18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Predicts Tumor Immune Microenvironment Function in Early Triple-negative Breast Cancer.

BACKGROUND/AIM: The maximum standardized uptake value (SUVmax) obtained using 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) is presumed to indicate tumor and active immune cells in the tumor immune microenvironment (TIME) based on their glycolysis activity. Therefore, this study investigated whether the metabolic parameter SUVmax could provide information regarding TIME in triple-negative breast cancer (TNBC) patients. PATIENTS AND METHODS: Fifty-four patients with TNBC underwent FDG PET/CT before neoadjuvant chemotherapy. Pretreatment biopsy specimens were pathologically evaluated. Expression statuses of CD8, forkhead box P3 (FOXP3), programmed cell death-1 (PD-1), and programmed cell death-ligand 1 (PD-L1) were assessed by immunohistochemistry. The relationships between immunological factors, including the tumor-infiltrating lymphocyte (TIL) grade and SUVmax or pathological complete response (pCR), were investigated. RESULTS: CD8, FOXP3, PD-1, and PD-L1 were high in 15 (27.8%), 39 (72.2%), 18 (33.3%), and 26 (48.2%) patients, respectively. SUVmax was significantly correlated with tumor size, Ki-67 labeling index, and CD8/FOXP3 ratio. Multiple linear regression analysis indicated that tumor size and the CD8/FOXP3 ratio predicted SUVmax. Seventeen patients (31.5%) achieved a pCR; TILs, the CD8/FOXP3 ratio, PD-1, and PD-L1 were significantly correlated with pCR rate. Multivariate analysis indicated that the CD8/FOXP3 ratio was the only independent predictive factor for pCR. CONCLUSION: SUVmax could provide metabolic information regarding TIME for TNBC patients and might be beneficial for formulating a treatment strategy and predicting pCR after neoadjuvant chemotherapy.

Impact of oral hygiene on febrile neutropenia during breast cancer chemotherapy.

PURPOSE: Oral hygiene is crucial in the management of oral and febrile complications during chemotherapy for cancer. This study aimed to investigate the impact of oral hygiene on the incidence of febrile neutropenia (FN) throughout the course of chemotherapy for breast cancer. METHODS: A total of 137 patients with breast cancer who underwent four cycles of adjuvant chemotherapy with docetaxel and cyclophosphamide (TC) combination therapy or docetaxel alone were assessed for oral hygiene by quantifying the number of oral bacteria they harbored. These patients received professional oral health care (POHC). Eighteen patients underwent primary prophylaxis with granulocyte colony-stimulating factors. The relationship between oral bacteria count and FN incidence was retrospectively assessed. RESULTS: The FN incidence rate was 47.4% throughout all treatment cycles (32.8%, 13.5%, 14.3%, and 14.4% in cycles 1, 2, 3, and 4, respectively). The oral bacteria count decreased with each treatment cycle (cycle 1: 9.10 × 106 colony-forming units (CFU)/mL, cycle 2: 5.89 × 106 CFU/mL, cycle 3: 4.61 × 106 CFU/mL, cycle 4: 5.85 × 106 CFU/mL, P = 0.004). Among 281 treatment cycles, FN occurred in 63 (22.4%). In the treatment cycle-based analysis, high oral bacteria count was an independent risk factor for FN. CONCLUSION: FN incidence decreased with each treatment cycle and was associated with changes in oral bacteria counts. The oral bacterial count was one of risk factors for FN development in breast cancer.

Effect of Secondary Prophylactic G-CSF on the Occurrence of Febrile Neutropenia in Breast Cancer.

BACKGROUND/AIM: Docetaxel and cyclophosphamide (TC) combination therapy is widely used as adjuvant chemotherapy for early-stage breast cancer and is associated with a high incidence of febrile neutropenia (FN). Granulocyte colony-stimulating factor (G-CSF) is recommended in the primary prevention of febrile neutropenia (FN). This study aimed to evaluate the FN-suppressing effect of G-CSF in patients with breast cancer receiving TC. PATIENTS AND METHODS: We performed 272 treatment cycles after FN onset in 106 patients with breast cancer receiving TC. We retrospectively evaluated the effect of G-CSF as secondary prophylaxis. The frequency of FN was calculated based on the treatment cycles to adjust for differences in the number of cycles per case and FN occurrence. RESULTS: FN occurred in 58 cycles (21.3%). The incidence of FN with and without secondary prophylactic G-CSF was 10.1% and 25.9%, respectively (p=0.003). Multivariate analysis showed secondary prophylactic G-CSF administration to be an independent predictor of FN incidence [odds ratio (OR)=0.33, 95% confidence interval (CI)=0.14-0.74, p=0.007]. CONCLUSION: Secondary prophylaxis with G-CSF is recommended for patients with breast cancer undergoing TC chemotherapy to reduce the incidence of FN.

The tumor-infiltrating lymphocyte ultrasonography score can provide a diagnostic prediction of lymphocyte-predominant breast cancer preoperatively.

PURPOSE: Tumor-infiltrating lymphocytes (TILs) are known to predict the therapeutic effect in breast cancer. Although a preoperative tissue biopsy can be used to evaluate TILs, TILs that are heterogeneously distributed might require examination of all preoperative tissue biopsy samples. We have recently reported that the TIL ultrasonography (US) score, as determined by characteristic US findings, provides excellent predictive performance for lymphocyte predominant breast cancer (LPBC). We herein aimed to determine whether the preoperative TIL-US score can more accurately predict LPBC than preoperative tissue biopsy. METHODS: We assessed 161 patients with invasive breast cancer that were treated with curative surgery between January 2014 and December 2017. Stromal lymphocytes were examined on preoperative tissue biopsy tissues and surgical pathological specimens. Breast cancer samples with ≥ 50% stromal TILs were defined as pre-LPBC (preoperative tissue biopsy) and LPBC (surgical pathological specimens). Useful factors for predicting LPBC were searched among clinicopathological factors. RESULTS: The TIL-US score cutoff value for predicting LPBC was 4 points based on the receiver operating characteristic curves (area under the curve: 0.88). Several significant predictors for LPBC were revealed by the undertaken multivariate logistic regression analysis (odds ratios: TIL-US score, 26.8; pre-LPBC, 18.6; HER2, 9.2; all, p < 0.05). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 0.74, 0.89, 0.85, 0.67, and 0.92 for the TIL-US score, respectively, and 0.51, 0.98, 0.87, 0.91, and 0.86 for the pre-LPBC, respectively. CONCLUSION: TIL-US scores can predict LPBC preoperatively and are characterized by a significantly high sensitivity and negative predictive value.

Dual-phase FDG PET/CT for predicting prognosis in operable breast cancer.

PURPOSE: We aimed to investigate the role of dual-phase FDG PET/CT in predicting the prognosis of patients with operable breast cancer. METHODS: We retrospectively reviewed the data of 998 patients who underwent radical treatment for breast cancer. Before treatment, PET/CT scans were performed 1 and 2 h after FDG administration. The maximum standardized uptake value (SUVmax) at both time points (SUVmax1 and SUVmax2) in the primary tumor and the retention index (RI) were calculated. PET recurrence risk (PET-RR) was determined based on the SUVmax1 and RI, and disease-free survival (DFS) and overall survival (OS) were evaluated according to the metabolic parameters. Propensity score matching was performed to adjust for biological characteristics. RESULTS: The cut-off values for SUVmax1 and RI were 3 and 5%, respectively. The 5-year DFS was 94.9% and 86.1% (P < 0.001), and the 5-year OS was 97.6% and 92.7% (P < 0.001) in the low and high PET-RR groups, respectively. In multivariate analysis, high T status, nodal metastasis, the triple-negative subtype, and high PET-RR were independent factors of poor DFS. Propensity score matching revealed similar findings (5-year DFS 91.8% vs. 88.6%, P = 0.041 and 5-year OS 97.1% vs. 94.2%, P = 0.240, respectively). CONCLUSION: The combined parameters of SUVmax1 and RI on dual-phase FDG PET/CT were useful for predicting prognosis of patients with breast cancer. Patients with a high SUVmax1 and a negative time course of FDG uptake had a favorable prognosis.

The TILs-US score on ultrasonography can predict the pathological response to neoadjuvant chemotherapy for human epidermal growth factor receptor 2-positive and triple-negative breast cancer.

BACKGROUND: The tumor-infiltrating lymphocyte (TIL)-ultrasonography (US) score determined through characteristic US findings has predictive performance of lymphocyte-predominant breast cancer (LPBC). This study aimed to investigate whether the TIL-US score before neoadjuvant chemotherapy (NAC) can predict the pathological complete response (pCR). METHODS: We evaluated patients with human epidermal growth factor receptor type 2 (HER2)-positive breast cancer (n = 55) and triple-negative breast cancer (TNBC) (n = 24) who underwent surgery after NAC from November 2012 to April 2019. Pre-NAC biopsy examination was performed to examine stromal TILs; the cutoff value for predicting pCR was defined as ≥50% stromal TILs. The TILs-US score was calculated from the pre-NAC US findings. Based on previous data, the cutoff value for predicting pCR was set at ≥4 points. RESULTS: Forty-six patients achieved pCR. The TIL-US score was significantly associated with the pCR rate (p = 0.003) but not the pre-NAC biopsy findings (p = 0.055). Multivariate logistic regression analysis revealed that a TILs-US score ≥4 and HER2 positivity were significant pCR predictors (odds ratio [OR] 3.69; p = 0.031; OR 8.74; p = 0.025). CONCLUSIONS: TILs-US scores can be used to evaluate the therapeutic effect of NAC, and may be used as a non-invasive, convenient, and an alternative method to assess stromal TILs in pre-treatment biopsies.

Malignant prediction of incidental findings using ring-type dedicated breast positron emission tomography.

The classification according to uptake patterns and metabolic parameters on ring-type dedicated breast positron emission tomography (dbPET) is useful for detecting breast cancer. This study investigated the performance of dbPET for incidental findings that were not detected by mammography and ultrasonography. In 1,076 patients with breast cancer who underwent dbPET, 276 findings were incidentally diagnosed before treatment. Each finding was categorized as focus (uptake size ≤ 5 mm), mass (> 5 mm), or non-mass (multiple uptake) according to uptake patterns. Non-mass uptakes were additionally classified based on their distributions as-linear, focal, segmental, regional, or diffuse. Thirty-two findings (11.6%) were malignant and 244 (88.4%) were benign. Visually, 227 (82.3%) findings were foci, 7 (2.5%) were masses, and 42 (15.2%) were non-masses. Malignant rates of focus, mass, and non-mass were 9.7%, 28.6%, and 19.0%, respectively. In the non-mass findings, 23 were regional and diffuse distributions, and presented as benign lesions. Focus uptake with low lesion-to-background ratio (LBR) and no hereditary risk were relatively low (2.7%) in breast cancer. In multivariate analysis, LBR and hereditary risk were significantly associated with breast cancer (p = 0.006 and p = 0.013, respectively). Uptake patterns, LBR, and hereditary risk are useful for predicting breast cancer risk in incidental dbPET findings.

Monitoring of Programmed Cell Death Ligand-1 Blockade Using FDG PET/CT for Microsatellite Instability-High Metastatic Breast Cancer.

ABSTRACT: Microsatellite instability-high/mismatch repair deficiency is one of biomarkers predicting the response to pembrolizumab, an immune checkpoint inhibitor for metastatic solid tumors. A 44-year-old woman with stage IIIC right breast cancer was treated with mastectomy and axillary node dissection after primary systemic chemotherapy followed by radiation, chemotherapy, and hormonal therapy. Eighteen months after surgery, recurrent diseases were revealed and refractory to multiple treatments. The recurrent site biopsy showed microsatellite instability-high, and programmed cell death ligand-1 inhibitor pembrolizumab was administrated. FDG PET/CT showed complete metabolic response over 12 months and is useful to monitor the response of active immunotherapy.

[A Case of Breast Metastasis from Renal Cell Carcinoma].

The patient was a woman in her 90s. Right radical nephrectomy for right renal cell carcinoma had been performed 2 years and 6 months ago. Since then, there had been no recurrence. However, computed tomography during postoperative follow- up period showed a 3 cm mass in the right breast, and the patient was referred to our department. Breast ultrasonography indicated a well-circumscribed, oval, and almost smooth-surfaced tumor, 27 mm in size, located in the D region of the right breast. Results of a core needle biopsy showed metastatic renal cell carcinoma and clear cell carcinoma. Preoperative examination confirmed intramammary metastases of renal cell carcinoma. Given that the patient did not experience systemic metastases, partial mastectomy of the right breast was performed. Metastatic renal cell carcinoma is associated with poor prognosis. Generally, standard treatment in this disease is chemotherapy. However, surgical resection is selected with the aim of improving the prognosis and achieving radical cure of patients with this complication if these patients are in an oligometastatic state and complete resection of metastatic lesions is feasible, as in the present case. To achieve radical cure, the patient underwent partial mastectomy under local anesthesia, which is a relatively minimally invasive surgery.

Effect of Wnt5a on drug resistance in estrogen receptor-positive breast cancer.

BACKGROUND: Previously, we reported that Wnt5a-positive breast cancer can be classified as estrogen receptor (ER)-positive breast cancer; its prognosis is worse than that of Wnt5a-negative breast cancer. This study aimed to investigate the mechanisms underlying the poor prognosis in Wnt5a-positive breast cancer patients. METHODS: In total, 151 consecutive ER-positive breast cancer patients who underwent resection between January 2011 and February 2014 were enrolled. DNA microarray and pathway analyses were conducted using MCF-7 cells stably expressing Wnt5a [MCF-7/Wnt5a (+)]. Based on the outcomes, cell viability/drug sensitivity assays, and mutation analysis were performed using cell cultures and breast cancer tissues. The relationship between Wnt5a and the PI3K-AKT-mTOR signaling pathway was also examined. RESULTS: The relapse-free survival rate in patients with Wnt5a-positive breast cancer was significantly lower than that in patients with Wnt5a-negative breast cancer (P = 0.047). DNA microarray data suggest that only the cytochrome P450 (CYP) pathway was significantly upregulated in MCF-7/Wnt5a (+) cells (P = 0.0440). Additionally, MCF-7/Wnt5a (+) cells displayed reduced sensitivity to the metabolic substrates of CYP, tamoxifen (P < 0.001), paclitaxel (P < 0.001), and cyclophosphamide (P < 0.001). Of note, PIK3CA mutations were not associated with the expression of Wnt5a in breast cancer tissue and culture cells. CONCLUSIONS: In ER-positive breast cancer, Wnt5a upregulates the CYP metabolic pathway and suppresses tamoxifen, paclitaxel, and cyclophosphamide resistance, all of the three, standard treatment methods for ER-positive breast cancer. Wnt5a is thus potentially involved in the poor prognosis of ER-positive breast cancer independently of the PI3K-AKT-mTOR signaling pathway.

Clinical effect of the pathological axillary assessment method in breast cancer without clinical nodal metastasis.

BACKGROUND: This study aimed to assess the clinical effect of the pathological axillary assessment method in breast cancer without clinical lymph node metastasis. METHODS: Data of patients with clinically node-negative breast cancer were retrospectively reviewed. The study period was divided into early (January 2000-July 2007) and late (August 2007-December 2014) periods based on the pathological assessment method used (single-sectional and detailed multi-sectional lymph node processing). In the late period, lymph nodes were evaluated at six levels including immunohistochemistry on each 1.5-2 mm interval section. The axillary diagnostic accuracy and role of chemotherapy were assessed. RESULTS: In 1698 patients, 27 isolated tumor cells (ITCs), 39 micrometastases, and 205 macrometastases were noted. The sensitivity for pathological N0 diagnosis was dependent on clinical T stage, Tis (97.8%), T1 (83.0%), T2 (74.2%), T3 (54.5%), and T4 (63.6%). ITCs and micrometastases were detected only in the late period, and 84.7% and 91.6% of cases in the early and late period, respectively, did not have macrometastases. The 5-year disease-free interval (DFI) rates were 95.2% in node-negative cases, 98.4% in ITCs/micrometastases, and 91.4% in macrometastases (P < 0.001). In multivariate analysis, the predictor for DFI was estrogen receptor negativity (P = 0.013). Chemotherapy did not improve DFI in patients with node-positive breast cancer. CONCLUSIONS: The detailed multi-sectional pathological assessment of axillary lymph nodes detected ITCs and micrometastases. Implementation of chemotherapy should not be based on the minimal nodal metastasis and this type of serially nodal sectioned processing had little clinical significance.

Breast cancer detection by dedicated breast positron emission tomography according to the World Health Organization classification of breast tumors.

OBJECTIVE: Considering the difficulty in detecting primary breast cancers using whole-body positron emission tomography (WBPET) owing to its limited spatial resolution, we aimed to evaluate the detectability of breast cancer by ring-type dedicated breast PET (DbPET) on the World Health Organization (WHO) histological classification in comparison with WBPET. METHODS: A total of 938 patients with breast cancer underwent WBPET and ring-type DbPET, and 1021 lesions were histologically assessed based on the WHO classification of tumors of the breast. The findings of WBPET and DbPET were retrospectively evaluated and compared. RESULTS: The size-related sensitivity of DbPET was superior to that of WBPET for subcentimetric tumors (81.9% vs. 52.4%, P < 0.001). The histological distribution was as follows: 11 lobular carcinoma in situ, 158 ductal carcinoma in situ, 738 infiltrating duct carcinoma not otherwise specified (NOS), 12 lobular carcinoma NOS, 40 mucinous adenocarcinoma, 13 tubular carcinoma, 36 invasive breast carcinoma others, and 13 papillary neoplasms. WBPET had low sensitivity for lobular carcinoma in situ, ductal carcinoma in situ, lobular carcinoma NOS, mucinous adenocarcinoma, and tubular carcinoma. DbPET showed improved sensitivity for all the above except lobular and tubular carcinoma. The maximum standardized uptake values (SUVmax) of DbPET were significantly higher than those of WBPET for histological types, excluding lobular carcinoma in situ. The SUVmax of papillary neoplasms was high regardless of low-grade histology and Ki-67 labeling index. CONCLUSIONS: DBPET was found to have high sensitivity and SUVmax values for all histologic types that showed low sensitivity of detection on WBPET, except lobular carcinoma in situ.

Performance of dedicated breast positron emission tomography in the detection of small and low-grade breast cancer.

PURPOSE: This study compares the sensitivity of dedicated breast positron emission tomography (DbPET) and whole body positron emission tomography (WBPET) in detecting invasive breast cancer based on tumor size and biology. Further, we explored the relationship between maximum standardized uptake value (SUVmax) of DbPET and biological features of the tumor. METHODS: A total of 639 invasive breast cancer lesions subjected to both DbPET and WBPET before surgery, between January 2016 and May 2019, were included in the study. The sensitivity of DbPET and WBPET in detection and the biology of the tumor according to the clinicopathological features were retrospectively evaluated. RESULTS: The overall sensitivity of DbPET was higher than that of WBPET (91.4% vs. 80.3%, p < 0.001). Subcentimetric tumors were significant (80.9% vs. 54.3%, p < 0.001). Regardless of the nuclear grade, DbPET could detect more lesions than WBPET. The SUVmax was positively correlated with tumor size (R = 0.395, p < 0.001) and the nuclear grade (p < 0.001). Luminal A-like breast cancer had significantly lower SUVmax values than the other subtypes (p < 0.001). CONCLUSIONS: DbPET is superior to WBPET in the detection of subcentimetric, low-grade breast cancers. Further, by using SUVmax, DbPET can distinguish luminal A-like breast cancer from the other subtypes.

Ultrasonography Combined With Contrast-enhanced Ultrasonography Can Predict Lymphocyte-predominant Breast Cancer.

Background: We investigated whether contrast-enhanced ultrasonography (CEUS) scores can predict lymphocyte-predominant breast cancer (LPBC). Patients and Methods: We evaluated 75 patients who underwent US and CEUS. LPBC was defined as tissues with ≥50% stromal tumour-infiltrating lymphocytes (TILs) preoperatively. Characteristic US images predicting LPBC were evaluated using TIL-US scores via three ultrasonic tissue characteristics: Shape, internal echo level, and posterior echoes. TIL-CEUS was evaluated based on TIL-US plus CEUS. Results: TIL-US and TIL-CEUS cut-offs for predicting LPBC were 4 and 6 (area under the curve=0.93 and 0.96, respectively) points based on receiver operating characteristics curves. Sensitivity, specificity, and accuracy values (95% confidence intervaI) were 0.94 (0.77-0.99), 0.75 (0.70-0.77), and 0.80 (0.72-0.82); and 0.94 (0.78-0.99), 0.86 (0.81-0.87), and 0.88 (0.80-0.90) for TIL-US and TIL-CEUS, respectively. TIL-CEUS score was a significant single predictor for LPBC in multivariate logistic regression (p=0.001). Conclusion: TIL-CEUS can be used for preoperative LPBC prediction and detection.

Febrile neutropenia and role of prophylactic granulocyte colony-stimulating factor in docetaxel and cyclophosphamide chemotherapy for breast cancer.

PURPOSE: Febrile neutropenia (FN) incidence during docetaxel and cyclophosphamide (TC) chemotherapy, known as a high-risk regimen, differs among countries. The role of prophylactic granulocyte colony-stimulating factor (G-CSF) in FN is unclear. This study aimed to investigate FN frequency and relative dose intensity (RDI) of TC chemotherapy in patients with breast cancer and identify the correct population requiring prophylactic G-CSF. METHODS: In total, 205 patients with breast cancer were scheduled for TC chemotherapy (docetaxel/cyclophosphamide 75/600 mg/m2, every 3 weeks, 4 cycles) as adjuvant chemotherapy. Trastuzumab (8 mg/kg; continued with 6 mg/kg) was administrated intravenously for human epidermal growth factor receptor 2 (HER2)-positive cancer. Fifty-five patients received primary prophylactic measures (G-CSF: 20 and antibiotics: 35). We investigated the frequency of FN and hospitalization, RDI, and the factors related to FN, adverse events, hospitalization, and RDI. RESULTS: FN occurred in 70 patients (35.7%). FN incidence was noted in 41.1% without any prophylactic measures and in 5.0% with prophylactic G-CSF. In multivariate analysis, the independent risk factors of FN were older age (≥ 60 years, P = 0.017) and without primary prophylactic G-CSF (P = 0.011). Eleven patients (5.6%) were hospitalized of which 8 (72.7%) were elderly. The median RDIs of docetaxel and cyclophosphamide were 96.7% and 99.7%, respectively. CONCLUSION: FN frequency during TC chemotherapy was high, and primary prophylactic G-CSF reduced FN incidence. Primary prophylactic G-CSF is an effective therapy for preventing FN during TC chemotherapy. However, prophylactic G-CSF should be considered for elderly patients based on the low hospitalization rate and the high RDI.

Microwave Breast Imaging Using Rotational Bistatic Impulse Radar for the Detection of Breast Cancer: Protocol for a Prospective Diagnostic Study.

BACKGROUND: Mammography is the standard examination for breast cancer screening; however, it is associated with pain and exposure to ionizing radiation. Microwave breast imaging is a less invasive method for breast cancer surveillance. A bistatic impulse radar-based breast cancer detector has recently been developed. OBJECTIVE: This study aims to present a protocol for evaluating the diagnostic accuracy of the novel microwave breast imaging device. METHODS: This is a prospective diagnostic study. A total of 120 participants were recruited before treatment administration and divided into 2 cohorts: 100 patients diagnosed with breast cancer and 20 participants with benign breast tumors. The detector will be directly placed on each breast, while the participant is in supine position, without a coupling medium. Confocal images will be created based on the analyzed data, and the presence of breast tumors will be assessed. The primary endpoint will be the diagnostic accuracy, sensitivity, and specificity of the detector for breast cancer and benign tumors. The secondary endpoint will be the safety and detectability of each molecular subtype of breast cancer. For an exploratory endpoint, the influence of breast density and tumor size on tumor detection will be investigated. RESULTS: Recruitment began in November 2018 and was completed by March 2020. We anticipate the preliminary results to be available by summer 2021. CONCLUSIONS: This study will provide insights on the diagnostic accuracy of microwave breast imaging using a rotational bistatic impulse radar. The collected data will improve the diagnostic algorithm of microwave imaging and lead to enhanced device performance. TRIAL REGISTRATION: Japan Registry of Clinical Trials jRCTs062180005; https://jrct.niph.go.jp/en-latest-detail/jRCTs062180005. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/17524.

Tumor-infiltrating Lymphocyte Score Based on FDG PET/CT for Predicting the Effect of Neoadjuvant Chemotherapy in Breast Cancer.

AIM: To investigate whether tumor-infiltrating lymphocyte (TIL) scoring based on 18F-fluorodeoxyglucose positron-emission tomography/computed tomography (FDG PET/CT) can predict the pathological response to neoadjuvant chemotherapy. PATIENTS AND METHODS: A total of 261 patients with breast cancer underwent complete resection after neoadjuvant chemotherapy. PET-TIL score was calculated using tumor size, Ki-67 labeling index, and maximum standardized uptake value (SUVmax) on FDG PET/CT. The efficacy of the PET-TIL score in predicting the pathological complete response (pCR) was retrospectively evaluated. RESULTS: pCR rates were 11.4%, 58.6%, and 38.8% in luminal, human epidermal growth factor receptor 2 (HER2)-positive, and triple-negative breast cancer, respectively. The corresponding median PET-TIL scores were 28, 37, and 45. pCR rates were 20.0% and 44.2% in the low and high PET-TIL score groups, respectively (p<0.001). HER2-positive and triple-negative subtypes and high PET-TIL score were independent predictors for pCR. CONCLUSION: PET-TIL score can predict pCR after neoadjuvant chemotherapy in breast cancer.

Classification of Abnormal Findings on Ring-type Dedicated Breast PET for the Detection of Breast Cancer.

AIM: To investigate the usefulness of classification of ring-type dedicated breast positron-emission tomography (dbPET) findings in detection of breast cancer. PATIENTS AND METHODS: A total of 709 patients with breast cancer underwent dbPET before treatment. Each finding was morphologically categorized as a focus (uptake size ≤5 mm), mass (>5 mm), or non-mass (multiple uptakes not belonging to a three-dimensional mass or without distinct mass features). Non-mass uptakes were additionally classified as linear, focal, segmental, regional, or diffuse distributions. Lesion-to-background ratios were calculated. RESULTS: Among 910 abnormal findings, 700 (76.9%) were malignant and 210 (23.1%) were benign. Morphologically, 198 (21.8%) lesions were foci, 431 (47.4%) were masses, and 281 (30.9%) were non-masses. In multivariate analysis, mass, focal and segmental distributions of non-mass lesions and high lesion-to-background ratio were significantly related to breast cancer (all p<0.001). CONCLUSION: Classification of abnormal findings on dbPET using morphology and lesion-to-background ratio were useful to detect breast cancer.

Identification of Axillary Lymph Node Metastasis in Patients With Breast Cancer Using Dual-Phase FDG PET/CT.

OBJECTIVE. The aim of this study was to assess the diagnostic performance of dual-phase 18F-FDG PET/CT in detecting axillary lymph node metastasis in patients with breast cancer. MATERIALS AND METHODS. A total of 826 patients with breast cancer were retrospectively evaluated. PET/CT scans were performed 1 hour and 2 hours after FDG administration before treatment. The maximum standardized uptake value (SUVmax) in the axillary lymph node at both time points (hereafter referred to as SUVmax1 and SUVmax2, respectively) and the retention index (RI) were calculated. RESULTS. Axillary lymph node metastasis was detected in 285 of 826 patients (34.5%). The median axillary SUVmax1, SUVmax2, and RI in patients with nodal metastasis were higher than those in patients without metastasis (1.5 vs 0.6, 1.6 vs 0.5, and 7.7 vs -3.7, respectively; all p < 0.001). The diagnostic accuracy of axillary SUVmax1 and SUVmax2 was equivalent, and the sensitivity and specificity of SUVmax1 were 74.7% and 83.4%, respectively. Although the performance of the axillary RI was inferior to that of SUVmax1 and SUVmax2, both the SUVmax and the RI were independent predictors of nodal metastasis, and a positive RI suggested axillary lymph node involvement when the SUVmax1 was significantly high. Of 533 patients with category T1-2 breast cancer without lymph node swelling, 101 (19.0%) had pathologic lymph node involvement; the negative predictive value of axillary SUVmax1 was 86.8%. CONCLUSION. Delayed phase imaging identified axillary lymph node metastasis as accurately as standard PET/CT. A high negative predictive value of PET/CT for the detection of nodal metastasis is helpful to avoid surgical axillary assessment in patients with category T1-2 breast cancer without lymph node swelling.