Locoregional Management and Prognostic Factors in Breast Cancer Patients with Ipsilateral Internal Mammary and Axillary Lymph Node Involvement

Outcomes and Trends in Axillary Management of Stage cN3b Breast Cancer Patients

BACKGROUND

There is limited data regarding sentinel lymph node biopsy (SLNB) after neoadjuvant chemotherapy (NAC) for cN3b patients, who present with both axillary and ipsilateral internal mammary node involvement. We examined trends in the use of SLNB in cN3b patients and survival by axillary procedure for those with nodal pathologic complete response (nPCR).

METHODS

Adult women with nonmetastatic cN3b invasive breast carcinoma between 2012 and 2021 were selected from the National Cancer Database. These patients were compared based on type of axillary surgery, specifically SLNB, SLNB with axillary lymph node dissection (ALND), and ALND alone. Kaplan-Meier analysis was used to compare overall survival.

RESULTS

A total of 4,236 patients were included. In 2012, 8.5% of these patients underwent SLNB alone and 18.3% underwent SLNB+ALND. In 2021, this increased to 35.1% for SLNB alone and 23.0% for SLNB with subsequent ALND (p < 0.0001). For patients who received NAC, the rate of nPCR was overall found to be 24.9%. Overall survival of patients receiving SLNB or SLNB+ALND with nPCR was not statistically significantly different from the ALND only group with nPCR (p = 0.22 and 0.57, respectively).

CONCLUSIONS

There has been increasing use of the SLNB procedure for patients with cN3b breast cancer over the past decade. In patients with nPCR, SLNB was not associated with reduced survival. For well-selected cN3b patients with an excellent clinical response to NAC, including nPCR, axillary de-escalation strategies, such as SLNB with omission of completion axillary dissection, may be considered.

Baseline cross-sectional imaging of locally advanced high-risk breast cancer facilitates highly customized radiation therapy in surgically inaccessible anatomical areas

Background

Routine medical imaging used for preliminary breast cancer workup, such as mammography (MMG) and ultrasound (US), has limited utility for radiation oncologists. We hypothesized that the inclusion of cross-sectional imaging (CT scan or PET-CT) prior to primary systemic therapy (PST) would improve clinical staging accuracy and facilitate customized postoperative radiation therapy planning. Therefore, this study aimed to compare the standard baseline imaging with extended radiological staging.

Methods

To assess our hypothesis, we performed a prospective, single-center study that included 132 participants who were recruited from October 2015 to March 2020. We quantified the value of cross-sectional imaging compared to those of MMG and US. Descriptive statistics, the Friedman and chi-square tests were performed, and p < 0.05 was considered significant.

Results

Patients were grouped into two cohorts: the CT scan cohort (n = 87) and the PET-CT cohort (n = 43). A comparison of the value of cross-sectional imaging with those of MMG and US revealed that staging and radiation planning were altered by this additional procedure. The originally determined disease stage changed in 36.8% and 51.2% of cases in the first and second groups, respectively. The consistency between the assessment of involved axillary lymph nodes using imaging (cN) and the postoperative pathology report (pN) were evaluated. In most cases, clinical and pathological evaluation were consistent, with χ2(1) = 18.98; p < 0.001 for CT scan, and χ2(1) = 6.41; p = 0.03 for PET-CT.

Conclusions

Cross-sectional imaging is recommended for patients with locally advanced high-risk breast cancer. A highly customized radiation therapy, including a dose boost, was administered in nine patients with affected lymph nodes that were surgically inaccessible. This procedure was facilitated by extended radiological staging.

Internal mammary lymph nodal response to neoadjuvant chemotherapy on imaging and breast cancer prognosis

Background

Pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC) is an important prognostic indicator in breast cancer. Internal mammary lymph node involvement is not currently included in pCR determination, as sampling at the time of surgery is not routinely performed.

Methods

Pre and post neoadjuvant chemotherapy MRI or PET/CT imaging response of the internal mammary lymph node chain was utilized as a surrogate to pCR and imaging data was correlated with patient outcomes.

Results

Internal mammary lymph node response to NAC was associated with disease free survival over the course of this study, regardless of whether axillary nodal pCR was achieved.

Conclusion

Internal mammary lymph nodal response to NAC is an important prognostic indicator. Potential use of internal mammary lymph node resolution as an imaging data input for AI models that predict pCR post-NAC may improve accuracy and other metrics in pCR prediction.