Baseline metabolic tumor volume as a strong predictive and prognostic biomarker in patients with non-small cell lung cancer treated with PD1 inhibitors: a prospective study

HER2-targeted PET/CT imaging provides potential biomarkers for differentiating HER2-zero, -low, and -positive breast cancer

PURPOSE

Human epidermal growth factor receptor 2 (HER2)-targeted antibody-drug conjugates (ADCs) in breast cancer is progressing rapidly, asking for precise categorization of HER2 expression. Our aim was to explore the HER2-affibody uptake characteristics in breast cancer and to find potential biomarkers for differentiating HER2 status, in comparison with 18F-FDG PET/CT.

METHODS

In this prospective study conducted from May 2024 to Jan 2025, participants with newly diagnosed breast cancer underwent both 68Ga-HER2-affibody and 18F-FDG PET/CT examinations. The relationship between PET parameters (such as maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), tumor-to-background SUV ratio (TBR)) and HER2 expression statuses (HER2-zero, -low and -positive) was analyzed.

RESULTS

A total of 57 female participants (58 primary lesions) with newly diagnosed breast cancer were included. In the paired comparison of 68Ga-HER2-affibody and 18F-FDG PET/CT, HER2-TBR was higher than FDG-TBR in the HER2-low and HER2-positive group, respectively (P < 0.001). HER2-SUVmax and HER2-SUVmean exhibited differences across most comparisons, especially HER2-zero vs. -low (P < 0.05). HER2-SUVmean emerged as an independent predictor (P = 0.01; OR: 2.8) for differentiating HER2-low/positive and -zero, yielding an AUC of 0.91. Under detailed HER2 immunohistochemistry, HER2-SUVmax, -SUVmean and -TBR demonstrated intergroup differences (P < 0.05).

CONCLUSION

HER2-targeted PET/CT imaging demonstrated distinct advantages over 18F-FDG PET/CT imaging in characterizing the HER2 status of primary lesions. Parameters based on HER2-affibody differed significantly among different HER2 statuses, and might be potential imaging indicators for screening patients with HER2-low/positive who could benefit from HER2-targeted ADCs.

CLINICALTRIALS

GOV IDENTIFIER

NCT06289517 (2024-03-04).

Survival analysis of patients with metastatic head and neck squamous cell carcinoma treated with metastasis-directed radiotherapy and immunotherapy

OBJECTIVE

Immunotherapy combined with chemotherapy is currently the first-line treatment for metastatic head and neck squamous cell carcinoma (HNSCC). This study aims to evaluate whether adding metastasis-directed radiotherapy (MDRT) to immunotherapy and chemotherapy could improve the survival rate of patients with metastatic HNSCC.

MATERIALS AND METHODS

A retrospective analysis was conducted on patients with HNSCC who developed distant metastases after curative treatment. Systemic treatment was determined by the multidisciplinary team, with a programmed cell death-1 (PD-1) inhibitor combined with chemotherapy as the primary approach. The feasibility of radiotherapy was evaluated by clinical and imaging examinations. Stereotactic body radiotherapy (SBRT) was used to deliver different doses according to the number and location of metastatic lesions. Kaplan-Meier method was used to estimate survival, and Cox regression analysis was performed to evaluate the association between clinical factors and survival outcomes.

RESULTS

From January 2018 to June 2023, a total of 94 patients with 164 metastatic sites were included for the analysis. The most common primary tumor was the nasopharynx (77.7%), with the lung being the most frequent site of metastasis (46.8%), followed by bone (37.2%). Radiotherapy was administered to 276 metastatic lesions, with a median dose of 52.3 Gy (range: 24-60 Gy). The median overall survival (OS) was 43.0 months (range: 20.2-65.8). The OS rates at 2 and 5 years were 70.1% (95% CI, 59.7-80.5%) and 30.1% (95%CI 11.7-48.5%), respectively. Univariate and multivariate analysis showed that the number of metastases and the location of the primary tumor were significantly associated with OS.

CONCLUSIONS

In patients with metastatic HNSCC, MDRT combined with immunotherapy and chemotherapy can effectively improve local control and OS. These findings warrant further validation through prospective clinical trials.

Real‑world evaluation of the efficacy of immune checkpoint inhibitors in the treatment of metastatic breast cancer

The present study aimed to assess the efficacy and safety of immune checkpoint inhibitor (ICI)-based therapy in patients with metastatic breast cancer (MBC). Therefore, eligible patients with histologically confirmed MBC, treated with ICI-based therapy, were enrolled. The primary endpoint was progression-free survival (PFS) and the secondary endpoints included objective response rate (ORR), disease control rate (DCR), overall survival (OS) and safety. A total of 90 patients with MBC, treated with ICI-based therapy, with different treatment lines, were included in the present study. The median age was 50 years (range, 27-76). The predominant tumor subtypes were triple negative (53.3%) and luminal (31.1%) breast cancer. The majority of patients (61.1%) were heavily pretreated (lines of treatment, ≥3). Approximately half of the patients (46.7%) had ≥3 metastatic sites. The overall ORR was 36.7% (33/90 patients), while a DCR of 78.9% (71/90 patients) was also recorded. With a median follow-up of 16.0 months, the median PFS and OS were 4.9 months [95% confidence interval (CI), 3.8-6.1] and 13.9 months (95% CI, 9.5-18.2), respectively. Patients treated with ICIs as first-line therapy exhibited notable improvement, with a median PFS of 11.0 months (95% CI, 6.0-16.0) and a median OS of 24.3 months (95% CI, 11.4-37.2). In addition, the pretreatment blood platelet-to-lymphocyte ratio was an independent risk factor for PFS [hazard ratio (HR)=2.406; 95% CI, 1.325-4.370; P=0.004] and OS (HR=2.376; 95% CI, 1.059-5.328; P=0.036). The most common adverse events were nausea (44.4%), neutropenia (42.0%) and alanine aminotransferase/aspartate aminotransferase elevation (22.2%). Furthermore, three (3.3%) patients developed grade 1/2 immuno-related toxicity and recovered after supportive care. Overall, the present study suggested that the ICI-based therapy exhibited encouraging clinical outcomes with manageable toxicity in patients with MBC in real-world settings, with the most favorable efficacy in first-line treatment.

Radiomicsmetabolic signature profiles for advanced non-small cell lung cancer with chemoimmunotherapy by reflecting biological function and survival

Background

Resistance to chemoimmunotherapy in patients with advanced non-small cell lung cancer (NSCLC) necessitates effective prognostic biomarkers. Although 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) has shown potential for efficacy assessment, it has been mainly evaluated in immuno-monotherapy setting, lacking elaborations in the scenarios of immunotherapy combined with chemotherapy. To tackle this dilemma, we aimed to build a non-invasive PET/CT-based model for stratifying tumor heterogeneity and predicting survival in advanced NSCLC patients undergoing chemoimmunotherapy. Meanwhile, we explored the interplay and combined effect between programmed death-ligand 1 (PD-L1) and metabolic parameters and probed into the prognostic differences between patients with similar total metabolic tumor volume (tMTV) but different tumor distribution (lesion locations and numbers).

Methods

We retrospectively recruited unresectable advanced NSCLC patients receiving immunotherapy in Jinling Hospital from 2018 to 2023 as the training cohort. The Cancer Imaging Archive (TCIA) cohort with early-stage NSCLC patients undergoing surgical resection was used for validation and the assessment of the biological function and tumor microenvironment (TME). PET/CT-based parameters were extracted, including radiomics score (Rad-score), bone marrow to liver ratio (BLR), tMTV, and total lesion glycolysis (TLG). The end-point events included overall survival (OS) and progression-free survival (PFS). Step-wise multivariate Cox regression and the least absolute shrinkage and selection operator (LASSO) were used to identify candidate variables and establish models.

Results

A total of 220 patients were identified for analysis, including 139 with unresectable advanced NSCLC receiving immunotherapy and 81 from TCIA. The Radiomicsmetabolicos model for OS encompassing Rad-score >0.705 [hazard ratio (HR) =2.455; 95% confidence interval (CI): 1.324-4.550], squamous cell subtype (HR =1.641; 95% CI: 0.900-2.992), liver metastases (HR =3.496; 95% CI: 1.435-8.517), BLR >0.94 (HR =1.885; 95% CI: 1.013-3.507), and tMTV >105 mL (HR =2.162; 95% CI: 1.134-4.119) exhibited reliable prognostic capacity with a notable 3-year area under the curve (AUC) of 0.837. Patients with Rad-score ≤0.705 demonstrated upregulation of immune-related pathways and favorable survival. Additionally, distant metastases metabolic tumor volume (MTV) and TLG, as well as intrathoracic lymph nodes MTV were associated with survival independently. For patients with similar tMTV (≤105 mL), the number of FDG-avid lesions was an independent protective factor for more-than-1-year OS, which indicated that patients with smaller lesions seemed to have better long-term prognoses than those with larger lesions, even of fewer in number.

Conclusions

Our findings proved that PET/CT could reveal survival and tumor heterogeneity in advanced NSCLC patients undergoing chemoimmunotherapy, which might guide the selection of immune-monotherapy for low-risk patients and facilitate the advancement of precision treatment.

The role of baseline 18F-FDG PET/CT for survival prognosis in NSCLC patients undergoing immunotherapy: a systematic review and meta-analysis

Background

The value of pretreatment baseline 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET)/computed tomography (CT) as a prognostic factor for survival of patients with non-small-cell lung cancer (NSCLC) receiving immunotherapy remained uncertain.

Objectives

To investigate the prognostic ability of baseline 18F-FDG PET/CT in patients with NSCLC receiving immunotherapy.

Design

A systematic review and meta-analysis.

Data sources and methods

We searched the PubMed, EMBASE, and Cochrane Central Register of Controlled Trials databases until May 7, 2024, and extracted data related to patient characteristics, semiquantitative parameters of 18F-FDG PET/CT, and survival. We pooled hazard ratios (HRs) to evaluate the prognostic value of the maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) for overall survival (OS) and progression-free survival (PFS).

Results

A total of 22 studies (1363 patients, average age range 30-88 years) were included. Baseline 18F-FDG PET/CT-derived MTV was significantly associated with both OS (HR: 1.124, 95% confidence interval (CI) 1.058-1.195, I 2 = 81.70%) and PFS (HR: 1.069, 95% CI: 1.016-1.124, I 2 = 71.80%). Other baseline 18F-FDG PET/CT-derived parameters, including SUVmax (OS: HR: 0.930, 95% CI: 0.718-1.230; PFS: HR: 0.979, 95% CI: 0.759-1.262), SUVmean (OS: HR: 0.801, 95% CI: 0.549-1.170; PFS: HR: 0.688, 95% CI: 0.464-1.020), and TLG (OS: HR: 0.999, 95% CI: 0.980-1.018; PFS: HR: 0.995, 95% CI: 0.980-1.010), were not associated with survival. Sensitivity analyses by removing one study at a time did not significantly alter the association between MTV and PFS or between MTV and OS. There was no evidence of publication bias.

Conclusion

Pretreatment baseline 18F-FDG PET/CT-derived MTV might be a prognostic biomarker in NSCLC patients receiving immunotherapy. Further studies are needed to support routine use.

Current and Future Perspectives of PDL1 PET and SPECT Imaging

Programmed Death 1 (PD1) and Programmed Death Ligand (PDL1) play a crucial role in tumor microenvironment by helping cancer cells evade innate immunity. Numerous inhibitor anticancer drugs targeting this interplay have been used in clinical practice and many more are in preclinical stage. These drugs have shown promising results in achieving good response and long-term clinical benefit, is routinely performed to identify patients who may benefit. However, there are major challenges associated with these immunohistochemistry tests which have opened the space for noninvasive imaging modalities using PD1 and PDL1 inhibitors labeled with either PET or SPECT radionuclides. These radiopharmaceuticals, although primarily developed for the field of immunotherapy, have great potential in expanding and optimizing the combination of radiopharmaceutical therapies with PD1-PDL1 targeting anticancer drugs. This review elaborates currently available PET and SPECT radiopharmaceuticals targeting PD1-PDL1 axis. It also explores the potential future role of newer targets which are being developed and tested in various preclinical studies.

DCE-CT parameters as new functional imaging biomarkers at baseline and during immune checkpoint inhibitor therapy in patients with lung cancer - a feasibility study

BACKGROUND

With the development of immune checkpoint inhibitors for the treatment of non-small cell lung cancer, the need for new functional imaging techniques and early response assessments has increased to account for new response patterns and the high cost of treatment. The present study was designed to assess the prognostic impact of dynamic contrast-enhanced computed tomography (DCE-CT) on survival outcomes in non-small cell lung cancer patients treated with immune checkpoint inhibitors.

METHODS

Thirty-three patients with inoperable non-small-cell lung cancer treated with immune checkpoint inhibitors were prospectively enrolled for DCE-CT as part of their follow-up. A single target lesion at baseline and subsequent follow-up examinations were enclosed in the DCE-CT. Blood volume deconvolution (BVdecon), blood flow deconvolution (BFdecon), blood flow maximum slope (BFMax slope) and permeability were assessed using overall survival (OS) and progression-free survival (PFS) as endpoints in Kaplan Meier and Cox regression analyses.

RESULTS

High baseline Blood Volume (BVdecon) (> 12.97 ml × 100 g-1) was associated with a favorable OS (26.7 vs 7.9 months; p = 0.050) and PFS (14.6 vs 2.5 months; p = 0.050). At early follow-up on day seven a higher relative increase in BFdecon (> 24.50% for OS and > 12.04% for PFS) was associated with an unfavorable OS (8.7 months vs 23.1 months; p < 0.025) and PFS (2.5 vs 13.7 months; p < 0.018). The relative change in BFdecon (categorical) on day seven was a predictor of OS (HR 0.26, CI95: 0.06 to 0.93 p = 0.039) and PFS (HR 0.27, CI95: 0.09 to 0.85 p = 0.026).

CONCLUSION

DCE-CT-identified parameters may serve as potential prognostic biomarkers at baseline and during early treatment in patients with NSCLC treated with immune checkpoint inhibitor therapy.

Strategies for overcoming tumour resistance to immunotherapy: harnessing the power of radiation therapy

Immune checkpoint inhibitors (ICI) have revolutionized cancer treatment; yet their efficacy remains variable across patients. This review delves into the intricate interplay of tumour characteristics contributing to resistance against ICI therapy and suggests that combining with radiotherapy holds promise. Radiation, known for its ability to trigger immunogenic cell death and foster an in situ vaccination effect, may counteract these resistance mechanisms, enhancing ICI response and patient outcomes. However, particularly when delivered at high-dose, it may trigger immunosuppressive mechanism and consequent side-effects. Notably, low-dose radiotherapy (LDRT), with its capacity for tumour reprogramming and reduced side effects, offers the potential for widespread application. Preclinical and clinical studies have shown encouraging results in this regard.

Targeting myeloid-derived suppressor cells promotes antiparasitic T-cell immunity and enhances the efficacy of PD-1 blockade (15 words)

Immune exhaustion corresponds to a loss of effector function of T cells that associates with cancer or chronic infection. Here, our objective was to decipher the mechanisms involved in the immune suppression of myeloid-derived suppressor cells (MDSCs) and to explore the potential to target these cells for immunotherapy to enhance checkpoint blockade efficacy in a chronic parasite infection. We demonstrated that programmed cell-death-1 (PD-1) expression was significantly upregulated and associated with T-cell dysfunction in advanced alveolar echinococcosis (AE) patients and in Echinococcus multilocularis-infected mice. PD-1 blockade ex vivo failed to reverse AE patients' peripheral blood T-cell dysfunction. PD-1/PD-L1 blockade or PD-1 deficiency had no significant effects on metacestode in mouse model. This was due to the inhibitory capacities of immunosuppressive granulocytic MDSCs (G-MDSCs), especially in the liver surrounding the parasite pseudotumor. MDSCs suppressed T-cell function in vitro in an indoleamine 2, 3 dioxygenase 1 (IDO1)-dependent manner. Although depleting MDSCs alone restored T-cell effector functions and led to some limitation of disease progression in E. multilocularis-infected mice, combination with PD-1 blockade was better to induce antiparasitic efficacy. Our findings provide preclinical evidence in support of targeting MDSC or combining such an approach with checkpoint blockade in patients with advanced AE. (200 words).

Site-Specific Response and Resistance Patterns in Patients with Advanced Non-Small-Cell Lung Cancer Treated with First-Line Systemic Therapy

Patients with advanced NSCLC have heterogenous responses to immune checkpoint inhibitors (ICIs) with or without chemotherapy. In NSCLC, the impact of the distribution of metastatic sites and the response to systemic therapy combinations remain poorly understood. In a retrospective cohort study of patients with unresectable stage III/IV NSCLC who received first-line systemic therapy, we sought to assess the association between the site of metastases with patterns of response and progression. Data regarding demographics, tumour characteristics (including site, size, and volume of metastases), treatment, and outcomes were examined at two cancer care centres. The endpoints included organ site-specific response rate, objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Two-hundred and eighty-five patients were included in the analysis. In a multivariate analysis, patients with bone metastases had a reduced ORR, PFS, and OS. Primary resistance was also more likely in patients with bone metastases. Patients with bone or liver metastases had a shorter OS when receiving ICIs with or without chemotherapy, but not with chemotherapy alone, suggesting an immunological basis for therapeutic resistance. A directed assessment of the tumour microenvironment in these locations and a deeper understanding of the drivers of organ-specific resistance to immunotherapy are critical to optimise novel combination therapies and sequencing in these patients.

Imaging-guided prognostic score-based approach to assess the benefits of combotherapy versus monotherapy with immune checkpoint inhibitors in metastatic MSI-H colorectal cancer patients

BACKGROUND

This retrospective study determined survival responses to immune checkpoint inhibitors (ICIs), comparing mono- (mono) and combo-immunotherapy (combo) in patients with microsatellite instability-high (MSI-H) metastatic colorectal cancer (mCRC) by analyzing quantitative imaging data and clinical factors.

METHODS

One hundred fifty patients were included from two centers and divided into training (n = 105) and validation (n = 45) cohorts. Radiologists manually annotated chest-abdomen-pelvis computed tomography and calculated tumor burden. Progression-free survival (PFS) was assessed, and variables were selected through Recursive Feature Elimination. Cutoff values were determined using maximally selected rank statistics to binarize features, forming a risk score with hazard ratio-derived weights.

RESULTS

In total, 2258 lesions were annotated with excellent reproducibility. Key variables in the training cohort included: total tumor volume (cutoff: 73 cm3), lesion count (cutoff: 20), age (cutoff: 60) and the presence of peritoneal carcinomatosis. Their respective weights were 1.13, 0.96, 0.91, and 0.38, resulting in a risk score cutoff of 1.36. Low-score patients showed similar overall survival and PFS regardless of treatment, while those with a high-score had significantly worse survivals with mono vs combo (P = 0.004 and P = 0.0001). In the validation set, low-score patients exhibited no significant difference in overall survival and PFS with mono or combo. However, patients with a high-score had worse PFS with mono (P = 0.046).

CONCLUSIONS

A score based on total tumor volume, lesion count, the presence of peritoneal carcinomatosis, and age can guide MSI-H mCRC treatment decisions, allowing oncologists to identify suitable candidates for mono and combo ICI therapies.

Total metabolic tumor volume on 18F-FDG PET/CT is a game-changer for patients with metastatic lung cancer treated with immunotherapy

PURPOSE

Because of atypical response imaging patterns in patients with metastatic non-small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICPIs), new biomarkers are needed for a better monitoring of treatment efficacy. The aim of this prospective study was to evaluate the prognostic value of volume-derived positron-emission tomography (PET) parameters on baseline and follow-up 18F-fluoro-deoxy-glucose PET (18F-FDG-PET) scans and compare it with the conventional PET Response Criteria in Solid Tumors (PERCIST).

METHODS

Patients with metastatic NSCLC were included in two different single-center prospective trials. 18F-FDG-PET studies were performed before the start of immunotherapy (PETbaseline), after 6-8 weeks (PETinterim1) and after 12-16 weeks (PETinterim2) of treatment, using PERCIST criteria for tumor response assessment. Different metabolic parameters were evaluated: absolute values of maximum standardized uptake value (SUVmax) of the most intense lesion, total metabolic tumor volume (TMTV), total lesion glycolysis (TLG), but also their percentage changes between PET studies (ΔSUVmax, ΔTMTV and ΔTLG). The median follow-up of patients was 31 (7.3-31.8) months. Prognostic values and optimal thresholds of PET parameters were estimated by ROC (Receiver Operating Characteristic) curve analysis of 12-month overall survival (12M-OS) and 6-month progression-free survival (6M-PFS). Tumor progression needed to be confirmed by a multidisciplinary tumor board, considering atypical response patterns on imaging.

RESULTS

110 patients were prospectively included. On PETbaseline, TMTV was predictive of 12M-OS [AUC (Area Under Curve) =0.64; 95% CI: 0.61 to 0.66] whereas SUVmax and TLG were not. On PETinterim1 and PETinterim2, all metabolic parameters were predictive for 12M-OS and 6M-PFS, the residual TMTV on PETinterim1 (TMTV1) being the strongest prognostic biomarker (AUC=0.83 and 0.82; 95% CI: 0.74 to 0.91, for 12M-OS and 6M-PFS, respectively). Using the optimal threshold by ROC curve to classify patients into three TMTV1 subgroups (0 cm3; 0-57 cm3; >57 cm3), TMTV1 prognostic stratification was independent of PERCIST criteria on both PFS and OS, and significantly outperformed them. Subgroup analysis demonstrated that TMTV1 remained a strong prognostic biomarker of 12M-OS for non-responding patients (p=0.0003) according to PERCIST criteria. In the specific group of patients with PERCIST progression on PETinterim1, low residual tumor volume (<57 cm3) was still associated with a very favorable patients' outcome (6M-PFS=73%; 24M-OS=55%).

CONCLUSION

The absolute value of residual metabolic tumor volume, assessed 6-8 weeks after the start of ICPI, is an optimal and independent prognostic measure, exceeding and complementing conventional PERCIST criteria. Oncologists should consider it in patients with first tumor progression according to PERCIST criteria, as it helps identify patients who benefit from continued treatment.

TRIAL REGISTRATION NUMBER

2018-A02116-49; NCT03584334.

Value of [18F]FDG PET/CT parameters of the primary tumor in assessing overall survival in NSCLC patients with cN1-cN3 lymph nodes involvement

Background

The aim of this retrospective study was to assess the value of 18F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography ([18F]FDG PET/CT parameters in cN1-cN3 non-small cell lung cancer (NSCLC) patients.

Materials and methods

59 consecutive patients (35 M, 24 F) with NSCLC who underwent pretreatment [18F]FDG PET/CT were enrolled to this study. Several primary tumor PET parameters, including the maximum and mean standardized uptake value (SUVmax and SUVmean), the metabolic active tumor volume (MTV) and the total lesion glycolysis (TLG = MTVxSUVmean), were extracted and analysed. Overall survival was defined as time from primary diagnosis to death or the last info.

Results

In the whole analysed group 44 patients underwent curative treatment, while 15, because of the severity of the disease, were classified for palliative treatment. Univariate Cox analysis of clinical and metric PET parameters revealed that MTV was a significant prognostic factor for OS (p = 0.024), while TLG and curative treatment showed a trend for significance (p < 0.1). In multivariate Cox regression (MTV and curative treatment) MTV remained a significant factor (p = 0.047).

Conclusions

Metabolic tumor volume of the primary tumor was the only independent prognostic factor for cN1-cN3 NSCLC patients.

SBRT for Liver Tumors: What the Interventional Radiologist Needs to Know

This review summarizes the clinical evidence supporting the utilization of stereotactic body radiotherapy (SBRT) for liver tumors, including hepatocellular carcinoma, liver metastases, and cholangiocarcinoma. Emerging prospective evidence has demonstrated the benefit and low rates of toxicity across a broad range of clinical contexts. We provide an introduction for the interventional radiologist, with a discussion of underlying themes such as tumor dose-response, mitigation of liver toxicity, and the technical considerations relevant to performing liver SBRT. Ultimately, we recommend that SBRT should be routinely included in the armamentarium of locoregional therapies for liver malignancies, alongside those liver-directed therapies offered by interventional radiology.

Metabolic tumor volume and sites of organ involvement predict outcome in NSCLC immune-checkpoint inhibitor therapy

PURPOSE

The purpose of this study was to assess the ability of pretreatment PET parameters and peripheral blood biomarkers to predict progression-free survival (PFS) and overall survival (OS) in NSCLC patients treated with ICIT.

METHODS

We prospectively included 87 patients in this study who underwent pre-treatment [18F]-FDG PET/CT. Organ-specific and total metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were measured using a semiautomatic software. Sites of organ involvement (SOI) were assessed by PET/CT. The log-rank test and Cox-regression analysis were used to assess associations between clinical, laboratory, and imaging parameters with PFS and OS. Time dependent ROC were calculated and model performance was evaluated in terms of its clinical utility.

RESULTS

MTV increased with the number of SOI and was correlated with neutrophil and lymphocyte cell count (Spearman's rho = 0.27 or 0.32; p =.02 or 0.003; respectively). Even after adjustment for known risk factors, such as PD-1 expression and neutrophil cell count, the MTV and the number of SOI were independent risk factors for progression (per 100 cm3; adjusted hazard ratio [aHR]: 1.13; 95% confidence interval [95%CI]: 1.01-1.28; p =.04; single SOI vs. ≥ 4 SOI: aHR: 2.26, 95%CI: 1.04-4.94; p =.04). MTV and the number of SOI were independent risk factors for overall survival (per 100 cm3 aHR: 1.11, 95%CI: 1.01-1.23; p =.03; single SOI vs. ≥ 4 SOI: aHR: 4.54, 95%CI: 1.64-12.58; p =.04). The combination of MTV and the number of SOI improved the risk stratification for PFS and OS (log-rank test p <.001; C-index: 0.64 and 0.67).

CONCLUSION

The MTV and the number of SOI are simple imaging markers that provide complementary information to facilitate risk stratification in NSCLC patients scheduled for ICIT.

Utility of Established Prognostic Scoring Systems for Patients with Advanced Pancreatic Adenocarcinoma Enrolled in Immunotherapy-Based Early-Phase Clinical Trials

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy for which multiagent chemotherapy is the mainstay of treatment resulting in limited survival and symptomatic benefit. Treatment with immune checkpoint inhibitors (ICI) has proven effective in a growing number of solid tumors but has yet to show clinical benefit in patients with PDAC. Given the growing number of ICI-based clinical trials in development for patients with PDAC and lack of clinical benefit thus far with ICI-based therapies in these patients, we sought to (1) determine the outcomes of patients with PDAC treated with ICI-based therapies as part of an early phase clinical trial, (2) validate the utility of established prognostic scoring systems, and (3) identify novel prognostic factors in an attempt to better identify patients that would benefit from enrollment onto an ICI-based early phase clinical trial.

METHODS

We conducted a single-center retrospective analysis of patients with advanced PDAC who were treated with ICI-based therapy as part of an early-phase clinical trial.

RESULTS

Patients were only able to stay on study for a limited time due to disease progression and/or a change in performance status and had a poor overall survival. Established prognostic scoring systems were not effective in predicting outcomes in this patient population, but factors such as pre-treatment albumin neutrophil to lymphocyte ratio (NLC) may be helpful in patient selection.

CONCLUSIONS

This study underscores the need for larger studies to help identify patient and tumor intrinsic factors that predict response to ICI-based therapies in patients with PDAC.

Prognostic value of pretreatment FDG PET-CT for short-term efficacy of radioactive iodine-125 seed implantation in patients with NSCLC

PURPOSE

To analyze the short-term clinical response of radioactive iodine-125 seed implantation (I125-SI) in patients of non-small-cell lung cancer (NSCLC) and explore possible correlations of various metabolic parameters of pretreatment FDG PET-CT with the short-term efficacy of this treatment modality.

METHODS AND MATERIALS

The present study is a retrospective analysis of treatment records of 46 NSCLC patients who were treated with I125-SI for lung tumors in Tianjin First Central Hospital from January 2016 to December 2018. The correlation among parameters D90, gender, pathological pattern, age, maximum tumor diameter, Metabolic Tumor Volume (MTV), SUVmax, SUVpeak, SUVmean, Total Lesion Glycolysis (TLG), High metabolic tumor cell ratio (HMR) and Carcinoembryonic antigen(CEA)with short-term efficacy of I125-SI was analyzed by two independent-sample t-test, Mann-Whitney U test or Chi-squared test and binary logistic regression.

RESULTS

After uneventful completion of treatment, patients were followed up at regular intervals. At the first month followup, none of cases showed complete response (CR), while 4 cases showed partial response (PR). After 3 months, there were 2 cases of CR, and 25 cases of PR; after 6 months, there were 5 cases of CR, and 27 cases of PR. D90 (p= 0.028, OR:1.075, 95% CI:1.008-1.147), MTV (p= 0.026, OR: 0.918, 95% CI: 0.851-0.990), HMR (p= 0.020, OR: 0.003, 95% CI: 0-0.407) were independent predictors for the short-term efficacy. The predictive accuracy of MTV was medium (AUC = 0.781; cutoff value = 44.58). However, the predictive accuracies of D90 and HMR were low, with the values of AUC being 0.650 for both the parameters, and their cutoff values being 127.8 Gy and 0.27 respectively.

CONCLUSIONS

I125-SI is an effective therapy with few complications in NSCLC patients. Small MTV, high D90 and low HRM were found to be linked with better local control at 6 months postimplantation.

The Value of Micro-CT in the Diagnosis of Lung Carcinoma: A Radio-Histopathological Perspective

Micro-computed tomography (micro-CT) is a relatively new imaging modality and the three-dimensional (3D) images obtained via micro-CT allow researchers to collect both quantitative and qualitative information on various types of samples. Micro-CT could potentially be used to examine human diseases and several studies have been published on this topic in the last decade. In this study, the potential uses of micro-CT in understanding and evaluating lung carcinoma and the relevant studies conducted on lung and other tumors are summarized. Currently, the resolution of benchtop laboratory micro-CT units has not reached the levels that can be obtained with light microscopy, and it is not possible to detect the histopathological features (e.g., tumor type, adenocarcinoma pattern, spread through air spaces) required for lung cancer management. However, its ability to provide 3D images in any plane of section, without disturbing the integrity of the specimen, suggests that it can be used as an auxiliary technique, especially in surgical margin examination, the evaluation of tumor invasion in the entire specimen, and calculation of primary and metastatic tumor volume. Along with future developments in micro-CT technology, it can be expected that the image resolution will gradually improve, the examination time will decrease, and the relevant software will be more user friendly. As a result of these developments, micro-CT may enter pathology laboratories as an auxiliary method in the pathological evaluation of lung tumors. However, the safety, performance, and cost effectiveness of micro-CT in the areas of possible clinical application should be investigated. If micro-CT passes all these tests, it may lead to the convergence of radiology and pathology applications performed independently in separate units today, and the birth of a new type of diagnostician who has equal knowledge of the histological and radiological features of tumors.

Comprehensive scientometrics and visualization study profiles lymphoma metabolism and identifies its significant research signatures

BACKGROUND

There is a wealth of poorly utilized unstructured data on lymphoma metabolism, and scientometrics and visualization study could serve as a robust tool to address this issue. Hence, it was implemented.

METHODS

After strict quality control, numerous data regarding the lymphoma metabolism were mined, quantified, cleaned, fused, and visualized from documents (n = 2925) limited from 2013 to 2022 using R packages, VOSviewer, and GraphPad Prism.

RESULTS

The linear fitting analysis generated functions predicting the annual publication number (y = 31.685x - 63628, R² = 0.93614, Prediction in 2027: 598) and citation number (y = 1363.7x - 2746019, R² = 0.94956, Prediction in 2027: 18201). In the last decade, the most academically performing author, journal, country, and affiliation were Meignan Michel (n = 35), European Journal of Nuclear Medicine and Molecular Imaging (n = 1653), USA (n = 3114), and University of Pennsylvania (n = 86), respectively. The hierarchical clustering based on unsupervised learning further divided research signatures into five clusters, including the basic study cluster (Cluster 1, Total Link Strength [TLS] = 1670, Total Occurrence [TO] = 832) and clinical study cluster (Cluster 3, TLS = 3496, TO = 1328). The timeline distribution indicated that radiomics and artificial intelligence (Cluster 4, Average Publication Year = 2019.39 ± 0.21) is a relatively new research cluster, and more endeavors deserve. Research signature burst and linear regression analysis further confirmed the findings above and revealed additional important results, such as tumor microenvironment (a = 0.6848, R² = 0.5194, p = 0.019) and immunotherapy (a = 1.036, R² = 0.6687, p = 0.004). More interestingly, by performing a "Walktrap" algorithm, the community map indicated that the "apoptosis, metabolism, chemotherapy" (Centrality = 12, Density = 6), "lymphoma, pet/ct, prognosis" (Centrality = 11, Density = 1), and "genotoxicity, mutagenicity" (Centrality = 9, Density = 4) are crucial but still under-explored, illustrating the potentiality of these research signatures in the field of the lymphoma metabolism.

CONCLUSION

This study comprehensively mines valuable information and offers significant predictions about lymphoma metabolism for its clinical and experimental practice.

Comprehensive scientometrics and visualization study profiles lymphoma metabolism and identifies its significant research signatures

Background

There is a wealth of poorly utilized unstructured data on lymphoma metabolism, and scientometrics and visualization study could serve as a robust tool to address this issue. Hence, it was implemented.

Methods

After strict quality control, numerous data regarding the lymphoma metabolism were mined, quantified, cleaned, fused, and visualized from documents (n = 2925) limited from 2013 to 2022 using R packages, VOSviewer, and GraphPad Prism.

Results

The linear fitting analysis generated functions predicting the annual publication number (y = 31.685x - 63628, R² = 0.93614, Prediction in 2027: 598) and citation number (y = 1363.7x - 2746019, R² = 0.94956, Prediction in 2027: 18201). In the last decade, the most academically performing author, journal, country, and affiliation were Meignan Michel (n = 35), European Journal of Nuclear Medicine and Molecular Imaging (n = 1653), USA (n = 3114), and University of Pennsylvania (n = 86), respectively. The hierarchical clustering based on unsupervised learning further divided research signatures into five clusters, including the basic study cluster (Cluster 1, Total Link Strength [TLS] = 1670, Total Occurrence [TO] = 832) and clinical study cluster (Cluster 3, TLS = 3496, TO = 1328). The timeline distribution indicated that radiomics and artificial intelligence (Cluster 4, Average Publication Year = 2019.39 ± 0.21) is a relatively new research cluster, and more endeavors deserve. Research signature burst and linear regression analysis further confirmed the findings above and revealed additional important results, such as tumor microenvironment (a = 0.6848, R² = 0.5194, p = 0.019) and immunotherapy (a = 1.036, R² = 0.6687, p = 0.004). More interestingly, by performing a “Walktrap” algorithm, the community map indicated that the “apoptosis, metabolism, chemotherapy” (Centrality = 12, Density = 6), “lymphoma, pet/ct, prognosis” (Centrality = 11, Density = 1), and “genotoxicity, mutagenicity” (Centrality = 9, Density = 4) are crucial but still under-explored, illustrating the potentiality of these research signatures in the field of the lymphoma metabolism.

Conclusion

This study comprehensively mines valuable information and offers significant predictions about lymphoma metabolism for its clinical and experimental practice.

Pretreatment 18-FDG-PET/CT parameters can serve as prognostic imaging biomarkers in recurrent NSCLC patients treated with reirradiation-chemoimmunotherapy

BACKGROUND AND PURPOSE

Our study aimed to assess whether quantitative pretreatment 18F-FDG-PET/CT parameters could predict prognostic clinical outcome of recurrent NSCLC patients who may benefit from ablative reirradiation.

MATERIALS AND METHODS

Forty-eight patients with recurrent NSCLC of all UICC stages who underwent ablative thoracic reirradiation were analyzed. Twenty-nine (60%) patients received immunotherapy with or without chemotherapy in addition to reirradiation. Twelve patients (25%) received reirradiation only and seven (15%) received chemotherapy and reirradiation. Pretreatment 18-FDG-PET/CT was mandatory in initial diagnosis and recurrence, based on which volumetric and intensity quantitative parameters were measured before reirradiation and their impact on overall survival, progression-free survival, and locoregional control was assessed.

RESULTS

With a median follow-up time of 16.7 months, the median OS was 21.8 months (95%-CI: 16.2-27.3). On multivariate analysis, OS and PFS were significantly influenced by MTV (p < 0.001 for OS; p = 0.006 for PFS), TLG (p < 0.001 for OS; p = 0.001 for PFS) and SUL peak (p = 0.0024 for OS; p = 0.02 for PFS) of the tumor and MTV (p = 0.004 for OS; p < 0.001 for PFS) as well as TLG (p = 0.007 for OS; p = 0.015 for PFS) of the metastatic lymph nodes. SUL peak of the tumor (p = 0.05) and the MTV of the lymph nodes (p = 0.003) were only PET quantitative parameters that significantly impacted LRC.

CONCLUSION

Pretreatment tumor and metastastic lymph node MTV, TLG and tumor SUL peak significantly correlated with clinical outcome in recurrent NSCLC patients treated with reirradiation-chemoimmunotherapy.

Predictive Value of Total Metabolic Tumor Burden Prior to Treatment in NSCLC Patients Treated with Immune Checkpoint Inhibition

OBJECTIVES

We aimed to assess the predictive value of the total metabolic tumor burden prior to treatment in patients with advanced non-small-cell lung cancer (NSCLC) receiving immune checkpoint inhibitors (ICIs).

METHODS

Pre-treatment 2-deoxy-2-[¹⁸F]fluoro-D-glucose positron emission tomography/computed tomography (PET/CT) scans performed in two consecutive years for staging in adult patients with confirmed NSCLC were considered. Volume, maximum/mean standardized uptake value (SUVmax/SUVmean), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were assessed per delineated malignant lesion (including primary tumor, regional lymph nodes and distant metastases) in addition to the morphology of the primary tumor and clinical data. Total metabolic tumor burden was captured by _totalMTV and _totalTLG. Overall survival (OS), progression-free survival (PFS) and clinical benefit (CB) were used as endpoints for response to treatment.

RESULTS

A total of 125 NSCLC patients were included. Osseous metastases were the most frequent distant metastases (n = 17), followed by thoracal distant metastases (pulmonal = 14 and pleural = 13). Total metabolic tumor burden prior to treatment was significantly higher in patients treated with ICIs (mean _totalMTV ± standard deviation (SD) 72.2 ± 78.7; mean _totalTLG ± SD 462.2 ± 538.9) compared to those without ICI treatment (mean _totalMTV ± SD 58.1 ± 233.8; mean _totalTLG ± SD 290.0 ± 784.2). Among the patients who received ICIs, a solid morphology of the primary tumor on imaging prior to treatment was the strongest outcome predictor for OS (Hazard ratio HR 28.04, p < 0.01), PFS (HR 30.89, p < 0.01) and CB (parameter estimation PE 3.46, p < 0.01), followed by the metabolic features of the primary tumor. Interestingly, total metabolic tumor burden prior to immunotherapy showed a negligible impact on OS (p = 0.04) and PFS (p = 0.01) after treatment given the hazard ratios of 1.00, but also on CB (p = 0.01) given the PE < 0.01. Overall, biomarkers on pre-treatment PET/CT scans showed greater predictive power in patients receiving ICIs, compared to patients without ICI treatment.

CONCLUSIONS

Morphological and metabolic properties of the primary tumors prior to treatment in advanced NSCLC patients treated with ICI showed great outcome prediction performances, as opposed to the pre-treatment total metabolic tumor burdens, captured by _totalMTV and _totalTLG, both with negligible impact on OS, PFS and CB. However, the outcome prediction performance of the total metabolic tumor burden might be influenced by the value itself (e.g., poorer prediction performance at very high or very low values of total metabolic tumor burden). Further studies including subgroup analysis with regards to different values of total metabolic tumor burden and their respective outcome prediction performances might be needed.

Predictive Biomarkers for Immune-Checkpoint Inhibitor Treatment Response in Patients with Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) has one of the highest mortality rates among solid cancers. Late diagnosis and a lack of efficacious treatment options contribute to the dismal prognosis of HCC. Immune checkpoint inhibitor (ICI)-based immunotherapy has presented a new milestone in the treatment of cancer. Immunotherapy has yielded remarkable treatment responses in a range of cancer types including HCC. Based on the therapeutic effect of ICI alone (programmed cell death (PD)-1/programmed death-ligand1 (PD-L)1 antibody), investigators have developed combined ICI therapies including ICI + ICI, ICI + tyrosine kinase inhibitor (TKI), and ICI + locoregional treatment or novel immunotherapy. Although these regimens have demonstrated increasing treatment efficacy with the addition of novel drugs, the development of biomarkers to predict toxicity and treatment response in patients receiving ICI is in urgent need. PD-L1 expression in tumor cells received the most attention in early studies among various predictive biomarkers. However, PD-L1 expression alone has limited utility as a predictive biomarker in HCC. Accordingly, subsequent studies have evaluated the utility of tumor mutational burden (TMB), gene signatures, and multiplex immunohistochemistry (IHC) as predictive biomarkers. In this review, we aim to discuss the current state of immunotherapy for HCC, the results of the predictive biomarker studies, and future direction.

Assessment of the Association between Entropy in PET/CT and Response to Anti-PD-1/PD-L1 Monotherapy in Stage III or IV NSCLC

Anti-PD-1/PD-L1 therapy indications are broadened in non-small cell lung cancer (NSCLC) although immune checkpoint inhibitors (ICI) do not provide benefits for the entire population. Texture features based on positron emission tomography/computed tomography (PET/CT), especially entropy (based on a gray-level co-occurrence matrix (GLCM)), could be interesting as predictors in NSCLC. The aim of our retrospective study was to evaluate the association between GLCM-entropy and response to anti-PD-1/PD-L1 monotherapy at the first evaluation in stage III or IV NSCLC, comparing patients with progressive disease (PD) and non-progressive disease (non-PD). In total, 47 patients were included. Response Evaluation Criteria in Solid Tumors (RECIST 1.1) were used to evaluate the response to ICI treatment (nivolumab, pembrolizumab, or atezolizumab). At the first evaluation, 25 patients were PD and 22 were non-PD. GLCM-entropy was not predictive of response at the first evaluation. Furthermore, GLCM-entropy was not associated with progression-free survival (PFS) (p = 0.393) or overall survival (OS) (p = 0.220). Finally, GLCM-entropy measured in PET/CT performed before ICI initiation in stage III or IV NSCLC was not predictive of response at the first evaluation. However, this study demonstrates the feasibility of using texture parameters in routine clinical practice. The interest of measuring PET/CT texture parameters in NSCLC remains to be evaluated in larger prospective studies.

High baseline tumor burden-associated macrophages promote an immunosuppressive microenvironment and reduce the efficacy of immune checkpoint inhibitors through the IGFBP2-STAT3-PD-L1 pathway

BACKGROUND

Several clinical studies have uncovered a negative correlation between baseline tumor burden and the efficacy of immune checkpoint inhibitor (ICI) treatment. This study aimed to uncover the specific mechanisms underlying the difference in sensitivity to ICI treatment between tumors with high (HTB) and low (LTB) tumor burden.

METHODS

For in vivo studies, several mouse models of subcutaneous tumors were established, and transcriptome sequencing, immunohistochemistry, and flow cytometry assays were used to detect the immune status in these subcutaneous tumors. For in vitro experiments, co-culture models, cytokine antibody arrays, western blotting, flow cytometry, and enzyme-linked immunosorbent assays were used to explore the underlying molecular mechanisms RESULTS: We found that MC38 or B16 subcutaneous tumors from the HTB group did not show any response to anti-programmed cell death protein-1 (PD-1) therapy. Through flow cytometry assays, we found that the infiltration with CD8⁺ T cells was significantly decreased whereas M2-like macrophages were enriched in subcutaneous tumors of HTB groups compared with those of LTB group. These changes were not affected by the initial number of injected tumor cells or tumor age, nor could they be reversed by surgical tumor reduction. Intraperitoneal colony-stimulating factor 1 receptor (CSF-1R) inhibitor PLX3397 injection at different time points of tumor growth only had an effect when administered in the early tumor stage to maintain the "heat" of the tumor microenvironment during the process of tumor growth, thereby achieving a response to ICI treatment when the tumor grew to a large size. Mechanistically, we found that insulin-like growth factor binding protein 2 (IGFBP2) expression levels were significantly elevated in HTB tumor tissues. IGFBP2 promoted the programmed death-ligand 1 (PD-L1) expression in M2-like macrophages by activating signal transducer and activator of transcription 3 (STAT3), and PD-L1⁺ M2-like macrophages exerted an immunosuppressive effect by inhibiting the proliferation and activation of CD8⁺ T cells in a PD-L1-dependent fashion.

CONCLUSIONS

This study suggested that the low efficacy of ICI treatment in HTB tumors is mainly attributed to the intratumoral accumulation of PD-L1⁺ M2-like macrophages via the IGFBP2-STAT3-PD-L1 signaling pathway and their substantial inhibitory effects on T cell proliferation and activation.

Predictive value of intratumor metabolic and heterogeneity parameters on [18F]FDG PET/CT for EGFR mutations in patients with lung adenocarcinoma

PURPOSE

This study aimed to investigate the value of metabolic and heterogeneity parameters of 2-deoxy-2[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) positron emission tomography/computed tomography (PET/CT) in predicting epidermal growth factor receptor (EGFR) mutations in patients with lung adenocarcinoma (ADC).

MATERIALS AND METHODS

A retrospective analysis was performed on 157 patients with lung ADC between September 2015 and June 2021, who had undergone both EGFR mutation testing and [¹⁸F]FDG PET/CT examination. Metabolic and heterogeneity parameters were measured and calculated, including maximum diameter (Dmax), maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and heterogeneity factor (HF). Relationships between PET/CT parameters and EGFR mutation status were evaluated and a multivariate logistic regression analysis was analyzed to establish a combined prediction model.

RESULTS

108 (68.8%) patients exhibited EGFR mutations. EGFR mutations were more likely to occur in females (51.9% vs. 48.1%, P = 0.007), non-smokers (83.3% vs. 16.7%, P < 0.001) and right lobes (55.6% vs. 44.4%, P = 0.017). High Dmax, MTV and HF and low SUVmean were significantly correlated with EGFR mutations, and the areas under the ROC curve (AUCs) measuring 0.647, 0.701, 0.757, and 0.661, respectively. Multivariate logistic regression analysis suggested that non-smokers (OR = 0.30, P = 0.034), low SUVmean (≤ 7.75, OR = 0.63, P < 0.001) and high HF (≥ 4.21, OR = 1.80, P = 0.027) were independent predictors of EGFR mutations. The AUC of the combined prediction model measured up to 0.863, significantly higher than that of a single parameter.

CONCLUSIONS

EGFR mutant in lung ADC patients showed more intratumor heterogeneity (HF) than EGFR wild type, which was combined clinical feature (non-smokers), and metabolic parameter (SUVmean) may be helpful in predicting EGFR mutation status, thus playing a guiding role in EGFR-tyrosine kinase inhibitors (EGFR-TKIs) targeted therapies.

Immune checkpoint inhibitors combined with angiogenic inhibitors in the treatment of locally advanced or metastatic lung adenocarcinoma patients

BACKGROUND

To report the efficacy and safety data of immunotherapy plus angiogenic inhibitors treatment in lung adenocarcinoma patients.

METHODS

Eligible patients with pathological or cytological confirmed locally advanced or metastatic lung adenocarcinoma and treated with immune checkpoint inhibitors (ICI) plus angiogenic inhibitors were enrolled. The primary endpoints were progressive free survival (PFS). The secondary endpoints were objective response rate (ORR), disease control rate (DCR), overall survival (OS), and safety.

RESULTS

A total of 46 consecutive enrolled patients received ICI plus angiogenic inhibitor, and the median follow-up was 9.6 months (range 1.5-32.5). The ORR and DCR were 8.7% (n = 4) and 50% (n = 23), respectively. Median PFS and OS were 2.9 months (95% CI 2.1-3.7) and 12.3 months (95% CI 7.6-17.0), respectively. Patients at stage IVB had an inferior PFS than stage IIIC or IVA (2.8 months vs 4.4 months, P = 0.003). The median PFS of patients who were treated with ICI plus bevacizumab was shorter than ICI plus anlotinib or apatinib (1.2 months vs 3.3 months, P = 0.005). The occurrence of hypertension during the combination treatment has been related to a tendency for prolonged PFS (5.5 months vs 2.6 months; P = 0.05). The overall incidence of treatment-related adverse events (TRAE) was 89.1% (n = 41), and grade 3-4 TRAE was occupied 21.4% (n = 10).

CONCLUSION

This study objectively demonstrated that the treatment of ICI and antiangiogenic agents in lung adenocarcinoma could be a promising alternative therapeutic regimen, and the toxic effects were manageable. Subgroup analysis revealed that small molecular angiogenic inhibitors plus ICI and low tumor burden during treatment were better prognostic factors.

Predicting pathological highly invasive lung cancer from preoperative [18F]FDG PET/CT with multiple machine learning models

PURPOSE

The efficacy of sublobar resection of primary lung cancer have been proven in recent years. However, sublobar resection for highly invasive lung cancer increases local recurrence. We developed and validated multiple machine learning models predicting pathological invasiveness of lung cancer based on preoperative [¹⁸F]fluorodeoxyglucose (FDG) positron emission tomography (PET) and computed tomography (CT) radiomic features.

METHODS

Overall, 873 patients who underwent lobectomy or segmentectomy for primary lung cancer were enrolled. Radiomics features were extracted from preoperative PET/CT images with the PyRadiomics package. Seven machine learning models and an ensemble of all models (ENS) were evaluated after 100 iterations. In addition, the probability of highly invasive lung cancer was calculated in a nested cross-validation to assess the calibration plot and clinical usefulness and to compare to consolidation tumour ratio (CTR) on CT images, one of the generally used diagnostic criteria.

RESULTS

In the training set, when PET and CT features were combined, all models achieved an area under the curve (AUC) of ≥ 0.880. In the test set, ENS showed the highest mean AUC of 0.880 and smallest standard deviation of 0.0165, and when the cutoff was 0.5, accuracy of 0.804, F1 of 0.851, precision of 0.821, and recall of 0.885. In the nested cross-validation, the AUC of 0.882 (95% CI: 0.860-0.905) showed a high discriminative ability, and the calibration plot indicated consistency with a Brier score of 0.131. A decision curve analysis showed that the ENS was valid with a threshold probability ranging from 3 to 98%. Accuracy showed an improvement of more than 8% over the CTR.

CONCLUSION

The machine learning model based on preoperative [¹⁸F]FDG PET/CT images was able to predict pathological highly invasive lung cancer with high discriminative ability and stability. The calibration plot showed good consistency, suggesting its usefulness in quantitative risk assessment.

Volumetric parameters of the primary tumor and whole-body tumor burden derived from baseline 18F-FDG PET/CT can predict overall survival in non-small cell lung cancer patients: initial results from a single institution

BACKGROUND

Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) are volumetric parameters derived from ¹⁸F-FDG PET/CT, suggested to have a prognostic value in cancer patients. Our study aimed to test whether these volumetric parameters of the primary tumor and whole-body tumor burden (WBTB) can predict overall survival (OS) in non-small cell lung cancer (NSCLC) patients.

MATERIALS AND METHODS

Thirty biopsy-proven NSCLC patients who had not begun anti-tumor therapy were included in this prospective study. A baseline ¹⁸F-FDG PET/CT study was acquired. Scans were interpreted visually and semi-quantitatively by drawing a 3D volume of interest (VOI) over the primary tumor and all positive lesions to calculate metabolic, volumetric parameters, and WBTB. The PET parameters were used to stratify patients into high- and low-risk categories. The overall survival was estimated from the date of scanning until the date of death or last follow-up.

RESULTS

At a median follow-up of 22.73 months, the mean OS was shorter among patients with higher tu MTV and tu TLG and high WBTB. High WB TLG was independently associated with the risk of death (p < 0.025). Other parameters, e.g., SUV_max, SUV_peak, and SUV_mean, were not predictive of outcomes in these patients.

CONCLUSION

In patients with NSCLC, tu MTV, tu TLG, and WBTB determined on initial staging ¹⁸F-FDG PET/CT seems to be a strong, independent imaging biomarker to predict OS, superior to the clinical assessment of the primary tumor. The WB TLG was found to be the best predictor of OS.

Predictive Value of Baseline FDG-PET/CT for the Durable Response to Immune Checkpoint Inhibition in NSCLC Patients Using the Morphological and Metabolic Features of Primary Tumors

Objectives: We aimed to investigate the predictive value of baseline 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) for durable responses to immune checkpoint inhibitors (ICIs) by linking the morphological and metabolic features of primary tumors (PTs) in nonsmall cell lung cancer (NSCLC) patients. Methods: For the purpose of this single-center study, the imaging data of the patients with a first diagnosis of NSCLC and an available baseline FDG-PET/CT between 2020 and 2021 were retrospectively assessed. The baseline characteristics were collected based on clinical reports and interdisciplinary tumor board documentation. The metabolic (such as standardized uptake value SUV maximum and mean (SUVmax, SUV mean), metabolic tumor volume (MTV), total lesion glycolysis (TLG)) and morphological (such as volume, morphology, margin, and presence of lymphangiosis through imaging) features of all the PTs were retrospectively assessed using FDG-PET/CT. Overall survival (OS), progression-free survival (PFS), clinical benefit (CB) and mortality rate were used as endpoints to define the long-term response to therapy. A backward, stepwise logistic regression analysis was performed in order to define the best model for predicting lasting responses to treatment. Statistical significance was assumed at p < 0.05. Results: A total of 125 patients (median age ± standard deviation (SD) 72.0 ± 9.5 years) were enrolled: 64 men (51.2%) and 61 women (48.8%). Adenocarcinoma was by far the most common histological subtype of NSCLC (47.2%). At the initial diagnosis, the vast majority of all the included patients showed either locally advanced disease (34.4%) or metastatic disease (36.8%). Fifty patients were treated with ICIs either as a first-line (20%) or second-line (20%) therapy, while 75 patients did not receive ICIs. The median values ± SD of PT SUVmax, mean, MTV, and TLG were respectively 10.1 ± 6.0, 6.1 ± 3.5, 13.5 ± 30.7, and 71.4 ± 247.7. The median volume of PT ± SD was 13.7 ± 30.7 cm3. The PTs were most frequently solid (86.4%) with irregular margins (76.8%). Furthermore, in one out of five cases, the morphological evidence of lymphangiosis was seen through imaging (n = 25). The median follow-up ± SD was 18.93 ± 6.98 months. The median values ± SD of OS and PFS were, respectively, 14.80 ± 8.68 months and 14.03 ± 9.02 months. Age, PT volume, SUVmax, TLG, the presence of lymphangiosis features through imaging, and clinical stage IV were very strong long-term outcome predictors of patients treated with ICIs, while no significant outcome predictors could be found for the cohort with no ICI treatment. The optimal cut-off values were determined for PT volume (26.94 cm3) and SUVmax (15.05). Finally, 58% of NSCLC patients treated with ICIs had a CB vs. 78.7% of patients in the cohort with no ICI treatment. However, almost all patients treated with ICIs and with disease progression over time died (mortality in the case of disease progression 95% vs. 62.5% in the cohort without ICIs). Conclusion: Baseline FDG-PET/CT could be used to predict a durable response to ICIs in NSCLC patients. Age, clinical stage IV, lymphangiosis features through imaging, PT volume (thus PT MTV due to a previously demonstrated linear correlation), PT SUVmax, and TLG were very strong long-term outcome predictors. Our results highlight the importance of linking clinical data, as much as morphological features, to the metabolic parameters of primary tumors in a multivariate outcome-predicting model using baseline FDG-PET/CT.

Tumor glycolytic profiling through 18F-FDG PET/CT predicts immune checkpoint inhibitor efficacy in advanced NSCLC

Background

A significant proportion of patients with non-small-cell lung cancer (NSCLC) do not respond to immune checkpoint inhibitors (ICIs). Since metabolic reprogramming with increased glycolysis is a hallmark of cancer and is involved in immune evasion, we used ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET/CT) to evaluate the baseline glycolytic parameters of patients with advanced NSCLC submitted to ICIs, and assessed their predictive value.

Methods

¹⁸F-FDG PET/CT results in the 3 months before ICIs treatment were included. Maximum standardized uptake values, whole metabolic tumor volume (wMTV), and whole-body total lesion glycolysis (wTLG) were evaluated. Cutoff values for high or low glycolytic categories were determined using receiver-operating characteristic curves. Progression-free survival (PFS) and overall survival (OS) were evaluated. Patients with a complete response and a matching group with resistance to ICIs underwent immunohistochemistry analysis. An unsupervised k-means clustering model integrating programmed cell death ligand 1 (PD-L1) expression, glycolytic parameters, and ICIs therapy was performed.

Results

In all, 98 patients were included. Lower baseline ¹⁸F-FDG PET/CT parameters were associated with responses to ICIs. Patients with low wMTV or wTLG had improved PFS and OS. High wTLG, strong tumor expression of glucose transporter-1, and lack of responses were significantly associated. Patients with low glycolytic parameters benefited from ICIs, regardless of chemotherapy. Conversely, those with high parameters benefited from the addition of chemotherapy. Patients with higher wTLG and lower PD-L1 were associated with progression and worse survival to ICIs monotherapy.

Conclusions

Glycolytic metabolic profiles established through baseline ¹⁸F-FDG PET/CT are useful biomarkers for evaluating ICI therapy in advanced NSCLC.

Prognostic value of 18F-FDG PET/CT in patients with advanced or metastatic non-small-cell lung cancer treated with immune checkpoint inhibitors: A systematic review and meta-analysis

PURPOSE

This study aimed to investigate the value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in predicting early immunotherapy response of immune checkpoint inhibitors (ICIs) in patients with advanced or metastatic non-small-cell lung cancer (NSCLC).

METHODS

A comprehensive search of PubMed, Web of science, Embase and the Cochrane library was performed to examine the prognostic value of 18F-FDG PET/CT in predicting early immunotherapy response of ICIs in patients with NSCLC. The main outcomes for evaluation were overall survival (OS) and progression-free survival (PFS). Detailed data from each study were extracted and analyzed using STATA 14.0 software.

RESULTS

13 eligible articles were included in this systematic review. Compared to baseline 18F-FDG PET/CT imaging, the pooled hazard ratios (HR) of maximum and mean standardized uptake values SUVmax, SUVmean, MTV and TLG for OS were 0.88 (95% CI: 0.69-1.12), 0.79 (95% CI: 0.50-1.27), 2.10 (95% CI: 1.57-2.82) and 1.58 (95% CI: 1.03-2.44), respectively. The pooled HR of SUVmax, SUVmean, MTV and TLG for PFS were 1.06 (95% CI: 0.68-1.65), 0.66 (95% CI: 0.48-0.90), 1.50 (95% CI: 1.26-1.79), 1.27 (95% CI: 0.92-1.77), respectively. Subgroup analysis showed that high MTV group had shorter OS than low MTV group in both first line group (HR: 1.97, 95% CI: 1.39-2.79) and undefined line group (HR: 2.11, 95% CI: 1.61-2.77). High MTV group also showed a shorter PFS in first line group (HR: 1.85, 95% CI: 1.28-2.68), and low TLG group had a longer OS in undefined group (HR: 1.37, 95% CI: 1.00-1.86). No significant differences were in other subgroup analysis.

CONCLUSION

Baseline MTV and TLG may have predictive value and should be prospectively studied in clinical trials. Baseline SUVmax and SUVmean may not be appropriate prognostic markers in advanced or metastatic NSCLC patients treated with ICIs.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=323906, identifier CRD42022323906.

Tumor metabolic and secondary lymphoid organ metabolic markers on 18F-fludeoxyglucose positron emission tomography predict prognosis of immune checkpoint inhibitors in advanced lung cancer

BACKGROUND

The purpose of this study was to investigate the predictive value of tumor metabolic parameters in combination with secondary lymphoid metabolic parameters on positron emission tomography (PET)/computed tomography (CT) for immune checkpoint inhibitor (ICI) prognosis in advanced lung cancer.

METHODS

This study retrospectively included 125 patients who underwent 18F-fludeoxyglucose (FDG) PET/CT before ICI therapy, including 41 patients who underwent a second PET/CT scan during ICI treatment. The measured PET/CT parameters included tumor metabolism parameters [maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), total lesion glycolysis (TLG), and total metabolic tumor volume (TMTV)] and secondary lymphoid organ metabolism parameters [spleen-to-liver SUVmax ratio (SLR) and bone marrow-to-liver SUVmax ratio (BLR)]. The correlation of PET/CT metabolic parameters with early ICI treatment response, progression-free survival (PFS), and overall survival (OS) was analyzed.

RESULTS

Within a median follow-up of 28.7 months, there were 44 responders and 81 non-responders. The median PFS was 8.6 months (95% confidence interval (CI): 5.872-11.328), and the median OS was 20.4 months (95% CI: 15.526-25.274). Pretreatment tumor metabolic parameters were not associated with early treatment responses. The high bone marrow metabolism (BLR >1.03) was significantly associated with a shorter PFS (p = 0.008). Patients with a high TMTV (>168 mL) and high spleen metabolism (SLR >1.08) had poor OS (p = 0.019 and p = 0.018, respectively). Among the 41 patients who underwent a second PET/CT scan, the ΔSUVmax was significantly lower (p = 0.01) and the SLR was significantly higher (p = 0.0086) in the responders. Populations with low-risk characteristics (low TMTV, low SLR, and ΔSLR > 0) had the longest survival times.

CONCLUSION

High pretreatment TMTV and SLR are associated with poor OS, and increased spleen metabolism after ICI therapy predicts treatment benefit. This indicates that the combination of tumor and spleen metabolic parameters is a valuable prognostic strategy.

PET/CT molecular imaging in the era of immune-checkpoint inhibitors therapy

Cancer immunotherapy, especially immune-checkpoint inhibitors (ICIs), has paved a new way for the treatment of many types of malignancies, particularly advanced-stage cancers. Accumulating evidence suggests that as a molecular imaging modality, positron emission tomography/computed tomography (PET/CT) can play a vital role in the management of ICIs therapy by using different molecular probes and metabolic parameters. In this review, we will provide a comprehensive overview of the clinical data to support the importance of 18F-fluorodeoxyglucose PET/CT (18F-FDG PET/CT) imaging in the treatment of ICIs, including the evaluation of the tumor microenvironment, discovery of immune-related adverse events, evaluation of therapeutic efficacy, and prediction of therapeutic prognosis. We also discuss perspectives on the development direction of 18F-FDG PET/CT imaging, with a particular emphasis on possible challenges in the future. In addition, we summarize the researches on novel PET molecular probes that are expected to potentially promote the precise application of ICIs.

Predictive value of baseline metabolic tumor volume for non-small-cell lung cancer patients treated with immune checkpoint inhibitors: A meta-analysis

Background

Immune checkpoint inhibitors (ICIs) have emerged as a promising treatment option for advanced non-small-cell lung cancer (NSCLC) patients, highlighting the need for biomarkers to identify responders and predict the outcome of ICIs. The purpose of this study was to evaluate the predictive value of baseline standardized uptake value (SUV), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) derived from 18F-FDG-PET/CT in advanced NSCLC patients receiving ICIs.

Methods

PubMed and Web of Science databases were searched from January 1st, 2011 to July 18th, 2022, utilizing the search terms “non-small-cell lung cancer”, “PET/CT”, “standardized uptake value”, “metabolic tumor volume”, “ total lesion glycolysis”, and “immune checkpoint inhibitors”. Studies that analyzed the association between PET/CT parameters and objective response, immune-related adverse events (irAEs) and prognosis of NSCLC patients treated with ICIs were included. We extracted the hazard ratio (HR) with a 95% confidence interval (CI) for progression-free survival (PFS) and overall survival (OS). We performed a meta-analysis of HR using Review Manager v.5.4.1.

Results

Sixteen studies were included for review and thirteen for meta-analysis covering 770 patients. As for objective response and irAEs after ICIs, more studies with consistent assessment methods are needed to determine their relationship with MTV. In the meta-analysis, low SUVmax corresponded to poor PFS with a pooled HR of 0.74 (95% CI, 0.57-0.96, P=0.02). And a high level of baseline MTV level was related to shorter PFS (HR=1.45, 95% CI, 1.11-1.89, P<0.01) and OS (HR, 2.72; 95% CI, 1.97-3.73, P<0.01) especially when the cut-off value was set between 50-100 cm³. SUVmean and TLG were not associated with the prognosis of NSCLC patients receiving ICIs.

Conclusions

High level of baseline MTV corresponded to shorter PFS and OS, especially when the cut-off value was set between 50-100 cm³. MTV is a potential predictive value for the outcome of ICIs in NSCLC patients.

Prognosis of different extrathoracic metastasis patterns in patients with M1c lung adenocarcinoma receiving immunotherapy

INTRODUCTION

Lung cancer with extrathoracic metastases is classified as M1c. However, extrathoracic metastases can be further classified into different patterns. The purpose of this study was to analyze the survival differences between different patterns of extrathoracic metastases in patients with stage M1c lung adenocarcinoma after receiving immunotherapy.

MATERIALS AND METHODS

This study included 160 stage M1c lung adenocarcinoma patients and treated with immunotherapy. The enrolled patients were divided into two groups: those with multiple extrathoracic metastases alone (EM group) and those with simultaneous multiple extrathoracic and intrathoracic metastases (EIM group). Progression-free survival (PFS) and overall survival (OS) were evaluated.

RESULTS

The median PFS and OS in the whole group were 7.7 months and 25.4 months, respectively. The patients in the EM group show better PFS (13.0 months vs. 5.0 months; hazard ratio [HR] = 0.462, 95% confidence interval [CI] 0.317-0.673, P < 0.0001) and OS (35.0 months vs. 18.9 months; HR 0.592, 95% CI 0.380-0.922, P = 0.019) compared with the EIM group. Furthermore, in patients with lung adenocarcinoma with simultaneous extrathoracic and intrathoracic metastases who received immunotherapy, immunotherapy combined with chemotherapy has better PFS and OS than immunotherapy alone. There was no difference between immunotherapy alone or combined with chemotherapy in patients with lung adenocarcinoma with extrathoracic metastasis alone.

CONCLUSION

The different patterns of extrathoracic metastasis were related to the efficacy and prognosis of immunotherapy in M1c cohort. In addition, patients with simultaneous extrathoracic and intrathoracic metastases were more recommended to choose immunotherapy in combination with chemotherapy rather than immunotherapy alone.

Interaction of Radiotherapy and Hyperthermia with the Immune System: a Brief Current Overview

Purpose of Review

This review focuses on the opposing effects on the immune system of radiotherapy (RT) and the consequences for combined cancer treatment strategies of RT with immunotherapies, including hyperthermia (HT). How RT and HT might affect cancer stem cell populations is also briefly outlined in this context.

Recent Findings

RT is one of the crucial standard cancer therapies. Most patients with solid tumors receive RT for curative and palliative purposes in the course of their disease. RT achieves a local tumor control by inducing DNA damage which can lead to tumor cell death. In recent years, it has become evident that RT does not only have local effects, but also systemic effects which involves induction of anti-tumor immunity and possible alteration of the immunosuppressive properties of the tumor microenvironment. Though, often RT alone is not able to induce potent anti-tumor immune responses since the effects of RT on the immune system can be both immunostimulatory and immunosuppressive.

Summary

RT with additional therapies such as HT and immune checkpoint inhibitors (ICI) are promising approaches to induce anti-tumor immunity effectively. HT is not only a potent sensitizer for RT, but it might also improve the efficacy of RT and certain chemotherapeutic agents (CT) by additionally sensitizing resistant cancer stem cells (CSCs).

Graphical abstract

The oligometastatic spectrum in the era of improved detection and modern systemic therapy

Metastases remain the leading cause of cancer-related mortality. The oligometastasis hypothesis postulates that a spectrum of metastatic spread exists and that some patients with a limited burden of metastases can be cured with ablative therapy. Over the past decade, substantial advances in systemic therapies have resulted in considerable improvements in the outcomes of patients with metastatic cancers, warranting re-examination of the oligometastatic paradigm and the role of local ablative therapies within the context of the improved therapeutic responses, shifting patterns of disease recurrence and possible synergy with systemic treatments. Herein, we reframe the oligometastatic phenotype as a dynamic state for which locally ablative, metastasis-directed therapy improves clinical outcomes, including by prolonging survival and increasing cure rates. Important risk factors defining the metastatic spectrum are highlighted that inform both staging and therapy. Finally, we synthesize the literature on combining local therapies with modern systemic treatments, identifying general themes to optimally integrate ablative therapies in this context.

Splenic volume as a predictor of treatment response in patients with non-small cell lung cancer receiving immunotherapy

Introduction

The spleen is a lymphoid organ and we hypothesize that clinical benefit to immunotherapy may present with an increase in splenic volume during treatment. The purpose of this study was to investigate whether changes in splenic volume could be observed in those showing clinical benefit versus those not showing clinical benefit to pembrolizumab treatment in non-small cell lung cancer (NSCLC) patients.

Materials and methods

In this study, 70 patients with locally advanced or metastatic NSCLC treated with pembrolizumab; and who underwent baseline CT scan within 2 weeks before treatment and follow-up CT within 3 months after commencing immunotherapy were retrospectively evaluated. The splenic volume on each CT was segmented manually by outlining the splenic contour on every image and the total volume summated. We compared the splenic volume in those achieving a clinical benefit and those not achieving clinical benefit, using non-parametric Wilcoxon signed-rank test. Clinical benefit was defined as stable disease or partial response lasting for greater than 24 weeks. A p-value of <0.05 was considered statistically significant.

Results

There were 23 responders and 47 non-responders based on iRECIST criteria and 35 patients with clinical benefit and 35 without clinical benefit. There was no significant difference in the median pre-treatment volume (175 vs 187 cm3, p = 0.34), post-treatment volume (168 vs 167 cm3, p = 0.39) or change in splenic volume (-0.002 vs 0.0002 cm3, p = 0.97) between the two groups. No significant differences were also found between the splenic volume of patients with partial response, stable disease or progressive disease (p>0.017). Moreover, there was no statistically significant difference between progression-free survival and time to disease progression when the splenic volume was categorized as smaller or larger than the median pre-treatment or post-treatment volume (p>0.05).

Conclusion

No significant differences were observed in the splenic volume of those showing clinical benefit versus those without clinical benefit to pembrolizumab treatment in NSCLC patients. CT splenic volume cannot be used as a potentially simple biomarker of response to immunotherapy.

Radiopharmaceuticals as Novel Immune System Tracers

Immune checkpoint inhibitors (ICIs) have transformed the treatment paradigms for multiple cancers. However, ICI therapy often fails to generate measurable and sustained antitumor responses, and clinically meaningful benefits remain limited to a small proportion of overall patients. A major obstacle to development and effective application of novel therapeutic regimens is optimized patient selection and response assessment. Noninvasive imaging using novel immunoconjugate radiopharmaceuticals (immuno–positron emission tomography and immuno-single-photon emission computed tomography) can assess for expression of cell surface immune markers, such as programmed cell death protein ligand-1 (PD-L1), akin to a virtual biopsy. This emerging technology has the potential to provide clinicians with a quantitative, specific, real-time evaluation of immunologic responses relative to cancer burden in the body. We discuss the rationale for using noninvasive molecular imaging of the programmed cell death protein-1 and PD-L1 axis as a biomarker for immunotherapy and summarize the current status of preclinical and clinical studies examining PD-L1 immuno–positron emission tomography. The strategies described in this review provide insight for future clinical trials exploring the use of immune checkpoint imaging as a biomarker for both ICI and radiation therapy, and for the rational design of combinatorial therapeutic regimens.

The value of the Standardized Uptake Value (SUV) and Metabolic Tumor Volume (MTV) in lung cancer

The diagnosis, staging and therapeutic monitoring of lung cancer were amongst the first applications for which the utility of FDG PET was documented and FDG PET/CT is now a routine diagnostic tool for clinical decision-making. As well as having high sensitivity for detection of disease sites, which provides critical information about stage, the intensity of uptake provides deeper biological characterization, while the burden of disease also has potential clinical significance. These disease characteristics can easily be quantified on delayed whole-body imaging as the maximum standardized uptake value (SUV_max) and metabolic tumor volume (MTV), respectively. There have been significant efforts to harmonize the measurement of these features, particularly within the context of clinical trials. Nevertheless, however calculated, in general, a high SUV_max and large MTV have been shown to have an adverse prognostic significance. Nevertheless, the use of these parameters in the interpretation and reporting of clinical scans remains inconsistent and somewhat controversial. This review details the current status of semi-quantitative FDG PET/CT in the evaluation of lung cancer.

Combined radio-immunotherapy: An opportunity to increase the therapeutic ratio of oligometastasis-directed radiotherapy

The utility of radiotherapy as a means of palliating symptoms due to metastatic cancer is well-accepted. A growing body of literature suggests that radiotherapy may play a role beyond palliation in some patients with low-burden metastatic disease. Recent data suggest that oligometastasis-directed radiotherapy may improve progression-free and even overall survival in select patients. Immunotherapy also has a growing role in the management of patients with metastatic cancer and, like radiotherapy, appears to be most effective in the setting of low-volume disease. Thus, the addition of immunotherapy may be a feasible means of increasing the therapeutic ratio of metastasis-directed radiotherapy, particularly among patients with oligometastatic cancer.

Differential role of residual metabolic tumor volume in inoperable stage III NSCLC after chemoradiotherapy ± immune checkpoint inhibition

BACKGROUND

The PET-derived metabolic tumor volume (MTV) is an independent prognosticator in non-small cell lung cancer (NSCLC) patients. We analyzed the prognostic value of residual MTV (rMTV) after completion of chemoradiotherapy (CRT) in inoperable stage III NSCLC patients with and without immune checkpoint inhibition (ICI).

METHODS

Fifty-six inoperable stage III NSCLC patients (16 female, median 65.0 years) underwent 18F-FDG PET/CT after completion of standard CRT. rMTV was delineated on 18F-FDG PET/CT using a standard threshold (liver SUVmean + 2 × standard deviation). 21/56 patients underwent additional ICI (CRT-IO, 21/56 patients) thereafter. Patients were divided in volumetric subgroups using median split dichotomization (MTV ≤ 4.3 ml vs. > 4.3 ml). rMTV, clinical features, and ICI-application were correlated with clinical outcome parameters (progression-free survival (PFS), local PFS (LPFS), and overall survival (OS).

RESULTS

Overall, median follow-up was 52.0 months. Smaller rMTV was associated with longer median PFS (29.3 vs. 10.5 months, p = 0.015), LPFS (49.9 vs. 13.5 months, p = 0.001), and OS (63.0 vs. 23.0 months, p = 0.003). CRT-IO patients compared to CRT patients showed significantly longer median PFS (29.3 vs. 11.2 months, p = 0.034), LPFS (median not reached vs. 14.0 months, p = 0.016), and OS (median not reached vs. 25.2 months, p = 0.007). In the CRT subgroup, smaller rMTV was associated with longer median PFS (33.5 vs. 8.6 months, p = 0.001), LPFS (49.9 vs. 10.1 months, p = 0.001), and OS (63.0 vs. 16.3 months, p = 0.004). In the CRT-IO subgroup, neither PFS, LPFS, nor OS were associated with MTV (p > 0.05 each). The findings were confirmed in subsequent multivariate analyses.

CONCLUSION

In stage III NSCLC, smaller rMTV is highly associated with superior clinical outcome, especially in patients undergoing CRT without ICI. Patients with CRT-IO show significantly improved outcome compared to CRT patients. Of note, clinical outcome in CRT-IO patients is independent of residual MTV. Hence, even patients with large rMTV might profit from ICI despite extensive tumor load.

Potentials of Non-Invasive 18F-FDG PET/CT in Immunotherapy Prediction for Non-Small Cell Lung Cancer

The immune checkpoint inhibitors (ICIs), by targeting cytotoxic-T-lymphocyte-associated protein 4, programmed cell death 1 (PD-1), or PD-ligand 1, have dramatically changed the natural history of several cancers, including non-small cell lung cancer (NSCLC). There are unusual response manifestations (such as pseudo-progression, hyper-progression, and immune-related adverse events) observed in patients with ICIs because of the unique mechanisms of these agents. These specific situations challenge response and prognostic assessment to ICIs challenging. This review demonstrates how 18F-FDG PET/CT can help identify these unusual response patterns in a non-invasive and effective way. Then, a series of semi-quantitative parameters derived from 18F-FDG PET/CT are introduced. These indexes have been recognized as the non-invasive biomarkers to predicting the efficacy of ICIs and survival of NSCLC patients according to the latest clinical studies. Moreover, the current situation regarding the functional criteria based on 18F-FDG PET/CT for immunotherapeutic response assessment is presented and analyzed. Although the criteria based on 18F-FDG PET/CT proposed some resolutions to overcome limitations of morphologic criteria in the assessment of tumor response to ICIs, further researches should be performed to validate and improve these assessing systems. Then, the last part in this review displays the present status and a perspective of novel specific PET probes targeting key molecules relevant to immunotherapy in prediction and response assessment.

Freely available convolutional neural network-based quantification of PET/CT lesions is associated with survival in patients with lung cancer

Background

Metabolic positron emission tomography/computed tomography (PET/CT) parameters describing tumour activity contain valuable prognostic information, but to perform the measurements manually leads to both intra- and inter-reader variability and is too time-consuming in clinical practice. The use of modern artificial intelligence-based methods offers new possibilities for automated and objective image analysis of PET/CT data.

Purpose

We aimed to train a convolutional neural network (CNN) to segment and quantify tumour burden in [¹⁸F]-fluorodeoxyglucose (FDG) PET/CT images and to evaluate the association between CNN-based measurements and overall survival (OS) in patients with lung cancer. A secondary aim was to make the method available to other researchers.

Methods

A total of 320 consecutive patients referred for FDG PET/CT due to suspected lung cancer were retrospectively selected for this study. Two nuclear medicine specialists manually segmented abnormal FDG uptake in all of the PET/CT studies. One-third of the patients were assigned to a test group. Survival data were collected for this group. The CNN was trained to segment lung tumours and thoracic lymph nodes. Total lesion glycolysis (TLG) was calculated from the CNN-based and manual segmentations. Associations between TLG and OS were investigated using a univariate Cox proportional hazards regression model.

Results

The test group comprised 106 patients (median age, 76 years (IQR 61–79); n = 59 female). Both CNN-based TLG (hazard ratio 1.64, 95% confidence interval 1.21–2.21; p = 0.001) and manual TLG (hazard ratio 1.54, 95% confidence interval 1.14–2.07; p = 0.004) estimations were significantly associated with OS.

Conclusion

Fully automated CNN-based TLG measurements of PET/CT data showed were significantly associated with OS in patients with lung cancer. This type of measurement may be of value for the management of future patients with lung cancer. The CNN is publicly available for research purposes.

Immunotherapy Monitoring with Immune Checkpoint Inhibitors Based on [18F]FDG PET/CT in Metastatic Melanomas and Lung Cancer

Immunotherapy with checkpoint inhibitors has prompted a major change not only in cancer treatment but also in medical imaging. In parallel with the implementation of new drugs modulating the immune system, new response criteria have been developed, aiming to overcome clinical drawbacks related to the new, unusual, patterns of response characterizing both solid tumors and lymphoma during the course of immunotherapy. The acknowledgement of pseudo-progression, hyper-progression, immune-dissociated response and so forth, has become mandatory for all imagers dealing with this clinical scenario. A long list of acronyms, i.e., irRC, iRECIST, irRECIST, imRECIST, PECRIT, PERCIMT, imPERCIST, iPERCIST, depicts the enormous effort made by radiology and nuclear medicine physicians in the last decade to optimize imaging parameters for better prediction of clinical benefit in immunotherapy regimens. Quite frequently, a combination of clinical-laboratory data with imaging findings has been tested, proving the ability to stratify patients into various risk groups. The next steps necessarily require a large scale validation of the most robust criteria, as well as the clinical implementation of immune-targeting tracers for immuno-PET or the exploitation of radiomics and artificial intelligence as complementary tools during the course of immunotherapy administration. For the present review article, a summary of PET/CT role for immunotherapy monitoring will be provided. By scrolling into various cancer types and applied response criteria, the reader will obtain necessary information for better understanding the potentials and limitations of the modality in the clinical setting.

The effect of tumor size and metastatic extent on the efficacy of first line pembrolizumab monotherapy in patients with high PD-L1 expressing advanced NSCLC tumors

BACKGROUND

Tumor size and metastatic extent may influence tumor response to immunotherapy in non-small cell lung cancer (NSCLC). The aim of this study was to examine the relationship between both baseline sum of longest diameters (bSLD) and number of metastatic organs (NMO) and the tumor response to pembrolizumab. Secondly, we aimed to analyze the association of baseline SLD and NMO with progression-free survival (PFS) and overall survival (OS).

METHODS

This retrospective study included patients with high PD-L1 expressing tumors (≥50%) and a good performance score (ECOG ≤ 2) that received first-line pembrolizumab monotherapy. Tumor response was calculated as the 'SLD-change score' and 'early treatment discontinuation' within 3 months on therapy (ETD). The relationship of both bSLD (based on RECIST v1.1) and NMO with tumor response and survival outcome (PFS, OS) was evaluated.

RESULTS

No significant differences in SLD-change score could be found using bSLD (OR = 1.010, 95%CI = 0.999-1.021), or using NMO at baseline (OR = 1.608, 95%CI = 0.943-2.743). A bSLD cut-off value of 90 mm was found to be most distinctive for ETD. This cut-off value showed a significant difference for PFS (HR = 2.28, 95%CI = 1.12-4.64, p = 0.023) and OS (HR = 2.99, 95%CI = 1.41-6.34, p = 0.004). NMO also showed a difference for PFS and OS, however, not statistically significant.

CONCLUSIONS

Tumor size and metastatic extent could not discriminate for tumor response, however, a bSLD of 90 mm could differentiate for PFS and OS.

Tumour burden and efficacy of immune-checkpoint inhibitors

Accumulating evidence suggests that a high tumour burden has a negative effect on anticancer immunity. The concept of tumour burden, simply defined as the total amount of cancer in the body, in contrast to molecular tumour burden, is often poorly understood by the wider medical community; nonetheless, a possible role exists in defining the optimal treatment strategy for many patients. Historically, tumour burden has been assessed using imaging. In particular, CT scans have been used to evaluate both the number and size of metastases as well as the number of organs involved. These methods are now often complemented by metabolic tumour burden, measured using the more recently developed 2-deoxy-2-[¹⁸F]-fluoro-D-glucose (FDG)-PET/CT. Serum-based biomarkers, such as lactate dehydrogenase, can also reflect tumour burden and are often also correlated with a poor response to immune-checkpoint inhibitors. Other circulating markers (such as circulating free tumour DNA and/or circulating tumour cells) are also attracting research interest as surrogate markers of tumour burden. In this Review, we summarize evidence supporting the utility of tumour burden as a biomarker to guide the use of immune-checkpoint inhibitors. We also describe data and provide perspective on the various tools used for tumour burden assessment, with a particular emphasis on future therapeutic strategies that might address the issue of inferior outcomes among patients with cancer with a high tumour burden.