Progress in cancer treatment varies by disease
The nation's leading cancer organizations report that Americans' risk of dying from cancer continues to decline and that the rate of new cancers is holding steady. The "Annual Report to the Nation on the Status of Cancer, 1975-2002," published in the Oct. 5, 2005, issue of the Journal of the National Cancer Institute,* shows observed cancer death rates from all cancers combined dropped 1.1 percent per year from 1993 to 2002. According to the report's authors, declines in death rates reflect progress in prevention, early detection, and treatment; however, not all segments of the U.S. population benefited equally from advances, a point outlined in a featured analysis of treatment trends.
First issued in 1998, the "Annual Report to the Nation" is a collaboration among the National Cancer Institute (NCI), which is part of the National Institutes of Health (NIH), the Centers for Disease Control and Prevention (CDC), the American Cancer Society (ACS), and the North American Association of Central Cancer Registries (NAACCR). It provides updated information on cancer rates and trends in the United States.
According to NCI Director Andrew C. von Eschenbach, M.D., "These numbers reflect a trend in reduction of cancer mortality that has now persisted for nine years. This can only be considered good news for the millions of cancer survivors who have benefited from recent research and treatment advances and emphasizes the expectation that we will achieve a time when no one will suffer or die from cancer."
Death rates from all cancers combined declined 1.5 percent per year from 1993 to 2002 in men, compared to a 0.8 percent decline in women from 1992 to 2002.** Lung cancer is the leading cause of cancer deaths in both men and women. Death rates decreased for 12 of the top 15 cancers in men, and nine of the top 15 cancers in women.
"Declines in mortality rates from many tobacco-related cancers in men represent an important, but incomplete, triumph of public health in the 21st century," said John R. Seffrin, Ph.D., chief executive officer of the ACS. "These trends reinforce the importance of tobacco control programs in the U.S., as well as measures to combat the increase in tobacco use in other parts of the world, particularly in developing countries."
Overall cancer incidence rates (the rate at which new cancers are diagnosed) for both sexes have been stable since 1992. Incidence rates were stable in men from 1995 to 2002 and increased 0.3 percent annually in women from 1987 to 2002. The persistent increase in overall cancer incidence rates for women can be attributed to increases in rates for breast and six other cancers: non-Hodgkin lymphoma, melanoma, leukemia, and thyroid, bladder and kidney cancer. However, according to more recent data from 1998 to 2002, female lung cancer incidence rates have begun to stabilize after increasing for many years, which is good news. Changes in overall incidence may result from changes in the prevalence of risk factors and from changes in detection practices due to introduction or increased use of screening and/or diagnostic techniques.
This year's report highlights patterns of care for cancer patients. The authors note that one strategy for reducing death and improving cancer survival is to ensure that evidence-based treatment services are available and accessible. In performing this analysis, the authors looked at data from NCI's Patterns of Care studies (which supplement routine data collection from NCI's Surveillance, Epidemiology and End Results, or SEER Program, with more detailed data on treatment patterns) and SEER-Medicare databases (which link data from SEER registries to Medicare claims data to assess treatment histories for those over age 65), as well as other resources. Using these data, they examined whether evidence-based care was delivered uniformly to diverse populations and how rapidly changes in evidence-based guidelines resulted in changes in cancer care.
"Day by day we are winning the war against cancer as more people than ever before are being screened and are receiving treatments necessary for them to lead healthy and productive lives," said CDC Director Julie Gerberding, M.D. "However, there are gaps and missed opportunities so we must continue to pull out all the stops to ensure proper screening and access to treatment regardless of one's age, race, or geographic location."
For breast cancer, data on trends in the treatment of early-stage disease show that the proportion of women diagnosed with stage I or II (earlier stage) breast cancer who received breast-conserving surgery with radiation treatment increased substantially during the 1990s. This change followed evidence-based guidelines that breast-conserving surgery followed by radiation therapy may be preferable to mastectomy because it provides similar survival but preserves the breast.
The authors also report findings of a separate study on use of chemotherapy and radiation therapy for women with early-stage breast cancer. For women with lymph node positive disease, multi-agent chemotherapy, along with tamoxifen (a hormonal therapy) for those with estrogen-receptor positive tumors, has been recommended since 1985 by the NIH. This study found that, between 1987 and 2000, the proportion of women who received both chemotherapy and tamoxifen increased substantially. However, use of concurrent therapy remained relatively low among women age 65 and older, who were more likely to receive tamoxifen only.
For colorectal cancer, the authors found that use of adjuvant (additional treatment that follows initial surgery) chemotherapy for stage III colon cancer patients increased rapidly between 1987 and 1995. However, delivery of this therapy was uneven across age groups, with much lower rates of treatment among patients age 65 and older. Also noted was the fact that the number of patients who received treatment decreased with the increasing number of pre-existing medical conditions, but the likelihood of receiving adjuvant therapy decreased with age even after taking other medical conditions into account. For patients with advanced non-small cell lung cancer, evidence-based guidelines recommend that chemotherapy may be beneficial for patients who are well enough to withstand the treatment. One analysis found that, among patients age 65 and older diagnosed with this type of lung cancer between 1991 and 1993, only 22 percent received chemotherapy. A study of patients diagnosed in 1996 found similarly low levels of treatment among patients age 65 and older. However, more recent studies have found increasing trends in the late 1990s in the use of chemotherapy among late-stage non-small cell lung cancer patients.
Unlike breast and lung cancers, treatment for prostate cancer is more controversial. The most notable trend in prostate cancer treatment from 1986 to 1999 was the decreasing proportion of cases that received watchful waiting, surgical or chemical castration, or hormonal deprivation therapy as primary treatment. More aggressive treatments, including newer radiation techniques, were found to be on the rise. However, black men were found to receive substantially less aggressive treatment than white men.
The report concludes that substantial geographical variations in treatment patterns exist, but that much of contemporary cancer treatment is consistent with evidence-based NIH Consensus Development Statements (http://consensus.nih.gov/ ), which are considered a "gold standard" for care recommendations.
"The value of cancer registries in population research is immeasurable. Through linkage with other data systems, the information can give us insight into getting effective treatments to the general population that will have an impact on survival and mortality," said NAACCR Director Holly L. Howe, Ph.D.
The authors also examined racial and ethnic disparities in cancer. From 1992 to 2002, prostate, lung, colon/rectum cancer in men, and breast, colon/rectum, and lung cancer in women, continue to be the leading sites for incidence and mortality for each racial and ethnic population. Rates for lung and prostate cancer decreased among men in all populations, while colorectal cancer incidence rates decreased only for white men. Among women, breast cancer incidence rates increased in Asian Pacific Islander women, decreased among American Indian/Alaska Native women, and were stable for other women. Colorectal incidence rates decreased only for white women. Differences in cancer incidence and mortality persist, especially among black men, who have 25 percent higher incidence rates and 43 percent higher mortality rates than white men for all cancers combined.
The authors emphasize that reaching all segments of the population with high-quality prevention, early detection, and treatment services could reduce cancer incidence and mortality even further, and that monitoring the dissemination of cancer treatment advances is an important aspect of ensuring uniformly high standards of care.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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