SABCS Friday Highlights
Diet and exercise in cancer prevention
Research has unequivocally shown that obesity increases the risk of breast cancer after menopause and increases the likelihood of worse breast cancer outcomes at any age, supporting recommendations to maitain a healthy weight through diet and exercise, particularly after a breast cancer diagnosis. Reporting on an updated analysis of the Women’s Health Initiative (WHI) Dietary Modification trial, a primary prevention trial involving more than 48,800 women, Dr. Rowen Cheblowsky of the Los Angeles BioMedical Research Institute presented data showing that women who followed a low-fat dietary pattern had a significantly increased overall survival following a breast cancer diagnosis. The effect was strongest in women with waist circumference greater than 88 cm (35 in.) and a baseline fat intake greater than 36% of total calories (720 calories from fat in a 2000 calorie diet). The same benefit was not seen in women who developed triple negative breast cancers or in women who were over 70 at the start of the trial. Dr. Cheblowsky stressed that the data suggest that a relatively minor reduction in fat intake—in earlier reports, the WHI investigators showed the women on the dietary intervention successfully decreased fat intake and increased fruit and vegetable intake—can have a significant effect on reducing breast cancer risk and mortality. Hear more from Dr. Cheblowsky in the ASCO News Reel.
In a separate study, Dr. Jennifer Ligibel of Dana Farber Cancer Institute reported on the effects of a short-term, pre-operative exercise intervention on gene expression in breast tumors of newly diagnosed patients. Compared to non-exercising patients, the patients engaging in at least 180 min/week of aerobic exercise showed an increase in gene activity in inflammatory and immune markers. While the results need to be validated in a larger study, Dr. Ligibel stressed that these findings demonstrate for the first time that exercise may have a direct effect on breast tumor tissue. BCRF investigators Drs. Melinda Irwin, Anne McTiernan, Eric Winer and Myles Brown are co-authors on the study. Dr. Ligibel discusses the study in this ASCO News Reel.
Balancing side effects of chemo and endocrine therapies and patient quality of life.
Breast cancer patients will receive chemo- and/or endocrine (anti-estrogen) therapy after surgical removal of the tumor—called adjuvant therapy because it is seen as an adjunct—or supplement to surgery.
Adjuvant therapy has played a major role in reducing recurrence of breast cancer for many patients. While patients stand to benefit from the adjuvant chemotherapy in terms of living longer, the toxic side effects can be both physically and emotionally debilitating and may affect a patient’s quality of life long after therapy ends. Friday morning featured several talks that dealt with the side effects of adjuvant therapy.
Hair loss, or alopecia, is a common symptom of cancer chemotherapies. Hair loss during chemotherapy can negatively impact a woman’s self-image and adversely affect her quality of life and emotional well-being. Scalp cooling caps worn while chemotherapy is being administered are designed to reduce hair loss by decreasing blood flow to the scalp and hair follicles.
Reporting on the first prospective randomized clinical trial on scalp cooling caps, Dr. Julie Rani Nangia of the Baylor College of Medicine explained that the scalp cooling system was safe and effective in more than half of the patients tested. The results surpassed a superiority boundary—a statistical measure of robust efficacy, prompting the investigators to stop the study prematurely. The manufacturers are currently seeking FDA approval of the system. You can read more about the study from this SABCS press release.
The International Breast Cancer Intervention (IBIS) studies, led by BCRF investigator Dr. Jack Cuzick, were designed to test whether adjuvant endocrine therapy (tamoxifen or aromatase inhibitor (AI)) could prevent breast cancer recurrence in high-risk women. Results from the IBIS studies have shown that five years of endocrine therapy, such as tamoxifen or an AI, can dramatically reduce the risk of recurrence and that this effect can last as much as 20 years.
In spite of this protective effect, adherence to long-term endocrine therapy remains a challenge due to side effects. Both tamoxifen and AIs can cause menopausal-like symptoms, such as hot flashes, night sweats, vaginal dryness and other gynecological symptoms.
In an analysis looking at factors affecting adherence to tamoxifen in women enrolled in the IBIS-I study, Dr. Samuel Smith of Cancer Research UK reported that women who experienced menopausal symptoms, particularly nausea/vomiting, headaches or gynecological symptoms such as irregular bleeding or vaginal dryness, were less likely to complete the full five year regimen. Hot flashes did not seem to be a factor in adherence.
While two-thirds of nearly 2,000 women did complete at least 4.5 years of therapy, most of those who dropped out did so in the first 6-12 months. Interestingly, women in the control group, who received a placebo—or sugar pill—instead of tamoxifen, also had higher non-compliance due to menopausal like symptoms. Commenting on this “placebo” effect, Dr. Smith noted that clinicians need to help women considering preventive therapy to manage expectations and provide accurate information about potential side effects versus normal physiological symptoms of natural menopause. You can read more about the study in this SABCS press release.
In postmenopausal women, aromatase inhibitors are recommended to block the action of the enzyme that converts estrogen precursors (testosterone and androstenedione) to estrogen. While the side effect profile is not as severe as tamoxifen, which can increase the risk of endometrial cancer, blood clots, stroke, and bone loss, AIs can increase the risk of cardiovascular disease, muscular-skeletal symptoms, and joint pain. Of particular concern to clinicians and patients is the risk of cardiovascular events, especially as breast cancer patients are living longer after their diagnosis.
Reporting on a small study of approximately 50 postmenopausal women, Dr. Anne Blaes of the University of Minnesota explained that breast cancer patients on AI therapy were more likely to experience endothelial dysfunction than healthy women. Compromised endothelial function—the ability of blood vessels to expand and contract—is an early sign of cardio vascular disease, lending caution to the long-term use of AIs for some women.
Dr. Blaes acknowledged the small sample size of the study and that additional studies are needed to confirm the results, but noted that women with a high risk of heart disease may want to limit the duration of AI therapy. Read more about the study in this SABCS press release.
Discussing the above studies, Dr. Patricia Ganz emphasized the need to balance quality of life and duration of preventive endocrine therapies, particularly in premenopausal women who will live many years after their diagnosis. The evidence that women taking AIs show early signs of cardiovascular disease is also a concern, since many postmenopausal women are at greater risk of dying from heart disease than breast cancer recurrence as they age.
BCRF investigator Dr. Dawn Hershman discusses other studies in survivorship presented at SABCS in this ASCO News Reel.
In other news, here are some highlights from the SABCS press room:
Breast Cancer Mortality Rates Decline in Many Countries
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