The advantages of digital mammography. As a screening measure for breast cancer, digital mammography has proven to be more accurate at detecting disease in women with dense breasts, women under fifty, and pre- or peri-menopausal women.
The report comparing the newer, digital procedure with standard mammography followed nearly 50,000 women and suggests that digital mammography should be used for routine screening of younger women. (N Engl J Med 2005;353)
Chemotherapy combination proves lethal. A study in which women with breast cancer were given two chemotherapy drugs simultaneously was cut short after the combination contributed to the deaths of two and caused life-threatening complications in an alarming number of others. The problems developed with the standard intravenous drug, doxorubicin (Adriamycin), when combined with a newer drug, docetaxel (Taxotere). The two drugs are frequently used successfully alone but the combination was just too toxic. (J Amer. Med. Assoc., May 18, 2005)
Best screening strategy for high-risk women. Women with BRCA1 or BRCA2 mutations should be screened using a combination of contrast-enhanced MRI with mammography, according to a study published in the Lancet. CE MRI plus mammography resulted in accurate detection in 94% of cases, as compared to 77% with MRI alone and 40% with mammography alone. There are no studies yet that demonstrate that screening with CE MRI reduces mortality from breast cancer. (Lancet 2005:365(9473):1769-1778)
Statins may reduce breast cancer risk. A comparison of statin use (a form of medication prescribed to reduce low-density cholesterol levels) among women with a history of breast cancer and women without breast cancer suggests that statin use may reduce the risk of breast cancer by as much as 50%. A randomized double-blind trial is planned to test this with a view to perhaps using statins as a form of chemoprevention. The study was reported at the 41st annual meeting of the American Society of Clinical Oncology in Florida. (www.medscape.com/viewarticle/504927)
Benefits of chemotherapy last. Standard chemotherapy, combined with tamoxifen, can significantly affect the risk of death for middle-aged women with early stage breast cancer. Adding six months of doxorubicin (Adriamycin) after surgery could halve the risk of death for at least 15 years. Women under 50 who had not received chemotherapy had a death rate 5% higher than women who had received chemotherapy. After 15 years, however, the death rate for untreated women was even higher — 10% higher — than that for treated women. (NY Times, May 13, 2005)
Genetic study may be flawed. A landmark 2003 study on genes and breast cancer posited that Ashkenazi women with the BRCA1 or BRCA2 gene had a 82% chance of developing breast cancer by age 80. Now this number, from The New York Breast Cancer Study, has been questioned by two separate teams of scientists who claim that this was a significant overestimate of risk. Based on follow-up studies, the risk appears to average 65% for BRCA1 mutations and 45% for BRCA2. According to genetic counsellors, it is too soon to say how the controversy will affect the women concerned. (Wall Street Journal, Jan. 7, 2005)
Low-level PCB exposure may affect women's menstrual cycles, confirming their suspected role as hormone disruptors. Examination of stored blood samples (collected from more than 2300 pregnant women in the 1960s) has revealed that higher PCB (polychlorinated biphenyls) levels are associated with longer menstrual cycles and more irregular periods. PCBs have been banned since the late 1970s because of a probable cancer risk but they linger in the environment and accumulate in fatty tissue. PCBs are one form of POPs (persistent organic pollutants). (Epidemiology, March 2005)
One in ten diagnoses is a false positive. A study reported in the March 3rd issue of the British Medical Journal involved nearly 43,000 women. Of these, the rate of over-diagnosis for women aged 55 to 69 was one in ten. This follow-up to the Malmo mammographic screening trial (1976-1986) confirms the high rate of false positives found in previous studies.
Elderly women fare less well. About 30% of breast cancer patients in Sweden are from 70 to 84 years of age but their rate of survival is well below that of younger women. This seems to result from an absence of routine mammography at older ages coupled with relatively fewer referrals to radiation and chemotherapy. This report highlights the need for better guidelines for the treatment of elderly breast cancer patients.
Menopausal hormone therapy is associated with three types of breast cancer. Risks of both ductal and lobular cancer were increased in women using medium-potency estrogen alone. Low-potency oral estrogen (mainly estriol) and medium-potency estrogen-progestin were associated with increased risk for lobular cancer. Medium-potency estrogen-progestin and alcohol were strongly associated with tubular cancer. (Breast Canc Res 2006;8:R11) In another study, current use of estrogen-progestin by postmenopausal women was found to increase risk of breast cancer by 29% per five years of use, while current use of estrogen only by postmenopausal women was found to increase risk of breast cancer by 10%. Risks associated with current use were greater for women with body mass indices below 25, and use of any postmenopausal hormones was significantly associated with receptor positive tumours. (Int J Cancer 2006;118:1285-1291)
Ocular toxicity common during adjuvant therapy. Eye problems are fairly common among women receiving chemotherapy for early breast cancer with slightly more than 10% of women complaining of impaired vision, irritation of the eyes, or cataracts reported. The authors warn that eye problems may be underestimated and suggest that nurses and physicians should inform patients about the possibility of such side effects. (Cancer 2006;106:505-513)
Weight gain during pregnancy and breast cancer. An interesting Finnish study has linked unusual weight gain during pregnancy (i.e., more than 15kg or 33lbs.) to an increased risk of breast cancer in later life. The researchers controlled for other variables (age at menarche, age at first birth, BMI before pregnancy, etc.) and speculate that elevated estrogen levels at a time when the breast changes in preparation for lactation may contribute to this increased risk. The researchers followed over 4,000 Finnish women who gave birth between 1954 and 1963. (BMC Women's Health 2004;4)
Drawbacks of genetic testing for breast cancer. Commercial genetic testing, currently monopolized by Myriad Genetics in the U.S., fails to detect all cancer-associated inherited mutations in women with a severe family history of breast or ovarian cancer. A research team from the University of Washington tested 300 cancer patients who had been given negative results using standard genetic testing. Of these 300, 35 (12%) had a variation of BRCA1 or -2, undetectable by standard methods, while 14 (5%) had a third mutation involving a doubled risk of breast cancer. Three (1%) had a 90% risk of developing a cancer. The senior researcher of the study called for "an open, competitive marketplace" with "non-exclusive licensing of patents on genes." (JAMA 2006;295:1379-1388)