Clinical Investigation
Association of Locoregional Control With High Body Mass Index in Women Undergoing Breast Conservation Therapy for Early-Stage Breast Cancer

A preliminary version of this study was presented at the 2014 American Society of Radiation Oncology 56th Annual Meeting, September 15, 2014, San Francisco, California.
https://doi.org/10.1016/j.ijrobp.2016.04.020Get rights and content

Purpose

Obesity, as measured by the body mass index (BMI), is a risk factor for distant recurrence and decreased survival in breast cancer. We sought to determine whether the BMI correlated with local recurrence and reduced survival in a cohort of predominantly obese women treated with breast conservation therapy.

Methods and Materials

From 1998 to 2010, 154 women with early-stage invasive breast cancer and 39 patients with ductal carcinoma in situ underwent prone whole breast irradiation. Cox proportional hazards regression, Kaplan-Meier methods with the log-rank test, and multivariate analysis were used to explore the association of the outcomes with the BMI.

Results

The median patient age was 60 years, and the median follow-up duration was 73 months. The median BMI was 33.2 kg/m2; 91% of the patients were overweight (BMI ≥25 kg/m2) and 69% of the patients were clinically obese (BMI ≥30 kg/m2). The BMI was significantly associated with the locoregional recurrence-free interval for patients with invasive cancer and ductal carcinoma in situ (hazard ratio [HR], 1.09; P=.047). Also, a trend was seen for increased locoregional recurrence with a higher BMI (P=.09) for patients with invasive disease, which was significant when examining the outcomes with a BMI stratified by the median value of 33.2 kg/m2 (P=.008). A greater BMI was also significantly associated with decreased distant recurrence-free interval (HR, 1.09; P=.011) and overall survival (HR, 1.09; P=.004); this association remained on multivariate analysis (distant recurrence-free interval, P=.034; overall survival, P=.0007).

Conclusions

These data suggest that the BMI might affect the rate of locoregional recurrence in breast cancer patients. A higher BMI predicted a worse distant recurrence-free interval and overall survival. The present investigation adds to the increasing evidence that BMI is an important prognostic factor in early-stage breast cancer treated with breast conservation therapy.

Introduction

The prevalence of obesity has increased dramatically in the United States during the past 25 years, with more than one-third of adult women in the United States estimated to be obese (1). Obesity is a risk factor for the development of several malignancies, including breast cancer. The association of obesity with breast cancer has been best-established in postmenopausal women, although the contribution of obesity to the development of breast cancer in premenopausal women is less clear 2, 3. In addition, obesity, measured by the body mass index (BMI), has been associated with worse breast cancer–specific survival, distant metastasis–free survival, and overall survival in breast cancer patients 4, 5, 6. However, the role of the BMI or obesity in increasing the risk of local or regional breast cancer recurrence has not been well established.

Several potential mechanisms have been proposed to underlie the association of obesity with less favorable breast cancer outcomes. We hypothesized that the factors in obese patients that promote breast cancer growth systemically could also affect local control. Systemic therapies lead to improved local control of breast cancer (7); thus, less effective systemic therapy in obese individuals could increase the risk of local recurrence. For invasive breast cancer, a deleterious effect on local control by additional obesity-related factors could contribute to the worse breast cancer–specific survival and/or distant metastasis–free survival seen in this population, given that improved local control from radiation therapy has been shown to increase breast cancer–specific survival (8).

In the present study, we used a unique patient population to examine the association of BMI with local control. All the patients in our cohort had undergone prone whole breast irradiation as part of breast conservation therapy. The primary indication for prone breast irradiation at our institution is large and/or pendulous breasts or a larger body habitus 9, 10; thus, most of the patients in our cohort were overweight and more than two-thirds were obese. We examined the association of obesity with locoregional control and additional survival and breast cancer–specific outcomes in a predominantly obese cohort of women who had undergone breast conservation therapy.

Section snippets

Methods and Materials

The present study was performed under the auspices of an institutional review board protocol approved by the Medical College of Wisconsin after training in human research and patient privacy. A retrospective medical record review was performed of women with early-stage breast cancer who had undergone whole breast irradiation in the prone position after lumpectomy from 1998 to 2010 using 3-dimensional conformal radiation therapy under the guidance of the Medical College of Wisconsin radiation

Results

The characteristics of the patient population are summarized in Table 1. The 154 patients with invasive breast cancer had a median age of 60 years and a median invasive tumor size of 1.2 cm. Of the 154 patients with invasive cancer, 79% had estrogen receptor– and/or progesterone receptor–positive disease and 17% had HER2/NEU-positive or HER2/NEU-amplified tumors. Also, 75% of the patients initiated anti-endocrine treatment and 41% had received chemotherapy after surgery. The 39 patients with

Discussion

Obesity has been associated with worse breast cancer–specific survival, distant metastasis–free survival, and overall survival in breast cancer patients 4, 5, 6. However, a relative paucity of data is available linking obesity with local control. Because improved local control can optimize breast cancer survival (8), the role of BMI in local recurrence can have important implications. In our cohort of predominantly overweight and obese patients with early-stage breast cancer receiving breast

Conclusion

Overall, the present study examined the association of BMI with locoregional control in a retrospective cohort of early-stage breast cancer patients receiving breast conservation therapy. Our study population was unique in that the median BMI was >33 kg/m2 and two-thirds of the patients were obese. The BMI was associated with increased locoregional recurrence, worse distant recurrence–free survival, and worse overall survival. However, the obese patients still had very favorable outcomes. These

References (26)

  • T.A. Buchholz et al.

    Impact of systemic treatment on local control for patients with lymph node-negative breast cancer treated with breast-conservation therapy

    J Clin Oncol

    (2001)
  • S. Darby et al.

    Effect of radiotherapy after breast-conserving surgery on 10-year recurrence and 15-year breast cancer death: Meta-analysis of individual patient data for 10,801 women in 17 randomised trials

    Lancet

    (2011)
  • C.A. Hudis et al.

    Proposal for standardized definitions for efficacy end points in adjuvant breast cancer trials: The STEEP system

    J Clin Oncol

    (2007)

    • Cited by (21)

    • Long-term outcomes of intraoperatively-placed applicator brachytherapy for rapid completion of breast conserving treatment: An analysis of a prospective registry data

      2023, Clinical and Translational Radiation Oncology

    • Cellular and molecular insights into the roles of visfatin in breast cancer cells plasticity programs

      2022, Life Sciences
      Citation Excerpt :

      Further, obese female patients also developed complications with the surgery regimen of BC treatment. Several studies have reported a significantly high local recurrence of tumors in the obese female patients undertaking breast-conservation therapy as compared to their lean counterparts [11–13]. These studies point at an intricate relationship between obesity and BC pathophysiology warranting a greater understanding of cross talks between adipose tissue microenvironment (ATME) and BC tumor microenvironment (TME) in the obese.

    • Tricks and tips for target volume definition and delineation in breast cancer: Lessons learned from ESTRO breast courses

      2021, Radiotherapy and Oncology
      Citation Excerpt :

      These challenges can be related to patient’s body habitus. In patients with a high BMI, surgery, delineation, and dose coverage for regional nodes may be challenging, and it is probably one of the main reasons for higher rates of locoregional failure and worse distant recurrence-free interval and overall survival in these patients [40,41]. In case of CTVp (breast or chest wall), treatment objective is that the doses in the range 95%-105% of the prescription dose and Dmax ≤ 110% [42].

    • Body Mass Index and Outcomes in Breast Cancer Treated With Breast Conservation

      2020, International Journal of Radiation Oncology Biology Physics
      Citation Excerpt :

      One-third (33%) of our patients had grade 3 tumors, similar to another series reporting 35%.12 Chemotherapy administration was similar to other reported retrospective reviews (44%),11 but lower than a Danish series (65%).13 An explanation for their high chemotherapy rates was the need to capture BMI data for chemotherapy usage.

    • Postdiagnosis body fatness, weight change and breast cancer prognosis: Global Cancer Update Program (CUP global) systematic literature review and meta-analysis

      2023, International Journal of Cancer

    • THE CORRELATION BETWEEN INCREASING BODY MASS INDEX AND THE INCIDENCE OF LOCAL RECURRENCE AND DISTANT METASTASIS IN BREAST CANCER PATIENTS

      2023, World Cancer Research Journal
    View all citing articles on Scopus

    This research was supported in part by the National Center for Research Resources, the National Center for Advancing Translational Sciences, and the Office of the Director, National Institutes of Health (NIH), through Grant #8KL2TR000056 and grant #8UL1TR000055. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH.

    Conflict of interest: A. Szabo and C. Bergom report grants from the National Institutes of Health National Center for Advancing Translational Sciences during the conduct of the present study. The authors have no other financial disclosures to report.

    View full text
    © 2016 Elsevier Inc. All rights reserved.