Research Brief: Annual Report to the Nation on the Status of Cancer

The American Cancer Society, the Centers for Disease Control and Prevention, the National Cancer Institute, and the North American Association of Central Cancer Registries collaborate annually to provide updates on cancer incidence and death rates and trends in these outcomes for the United States. This year’s Annual Report to the Nation on the status of cancer, 1975-2010 includes the prevalence of comorbidity (the simultaneous presence of two chronic diseases or conditions in a patient, such as diabetes, chronic lung disease, cardiovascular disease and others) at the time of first cancer diagnosis among Medicare patients with lung, colorectal, breast, or prostate cancer. The report also reported on survival among these cancer patients based on the level of comorbidity found.

The analysis is based on population-based data on newly diagnosed invasive cancers obtained from registries that participate in the National Cancer Institute’s SEER (Surveillance, Epidemiology, and End Results) Program and/or the National Program of Cancer Registries managed by the Centers for Disease Control and Prevention.

Incidence Rates

Cancer incidence rates track the number of new cancer cases per 100,000 persons. The rates are then “age-adjusted” based on the 2000 U.S. standard population, to make groups with different age distributions more comparable. Age adjustment takes into account, for example, that an area with a lower rate of death or hospitalization may also have a higher percentage of younger people compared to an area with a higher percentage of elderly people who use hospital services with greater frequency.

Continuing trends found in other recent reports, the overall cancer incidence rates decreased from 2001 to 2010 by 0.6 percent per year among men. The rates were stable among women, and increased by 0.8 percent per year among children to age 19, continuing a trend dating back to 1992.

During the 2001-2010 time period, incidence rates decreased for six of the 17 most common cancers among men (prostate, lung, colon and rectum, stomach, larynx, and brain and other nervous systems) and increased for eight others (kidney, pancreas, liver, non-Hodgkin lymphoma, thyroid, leukemia, melanoma of the skin, and myeloma).  Among women, incidence rates decreased for six of the 18 most common cancers (colon and rectum, bladder, cervix, oral cavity and pharynx, ovary, and stomach), and increased for eight others (thyroid, melanoma of the skin, kidney, pancreas, leukemia, liver, myeloma and uterus).

In addition to changes in exposure to certain risk factors, incidence rates may also change as a result of differences in disease classification, updates to data collection systems, variability in population estimates, and changes in diagnostic practices. After previously increasing for many decades, for example, breast cancer incidence declined sharply between 2002 and 2003 likely due to a decrease in the use of postmenopausal hormone-replacement therapy. Then, the incidence rates stabilized to 2010. In addition, the rates of diagnosis of advanced breast cancers have remained stable since 1975 despite an increase in early stage breast cancer diagnoses.

Death Rates

Following many years of a sustained increase in cancer mortality, death rates (the number of deaths per 100,000 persons, also “age-adjusted” based on the 2000 U.S. standard population) began to stabilize and then decline for both men and women in the early 1990s, and among children since the 1970s. From 2001 through 2010, death rates declined for all cancers combined for men and women of all major racial and ethnic groups and for most major cancer sites. However, the average annual decline was slightly larger for men (1.8 percent per year) than it was for women (1.4 percent per year).

Of the 17 most common cancers in men, death rates declined for 11 of them (lung, prostate, colon and rectum, leukemia, NHL, esophagus, kidney, stomach, myeloma, oral, and larynx). Of the 18 most common cancers in women, there was a decline in the death rate for 15 of them (lung, breast, colon and rectum, ovary, leukemia, NHL, brain, myeloma, kidney, stomach, cervix, bladder, esophagus, oral, and gallbladder). Decreased rates of death for lung, colorectal, breast, and prostate cancers accounted for more than two-thirds of the overall reduction in cancer death rates from 2001 to 2010.

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Source: NCI Press Release posted Dec. 16, 2013.

The rate of death from lung cancer, which accounts for more than 25 percent of cancer deaths, dropped faster than in previous years. The report speculates that this decline reflects a decrease in cigarette smoking, however, lung cancer remains the leading cause of cancer death in both men and women. Death rates also increased for some cancers (e.g., liver and pancreas for both men and women; cancers of the uterus in women; and, in men only, melanoma of the skin and soft tissue cancers).

Despite the overall decline in the cancer death rate, the Cancer Journal for Clinicians estimated 1,665,540 new cancers diagnosed in the United States and 585,720 cancer deaths in 2014. In addition, data from the National Cancer Institute show a slowdown in the decline in the breast cancer death rate. The five-year survival rate for people diagnosed with metastatic breast cancer is still only about 20 percent (with an average prognosis of two to four years). An estimated 20 to 30 percent of women diagnosed with invasive breast cancer have a recurrence of the disease, and nearly 40 thousand women and hundreds of men die of metastatic breast cancer every year, a number that has barely changed in four decades.

Comorbidities and Cancer

The report also discussed how comorbidities affect cancer outcomes. By linking cancer registries with data from Medicare claims, the researchers analyzed the prevalence of comorbidities and their impact on survival for people diagnosed with lung, colorectal, breast, and prostate cancer in the year prior to the cancer diagnosis.

Overall, forty percent of patients aged 66 years or older who had any of these four cancers also had at least one comorbidity, with the four most common being diabetes, chronic lung disease, congestive heart failure, and cerebrovascular disease. In total, sixteen comorbidities were identified including heart attack, AIDS, stroke, chronic kidney failure, chronic hepatitis, and others.

Prevalence Comorbidities

Source: NCI Press Release posted Dec. 16, 2013.

Lung cancer had the highest prevalence of comorbidities (52.9 percent) and 40.7 percent of patients with colorectal cancer had them. The prevalence for those with breast cancer (32.2 percent) or prostate cancer (30.5 percent) was similar to those of non-cancer patients (31.8 percent).

For women aged 66 to 74 who were diagnosed with early-stage breast cancer, those who had low or moderate comorbidity levels had twice the probability of death compared to the women with no comorbidity, and the probability of death was three times greater for women with severe comorbidity. Even after accounting for these, patients with advanced cancers still had higher death rates. The influence of comorbidities on survival for lung cancer, for example, was relatively small most likely because the prognosis is often poor even at early stages of the disease.

The Annual Report highlights that the prevalence of comorbidity does have an impact on survival for older persons diagnosed with lung, colorectal, breast, or prostate cancer. The report did not analyze the impact of comorbidities on survival for patients younger than age 66. However, the findings suggest that the presence of multiple chronic conditions or diseases must be taken into account when caring for cancer patients and making clinical decisions. The report states as well that comorbidity-adjusted survival data would be more useful for clinical decision making if the analyses could be stratified by treatment and other prognostic markers.

Source: Edwards BK, Noone AM, Mariotto AB, Simard EP, Boscoe FP, Henley SJ, Jemal A, Cho H, Anderson RN, Kohler BA, Eheman CR, Ward EM, et al. 2013. Annual Report to the Nation on the Status of Cancer, 1975-2010, Featuring Prevalence of Comorbidity and Impact on Survival Among Persons with Lung, Colorectal, Breast, or Prostate Cancer. Cancer.

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