Neoadjuvant therapy in locally advanced breast cancer: 99mTc-MIBI mammoscintigraphy is not a reliable technique to predict therapy response

Assessment of Residual Disease With Molecular Breast Imaging in Patients Undergoing Neoadjuvant Therapy: Association With Molecular Subtypes

BACKGROUND

Assessment of residual disease after neoadjuvant therapy for breast cancer is an ongoing challenge of breast imaging. This study evaluates the accuracy of a novel dedicated system for molecular breast imaging (MBI) composed of the new generation of cadmium zinc telluride detectors in assessing residual disease after neoadjuvant therapy in patients with breast cancer.

PATIENTS AND METHODS

Clinical data, imaging, surgical, and pathological findings of 51 women with breast cancer undergoing neoadjuvant therapy were recorded. MBI findings were correlated with surgical pathology results. Accuracy of MBI in predicting complete pathological response and size of residual disease was assessed according to molecular subtypes.

RESULTS

The size of the largest focus of uptake on MBI correlated with the largest dimension measured on pathology (r = 0.55; P < .001). This correlation was stronger for triple negative and HER2/neu positive subtypes (r = 0.92 and 0.62, respectively). Sixteen patients (31%) had complete pathological response. The sensitivity and specificity of MBI for detecting residual disease were 83% (95% confidence interval [CI], 66-93) and 69% (95% CI, 42-88), respectively. For triple negative or HER2/neu positive disease the sensitivity and specificity were 88% (95% CI, 62-98) and 75% (95% CI, 43-93), respectively.

CONCLUSION

The accuracy of MBI in assessing residual disease after neoadjuvant treatment might be related to the molecular subtype. Accuracy is highest in the triple negative and HER2/neu positive subtypes.

Technetium-99m methoxyisobutylisonitrile scintimammography for monitoring and early prediction of breast cancer response to neoadjuvant chemotherapy

PURPOSE

The aim of the study was to evaluate the clinical value of scintimammography (SMG) with technetium-99m methoxyisobutylisonitrile (Tc-MIBI) for evaluating the efficacy of neoadjuvant chemotherapy (NAC).

MATERIALS AND METHODS

A total of 65 patients with advanced breast cancer (BC) were included in the study. Planar SMG with 740 MBq of Tc-MIBI was performed before the start and after two to three and four to six cycles of NAC. NAC efficacy was estimated as progression (grade I), stabilization (grade II), partial effect (grade III), prominent efficacy (grade IV), and complete response (grade V). In 59 women, histopathologic verification of BC response to NAC was performed according to the Miller-Payne classification with the same scores as were used in the evaluation of scintigraphic response.

RESULTS

After two to three cycles of NAC, disease progression was detected in five of 65 (7.7%) patients. In 27 (41.5%) patients SMG detected early stabilization of BC. Only one of these patients achieved prominent (grade IV) response after the end of NAC. Partial (grade III) response after two to three cycles of NAC was seen in 24 (36.9%) patients. One-third of them had grades IV-V response at the end of treatment. The most promising was the group of nine (13.8%) patients with early-grades IV-V response, all of which transformed to complete response at the end of NAC. As per histopathologic verification, early SMG had 85.7% sensitivity, 94.2% specificity, and 93.2% accuracy in predicting complete pathologic response to four to six cycles of NAC.

CONCLUSION

After two to three cycles of NAC, SMG with Tc-MIBI can determine patients with low, intermediate, and high probability of complete response to five to six cycles of NAC Video Abstract: http://links.lww.com/NMC/A43.

Role of imaging in neoadjuvant therapy for breast cancer

Neoadjuvant chemotherapy (NAC) involves administration of chemotherapeutic agents to patients with newly diagnosed breast cancer prior to definitive surgical treatment. Assessment of disease response to chemotherapeutic agents in vivo prior to any surgical intervention is necessary as medical oncologists are commonly tailoring or changing therapy during NAC based on response. It can also maximize the pathologic complete response (pCR) rate, resulting in more women undergoing breast conservation rather than mastectomy. Although some studies show a pCR to NAC in only 13-26 % of women, recent studies have shown higher pCR rates, especially for HER2-positive disease treated with targeted anti-HER2 therapy. Thus, accurate imaging tools for quantifying disease response are critical in the evaluation and management of patients undergoing NAC. There is currently no standard imaging method for monitoring response to therapy. Response to therapy tends to vary by tumor subtype and can be accurately assessed on imaging. We review the role of imaging before and after neoadjuvant therapy and discuss the advantages and limitations of currently available modalities, including mammography, ultrasonography, magnetic resonance imaging, and nuclear imaging.

Scientific Impact Recognition Award: Molecular breast imaging: a review of the Mayo Clinic experience

BACKGROUND

Molecular breast imaging (MBI) depicts functional uptake of targeted radiotracers in the breast using dedicated gamma cameras.

METHODS

MBI studies were performed under several institutional protocols evaluating the use of MBI in screening and diagnosis.

RESULTS

By using a single-head system, sensitivity for breast cancer detection was 85% (57 of 67) overall and 29% for tumors 5 mm or less in diameter. Sensitivity improved to 91% (117 of 128) overall and 69% for tumors 5 mm or less using a dual-head system. In 650 high-risk patients undergoing breast cancer screening, MBI detected 7 cancers, 5 of which were missed on mammography. In 24 of 149 (16%) breast cancer patients MBI detected additional disease not seen on mammography. The sensitivity of MBI was 88% (83 of 94) for invasive ductal carcinoma, 79% (23 of 29) for invasive lobular carcinoma, and 89% (25 of 28) for ductal carcinoma in situ.

CONCLUSIONS

MBI can detect invasive ductal carcinoma, ductal carcinoma in situ, and invasive lobular carcinoma. It has a promising role in evaluating the extent of disease and multifocal disease in the breast for surgical treatment planning.