Pretreatment 18F-FDG Uptake Heterogeneity Predicts Treatment Outcome of First-Line Chemotherapy in Patients with Metastatic Triple-Negative Breast Cancer

Innovations in Positron Emission Tomography and State of the Art in the Evaluation of Breast Cancer Treatment Response

The advent of hybrid Positron Emission Tomography/Computed Tomography (PET/CT) and PET/Magnetic Resonance Imaging (MRI) scanners resulted in an increased clinical relevance of nuclear medicine in oncology. The use of [18F]-Fluorodeoxyglucose ([18F]FDG) has also made it possible to study tumors (including breast cancer) from not only a dimensional perspective but also from a metabolic point of view. In particular, the use of [18F]FDG PET allowed early confirmation of the efficacy or failure of therapy. The purpose of this review was to assess the literature concerning the response to various therapies for different subtypes of breast cancer through PET. We start by summarizing studies that investigate the validation of PET/CT for the assessment of the response to therapy in breast cancer; then, we present studies that compare PET imaging (including PET devices dedicated to the breast) with CT and MRI, focusing on the identification of the most useful parameters obtainable from PET/CT. We also focus on novel non-FDG radiotracers, as they allow for the acquisition of information on specific aspects of the new therapies.

Pretreatment 18F-FDG uptake heterogeneity may predict treatment outcome of combined Trastuzumab and Pertuzumab therapy in patients with metastatic HER2 positive breast cancer

OBJECTIVE

Intra-tumoral heterogeneity of 18F-fluorodeoxyglucose (18F-FDG) uptake has been proven to be a surrogate marker for predicting treatment outcome in various tumors. However, the value of intra-tumoral heterogeneity in metastatic Human epidermal growth factor receptor 2(HER2) positive breast cancer (MHBC) remains unknown. The aim of this study was to evaluate 18F-FDG uptake heterogeneity to predict the treatment outcome of the dual target therapy with Trastuzumab and Pertuzumab(TP) in MHBC.

METHODS

Thirty-two patients with MHBC who underwent 18F-FDG positron emission tomography/computed tomography (PET/CT) scan before TP were enrolled retrospectively. The region of interesting (ROI) of the lesions were drawn, and maximum standard uptake value (SUVmax), mean standard uptake value (SUVmean), total lesion glycolysis (TLG), metabolic tumor volume (MTV) and heterogeneity index (HI) were recorded. Correlation between PET/CT parameters and the treatment outcome was analyzed by Spearman Rank Test. The ability to predict prognosis were determined by time-dependent survival receiver operating characteristic (ROC) analysis. And the survival analyses were then estimated by Kaplan-Meier method and compared by log-rank test.

RESULTS

The survival analysis showed that HI50% calculated by delineating the lesion with 50%SUVmax as threshold was a significant predictor of patients with MHBC treated by the treatment with TP. Patients with HI50% (≥ 1.571) had a significantly worse prognosis of progression free survival (PFS) (6.87 vs. Not Reach, p = 0.001). The area under curve (AUC), the sensitivity and the specificity were 0.88, 100% and 63.6% for PFS, respectively.

CONCLUSION

18F-FDG uptake heterogeneity may be useful for predicting the prognosis of MHBC patients treated by TP.

Effectiveness of hypofractionated and normofractionated radiotherapy in a triple‐negative breast cancer model

Breast cancer (BC) is one of the most diagnosed malignant carcinomas in women with a triple-negative breast cancer (TNBC) phenotype being correlated with poorer prognosis. Fractionated radiotherapy (RT) is a central component of breast cancer management, especially after breast conserving surgery and is increasingly important for TNBC subtype prognosis. In recent years, moderately hypofractionated radiation schedules are established as a standard of care, but many professionals remain skeptical and are concerned about their efficiency and side effects. In the present study, two different triple-negative breast cancer cell lines, a non-malignant breast epithelial cell line and fibroblasts, were irradiated daily under normofractionated and hypofractionated schedules to evaluate the impact of different irradiation regimens on radiation-induced cell-biological effects. During the series of radiotherapy, proliferation, growth rate, double-strand DNA break-repair (DDR), cellular senescence, and cell survival were measured. Investigated normal and cancer cells differed in their responses and receptivity to different irradiation regimens, indicating cell line/cell type specificity of the effect. At the end of both therapy concepts, normal and malignant cells reach almost the same endpoint of cell count and proliferation inhibition, confirming the clinical observations in the follow-up at the cellular level. These result in cell lines closely replicating the irradiation schedules in clinical practice and, to some extent, contributing to the understanding of growth rate or remission of tumors and the development of fibrosis.

Evaluation of tumour heterogeneity by 18F-fluoroestradiol PET as a predictive measure in breast cancer patients receiving palbociclib combined with endocrine treatment

Background

Predictive biomarkers are needed to identify oestrogen receptor-positive, human epidermal growth factor receptor 2-negative (ER + /HER2-) metastatic breast cancer (MBC) patients who would likely benefit from cyclin-dependent kinase 4 and 6 inhibitors combined with endocrine therapy. Therefore, we performed an exploratory study to evaluate the tumour heterogeneity parameters based on 16α-¹⁸F-fluoro-17β-oestradiol (¹⁸F-FES)-PET imaging as a potential marker to predict progression-free survival (PFS) in MBC patients receiving palbociclib combined with endocrine therapy.

Methods

Fifty-six ER + MBC patients underwent ¹⁸F-FES-PET/CT before the initiation of palbociclib. ¹⁸F-FES uptake was quantified and expressed as the standardized uptake value (SUV). Interlesional heterogeneity was qualitatively identified according to the presence or absence of ¹⁸F-FES-negative lesions. Intralesional heterogeneity was measured by the SUV-based heterogeneity index (HI = SUVmax/SUVmean). Association with survival was evaluated using the Cox proportional hazards model.

Results

A total of 551 metastatic lesions were found in 56 patients: 507 lesions were identified as ¹⁸F-FES-positive, 38 lesions were distributed across 10 patients without ¹⁸F-FES uptake, and the remaining 6 were liver lesions. Forty-three patients obtained a clinical benefit, and 13 developed progressive disease (PD) within 24 weeks. Nine out of 10 patients with an ¹⁸F-FES-negative site developed PD, and the median PFS was only 2.4 months. Among 46 patients with only ¹⁸F-FES-positive lesions, only four patients had PD, and the median PFS was 23.6 months. There were statistically significant differences between the two groups (P < 0.001). For the subgroup of patients with only ¹⁸F-FES-positive lesions, low FES-HI patients experienced substantially longer PFS times than those with high FES-HI (26.5 months vs. 16.5 months, P = 0.004).

Conclusions

¹⁸F-FES-PET may provide a promising method for identifying and selecting candidate ER + /HER2- MBC patients who would most likely benefit from palbociclib combined with endocrine treatment and could serve as a predictive marker for treatment response.

Trial registration NCT04992156, Date of registration: August 5, 2021 (retrospectively registered).

Temporal Heterogeneity of HER2 Expression and Spatial Heterogeneity of 18F-FDG Uptake Predicts Treatment Outcome of Pyrotinib in Patients with HER2-Positive Metastatic Breast Cancer

Background: This study aimed to evaluate tumor heterogeneity of metastatic breast cancer (MBC) and investigate its impact on the efficacy of pyrotinib in patients with HER2-positive MBC. Methods: MBC patients who underwent 18F-FDG PET/CT before pyrotinib treatment were included. Temporal and spatial tumor heterogeneity was evaluated by the discordance between primary and metastatic immunohistochemistry (IHC) results and baseline 18F-FDG uptake heterogeneity (intertumoral and intratumoral heterogeneity indexes: HI-inter and HI-intra), respectively. Progression-free survival (PFS) was estimated by the Kaplan−Meier method and compared by a log-rank test. Results: A total of 572 patients were screened and 51 patients were included. In 36 patients with matched IHC results, 25% of them had HER2 status conversion. Patients with homogenous HER2 positivity had the longest PFS, followed by patients with gained HER2 positivity, while patients with HER2 negative conversion could not benefit from pyrotinib (16.8 vs. 13.7 vs. 3.6 months, p < 0.0001). In terms of spatial heterogeneity, patients with high HI-intra and HI-inter had significantly worse PFS compared to those with low heterogeneity (10.6 vs. 25.3 months, p = 0.023; 11.2 vs. 25.3 months, p = 0.040). Conclusions: Temporal heterogeneity of HER2 status and spatial heterogeneity of 18F-FDG uptake could predict the treatment outcome of pyrotinib in patients with HER2-positive MBC, which provide practically applicable methods to assess tumor heterogeneity and guidance for treatment decisions.

Prognostic Value of Heterogeneity Index Derived from Baseline 18F-FDG PET/CT in Mantle Cell Lymphoma

Objectives

Mantle cell lymphoma (MCL) represents a group of highly heterogeneous tumors, leading to a poor prognosis. Early prognosis prediction may guide the choice of therapeutic regimen. Thus, the purpose of this study was to investigate the potential application value of heterogeneity index (HI) in predicting the prognosis of MCL.

Methods

A total of 83 patients with histologically proven MCL who underwent baseline fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) were retrospectively enrolled. The clinicopathologic index and PET/CT metabolic parameters containing maximum and mean standard uptake value (SUVmax and SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and HI were evaluated. Receiver operating characteristic (ROC) curve analyses were performed to determine the optimal cutoff values of the parameters for progression-free survival (PFS) and overall survival (OS). Univariate and multivariate Cox regression were used to assess relationships between risk factors and recurrence. Kaplan–Meier plots were applied for survival analyses.

Results

In univariate analyses, age [HR = 2.51, 95% CI = 1.20–5.24, p = 0.041 for body weight (BW)] and HI-BW (HR = 4.17, 95% CI = 1.00–17.38, p = 0.050) were significantly correlated with PFS. In multivariate analyses, age (HR = 2.61, 95% CI = 1.25–5.47, p = 0.011 for BW) and HI-BW (HR = 4.41, 95% CI = 1.06–18.41, p = 0.042) were independent predictors for PFS, but not for OS. B symptoms (HR = 5.00, 95% CI = 1.16–21.65, p = 0.031 for BW) were an independent prognostic factor for OS, but not for PFS. The other clinicopathologic index and PET/CT metabolic parameters were not related to outcome survival in MCL.

Conclusion

The age and HI derived from baseline PET/CT parameters were significantly correlated with PFS in MCL patients.

Heterogeneity derived from 18 F-FDG PET/CT predicts immunotherapy outcome for metastatic triple-negative breast cancer patients

Background

Recently, immunotherapy has been used to treat metastatic triple‐negative breast cancer (mTNBC). Basic research has indicated a relation between tumor heterogeneity and the immune response. Tumor heterogeneity derived from ¹⁸F‐FDG PET/CT is a potential predictor of chemotherapy results; however, few studies have focused on immunotherapy. This study aims to develop a convenient and efficient measurement of tumor heterogeneity for the prediction of immunotherapy in mTNBC patients.

Methods

We enrolled mTNBC patients who received immunotherapy (PD‐1/PD‐L1 antibody) plus chemotherapy as first‐line treatment and underwent ¹⁸F‐FDG PET/CT scans before treatment. We defined a novel index representing tumor heterogeneity calculated from the standard uptake value (SUV) as IATH and IETH. Optimal cutoffs were determined using time‐dependent receiver operator characteristics (ROC) analysis.

Results

A total of 32 patients were enrolled and analyzed in this trial. A significantly longer median PFS was observed in the low SUVmax group than in the high SUVmax group (9.4 vs. 5.8 months, HR = 0.3, 95% CI 0.1–0.9, p = 0.025). The median PFS of low‐IATH patients was significantly longer than that of high‐IATH patients (HR = 0.3, 95% CI 0.1–0.8, p = 0.022). Similarly, patients with low IETH had significantly longer PFS than patients with high IETH (9.4 vs. 4.9 months, HR = 0.3, 95% CI 0.1–0.7, p = 0.01). Multivariate analysis demonstrated IETH as an independent predictor of PFS.

Conclusions

This study proposed a novel method to assess intratumor and intertumor heterogeneity among metastatic breast cancer patients and determined that baseline IETH derived from ¹⁸F‐FDG PET/CT could represent a simple and promising predictor for first‐line immunotherapy among mTNBC patients.

Pretreatment 18F-FDG uptake heterogeneity can predict treatment outcome of carbon ion radiotherapy in patients with locally recurrent nasopharyngeal carcinoma

OBJECTIVE

Our study was to investigate the value of pretreatment 18F-FDG uptake heterogeneity to predict the prognosis of patients with locally recurrent nasopharyngeal carcinoma (LRNPC) treated by carbon ion radiotherapy (CIRT).

METHODS

Twenty-nine LRNPC patients who underwent whole-body 18F-FDG PET/CT scanning before CIRT were enrolled. Heterogeneity index (HI)-based 18F-FDG uptake, and the PET/CT traditional parameters, including SUVmax, MTV, and TLG were assessed. Receiver operator characteristics (ROC) determined the best cutoff value, and local recurrence-free survival (LRFS) and progression-free survival (PFS) were evaluated by the Kaplan-Meier method and log-rank test. And the predictive ability was evaluated by the ROC curve. Cox analyses were performed on LRFS and PFS.

RESULTS

In this study, univariate analysis showed that HI was a significant predictor of LRNPC treated by CIRT. HI could be used to predict LRFS and PFS. Patients with HI (≥ 0.81) had a significantly worse prognosis of LRFS (12.25 vs. NR, p = 0.008), and of PFS (10.58 vs. NR, p = 0.014). The AUC and its sensitivity and sensitivity and specificity were 0.75, 84.21% and 70.00% for LRFS and 0.82, 80.95% and 75.00% for PFS, respectively. Multivariate analysis showed that HI was an independent predictor for the LFRS of LRNPC with CIRT.

CONCLUSION

18F-FDG uptake heterogeneity may be useful for predicting the prognosis of patients with LRNPC treated by CIRT.

Prediction of Pretreatment 18F-FDG-PET/CT Parameters on the Outcome of First-Line Therapy in Patients with Metastatic Breast Cancer

Objective

18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) can provide prognostic information, especially 18F-FDG uptake has been proven to be a predictor for the prognosis of various tumors. Nevertheless, the prognosis of other PET parameters in the metastatic setting remains unclear. This study was aimed at investigating pretreatment parameters based on 18F-FDG-PET/CT so as to estimate the progression-free survival (PFS) of metastatic breast cancer (MBC) patients receiving first-line treatment.

Methods

MBC patients who underwent a whole-body 18F-FDG-PET/CT prior to first-line therapy were enrolled. The heterogeneity parameter of PET/CT was analyzed, including heterogeneity index (HI) and general parameters (metabolic tumor volume (MTV), total lesion glycolysis (TLG), maximum standardized uptake value (SUVmax) and mean SUV (SUVmean). PFS was used to evaluate the treatment outcome. Kaplan-Meier method was adopted to carry out survival analysis and Log rank test was conducted to make a comparison.

Results

A total of 177 MBC patients were selected, in which 68 were in De novo stage IV. Thirty patients were human epidermal growth factor receptor 2 (HER2)-positive, 60 patients were triple-negative, and 87 patients were hormone receptor (HR)-positive and HER2-negative. In the whole population, patients with high baseline SUVmax, SUVmean, MTV, TLG or HI were associated with lower PFS (P=0.028, 0.005, 0.017, 0.026 and 0.035, respectively). Among the patients in De novo stage IV, those with high HI at baseline had significantly shorter PFS (P=0.001). In HR+/HER2- and HER2+ subgroups, only baseline HI showed the predictive value of PFS (P=0.023 and 0.049, respectively). In the triple-negative subgroup, high baseline SUVmax, MTV or TLG showed the predictive value of worse PFS (P=0.030, 0.011 and 0.023, respectively).

Conclusion

Pretreatment 18F-FDG-PET/CT parameters show the predictive value of PFS in MBC patients receiving first-line treatment. However, predictive PET/CT parameters might be different in patients with different molecular subtypes and De novo stage IV.

Intratumoral Metabolic Heterogeneity and Other Quantitative 18F-FDG PET/CT Parameters for Prognosis Prediction in Esophageal Cancer

PURPOSE

To evaluate the impact of intratumoral metabolic heterogeneity (IMH) and other quantitative fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG) PET/CT parameters for predicting progression-free survival (PFS) and overall survival (OS) in patients with esophageal cancer.

MATERIALS AND METHODS

In this retrospective study, an automated gradient-based segmentation method was used to assess the maximum standardized uptake value, mean standardized uptake value, metabolic tumor volume (MTV), and IMH index of the primary tumor in patients with biopsy-proven adenocarcinoma or squamous cell carcinoma of the esophagus with an initial staging ¹⁸F-FDG PET/CT. Data were collected between July 2006 and February 2016. OS and PFS were calculated using multivariable Cox proportional hazards regression with the adjustment (as covariates) of age, sex, weight, stage, tumor type, tumor grade, and treatment. All PET parameters were standardized before analysis. Log-rank tests were performed, and corresponding Kaplan-Meier survival plots were generated.

RESULTS

A total of 71 patients (mean age, 64 years ± 10 [standard deviation], 62:9 men:women) were included. Median follow-up time was 28.2 months (range, 4-38 months), and median survival was 16.1 months (range, 0.1-60.3 months). Higher MTV was associated with reduced PFS for every standard deviation increase (hazard ratio [HR], 0.193; 95% CI: 0.052, 0.711; P = .01). Higher IMH was associated with reduced PFS for every standard deviation decrease in the area under the curve (HR, 10.78; 95% CI: 1.31, 88.96; P = .03).

CONCLUSION

PFS for patients with esophageal cancer was associated with MTV and with IMH.Keywords: Esophagus, Neoplasms-Primary, PET/CT, Tumor Response © RSNA, 2020.

Heterogeneous parameters based on 18F-FET PET imaging can non-invasively predict tumor grade and isocitrate dehydrogenase gene 1 mutation in untreated gliomas

Background

The present study aimed to explore the efficacy of easily obtained intratumoral heterogeneous parameters, other than regular semi-quantitative parameters, based on static O-(2-[18F]fluoroethyl)-l-tyrosine (¹⁸F-FET) positron emission tomography (PET) imaging in glioma grade and isocitrate dehydrogenase (IDH) gene 1 mutation prediction.

Methods

Fifty-eight adult patients with untreated glioma (grades II-IV) who underwent preoperative ¹⁸F-FET PET/computed tomography (CT) imaging were enrolled in the present study. Eight semi-automatically obtained static PET imaging parameters after lesion delineation were chosen for analysis. These were: maximal tumor-to-background ratio (TBRmax), peak tumor-to-background ratio (TBRpeak), mean tumor-to-background ratio (TBRmean), coefficient of variation (COV), heterogeneity index (HI), the standard deviation of lesion standardized uptake value (SUVsd), metabolic tumor volume (MTV), and total lesion tracer standardized uptake (TLU). Pathological and immunohistochemical results were used as a reference. The receiver-operating characteristic analysis was used to investigate the predictive efficacy of these parameters in glioma grade and IDH1 mutation status.

Results

TLU [area under the curve (AUC): 0.841, P<0.0001], TBRpeak (AUC: 0.832, P<0.0001), and HI (AUC: 0.826, P<0.0001) had the top 3 single-parameter predictive performance between grade II or III and grade IV glioma patients. Combinations of TBRmax, SUVsd, and TBRmean (AUC: 0.850, P<0.0001); HI, SUVsd, and MTV (AUC: 0.848, P<0.0001); and HI, SUVsd, and TLU (AUC: 0.848, P<0.0001) had the top 3 multiple-parameter predictive performance. SUVsd (AUC: 0.710, P=0.0028), TLU (AUC: 0.698, P=0.0074), and HI (AUC: 0.676, P=0.0159) had the top 3 single-parameter predictive performance in the IDH1 genotype. Combinations of TBRmax, SUVsd, and TBRmean (AUC: 0.821, P<0.0001); SUVsd and TBRmean (AUC: 0.804, P<0.0001); and SUVsd, HI, and TBRmean (AUC: 0.799, P<0.0001) had the top 3 multiple-parameter predictive performance.

Conclusions

These easily obtained and highly repetitive heterogeneous parameters based on static ¹⁸F-FET PET/CT imaging can non-invasively predict glioma grade and IDH1 mutation, crucial in treatment planning, and prognostic evaluation.

Molecular Investigation on a Triple Negative Breast Cancer Xenograft Model Exposed to Proton Beams

Specific breast cancer (BC) subtypes are associated with bad prognoses due to the absence of successful treatment plans. The triple-negative breast cancer (TNBC) subtype, with estrogen (ER), progesterone (PR) and human epidermal growth factor-2 (HER2) negative receptor status, is a clinical challenge for oncologists, because of its aggressiveness and the absence of effective therapies. In addition, proton therapy (PT) represents an effective treatment against both inaccessible area located or conventional radiotherapy (RT)-resistant cancers, becoming a promising therapeutic choice for TNBC. Our study aimed to analyze the in vivo molecular response to PT and its efficacy in a MDA-MB-231 TNBC xenograft model. TNBC xenograft models were irradiated with 2, 6 and 9 Gy of PT. Gene expression profile (GEP) analyses and immunohistochemical assay (IHC) were performed to highlight specific pathways and key molecules involved in cell response to the radiation. GEP analysis revealed in depth the molecular response to PT, showing a considerable immune response, cell cycle and stem cell process regulation. Only the dose of 9 Gy shifted the balance toward pro-death signaling as a dose escalation which can be easily performed using proton beams, which permit targeting tumors while avoiding damage to the surrounding healthy tissue.

CPNE1 predicts poor prognosis and promotes tumorigenesis and radioresistance via the AKT singling pathway in triple-negative breast cancer

Elevated expression of Copine 1 (CPNE1) has been observed in multiple cancers; however, the underlying mechanisms by which it affects cancer cells are unclear. We aimed to study the effect of CPNE1 on the tumorigenesis and radioresistance of triple‐negative breast cancer (TNBC). Quantitative real‐time polymerase chain reaction was used to detect the expression of CPNE1 in TNBC tissues and cell lines. Western blot, immunohistochemistry, and immunofluorescence were used to investigate the levels of CPNE1, p‐AKT, AKT, cleaved caspase‐3, cleaved PARP1, and γ‐H2AX. Cell viability and apoptosis were measured by CCK‐8 and flow cytometry, respectively. CPNE1 was overexpressed in TNBC tissues and cell lines and was associated with tumor size, distant metastases, and survival rates of patients with TNBC. Moreover, function study shows that CPNE1 promoted cell viability and inhibited cell apoptosis in vitro and inhibited the radiosensitivity of TNBC. Importantly, inactivation of AKT signaling inhibited the tumorigenesis and radioresistance mediated by CPNE1 in TNBC cells. In vivo xenograft study also shows that CPNE1 knockdown inhibited tumor growth and promoted cell apoptosis. Overall, our findings suggest that CPNE1 promotes tumorigenesis and radioresistance in TNBC by regulating AKT activation and targeted CPNE1 expression may be a strategy to sensitize TNBC cells toward radiation therapy.

Gene Expression Profiles Induced by High-dose Ionizing Radiation in MDA-MB-231 Triple-negative Breast Cancer Cell Line

BACKGROUND/AIM

Radiation therapy (RT) represents a therapeutic option in breast cancer (BC). Even if a great number of BC patients receive RT, not all of them report benefits, due to radioresistance that gets activated through several factors, such as the hormone receptor status. Herein, we analyzed the gene expression profiles (GEP) induced by RT in triple-negative BC (TNBC) MDA-MB-231, to study signalling networks involved in radioresistance.

MATERIALS AND METHODS

GEP of MDA-MB-231 BC cells treated with a high dose of radiation, went through cDNA microarray analysis. In addition, to examine the cellular effects induced by RT, analyses of morphology and clonogenic evaluation were also conducted.

RESULTS

A descriptive report of GEP and pathways induced by IR is reported from our microarray data. Moreover, the MDA-MB-231 Radioresistent Cell Fraction (RCF) selected, included specific molecules able to drive radioresistance.

CONCLUSION

In summary, our data highlight, the RT response of TNBC MDA-MB-231 cell line at a transcriptional level, in terms of activating radioresistance in these cells, as a model of late-stage BC.

Heterogeneity of targeted lung lesion predicts platinum-based first-line therapy outcomes and overall survival for metastatic triple-negative breast cancer patients with lung metastasis: a "PET biopsy" method

Background: Platinum-based chemotherapy is widely used as first-line therapy for metastatic triple-negative breast cancer (mTNBC). Intratumor heterogeneity derived from fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) is a potential predictor of treatment outcomes and the prognosis of breast cancer. However, the presence of multiple lesions and complex calculation methods leads to difficulties in the clinical use of this parameter for metastatic breast cancer. The aim of this study is to provide a convenient and effective measurement of intratumor heterogeneity to predict treatment outcomes for mTNBC patients with lung metastasis.

Patients and methods: We enrolled mTNBC patients with lung metastasis who underwent ¹⁸F-FDG PET/CT scans before first‐line therapy from three clinical trials (NCT01287624, NCT02341911 and NCT02546934). Apart from the regular FDG parameters, including standard uptake value (SUV), total lesion glycolysis (TLG) and metabolic tumor volume (MTV), we defined the lung index as the SUVmean divided by the difference between the SUVmax and SUVmean for the targeted lung lesion. The MTV was automatically exported from the manual delineation using software based on an adaptive threshold of SUV intensity >2.5 within the contouring margin. The TLG was calculated using the following formula: TLG=SUVmean×MTV. Progression‐free survival (PFS) and overall survival were estimated by the Kaplan–Meier method, and univariate and multivariate analyses were performed using the Cox proportional hazard model.

Results: The data from 31 patients were available for analysis. The median PFS of low-lung index (LI) patients was 8.1 months, which was significantly longer than that of high-LI patients (HR=3.3, 95% CI 1.5–7.3, p=0.003). Patients with low TLG had a significantly better PFS than those with high TLG (HR=2.6, 95% CI 1.2–5.8, p=0.014). Patients with low TLG had significantly longer overall survival than those with high TLG (31.2 months vs 13.9 months, HR=3.1, 95% CI 1.2–8.6, p=0.029). Multivariate analysis confirmed the predictive value of LI and TLG.

Conclusions: This study proposed a new “PET biopsy” method to evaluate the intratumor heterogeneity of mTNBC on pretreatment ¹⁸F-FDG PET/CT scans and indicated the predictive value of LI and TLG for first-line platinum-based treatment outcomes and overall survival. These findings could help clinicians recognize patients who are likely to not only have a favorable response to platinum-based therapy but also a good prognosis.

Radiotherapy after surgery has significant survival benefits for patients with triple-negative breast cancer

Objectives

The value of adjuvant radiotherapy for triple‐negative breast cancer (TNBC) has been controversial recently. This study aims to clarify the influence of radiotherapy on the survival of TNBC patients after surgery based on a large population analysis.

Methods

The Surveillance, Epidemiology, and End Results (SEER) database was exploited to select eligible patients from 2010 to 2014. The categorical variables were examined by chi‐square tests. Breast cancer‐specific survival (BCSS) and overall survival (OS) were compared among patients who received or not received adjuvant radiotherapy after surgery by Kaplan‐Meier method with log‐rank test. Univariate and multivariate survival analysis of BCSS and OS were performed using the Cox proportional hazard model.

Results

Totally 22 802 patients were enrolled in this study, of which 10 905 patients received radiotherapy after surgery while 11 897 patients did not receive radiotherapy. Compared with those patients who did not receive radiotherapy, the radiation group had a larger proportion of tumor size <2.0 cm (45.8% vs 38.8%) and chemotherapy (82.5% vs 67.4%). The Kaplan‐Meier plots displayed that patients in the radiation group had better survival than the no radiation group in both BCSS and OS (P < 0.001, respectively). In univariate Cox analysis of BCSS, age 40‐60, married status, white and other race, chemotherapy, radiation, and surgery were associated with better survival (HR < 1, P < 0.05). Specifically, patients who received radiotherapy exhibited better BCSS (HR = 0.52, 95% CI = 0.48‐0.57, P < 0.001). After adjusting for confounding factors by multivariable Cox regression analysis, receipt of radiotherapy was still associated with improved BCSS (HR = 0.79, 95% CI = 0.72‐0.87, P < 0.001). Survival analysis of OS produced similar results. Generally, these data indicate that radiotherapy after surgery has significant survival benefits for the TNBC patients.

Conclusions

This study has confirmed the survival advantage of adjuvant radiotherapy for the TNBC patients. These findings may optimize the current individualized treatment decisions for this patient population.