Drop in Cancer Death Rates in US Continues

< Oct. 17, 2007 > -- Death rates from cancer are dropping more quickly across the US, offering what one expert calls a "glimmer of hope" against a leading killer.

According to a new report, cancer death rates fell by 2.1 percent each year from 2002 through 2004 - almost double the 1.1 percent annual decline recorded between 1993 and 2003.

"That's a very encouraging finding. It's the key indicator of progress in cancer," says Dr. David Espey, a cancer epidemiologist from the US Centers for Disease Control and Prevention (CDC) in Atlanta. Dr. Espey is assigned to the Indian Health Service Division of Epidemiology and Disease Control, in Albuquerque, N.M.

Dr. Espey is lead author of the Annual Report to the Nation on the Status of Cancer, 1975-2004, Featuring Cancer in American Indians and Alaska Natives. This report was published in the medical journal Cancer.

The report, which appears annually, is a joint effort from the American Cancer Society (ACS), the CDC, the US National Cancer Institute (NCI), and the North American Association of Central Cancer Registries (NAACCR).

Most Cancer Types See Decline

Data on new cancer diagnoses came from state and regional population-based cancer registries, while data on cancer deaths came from the CDC's National Vital Statistics System.

Death rates declined for many of the top 15 cancers in both men and women. Most notably, men saw declines in death rates for lung, prostate, and colorectal cancers, while women saw declines in colorectal and breast cancer. The breast cancer declines could be due to declines in the use of hormone replacement therapy (HRT), experts say.

In addition, the increase in death rates from lung cancer among women slowed considerably. Lung cancer incidence in women stabilized from 1998 through 2004, after a long period of increases. In men, the lung cancer rate declined 1.8 percent annually from 1991 through 2004.

Rates of colorectal cancer fell by more than 2 percent per year for both men and women, probably because of better screening and removal of precancerous polyps.

Overall, incidence rates for all cancers decreased slightly from 1992 through 2004, after increasing between 1975 and 1992.

"This is the first time we have seen good news in lung cancer," says Dr. Corey J. Langer, director of thoracic and head and neck medical oncology at Fox Chase Cancer Center in Philadelphia. "It's probably mostly a reflection of the drop in smoking rates."

American Indians/Alaska Natives Studied

This year's report also gives a detailed view of cancer in American Indians and Alaska Natives across the US. American Indians and Alaska Natives (AI/AN) generally had lower rates of most cancers than non-Hispanic whites between 1999 and 2004, but they had a higher incidence of cancers of the stomach, liver, kidney, gallbladder, and cervix.

Incidence rates in these populations varied largely depending on the specific geographic region. From 1999 through 2004, AI/AN men from the Northern Plains region and AI/AN women from Alaska and the Northern and Southern Plains had higher incidence rates than non-Hispanic white men and women living in the same areas.

Lung and colorectal cancer incidence rates were the highest in the Northern Plains and Alaska. AI/AN women, regardless of location, were less likely than non-Hispanic white women to be diagnosed with early breast cancer.

AI/AN populations have less access to cancer prevention and control services, experts note. They also have higher smoking rates as well as higher rates of obesity, both of which can contribute to cancer.

"The issue of cancer in Native Americans has not previously been reported this broadly," Dr. Espey says. "The findings point to a need for intervention. These populations have low screening rates. Regionally, there are very specific needs that should drive policy."

Still More Work to be Done

The acceleration in decline of cancer deaths is "a good news story," adds Dr. Langer. "It's the first glimmer of hope in a long time."

"We have a lot of work in colorectal cancer," Dr. Espey says. "We've been making progress in lung cancer, but that's a perennial battle to try to control tobacco use initiation and tobacco cessation."

The "low-hanging fruit" in terms of cancer prevention and early detection right now is colorectal cancer, Dr. Espey continues. Less progress has been made here than in breast and cervical cancer, he says.

“We now have an infrastructure in this country for obtaining high-quality information about new cases of cancer and we can now describe the successes in cancer interventions and treatment as well as uncover populations with varying risks and outcomes,” says Holly L. Howe, Ph.D., executive director of NAACCR. “Without this surveillance, we would be ill-equipped to address the challenges we face in further reducing the cancer burden.”

The authors report that earlier detection of disease through screening, improved prognosis through more effective treatment, tobacco control, and reduction in inequalities in cancer care all point to the success of the nation’s dedication and focus on reducing the burden of cancer in the US

Always consult your physician for more information.

More About Cancer

Cancer is an abnormal growth of cells. Cancer cells rapidly reproduce despite restriction of space, nutrients shared by other cells, or signals sent from the body to stop reproduction.

Cancer cells are often shaped differently from healthy cells - they do not function properly, and they can spread to many areas of the body. Tumors (abnormal growth of tissue) are clusters of cells that are capable of growing and dividing uncontrollably; their growth is not regulated.

Oncology is the branch of medicine concerned with the diagnosis and treatment of cancer.

Tumors can be benign (noncancerous) or malignant (cancerous). Benign tumors tend to grow slowly and do not spread. Malignant tumors can grow rapidly, invade and destroy nearby normal tissues, and spread throughout the body.

Cancer is malignant because it can be "locally invasive" and "metastatic":

• locally invasive - the tumor can invade the tissues surrounding it by sending out "fingers" of cancerous cells into the normal tissue.

• metastatic - the tumor can send cells into other tissues in the body, which may be distant from the original tumor.

What causes cancer?

There is no one single cause for cancer. Scientists believe that it is the interaction of many factors together that produces cancer. The factors involved may be genetic, environmental, or constitutional characteristics of the individual.

Diagnosis, treatment, and prognosis for childhood cancers are different than for adult cancers. The main differences are the survival rate and the cause of the cancer. The survival rate for childhood cancer is about 79 percent, while in adult cancers the survival rate is 66 percent. This difference is thought to be because childhood cancer is more responsive to therapy, and a child can tolerate more aggressive therapy.

Childhood cancers often occur or begin in the stem cells, which are simple cells capable of producing other types of specialized cells that the body needs. A sporadic (occurs by chance) cell change or mutation is usually what causes childhood cancer.

In adults, the type of cell that becomes cancerous is usually an "epithelial" cell, which is one of the cells that line the body cavity, including the surfaces of organs, glands, or body structures, and cover the body surface. Cancer in adults usually occurs from environmental exposures to these cells over time. Adult cancers are sometimes referred to as "acquired" for this reason.

Always consult your physician for more information.