Is FDG maximum standardized uptake value of primary breast cancer a prognostic factor for locoregional axillary lymph node metastasis?

Prognostic Prediction of BRCA Mutations by 18F-FDG PET/CT SUVmax in Breast Cancer

Objectives:

This study aimed to investigate the prognostic prediction of germline BRCA1 and BRCA2 mutations by comparing the maximum standardized uptake value (SUV_max) obtained from ¹⁸fluoride-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT), which is considered a prognostic factor in breast cancer (BC).

Methods:

Retrospective interdisciplinary laboratory results of 92 patients with BC who had germline BRCA1 or BRCA2 mutation profiles and underwent ¹⁸F-FDG PET/CT were compared. Genotyping was made by next-generation sequencing, and PET/CT scans were re-evaluated. The histopathological data, genetic results, and clinical demographics of all patients were recorded. Patients were divided into two groups in accordance with the presence of germline BRCA1 and/or BRCA2 mutations. Between-group statistical comparison was performed.

Results:

In PET/CT performed for primary staging, patients with BRCA-positive BC had significantly higher SUV_max (p=0.039), larger tumor size (p=0.025), and presence of axillary nodal metastases (p=0.023) than patients with BRCA-negative BC. Although the Ki-67 index was higher in the BRCA-positive group than BRCA-negative group, this difference was not significant (p=0.157). Moreover, in the BRCA-positive and negative groups, SUV_max, Ki-67 index, and tumor size, grade, and stage were significantly correlated with each other.

Conclusion:

The results of this study showed a strong association between BRCA mutations and SUV_max, which indicates the poor prognosis of BC.

Efficacy of sentinel lymph node biopsy with radioisotope alone and the prediction of sentinel node status using PET-CT in breast cancer

Purpose

Sentinel lymph node biopsy (SLNB) using both a radioactive isotope (RI) and blue dye is considered highly effective; however, there were limitations with the use of both agents in some hospitals, and blue dye has been shown to have some adverse effects. Additionally, preoperative prediction of sentinel lymph node (SLN) status using the maximum standardized uptake value (SUVmax) on positron emission tomography-computed tomography (PET-CT) can help avoid unnecessary axillary dissection or SLNB. Thus, we evaluated the efficacy and oncologic safety of SLNB using an RI alone in terms of long-term outcomes and determined the association between SLN metastasis and SUVmax of the primary tumor.

Methods

This retrospective study was conducted at Konyang University Hospital between March 2011 and May 2018. Overall, 142 patients with breast cancer who underwent SLNB using an RI alone were enrolled. Data on identification and false-negative rates were collected. The SUVmax of primary tumors on PET-CT were analyzed for their association with SLN metastasis.

Results

The identification and false-negative rates were 98.6% and 0%, respectively. There was no axillary local recurrence in patients with negative SLN findings. The correlation between the SUVmax of the primary tumor and SLN status was significant (r=0.249, P=0.005); the cutoff value for negative SLN metastasis was <2.15.

Conclusion

The single agent method using an RI is not inferior to other methods and serves as a feasible option for SLNB. And the number of excised SLNs could be minimized when the SUVmax of primary tumor is extremely low.