***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: PURPOSE Single-variable analyses have associated physical activity , diet , and obesity with survival  after breast cancer . This report investigates interactions among these variables . PATIENTS AND METHODS A prospect i ve study was performed of 1,490 women diagnosed and treated for early-stage breast cancer between 1991 and 2000 . Enrollment was an average of 2 years postdiagnosis . Only seven women were lost to follow-up through December 2005 . RESULTS In univariate analysis , reduced mortality was weakly associated with higher vegetable-fruit consumption , increased physical activity , and a body mass index that was neither low weight nor obese . In a multivariate Cox model , only the combination of consuming five or more daily servings of vegetables-fruits , and accumulating 540 + metabolic equivalent tasks-min/wk ( equivalent to walking 30 minutes 6 d/wk ) , was associated with a significant survival advantage ( hazard ratio , 0.56 ; 95 % CI , 0.31 to 0.98 ) . The approximate 50 % reduction in risk associated with these healthy lifestyle behaviors was observed in both obese and nonobese women , although fewer obese women were physically active with a healthy dietary pattern ( 16 % v 30 % ) . Among those who adhered to this healthy lifestyle , there was no apparent effect of obesity on survival . The effect was stronger in women who had hormone receptor-positive cancers . CONCLUSION A minority of breast cancer survivors follow a healthy lifestyle that includes both recommended intakes of vegetables-fruits and moderate levels of physical activity . The strong protective effect observed suggests a need for additional investigation of the effect of the combined influence of diet and physical activity on breast cancer survival Objective We examined the association between body mass index ( BMI ) around the time of diagnosis , weight change post-diagnosis , and breast cancer prognosis in a prospect i ve cohort study of 1,692 breast cancer survivors . Methods Pre-diagnosis weight , weight at study entry , and height was obtained from mailed question naires and then weight change and BMI were calculated . After approximately seven years of follow-up , 207 recurrences , 99 deaths due to breast cancer , and 162 deaths due to any cause were reported . Delayed entry Cox proportional hazard models were used to estimate hazard ratios ( HR ) and 95 % confidence intervals ( CI ) , controlling for treatment and known prognostic factors . Results Being obese one year before diagnosis was associated with an increased risk of death from any cause ( HR = 1.6 ; 95 % CI : 1.1–2.3 ) and a suggestion of increased risk of death from breast cancer ( HR = 1.6 ; 95 % CI : 0.9–2.7 ) . However , weight gain up to four years after a breast cancer diagnosis was not associated with an increased risk of recurrence or death from any cause nor did moderate weight loss ( 5–10 % ) decrease risk of these outcomes . There was some evidence that women who had larger weight losses ( ≥10 % ) between pre-diagnosis and study entry had an increased risk of recurrence ( HR = 1.7 ; 95 % CI 1.0–2.6 ) and death due to any cause ( HR = 2.1 ; 95 % CI 1.3–3.4 ) compared to being weight stable . This elevated risk was more pronounced among women who were obese before diagnosis ( BMI ≥ 30 kg/m2 ) or who had ER− or PR− tumors . Conclusion We found that being obese before breast cancer diagnosis was associated with increased risk of recurrence and poorer survival , corroborating results from previous studies . However , weight gain after diagnosis did not confer additional risk . Body weight pre-diagnosis appears to be the strongest predictor of an adverse breast cancer prognosis The association between anthropometric indices and the risk of breast cancer  was analyzed using pooled data from seven prospect i ve cohort studies . Together , these cohorts comprise 337,819 women and 4,385 incident invasive breast cancer cases . In multivariate analyses controlling for reproductive , dietary , and other risk factors , the pooled relative risk ( RR ) of breast cancer per height increment of 5 cm was 1.02 ( 95 % confidence interval ( CI ) : 0.96 , 1.10 ) in premenopausal women and 1.07 ( 95 % CI : 1.03 , 1.12 ) in postmenopausal women . Body mass index ( BMI ) showed significant inverse and positive associations with breast cancer among pre- and postmenopausal women , respectively ; these associations were nonlinear . Compared with premenopausal women with a BMI of less than 21 kg/m2 , women with a BMI exceeding 31 kg/m2 had an RR of 0.54 ( 95 % CI : 0.34 , 0.85 ) . In postmenopausal women , the RRs did not increase further when BMI exceeded 28 kg/m2 ; the RR for these women was 1.26 ( 95 % CI : 1.09 , 1.46 ) . The authors found little evidence for interaction with other breast cancer risk factors . Their data indicate that height is an independent risk factor for postmenopausal breast cancer ; in premenopausal women , this relation is less clear . The association between BMI and breast cancer varies by menopausal status . Weight control may reduce the risk among postmenopausal women Purpose : The purpose of this retrospective study was to determine the association and prognostic value of  body mass index ( BMI ) at the time of initial diagnosis in patients with locally advanced breast cancer ( LABC ) . The analysis includes the subsets of inflammatory ( IBC ) and noninflammatory ( non-IBC LABC ) breast cancer . Experimental Design : We identified 602 patients who had LABC treated on prospect i ve clinical trials . BMI was divided into three groups : ( a ) ≤24.9 ( normal/underweight ) , ( b ) 25.0 to 29.9 ( overweight ) , and ( c ) ≥30 ( obese ) . Kaplan-Meier product limit method was used to estimate survival outcomes . Cox proportional hazards were used to determine associations between survival and BMI and to test for an interaction between BMI and breast cancer type . Results : Eighty-two percent had non-IBC LABC and 18 % had IBC . Obese patients tended to have a higher incidence of IBC compared with overweight and normal/underweight groups ( P = 0.01 ) . Median follow up was 6 years for all patients . Median overall survival ( OS ) and recurrence-free survival ( RFS ) were 8.8 and 5.9 years , respectively . Patients with LABC who were obese or overweight had a significantly worse OS and RFS ( P = 0.001 ) and a higher incidence of visceral recurrence compared with normal/underweight patients . In a multivariable model , BMI remained significantly associated with both OS and RFS for the entire cohort . The interactions between BMI and LABC subsets and between BMI and menopausal status were not statistically significant . Conclusion : Patients with LABC and high BMI have a worse prognosis . Evaluation of the biological factors associated with this observation can provide tools for additional therapeutic interventions Substantial observational epidemiological evidence exists that physical activity and weight control are associated with decreased risk of postmenopausal breast cancer .  Uncertainty remains regarding several aspects of these associations , including the effect of possible confounding factors on these associations . We present the rationale and design for two r and omized controlled trials that can help resolve this uncertainty . In a 5-year prevention trial conducted among women at high risk of breast cancer , the primary endpoint would be breast cancer incidence . For a comparable survivorship trial , the primary endpoint would be the disease-free interval and secondary endpoints would be breast cancer recurrence-free interval , second primary breast cancer , and total invasive plus in situ breast cancer . A set of inclusion and exclusion criteria is proposed for both trials . Intervention goals are the same for both trials . Goals for the weight control intervention would be , for women whose body mass index ( BMI ) is greater than 25 kg/m(2 ) , to lose 10 % of body weight and , for women whose BMI is less than or equal to 25 kg/m(2 ) , to avoid weight gain . The goal for the physical activity intervention would be to achieve and maintain regular participation in a  moderate-intensity physical activity program for a total of 150 - 225 minutes over at least 5 days per week . Sample size calculations are based on alternative assumptions about hazard ratio , adherence , follow-up duration , and power and are presented for the primary prevention and survivorship trials . Although both studies could enhance our underst and ing of breast cancer etiology and benefit public health , practical considerations , including smaller sample size , ease of recruitment , and reduced likelihood of early termination , favor the survivorship trial at this time A historical prospect i ve study was conducted at the Mercy Hospital of Pittsburgh , Pennsylvania ( USA ) , to study the role of post-menopausal obesity in the recurrence and survival of breast cancer . Records from 301 post-menopausal women diagnosed with breast cancer from 1977 to 1985 were followed for at least 5 years from data supplied by the Tumor Registry and medical records .  Data collected included age , height , weight , race , hormone receptor status , stage and size of tumour , number of positive nodes , site of distant metastasis , first course of treatment , and 5 year recurrence and survival . Forty-five per cent of patients were obese ( n = 136 ) , while 55 % were non-obese ( n = 165 ) . Obesity was defined by the Quetelet index ( patients with values > 27 were considered obese ) . The recurrence rates for the obese and non-obese groups were 40 % and 39 % respectively , and were not significantly different . Univariate and multivariate analyses showed that there was no significant association between obesity in post-menopausal women and likelihood of recurrence of or death from breast cancer Background : Obesity has been shown to be an indicator of poor prognosis for patients with primary breast cancer ( BC ) regardless of the use of adjuvant systemic therapy . Patients and methods : This is a retrospective analysis of 2,887 node-positive BC patients enrolled in the BIG 02 - 98 adjuvant study , a r and omised phase III trial whose primary objective was to evaluate disease-free survival ( DFS ) by adding docetaxel to doxorubicin-based chemotherapy . In the current analysis , the effect of body mass index ( BMI ) on DFS and overall survival ( OS ) was assessed .  BMI was obtained before the first cycle of chemotherapy . Obesity was defined as a BMI ≥ 30 kg/m² . Results : In total , 547 ( 19 % ) patients were obese at baseline , while 2,340 ( 81 % ) patients were non-obese . Estimated 5-year OS was 87.5 % for non-obese and 82.9 % for obese patients ( HR 1.34 ; P = 0.013 ) . Estimated 5-years DFS was 75.9 % for non-obese and 70.0 % for obese patients ( HR 1.20 ; P = 0.041 ) . In a multivariate model , obesity remained an independent prognostic factor for OS and DFS . Conclusions : In this study , obesity was associated with poorer outcome in node-positive BC patients . Given the increasing prevalence of obesity worldwide , more research on improving the treatment of obese BC patients is needed Background Breast cancer and obesity represent important public health issues in most western countries . A number of studies found a negative prognosis effect of obesity or excess of weight in woman breast cancer . However , to date , this issue remains controversial . The objectives of this study were to confirm the prognosis role of obesity on a large cohort of patients and to investigate a potential independent effect . Material s and methods We constituted a cohort of 14,709 patients who were recruited and treated at the Curie Institute ( Paris ) from 1981 to 1999 . These patients were followed prospect ively for a first unilateral invasive breast cancer without distant metastasis . Obesity was defined by a Body Mass Index ( BMI ) above 30 kg/m2 according to the World Health Organization recommendations . Results Obese patients ( 8 % ) presented more extended tumors at diagnosis time suggesting a delayed breast cancer diagnosis . However , obesity appeared as a negative prognosis factor for several events in respectively univariate and multivariate survival analysis : metastasis recurrence ( HR = 1.32[1.19–1.48 ] ; HR = 1.12[1.00–1.26 ] ) , disease free interval ( 1.20[1.08–1.32 ] ; 1.10[0.99–1.22 ] ) , overall survival ( 1.43[1.28–1.60 ] ; 1.12[0.99–1.25 ] ) and second primary cancer outcome ( 1.57[1.19–2.07 ] ; 1.43[1.09–1.89 ] ) . Even if obese patients presented more advanced tumors at diagnosis time , multivariate analysis showed that there was a relevant independent effect . Other BMI codings , distinguishing overweight patients or using BMI as a continuous variable , showed a consistent correlation between BMI ’s value and prognosis effect . Interaction analysis revealed a more important obesity effect in the presence of tumor estrogen receptors and among limited extent tumors . Conclusions This survey confirms the prognosis role of obesity on one of the largest cohort by investigating several prognosis events . While independent obesity effect linked to hormonal disorders appeared consistent as obesity ’s mechanism , we stress that obesity prognosis effect was also related to 
    Output:
    
Women with breast cancer , who are obese , have poorer survival than women with breast cancer , who are not obese .
However , no study has eluci date d the causal mechanism and there is currently no evidence that weight loss after diagnosis improves survival .
Consequently , there is currently no reason to place the additional burden of weight loss on women already burdened with a diagnosis of cancer .