The death rate from breast cancer dropped by almost 5 percent from 1989 to 1992, the most recent year for which statistics are available, according to new federal figures released this week.
The decline for white women was 5.5 percent, which Dr. Samuel Broder, director of the National Cancer Institute, said was the largest decrease since 1950.
Among African-American women, however, the rate of death increased over the three year period, going up 2.6 percent. Breast cancer is one of many diseases that kill African-Americans disproportionately.
The largest single factor in the decline, according to Broder, speaking to a federal cancer advisory board, was the increased use of “adjuvant therapy” - anti-cancer drugs and radiation in addition to surgery. He also pointed to breast cancer awareness and screening by mammography, as well as changes in risk factors like diet, fertility and oral contraceptive use, as important factors in the decline.
The overall decline among American women was 4.7 percent from 1989 to 1992.
There were 27.5 breast cancer deaths per 100,000 women in 1989, 27.4 in 1990, 27.1 in 1991, and 26.2 in 1992. The data come from the National Center for Health Statistics project called SEER, for Survey, Evaluation and End Result.
“This is very encouraging news. We invested in research and it looks like it has paid off,” said Dr. Robert A. Smith, director of the department of detection and treatment at the American Cancer Society. “And with some other drugs coming on line, and screening continuing to increase, it is possible that the trend will continue.”
Dr. Larry Kessler, chief of the applied research branch of the National Cancer Institute, said: “This is the first really good news in breast cancer in a very long time.” He said the numbers were fresh, and it would take some time to analyze them to determine how likely they are to begin a new, positive trend and what caused them in the first place.
But, he said, “There are three reasons to think these numbers are real and may continue.”
“First, there is a documented improvement in the outcomes of adjuvant therapy, especially in young women.” The best improvement in the death rates announced on Thursday were among young women. The death rate declined 8.7 percent for women aged 30 to 39, 8.1 percent for women 40 to 49, and 9.3 percent for women 50 to 59.
The decline in the rate for those 60 to 69 was lower, 4.8 percent. For those 70 to 79, the rate decreased 3.4 percent. And for women 80 to 89, the numbers increased about 1 percent.
The second reason, said Kessler, is that the rate of women who have routine screening mammograms “went from next to nothing in the early 1980s to 17 percent in 1987, and to 33 percent in 1990, and they are still going up.”
He added that the trend appears to be real because it includes a decline over three years and a substantial decline for two years in a row, 1991 and 1992.
The change over the past 10 to 15 years in the screening and treatment of breast cancer is chiefly one of earlier, more aggressive action in giving women radiation and chemotherapy, while cutting out less breast tissue surgically. For example, 15 years ago a woman whose breast disease was detected early and whose lymph nodes didn’t show signs of cancer, might not have been given radiation or chemotherapy until the disease had spread.
Today it is more likely that she would get a lumpectomy, in which only the tumor is cut out of the breast, followed by radiation treatment and chemotherapy.
“The difference is that we are likely to treat breast cancer with more intense drugs, with higher doses than 15 years ago. Also we have found groups, such as older women, who respond to chemotherapy as well as hormone therapy, which we did not expect,” said Dr. Michael A. Friedman, associate director of the cancer therapy evaluation program at the National Cancer Institute.
In a talk before the National Cancer Advisory Board on Wednesday, at which the data were first reported by the cancer institute, Broder said the new information that led to the change in therapy came from studies carried out in the 1980s. That led to a “clinical alert” in 1988 from Dr. Vincent DeVita, then the director of the National Cancer Institute, who recommended that doctors change their practice to include more radiation and chemotherapy.