High- and Low-Fat Dairy Intake, Recurrence, and Mortality After Breast Cancer Diagnosis

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cancer incidence and mortality inpostmenopausal women. JAMA.2010;304:1684-1692.

26 Breast Diseases: A Year Book� Quarte

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2. Beral V, Reeves G, Bull D, Green J;Million Women Study Collaborators.Breast cancer risk in relation to the

rly

interval between menopause andstarting hormone therapy. J NatlCancer Inst. 2011;103:296-305.

High- and Low-Fat Dairy Intake,Recurrence, and Mortality AfterBreast Cancer DiagnosisKroenke CH, Kwan ML, Sweeney C, et al(Kaiser Permanente, Oakland, CA; Univ ofUtah, Salt Lake City)

J Natl Cancer Inst 105:616-623, 2013

Background.dDietary fat in dairyis a source of estrogenic hormonesand may be related to worse breastcancer survival. We evaluated associa-tions between high- and low-fat dairyintake, recurrence, and mortality afterbreast cancer diagnosis.

Methods.dWe included 1893women from the Life After CancerEpidemiology study diagnosed withearly-stage invasive breast cancer from1997 to 2000, who completed the FredHutchinson Cancer Research CenterFood Frequency Questionnaire afterdiagnosis. A total of 349 women had arecurrence and 372 died during amedian follow-up of 11.8 years, with189 deaths from breast cancer. Weused delayed entry Cox proportionalhazards regression to evaluate associa-tions between categories of the cumula-tive average of dairy fat at baseline andat follow-up 5 to 6 years later andsubsequent outcomes. Tests of statis-tical significance were two-sided.

Results.dIn multivariable-adjusted analyses, overall dairy intakewas unrelated to breast cancer-specificoutcomes, although it was positivelyrelated to overall mortality. Low-fatdairy intake was unrelated to recurrenceor survival. However, high-fat dairyintake was positively associated with

outcomes. Compared with the reference(0 to <0.5 servings/day), thoseconsuming larger amounts of high-fatdairy had higher breast cancer mortality(0.5 to <1.0 servings/day: hazard ratio[HR]¼ 1.20, 95% confidence interval[CI]¼ 0.82 to 1.77; and $1.0 servings/day: HR¼ 1.49, 95% CI¼ 1.00 to2.24, Ptrend¼ .05), higher all-causemortality (Ptrend < .001), and highernon-breast cancer mortality(Ptrend¼ .007); the relationship withbreast cancer recurrence was positivebut not statistically significant. Thehigher risk appeared consistent acrossdifferent types of high-fat dairyproducts.

Conclusions.dIntake of high-fatdairy, but not low-fat dairy, was relatedto a higher risk of mortality after breastcancer diagnosis.

In the last several years, the roleof diet in cancer prevention andsurvival has garnered much attention.Given this fact, together with recentconcerns about food preparationmethods and unwanted antibiotics andhormones in food sources, this studyby Kroenke and colleagues providesintriguing and timely insights into thepotential association between high-fatdairy intake and poor breast canceroutcomes.

Prior to this work, no study ofbreast cancer outcomes had specifi-cally compared the influence of low-fatand high-fat intake from dairy sources.Interestingly, high-fat dairy intake wasassociated with increased breastcancer mortality and higher overall

mortality; low-fat dairy consumptionwas associated with decreased overallmortality but was found to be of onlyborderline significance with regard tobreast cancer-specific mortality. Over-all dairy intake was not significantlyassociated with breast canceroutcomes, suggesting that there may beadditional contributing factors. Otherclues that the story is more complexthan a straightforward “high-fat dairyis bad, low-fat dairy is good” inter-pretation is suggested by the somewhatincongruent demographics of the high-fat dairy group. For example, the factthat the women in the high-fat dairy-intake group had both higher levels ofphysical activity and higher body massindex suggests that the group’scomposition may have been mixed interms of overall health and that otherlifestyle factors may be involved in theimproved mortality rate of the low-fat-dairy-consuming group.

Other important caveats aboutthe study include the fact that themajority of participants (75%) werepostmenopausal, and the studyexcluded women with stage IIIB-IVtumors, which represents a potentiallysignificant bias against inclusion offast-moving, aggressive cancers, asthese tend to be more common inyounger women. As such, the appli-cability of these dairy fat results maybe better confined to postmenopausalwomen with early-stage, non-aggres-sive disease. In spite of its large size,the study offers limited statisticalpower for subset analyses to comparepatients by menopausal status and

assess independent associationsbetween high-fat dairy intake andoverall high-fat intake and breastcancer outcomes, and it lacks data onpatient hormone levels. These defi-ciencies prevent clear resolution ofwhether the mortality outcomes asso-

ciated with increased high-fat dairyintake are due to hormones in thedairy fat or overall high-fat diet andlifestyle-related factors. Despite theselimitations, this study provides atimely and interesting insight and setsthe stage for more targeted analyses

Breast D

that take into account both hormonelevels and menopausal status.

J. S. Davis, PhDS. Y. Jung, PhDS. Chang, PhD

TUMOR BIOLOGY

Male Breast Cancer Accordingto Tumor Subtype and Race:A Population-Based Study

Chavez-MacGregor M, Clarke CA,Lichtensztajn D, et al (The Univ of TexasMD Anderson Cancer Ctr, Houston; CancerPrevention Inst of California, Fremont)

Cancer 119:1611-1617, 2013

Background.dBreast cancer oc-curs rarely in men. To the authors’knowledge, no population-based esti-mates of the incidence of human epi-dermal growth factor receptor 2(HER2)-positive breast cancer or of thedistribution of breast cancer subtypesamong male breast cancer patientshave been published to date. Therefore,the objective of the current study wasto explore breast tumor subtype distribu-tion by race/ethnicity among men in thelarge, ethnically diverse population ofCalifornia.

Methods.dThis study includedmen who were diagnosed with invasivebreast cancer between 2005 and 2009with known estrogen receptor (ER) andprogesterone receptor (PR) (together,hormone receptor [HR]) status andHER2 status reported to the California

Cancer Registry. Among the men withHR-positive tumors, survival probabili-ties between groups were comparedusing log-rank tests.

Results.dSix hundred six patientswere included. The median age at diag-nosis was 68 years. Four hundredninety-four men (81.5%) had HR-positive tumors (defined as ER-positiveand/or PR-positive and HER2-negative). Ninety men (14.9%) hadHER2-positive tumors, and 22 (3.6%)had triple receptor-negative (TN)tumors. Among the patients with HR-positive tumors, non-Hispanic blackmen and Hispanic men were more likelyto have PR-negative tumors than non-Hispanic white men. No statisticallysignificant differences in survival wereobserved according to tumor subtype(P¼ .08). Differences in survival ac-cording to race/ethnicity were observedamong all patients (P¼ .087) andamong those with HR-positive tumors(P¼ .0170), and non-Hispanic blackmen had poorer outcomes.

Conclusions.dIn this large, repre-sentative cohort of men with breast can-cer, the distribution of tumor subtypeswas different from that reported forwomen and varied by patient race/ethnicity. Non-Hispanic black men

were more likely to have TN tumorsand ER-positive/PR-negative tumorsthan white men.

Approximately 1% of breastcancer patients are men, and theirdisease management is identical tothat of women. Although this is in largepart because good results are beingachieved with this approach, it is alsobecause there had been no largestudies of male breast cancer thatmight reveal biological differences thatwould inform treatment. Now, Chavez-MacGregor and colleagues have madean important contribution to filling thisgap, with a large population-basedstudy of HR and HER2 status in 602men in California. The study found thatthe distribution of subtypes wasdifferent in men than in women, and theauthors suggested that in men, subtypeis also linked to prognosis. The anal-ysis confirmed the findings of severalprevious, smaller studies by showingthat male breast cancers were morelikely to be HR positive (81.5% in menvs 63.8% in women), and it providedimportant new information showingthat male breast cancers are less likelyto be HER2 positive (14.9% vs 22.8%).Additionally, for the first time, we

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