Older women who had other health problems when they were first diagnosed with breast tumors received less aggressive cancer treatment and pretreatment assessments than women who were younger and healthier, according to a new study by the National Institute on Aging (NIA) and the National Cancer Institute (NCI). The study characterizes the health problems that postmenopausal women may have concurrent with breast cancer.
"There is a major gap in knowledge about diseases that are associated with age and their impact on the cancer trajectory, prognosis, and treatment," said lead author Rosemary Yancik, PhD, chief of the cancer section of the NIA's Geriatrics Program. "We want to improve the knowledge base of health conditions that women have in addition to newly diagnosed breast cancer because these could affect the care, treatment, and outcome of the malignancy." Yancik conducted the study with Margaret Wesley, PhD (Information Management Services in Silver Spring, MD), Lynn Ries, MS, (NCI), Richard Havlik, MD, MPH, (NIA), Brenda Edwards, PhD, (NCI), and Jerome Yates, MD, MPH (Roswell Park Cancer Institute in Buffalo, NY). The Effect of Age and Comorbidity in Postmenopausal Breast Cancer Patients Aged 55 Years and Older appears in the Journal of the American Medical Association (Feb. 21, 2001).
The NIA/NCI study included 1800 postmenopausal patients to ascertain the other health problems they had when they were first diagnosed with breast cancer. This information was merged with other medical record data on the patients' tumors collected from six regional NCI Surveillance, Epidemiology, and Ends Results (SEER) cancer registries.
This study included women with breast cancer in three age groups: 55 to 64 years, 65 to 74 years, and 75 years and older. In all age groups, hypertension was the most prevalent condition followed by arthritis. Severe heart disease affected less than 6 percent of patients 55 to 59 years but increased to second or third among conditions affecting the oldest age groups. Overall, 13 percent of the group had a previous cancer. Other diseases that became more prevalent with age were eye problems, low-severity heart disease, anemia, depression, fractures, hearing problems, osteoporosis, Parkinson's disease, renal failure, and low-severity urinary tract problems. Almost half (49 percent) of the group had 1 to 3 other preexisting health conditions (i.e., comorbidities), one-third (34 percent) had 4 to 6 comorbidities, and 9 percent had 7 to 13 comorbidities. Seven percent had no comorbidities recorded.
"For many older women, cancer occurs in individuals who already may be coping with other physical illnesses. An older woman is likely to have age-related health conditions. We wanted to know what are those other conditions and how they interact with the breast cancer. We now know, thanks to the study," Yancik said.
Women 70 years and older who had diabetes requiring insulin, stroke, gastrointestinal tract problems, mental health problems, and previous cancers were "significantly less likely" to receive axillary lymph node dissections (AxLND) compared to the youngest age group, according to the study. AxLND, a procedure with its own risks, is used to establish the prognosis or stage of the breast cancer. The stage of the disease is a strong indicator of survival for breast cancer patients. Reasons that the older women did not receive this staging procedure as frequently were undefined but the absence of adequate staging is likely to lead to substandard treatment and poorer survival.
Women in the older age groups with preexisting diseases also tended to receive less aggressive cancer treatment, according to the study. The preferred treatment for breast cancer is a partial mastectomy (also known as a lumpectomy) and radiation or a modified radical mastectomy, according to the 1990 NIH Consensus Statement for Treatment of Early Stage Breast Cancer. Of those who received partial mastectomies, older patients received radiation therapy less frequently.
Among those who had early stage disease and an AxLND, the older women were lesslikely to also receive breast-conserving surgery (9 percent vs. 41 percent). Poor health status may interact with the breast cancer and its treatment, increasing the severity of other conditions and the risk of death from causes other than breast cancer, according to the study.
More research is crucial to determine if treatment should differ according to age and health status, say the authors. In addition, Yancik advocates research and development of an assessment tool – a comorbidity index – that clinicians can use to communicate with each other about the influence of age-related diseases on the cancer. Breast cancer is second only to lung cancer as the most common cause of cancer death in women. Two-thirds of breast cancer cases occur in women over 55, with the highest rates of breast cancer occurring in women aged 70 to 84 years. Breast cancer could become an even greater public health concern as the proportion of women over 65 increases from the current 14.5 percent to 21.3 percent in 2030.
The study is part of a series of collaborative investigations by the NIA's Epidemiology, Demography, and Biometry Program and the NCI SEER Program to determine the impact of preexisting diseases on treatment of various types of cancer. In 1997, Yancik and her colleagues published a similar study on colon cancer.
The NIA and the NCI are two of the 26 institutes and centers at the National Institutes of Health. NIA (www.nia.nih.gov) supports basic, clinical, epidemiological and social research on aging. The NCI (www.cancer.gov) fights cancer by supporting and conducting research in cancer biology, causation, prevention, detection, treatment, and survivorship.