A Relationship Between Diet and Breast Cancer Survival?
A recent study in the journal Cancer takes a leap forward in defining the role of diet in survival after the diagnosis of breast cancer.
Study participants were a group of 1,982 female registered nurses who completed a food frequency questionnaire after being diagnosed with invasive breast cancer between 1976 and 1990. The questionnaire assessed their intake of 83 different nutrients, total calories, and alcohol. Of particular interest to researchers were intake of fat, vitamin A, and alcohol, because these dietary factors were hypothesized to have an association with survival.
Surprisingly, the study found no significant association between fat intake and risk of death. Although the risk of death was slightly elevated in those with the highest fat intake compared with those with the lowest, the result was not found to be statistically significant. Likewise, intake of vitamin A and moderate alcohol consumption showed no clear relationship to death rates. Furthermore, there was little association between risk of death and intake of red meat, fruit, and grain-based products.
Increased survival was observed among women eating more protein and poultry. Compared with those with the lowest intake, women with the highest intake of protein had a 35% lower risk of death. A 30% reduction in mortality was observed in women with the highest intake of poultry compared with those with the lowest poultry intake. Since no association was seen with red meat, the associations observed for protein are most likely due to intake of poultry and dairy products.
The protein and poultry findings were strongest in women who had no metastatic disease, although the association also existed in women with metastases. The reasons for increased survival among women eating more protein and poultry are unknown.
Source: Cancer. Sep. 1, 1999. Volume 86, No. 5, pp. 826-835
Alcohol Consumption and Breast Cancer Risk
A study in the journal Cancer Epidemiology, Biomarkers & Prevention reports that moderate alcohol consumption is unlikely to have a large effect on breast cancer risk for young women.
Researchers looked at 116,671 women who were between the ages of 25 and 42 at the time of study enrollment in 1989. Participants completed a questionnaire every two years. In the first questionnaire, participants were asked about their alcohol consumption during five different time periods: ages 15 to 17, ages 18 to 22, ages 23 to 30, ages 31 to 40, and during the previous year. The group was followed for six years; during this time, 445 cases of invasive breast cancer were diagnosed.
When the data were analyzed, researchers found that neither alcohol consumption in the previous year nor average lifetime alcohol consumption was significantly associated with an increased risk for breast cancer. When the data for the four different age groups were analyzed, a small positive association was observed only for drinking at ages 23 to 30. The significance of this finding is unclear, and the researchers believe it warrants further study.
Because drinking levels in the group studied were fairly low (only five women in the group drank more than two alcoholic drinks per day), the researchers lacked sufficient information to address the risk of breast cancer in heavy drinkers.
Source: Cancer Epidemiology, Biomarkers & Prevention. November, 1999. Volume 8, No. 11., pp. 1017-1021
Should You Take It Easy During Chemotherapy?
A study published in the journal Oncology Nursing Forum looked at the relationship between cancer-related fatigue and 24-hour activity and rest cycles in women undergoing the first three cycles of chemotherapy following surgery for stage I/II breast cancer. A total of 82 women between the ages of 33 and 69 participated in the study. Researchers asked participants to rate their levels of cancer-related fatigue at the start of each chemotherapy treatment and again at the midpoint of each chemotherapy cycle. (Cycles were 21 or 28 days, depending on the chemotherapy regimen; the midpoint is halfway through the recovery time between treatments.)
Participants also wore a device on their wrists for 96 hours at the start of each treatment and for 72 hours at the midpoint of each chemotherapy cycle. The device monitored their body movements, providing data on daily activity and rest cycles and the timing, duration, and disruption of sleep.
Women who were less active and had increased night awakenings reported higher cancer-related fatigue levels at all three cycle midpoints. The strongest association was between number of night awakenings and fatigue. During the third chemotherapy cycle, women who were less active during the day, took more naps, and spent more time resting during a 24-hour period experienced higher cancer-related fatigue.
The study authors point out that these findings contradict the advice often given to patients with cancer as they begin treatment. These patients may be told to reduce their activity and increase their rest periods during chemotherapy cycles. However, there is no evidence to support that these behaviors decrease fatigue; in fact, inactivity may contribute to fatigue.
Source: Oncology Nursing Forum. Nov.-Dec., 1999. Volume 26, No. 10, pp. 1663-1671
Racial Differences in Breast Cancer Trends
Early detection of breast cancer and improved breast cancer treatment appear to be contributing to improving mortality trends in older women. However, white women seem to have benefited more than black women, according to a study published in the journal Archives of Family Medicine.
Researchers looked at the U.S. rates of breast cancer deaths from 1970-1995, breast cancer incidence from 1980-1995, and three-year survival from 1980-1993. For both white and black women younger than age 40, breast cancer death rates began decreasing in 1987. For white women ages 40 to 79, breast cancer death rates declined after 1989. For black women ages 40 to 69, death rates did not decline but stopped increasing in the mid to late 1980s.
The disparity in breast cancer death rates between black and white women is increasing, as rates remain stable for black women but decline for white women. In 1980, the mortality rates were nearly the same. In 1990, the rates for black women were 16% higher than those for white women; in 1995, black women's rates were 29% higher.
The difference in mortality rates between black and white women can probably be attributed in part to a difference in health care access. One solution might be more programs aimed at black women that remove the cultural and economic barriers to getting regular examinations. The authors conclude: "The full range of health promotion and cancer control activities targeted at black women and their health care providers is required to close the widening racial gap in breast cancer mortality rates."
Source: Archives of Family Medicine. Nov.-Dec., 1999. Volume 8, No. 6., pp. 521-528
Side Effects of Tamoxifen When Used for Breast Cancer Prevention
When used to prevent breast cancer in healthy women, tamoxifen therapy resulted in slightly increased frequency of some physical symptoms and some problems of sexual function compared with placebo. However, two problems that are anecdotally associated with tamoxifen therapy-weight gain and depression-were not increased compared with placebo. These study findings were published in the Journal of Clinical Oncology.
Data on health-related quality of life (HRQL) for 11,064 healthy women taking either tamoxifen for breast cancer prevention or placebo were collected over three years and analyzed. HRQL includes "everyday physical, emotional, and social functioning."
No significant differences were found in overall physical and emotional well being between the tamoxifen and placebo groups. However, the tamoxifen group had increased frequency of the following physical symptoms: cold sweats, night sweats, hot flashes, vaginal discharge, and genital itching.
In addition, the tamoxifen group had increased frequency of some problems of sexual function (sexual interest, becoming aroused, and achieving orgasm). Despite these findings, there was no evidence that fewer women in the tamoxifen group were sexually active because of these problems.
The researchers point out that the participants in this study-predominantly white, middle class, and well educated-are not representative of the general population, and they caution that the study results must be interpreted with these characteristics of the participants in mind.
Source: Journal of Clinical Oncology. September, 1999. Volume 17, No. 9, pp. 2659-2669
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