The overall rate at which Americans were either diagnosed with or died from cancer decreased in the 1990s, according to a new report. This is a reverse in the pattern of increasing cancer rates that occurred from 1973 to 1992. However, breast cancer and a few other cancers were exceptions to the decline. The rate of breast cancer actually increased by more than 40% from 1973 to 1998. The report also shows increases in the number of female deaths from lung cancer, and increases in the incidence of other cancers including non-Hodgkins lymphoma, liver cancer, and melanoma skin cancer.
"These findings highlight the progress weve made against cancer but also underscore the critical need for research and for equitably applying what we already know to sustain this progress," said Richard D. Klausner, MD, Director of the National Cancer Institute (NCI), in NCI press release. The study was a collaboration of the North American Association of Central Cancer Registries (NAACR), the Centers for Disease Control and Prevention (CDC), the American Cancer Society, (ACS), and the NCI. The results are published in the June 6, 2001 issue of the Journal of the National Cancer Institute.
When looking at all cancers combined, the rate at which Americans were diagnosed with cancer decreased by 1.1% from 1992 to 1998, according to Holly L. Howe, PhD, of the NAACR, and her colleagues (rate is defined as the number of cases per 100,000 people). This is in contrast to the increase in cancer incidence between 1973 and 1992. The overall death rate from cancer also declined from 1994 to 1998 by 1.4%. Data show that the number of deaths from cancer increased from 1973 to 1991 and then leveled off between 1991 to 1994 before they began to decline.
According to the researchers, the decline in cancer diagnoses in the 1990s was mainly due to decreases in cancer rates among white males and African-American males. The four leading types of cancer among all racial and ethnic groups were lung/bronchus cancer, prostate cancer, breast cancer, and colorectal cancer. With the exception of breast cancer, African-Americans had the highest level of incidence and death from these cancers compared to whites, Asian and Pacific Islanders, American Indians/Alaska Natives, or Hispanics.
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While the overall rate of cancer decreased in the 1990s, the rate of breast cancer increased by 1.2% from 1992 to 1998. When examining data from 1973 to 1998, the researchers found that the number of breast cancer cases rose by more than 40%, from 82.6 cases per 100,000 to 118.1 per 100,000.
One possible explanation for the increased number of breast cancer cases is the significant improvement and widespread use of screening mammography. Mammography helps detect breast cancer in its early stages when the chances for successful treatment and survival are the greatest. The increase in breast cancer cases was only seen among early stage cancers (Stage I and Stage II) and in Stage 0 cancers (called "in situ" cancers) in women over age 50. There was no increase in the rate of late stage breast cancers. Researchers do not know to what extent factors such as an increased rate of obesity (being excessively overweight) or the use of hormone replacement therapy (HRT) contributed to the higher breast cancer rate.
While the incidence of breast cancer increased in the 1990s, the number of deaths from the disease decreased by 1.6% each year from 1989 to 1995 and then by 3.4% from 1995 to 1998. The decrease in breast cancer deaths can most likely be attributed to improvements in early detection and treatment. According to the report, the highest number of breast cancer deaths was among African-American women. Also, breast cancer was the leading cause of cancer death in Hispanic women in the 1990s.
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The report also found the following trends with respect to other types of cancer:
- Lung cancer: Lung cancer is the leading cause of cancer death among both men and women of all races except for Hispanic women (breast cancer is the leading cause of death among these women). Lung cancer rates decreased among men in the 1990s and leveled off among women. However, the death rate from lung cancer increased among women in the 1990s. This may be due to a reluctance to quit smoking.
- Colorectal cancer: Cancers of the colon and rectum increased until 1985, decreased through 1995, and leveled off through 1998. Deaths from colorectal cancer decreased among most races in the 1990s and remained stable among African-American females. Early detection and improved treatments are thought to be responsible for the decrease in deaths.
- Prostate cancer: The incidence of prostate cancer among men increased between 1992 and 1998 with the advent of the PSA blood test used to screen for prostate cancer. However, prostate cancer diagnoses decreased after 1992. Deaths from prostate cancer decreased among white and African-American men since the mid-1990s.
In addition to breast cancer and the increased number of deaths from lung cancer, the researchers also found an overall increase in the following types of cancers:
- Non-Hodgkins lymphoma (cancer of lymphatic tissue)
- Liver and intrahepatic bile duct
- Esophagus
- Melanoma (type of skin cancer)
- Acute myeloid leukemia (cancer of blood-forming cells)
- Soft tissue, including heart
- Thyroid
- Small intestine
- Vulva
- Peritoneum, omentum, and mesentery (abdominal lining and two folds of the lining)
In many cases, the earlier cancer is detected, the greater the chances it can be successfully treated. Regular physical examinations and cancer screening exams can increase the chances of detecting cancer at an early stage. Click here to learn about the different screening exams and when to begin having these exams.
- The report discussed in this article is published in the June 6, 2001 issue of the Journal of the National Cancer institute, http://jnci.oupjournals.org/
- The June 5, 2001 National Cancer Institute/American Cancer Society/Center for Disease Control and Prevention/North American Association of Central Cancer Registries news release, "Annual Report Shows Overall Decline in U.S. Cancer Incidence and Death Rates; Feature Focuses on Cancers with Recent Increasing Trends," is available at http://newscenter.cancer.gov/pressreleases/reportnation.html
- The National Cancer Institute/American Cancer Society/Center for Disease Control and Prevention/North American Association of Central Cancer news release, "Questions and Answers: Annual Report to the Nation on the Status of Cancer, 1973-1998; Feature Focuses on Cancers With Recent Increasing Trends," is available at http://newscenter.cancer.gov/pressreleases/reportq&a.html
- To learn more about cancer, please visit http://www.imaginis.com/cancer/
- To learn more about breast cancer, please visit http://www.imaginis.com/breasthealth/breast_cancer.asp