Clinical evaluation of molecular surrogate subtypes in patients with ipsilateral multifocal primary breast cancer

BACKGROUND

When ipsilateral multifocal primary breast cancer (IMBC) is detected, standard routine is to evaluate the largest tumor with immunohistochemistry (IHC). As all foci are not routinely characterized, many patients may not receive optimal adjuvant treatment. Here, we assess the clinical relevance of examining at least two foci present in patients with IMBC.

METHODS

Patients diagnosed and treated for IMBC at Sahlgrenska University Hospital (Gothenburg, Sweden) between 2012 and 2017 were screened. In total, 180 patients with ≥ 2 invasive foci (183 specimens) were assessed with IHC and included in this study. Expression of the estrogen (ER) and progesterone (PR) receptors, Ki67, HER2, and tumor grade were used to determine the molecular surrogate subtypes and discordance among the foci was recorded. An additional multidisciplinary team board was then held to re-assess whether treatment recommendations changed due to discordances in molecular surrogate subtype between the different foci.

RESULTS

Discordance in ER, PR, HER2, and Ki67 was found in 2.7%, 19.1%, 7.7%, and 16.9% of invasive foci, respectively. Discordance in the molecular surrogate subtypes was found in 48 of 180 (26.7%) patients, which resulted in therapy changes for 11 patients (6.1%). These patients received additional endocrine therapy (n = 2), chemotherapy (n = 3), and combined chemotherapy and trastuzumab (n = 6).

CONCLUSION

Taken together, when assessing at least two tumor foci with IHC, regardless of shared morphology or tumor grade between the different foci, 6.1% of patients with IMBC were recommended additional adjuvant treatment. A pathologic assessment using IHC of all foci is therefore recommended to assist in individualized treatment decision making.

A prospective validation study of sentinel lymph node biopsy in multicentric breast cancer: SMMaC trial. Eur J Surg Oncol. 2014;40:1250-1255. [PMID: 24685336 DOI: 10.1016/j.ejso.2013.11.004]

BACKGROUND

Multicentric breast cancer is often considered a contra-indication for sentinel lymph node (SLN) biopsy due to concerns with sensitivity and false negative rate. To assess SLN feasibility and accuracy in multicentric breast cancer, the multi-institutional SMMaC trial was conducted.

METHODS

In this study 30 patients with multicentric breast cancer and a clinically negative axilla were prospectively included. Periareolar injection of radioisotope and blue dye was administered. In all patients SLN biopsy was validated by back-up completion axillary lymph node dissection.

RESULTS

the SLN was successfully identified in 30 of 30 patients (identification rate 100%). The incidence of axillary metastases was 66.7% (20/30). The false negative rate was 0% (0/20) and the sensitivity was 100% (20/20). The negative predictive value was 100% (10/10).

CONCLUSION

SLN biopsy in multicentric breast cancer seems feasible and accurate and should therefore be considered in patients with multicentric breast cancer and clinically negative axilla.

[Sentinel node biopsy in patients with multifocal and multicentric breast cancer: A 5-year follow-up]

OBJECTIVE

Sentinel lymph node biopsy (SLNB) as a staging procedure in multiple breast cancer is a controversial issue. We have aimed to evaluate the efficacy of sentinel node (SN) detection in patients with multifocal or multicentric breast cancer as well as the safety of its clinical application after a long follow-up.

MATERIAL AND METHODS

A prospective descriptive study was performed. Eighty-nine patients diagnosed of multiple breast cancer (73 multifocal; 16 multicentric) underwent SLNB. These patients were compared to those with unifocal neoplasia. Periareolar radiocolloid administration was performed in most of the patients. Evaluation was made at an average of 67.2 months of follow-up (32-126 months).

RESULTS

Scintigraphic and surgical SN localization in patients with multiple breast cancer were 95.5% and 92.1%, respectively. A higher percentage of extra-axillary nodes was observed than in the unifocal group (11.7% vs 5.4%) as well as a significantly higher number of SN per patient (1.70 vs 1.38). The rate of SN localization in multicentric cancer was slightly lower than in multifocal cancer (87.5% vs 93.1%), and the finding of extra-axillary drainages was higher (20% vs 10%). Number of SN per patient was significantly higher in multicentric breast cancer (2.33 vs 1.57). No axillary relapses have been demonstrated in the follow-up in multiple breast cancer patients group.

CONCLUSIONS

SLNB performed by periareolar injection is a reliable and accurate staging procedure of patients with multiple breast cancer, including those with multicentric processes.