No clear link between passive smoking and lung cancer.

MRI every 6 months was associated with an absence of interval cancers and with high sensitivity/specificity for detecting tumors smaller than 1 cm. Led by Olufunmilayo I. Olopade, MD, a hematologist–oncologist at the University of Chicago Hospitals, the authors concluded that their results " support this screening strategy as a viable alternative to prophylactic mastectomy. " According to Domchek, women under surveillance at the Perelman School of Medicine get staggered mammograms and MRI 6 months apart. When women complete (or forgo) child rearing, chemoprevention alone or in combination with oophorectomy may also offer an alternative to mastectomy. But according to Davidson, the evidence for chemopre-vention benefits in BRCA-positive women derives almost entirely from studies showing that agents such as tamoxifen and ralox-ifene reduce the risk of tumors in the other breast in women who have already had breast cancer. In 2000, for instance, Steven Narod, MD, a fellow of the Royal Society of Canada in Toronto, published findings in The Lancet showing that tamoxifen halves the risk of cancer in the opposite breast in women with BRCA1 and BRCA 2 mutations. And this year, Kelly-Anne Phillips, MD, of the Peter MacCallum Cancer Centre in Victoria, Australia, published virtually identical risk reductions in the Journal of Clinical Oncology. Davidson said that scientists have tried to look at primary prevention of the first tumor in BRCA-positive individuals (for instance, through the National Surgical Adjuvant Breast and Bowel Project's P1 trial), but since the mutations are so rare, the results so far lack statistical power. Still, Davidson asserted that results from the secondary prevention trials should translate equally to the prevention of primary cancers, even regardless of their estrogen receptor (ER) status. Tamoxifen and raloxifene are both geared toward ER-positive cancer cells, but Davidson pointed out that these cells can become ER negative over time. Moreover, tumors are often heterogeneous with respect to their ER-positive or-negative composition. " There is some evidence that chemopre-vention can prevent ER-negative tumors, or tumors that become ER negative later, " Davidson said. " But the evidence isn't strong and we need more work to explain why that might be happening. " Adding oophorectomy to chemopre-vention should boost primary cancer prevention even further, because tamoxifen, for instance, does not affect the ovaries, whereas oophorectomy reduces the risk of ovarian cancer by roughly 90% and reduces circulating hormone levels that can promote growth of breast tumors. Narod's 2000 paper …