Diseases - Cancer Trends

As we saw in Chapter 1, cancer is the second most common cause of death in the United States. The graphic shows a 20-year history of the eight most common cancers. Trends are expressed as death rates per 100,000 population. Death rates are age-adjusted so that results from one year to the next are comparable despite changes in the population's age structure. A value of 57.6 for lung cancer means that of a population of 100,000, 57.6 people die of lung cancer. If only females are reported (breast cancer), only the female population is used.

What trends do we see? In cases in which new diagnostic methods are available and used, cancers are being detected earlier, survival rates are improving, and the death rate is trending down. Cancers that arise from — or are in some way linked with — human pleasures have been gaining ground. Difficult-to-detect cancers continue to have roughly the same death rate at the end as they had at the beginning of the 20-year period shown.

Death rates from lung cancer and lymphoid cancer and leukemia (the last two shown in combination) have been increasing. Lung cancer survival rates ("still alive 5 years after diagnosis") have improved slightly for whites, from 13.1 to 14.5% of patients from 1974-1979 to 1989-1996. For blacks the rate in these two periods has been the same, 11.3% of patients. Primary lung cancer — cancer that has not spread to the lungs from other organs — is principally caused by cigarette smoking. Note that since 1990 the death rate has flattened and now seems to be declining — as smokers quit.

Lymphoid cancer, or, Non-Hodgkin's lymphoma, has shown increased survival rates, from 48.2% to 52.6% of whites — but a decline from 50.5% to 41.9% for blacks. The disease is treated with radiation and chemotherapy. Leukemia survival has improved for both whites and blacks — 36.7% to 45.4% for the former, 31% to 34% for the latter. Leukemia is a cancer of the blood cells. Treatment usually involves chemotherapy. Lymphoma appears when the immune system is suppressed; one kind of leukemia is produced by a sexually transmitted virus (human T-cell leukemia virus). Thus the uptrend in the death rate for these two families of cancers may be linked to the HIV epidemic and loosening of sexual restraints — younger and younger onset of sexual activity, more partners, etc.

Prostate cancer in men, breast cancer in women, and colorectal and stomach cancer in both sexes are down — substantially so for breast and colorectal cancers. These are all cases where methods of early diagnosis/screening have been developed. The story of prostate cancer is presented in full in Chapter 1 (see Men's Health: Prostate Cancer). Breast cancer has been declining because mammography works. Excellent screening tools have been developed for colorectal cancer. Stomach cancer requires an upper-GI examination; barium is swallowed, X-rays are taken. The highest survival rates are seen (1989-1996) by white men for prostate cancer (94.1%); breast cancer survival is high as well (86.3% for whites and 71.4% for blacks). Stomach cancer survival is lowest for whites (15.9%) and only somewhat better for blacks (21.6%). (All survival rates are shown in Part II in tabular format.)

Pancreatic cancer causes loss of appetite, weight loss, abdominal discomfort, and nausea. Diagnosis may require a biopsy, and may be delayed because the initial symptoms are not very specific. Only about 20% of cases can be treated surgically. Survival rate is quite low. In the 1989-1996 time frame, it was 4.2% of patients. The disease is thought to be linked to smoking in some way. The death rate has been virtually unchanged in the last 20 years. It was 10.7 in 1979 and 10.6 in 1998.

Ovarian cancer is rare. Its symptoms are vague. It often has spread by the time of diagnosis. Outcomes are often poor although slight decreases in the death rate have been seen. Rates for cervical cancer and uterine cancer (not shown on the graphic) have both improved. Deaths from cervical cancer have dropped from 4.6 to 3.0 between 1978 to 1998; those from uterine cancer from 5.0 to 4.1. Pap smears are used to screen for cervical cancer. Uterine cancer usually requires dilation and curettage (D&C). Survival rates are high.

Source: Centers for Disease Control and Prevention. National Center for Health Statistics. National Vital Statistics System. Online. Available: http://www.cdc.gov/nchs/default.htm. May 29, 2002; and MEDLINEplus. Online. Available: http://www.nlm.nih.gov/medlineplus/ency/article/001566.htm. Survival rates are from the National Institutes of Health, National Cancer Institute, from Health, United States, 2002, Table 57.