantaged, once they have cancer, are then more likely to die from it, according to Prof. Harry Burns. "Poverty influences cancer in some quite unexpected ways," said Prof. Burns, director of public health, Greater Glasgow Health Board, Glasgow, Scotland. "The politicians, and all of us as voters, have a responsibility to think about this."

Speaking at a conference sponsored by Gilda’s Club International and Marie Curie Cancer Care, Prof. Burns drew upon medical research and social theory to suggest why poor persons living in deprived areas are more likely to get and die from cancer.

Scottish data show that there is an approximate 10% decrement in survival between affluent and deprived Glasgow residents across a whole range of common cancers, including breast cancer, colon cancer, non-Hodgkin’s lymphoma, and melanoma. Five-year survival in breast cancer is 58% and 48%, respectively, for the most affluent and most deprived Glaswegians.

Evidence that these higher cancer mortality rates in the poor are not just related to smoking, diet, and other lifestyle choices can be found in a comparison of four major cohort studies, he said.

The comparison shows that the average annual rate of death from lung cancer among individuals who smoke an average of 20 cigarettes per day is similar (around 100 per 100,000 individuals) for cohorts of US veterans, UK doctors, and American Cancer Society volunteers. By contrast, a cohort of smokers in the West of Scotland showed a risk of dying of lung cancer about 3.5 times higher.

A large part of that excess mortality was related to socioeconomic status: Lung cancer death rates were significantly higher among manual laborers who smoked, compared with nonmanual laborers who smoked the same number of cigarettes.

Likewise, breast cancer mortality appears related to socioeconomic status. The Scottish data show that while affluent women are more likely to have breast cancer, mortality rates are about the same across economic strata, suggesting that poorer women are more likely to die of breast cancer when they have it.

The data show that deprived women have, on average, larger tumors and are more likely to have lymph node involvement. Deprived women are also more likely to have a poorly differentiated tumor and are less likely to have a large number of estrogen receptors. "These poor women appear to have different kinds of breast cancer, and this may account for the bigger risk of larger tumors at presentation," Prof. Burns said

Treatment differences do not appear to account for the mortality discrepancy, he said. Further analysis did not reveal any evidence that adjuvant therapy was used less often in deprived women.

Interestingly, psychological state, as reflected in measures such as hope for the future, could account for some of the difference, Prof. Burns said. Everson et al (Psychosom Med 58:113-121, 1996) showed that Finnish males with a higher level of hopelessness, after adjusting for cigarette and alcohol consumption, were four times more likely to die prematurely of heart disease as men with a more optimistic view, and were 2.5 times more likely to die of cancer. "The only difference was degree of negativity about the future," Prof. Burns said.

Subsequently, Dr. Everson and colleagues studied degree of carotid artery thickening in men over 4 years, according to the level of hopelessness they reported at baseline. They found faster progression of carotid atherosclerosis in the men who reported higher levels of hopelessness. "The hopeless men were experiencing activation of adrenals, leading to mobilization of fatty acids and deposition in the arteries," Prof. Burns said. "This was the first time that we had a biological explanation for effects of environmental unease."

Prof. Burns said he would like to see patient organizations such as Gilda’s Club Worldwide and Marie Curie Cancer Care form an alliance to question the system on social issues that "we as doctors don’t dabble in." He added that physicians should not be surprised "if we see a high risk of cancer in our deprived, threatening communities, where there is unemployment, poverty, negativity about the future, and stress from violence."