This document discusses the impact of obesity on breast cancer diagnosis and outcomes. It defines obesity using BMI and body fat distribution measures. Obesity is associated with worse breast cancer prognosis, including increased risk of recurrence and mortality. Biological factors like increased estrogen production in fatty tissue may contribute to these effects. Obesity also presents challenges for screening, diagnosis, treatment and surgical procedures in breast cancer patients. Maintaining a healthy lifestyle and weight after a breast cancer diagnosis could help reduce risks.

1. 9/28/23
Impact of Post-Diagnosis Weight Change
Manmeet Malik, DO, FACS
Director, Breast Program
Assistant Professor of Clinical Surgery
Weill Cornell Medicine | NewYork-Presbyterian Queens

2. How Do You Define Obesity?
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• Height, Weight
BMI
• Subcutaneous
• Visceral
Body fat
distribution
better predictor of health hazards

3. BMI
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Does not take into account percentage of body fat vs. muscle.

4. 4
A NY based company (Body
Labs) developed this chart
for Cosmopolitan.com to
show how six women with
the same BMI can look
different.
Each body is 5’7”,
weighs 145lbs and
has a BMI of 22.8

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Images from The Lancet. https://doi.org/10.1016/S2213-8587(20)30110-8

6. Body Fat Distribution
How to measure:
–Waist circumference
–Waist to hip ratio
–Waist to height ratio
–Scans
▫ DEXA
▫ CT
▫ PET
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7. How Common is Obesity?
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8. 8

9. Obesity and Cancer
https://www.cdc.gov/cancer/obesity/index.htm 9

10. Obesity and Breast Cancer
Current Oncology Reports volume 21, Article number: 41 (2019) 10
• Associated with worse
outcomes.
Obesity was first reported
to have an impact on
breast cancer diagnosis
and outcome in 1976
• the main cause of mortality in
women with early-stage breast
cancer.
Obesity is an established
risk factor for metabolic
syndrome, type 2
diabetes, and
cardiovascular events.
The reasons for the
adverse effects of obesity
on breast cancer are
numerous and complex.

11. 11
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Obesity and Downstream Effects

12. Epidemiological studies of Obesity and Breast
Cancer
Cancers 2020, 12, 1686 12

13. Biological Factors
Current Oncology Reports volume 21, Article number: 41 (2019)
13
• Fat is a metabolically active
tissue with high levels of
the aromatase enzyme
which converts androgen to
estrogen.
• Excess estrogen
production from expanded
adipose tissue has been
proposed as a possible
mechanism for the adverse
outcomes in obese women
with breast cancer.
DOI: 10.1056/NEJMcibr1315176

14. Obesity Associated Adipose Tissue Inflammation
Cancers 2020, 12, 1686 14
Obesity produces inflammation in adipose tissue, and activated
macrophages in adipose tissues of obese individuals produce
pro-inflammatory mediators such as TNFα and IL-6.

15. Mechanisms of Obesity Driven Breast Cancer
Cancers 2020, 12, 1686 15

16. Effects on Screening, Diagnosis and Treatment
 Correlation between Obesity and TNM stage at diagnosis
(increased LN involvement and metastasis.)
– Unclear whether due to diagnostic difficulties/reduced adherence to
mammographic screening in obese patients.
 Increased risk of surgical complications for obese breast cancer
patients.
– increased risk of complication with anesthesia/intubation
– increased risk of bleeding complications and surgical site infections
– patients with a BMI > 30 kg/m2 were noted to have more postoperative breast
asymmetry and less favorable esthetic results
– Obese women may not be candidates for reconstruction due to limited
reconstructive options or due to comorbidities
Cancers 2020, 12, 1686 16

17. Lymphedema Risk
 There are known risk factors associated with of the development of LE including
– the number of lymph nodes removed during surgery,
– development of surgical complications such as infection or seroma,
– use of chemotherapy, radiation therapy, and comorbid medical conditions,
including obesity.
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Current Oncology Reports volume 21, Article number: 41 (2019)

18. Barriers to Chemotherapy
 Obesity associated with reduced response to therapeutic treatments.
– Possible related to dose limiting toxicities/undertreatment in obese patients.
 In the adjuvant setting, full doses of chemotherapy are associated with a greater
improvement in overall survival.
 Obese patients require higher doses of chemotherapy to achieve therapeutic levels
of tumor suppression.
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Current Oncology Reports volume 21,Article number: 41 (2019)

19. Endocrine Therapy
 The therapeutic dose of individual endocrine agents is fixed, regardless of weight or
body surface area.
 The Austrian Breast and Colorectal Cancer Study Group (ABCSG) 12 trial
randomized 1804 premenopausal women with early-stage breast cancer treated
with a luteinizing hormone-releasing hormone (LHRH) agonist for ovarian
suppression, to receive adjuvant tamoxifen or anastrozole.
 They reported that overweight women assigned anastrozole had a 60% increase
risk of disease recurrence (HR, 1.60; 95% CI, 1.06 to 2.41; P = 0.02) and death
(HR, 2.14; 95% CI, 1.17 to 3.92; P = 0.01), compared to normal-weight survivors.
 The benefits of adjuvant chemotherapy and/or endocrine therapy were significantly
less in the obese population and were independent of tumor size, nodal status, and
known prognostic factors, including hormone receptor status.
Current Oncology Reports volume 21, Article number: 41 (2019)
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20. Where do we go from here???
Being overweight DOES NOT DIRECTLY
cause breast cancer.
We do NOT know what causes breast cancer!
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21. But we know we need to do something about it…
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22. What we do know…
150 minutes of physical activity a week may reduce
breast cancer recurrence.
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Photo from: http://www.clker.com

23. Steps We Can Take
Healthy Balanced lifestyle
Diet Exercise Mental Health
Hormonal Homeostasis
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24. Thank You
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