Simultaneous contralateral prophylactic mastectomy compared to unilateral nipple-sparing mastectomy for breast cancer surgical treatment: Are complications higher?

Effect of mastectomy on gut microbiota and its metabolites in patients with breast cancer

Background

The relationship between gut microbiota and breast cancer has been extensively studied; however, changes in gut microbiota after breast cancer surgery are still largely unknown.

Materials and methods

A total of 20 patients with breast cancer underwent routine open surgery at the First Affiliated Hospital of Hainan Medical College from 1 June 2022 to 1 December 2022. Stool samples were collected from the patients undergoing mastectomy for breast cancer preoperatively, 3 days later, and 7 days later postoperatively. The stool samples were subjected to 16s rRNA sequencing.

Results

Surgery did not affect the α-diversity of gut microbiota. The β-diversity and composition of gut microorganisms were significantly affected by surgery in breast cancer patients. Both linear discriminant analysis effect size (LEfSe) analysis and between-group differences analysis showed that surgery led to a decrease in the abundance of Firmicutes and Lachnospiraceae and an increase in the abundance of Proteobacteria and Enterobacteriaceae. Moreover, 127 differential metabolites were screened and classified into 5 categories based on their changing trends. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed significant changes in the phenylalanine metabolic pathway and exogenous substance metabolic pathway. Eight characterized metabolites were screened using ROC analysis.

Conclusion

Our study found that breast cancer surgery significantly altered gut microbiota composition and metabolites, with a decrease in beneficial bacteria and an increase in potentially harmful bacteria. This underscores the importance of enhanced postoperative management to optimize gut microbiota.

Contralateral prophylactic mastectomy: Weighing the risks of delayed chemotherapy, radiotherapy, and hormonal therapy

BACKGROUND

Many patients with unilateral breast cancer opt for contralateral prophylactic mastectomy (CPM) at the time of therapeutic mastectomy (immediate CPM) or following completion of adjuvant therapy. Studies show that immediate CPM increases the risk of surgical complications related to unilateral mastectomy (UM) alone, which may lead to delays in adjuvant therapy initiation. However, it is unclear if these complications cause clinically significant delays in initiating adjuvant chemotherapy, radiotherapy, or hormonal therapy.

METHODS

A retrospective chart review was conducted on patients with breast cancer who underwent immediate CPM versus UM alone at Columbia University Medical Center from January 2000 to December 2020. Patient demographic and oncologic characteristics; complications; and timing of adjuvant chemotherapy, radiotherapy, and/or hormonal therapy relative to therapeutic mastectomy were collected.

RESULTS

In this study, 239 UM alone patients were propensity score matched to 239 immediate CPM patients. No significant difference in complication rates was found between the index and contralateral breasts in CPM patients. A similar percentage of CPM and UM patients experienced postoperative complications (19% vs. 17%, p = 0.64). No significant difference in time to adjuvant chemotherapy, radiotherapy, or hormonal therapy was found between CPM patients with complications and all CPM patients or all UM patients.

CONCLUSIONS

There is a lack of clear guidance for clinical decision-making regarding timing of CPM relative to adjuvant therapy. Our study suggests that immediate CPM does not significantly increase the risks of postoperative complications or complication-related delays in the initiation of adjuvant chemotherapy, radiotherapy, or hormonal therapy. This information may help patients and providers to plan, select, and schedule breast cancer treatment options.