Breast Cancer Characteristics and Outcomes After Metabolic and Bariatric Surgery
Overview
This study compared breast cancer (BC) features and outcomes in patients with severe obesity who underwent metabolic and bariatric surgery (MBS) versus those who did not. Despite significant weight loss and BMI reduction in the MBS group, disease-free survival (DFS) and recurrence rates were similar between groups. Notably, BC subtypes differed, with fewer Luminal A and more Luminal B tumors in the MBS group.
Background
Breast cancer is the most commonly diagnosed cancer worldwide and a leading cause of cancer mortality. Severe obesity is a modifiable risk factor linked to increased BC risk, likely due to hormonal and metabolic changes. Metabolic and bariatric surgery is the most effective treatment for severe obesity and has been shown to reduce BC risk. However, the characteristics and outcomes of BC occurring after MBS remain unclear, prompting this comparative analysis.
Data Highlights
Parameter
MBS Group (n=29)
Non-MBS Group (n=116)
p-value
Mean BMI at BC surgery (kg/m2)
32.4 ± 6.5
38.6 ± 4.1
<0.0001
DCIS prevalence (%)
0
20
0.03
Luminal A subtype (%)
34.4
59.4
0.01
Luminal B subtype (%)
58.6
27.6
0.001
Preoperative LN biopsy (%)
55
76.7
0.02
DFS (months, mean)
114
146.6
0.75
Local recurrence rate (%)
6.8
9.5
0.66
Systemic recurrence rate (%)
3.4
2.5
0.80
Deaths (n)
2
13
0.49
Key Findings
Patients in the MBS group had significantly lower BMI at BC surgery compared to non-MBS patients (32.4 vs 38.6 kg/m2, p < 0.0001).
DCIS was significantly more prevalent in the non-MBS group (20% vs 0%, p = 0.03).
The MBS group had fewer Luminal A subtype tumors (34.4% vs 59.4%, p = 0.01) and more Luminal B subtype tumors (58.6% vs 27.6%, p = 0.001).
Preoperative lymph node biopsy was less frequent in the MBS group (55% vs 76.7%, p = 0.02), though biopsy results did not differ significantly.
No significant differences were observed in disease-free survival (114 vs 146.6 months, p = 0.75), local recurrence, systemic recurrence, or mortality between groups.
Perioperative outcomes including surgery type, duration, hospital stay, and complications were similar between groups.
Clinical Implications
Metabolic and bariatric surgery leads to significant weight loss and BMI reduction in patients with severe obesity undergoing breast cancer surgery. Despite differences in tumor subtype distribution, oncologic outcomes such as disease-free survival and recurrence rates are comparable to those in severely obese patients without prior MBS. Clinicians should consider that breast cancer after MBS may present with distinct biological features but similar prognosis, supporting continued standard oncologic management.
Conclusion
Breast cancer following metabolic and bariatric surgery exhibits different subtype profiles but similar disease-free survival and recurrence rates compared to breast cancer in patients with severe obesity without prior surgery. These findings suggest that MBS does not adversely affect breast cancer outcomes and may influence tumor biology.
References
Global Cancer Statistics 2020 -- Breast Cancer Incidence and Mortality
Obesity and Cancer Risk -- Mechanistic Insights
Metabolic and Bariatric Surgery and Cancer Outcomes -- Systematic Reviews
