A Korean study finds trends in breast cancer that are similar to those already documented in Western countries, with a higher incidence rate, a larger proportion of young patients and patients with asymptomatic disease, and treatment trends toward breast-conserving surgery and immediate reconstruction after mastectomy, according to an article in the February issue of Archives of Surgery.

More than 1 million women worldwide develop breast cancer every year and almost 600,000 die, according to background information in the article. Although rates of the disease in Korea remain lower than those in Western countries, the incidence of breast cancer is increasing at a more rapid rate than the world average. This is likely because of continued westernization of the Korean lifestyle, lower birth rates, lower breastfeeding rates and an increase in the number of check-ups for breast cancer, according to the authors.

Byung Ho Son, MD, and colleagues at the University of Ulsan and Asan Medical Center, Seoul, Korea, analyzed data from 5,001 women who underwent surgery for breast cancer at the hospital between July 1989 and March 2004. They examined a number of factors, including age distribution, surgical treatments, staging, survival rate, and risk factors.

Compared with data from 1991, the median (mid-point) age of Korean patients with breast cancer increased from age 44 years to 46 years. About 64.9 percent of cases occurred in premenopausal women younger than age 50. The proportion of asymptomatic patients whose cancer was detected by mammography increased from 3.8 percent in 1991 to 21 percent in 2003. The proportion of early cancers (stages 0 and 1) also increased between 1991 and 2003, from 34.2 percent to 48.8 percent. Although it is increasing, this proportion “is still considerably lower compared with that of Western countries, so we believe that more efforts for early detection of breast cancer through screening are necessary.”

An increasing number of women (39.1 percent from 5.1 percent) opted for breast-conserving therapies rather than radical mastectomy between 1991 and 2003. Of the 67.1 percent of women who received radical mastectomy, 12 percent underwent immediate breast reconstruction. The five-year survival rate among women in the study was 84.1 percent.

The proportion of patients with some risk factors, including early menarche (first menstrual period) and delivering a first child after age 30, was significantly higher among women in the current study than in 1991.

“We believe that the younger generations of Korean women have been directly affected by the progressive westernization of the Korean lifestyle,” the authors wrote. “According to the biennial report of the Korean Breast Cancer Society, the proportion of risk factors, such as early menarche, late menopause, high-fat diet and obesity, was significantly increased among the patients between 1996 and 2000.”

“The present results suggest that the rate of breast cancer in Korea will continue to increase owing to westernized lifestyles, and the clinical characteristics of Korean breast cancer are now reflecting the patterns of Western countries.”