More than 1.5 million cancer deaths averted during 2 decades of dropping mortality

http://www.eurekalert.org/pub_releases/2014-12/acs-mt1123014.php

Public Release: 31-Dec-2014
American Cancer Society

Jan. 6, 2015-The American Cancer Society's annual cancer statistics report finds that a 22% drop in cancer mortality over two decades led to the avoidance of more than 1.5 million cancer deaths that would have occurred if peak rates had persisted. And while cancer death rates have declined in every state, the report finds substantial variation in the magnitude of these declines, generally with the states in the south showing the smallest decline and in the Northeast the largest decline.

•••••

Largely driven by rapid increases in lung cancer deaths among men as a consequence of the tobacco epidemic, the overall cancer death rate rose during most of the 20th century, peaking in 1991. The subsequent, steady decline in the cancer death rate is the result of fewer Americans smoking, as well as advances in cancer prevention, early detection, and treatment.

•••••

"The continuing drops we're seeing in cancer mortality are reason to celebrate, but not to stop," said John R. Seffrin, PhD, chief executive officer of the American Cancer Society. "Cancer was responsible for nearly one in four deaths in the United States in 2011, making it the second leading cause of death overall. It is already the leading cause of death among adults aged 40 to 79, and is expected to overtake heart disease as the leading cause of death among all Americans within the next several years.

•••••

Each year, Cancer Facts & Figures includes a Special Section that focuses on a specific, timely cancer topic. This year, the report highlights breast carcinoma in situ. An estimated 60,290 new cases of breast carcinoma in situ are expected to be diagnosed in 2015, accounting for about one in five breast tumors diagnosed in women. Although in situ breast cancer is a relatively common diagnosis, it is not as widely known or understood as invasive breast cancer.

The term "carcinoma in situ" describes abnormal cells that have not invaded nearby tissues, but that look very similar to cells of invasive carcinoma when viewed under a microscope. For many years, it was assumed that these cells were potentially able to become invasive, and that in the absence of treatment, they would eventually progress to cancer. More recent research indicates that the transition from normal tissue to carcinoma in situ to invasive carcinoma involves a series of molecular changes that are more complex and subtle than the older view based on microscopic appearances. Long-term follow-up studies of patients with carcinoma in situ also find that even without treatment, not all patients develop invasive cancer.

The vast majority (83%) of in situ breast cancers will be ductal carcinoma in situ (DCIS). DCIS refers to abnormal cells lining the breast duct that appear similar to those of invasive breast cancers, but are still within the tissue layer of origin. It is most often detected by a mammogram. While DCIS cannot spread to other organs and cause serious illness or death, it has the potential if left untreated to evolve into invasive cancer and is considered a true cancer precursor. Studies of women with DCIS that was untreated because it was originally misclassified as benign found that 20 to 53% were eventually diagnosed with an invasive breast cancer.

Lobular carcinoma in situ (LCIS) refers to cells that look like cancer cells growing within the walls of the lobules of the milk-producing glands of the breast. LCIS is not generally thought to be a precursor of invasive cancer, but is considered a marker for increased risk of developing invasive breast cancer.

The authors say they hope that the information in the Special Section will help patients facing the disease, as well as friends, family, and others who can provide support and perspective for women who are newly diagnosed and those living after a diagnosis of DCIS or LCIS.