Stereotactic Ablative Radiation Therapy for Lung Oligometastases: Predictive Parameters of Early Response by 18FDG-PET/CT

Metabolic factors associated with the prognosis of oligometastatic patients treated with stereotactic body radiotherapy

Over the past two decades, it has been established that cancer patients with oligometastases, i.e., only a few detectable metastases confined to one or a few organs, may benefit from an aggressive local treatment approach such as the application of high-precision stereotactic body radiotherapy (SBRT). Specifically, some studies have indicated that achieving long-term local tumor control of oligometastases is associated with prolonged overall survival. This motivates investigations into which factors may modify the dose-response relationship of SBRT by making metastases more or less radioresistant. One such factor relates to the uptake of the positron emission tomography tracer 2-deoxy-2-[18F]fluoro-D-glucose (FDG) which reflects the extent of tumor cell glycolysis or the Warburg effect, respectively. Here we review the biological mechanisms how the Warburg effect drives tumor cell radioresistance and metastasis and draw connections to clinical studies reporting associations between high FDG uptake and worse clinical outcomes after SBRT for oligometastases. We further review the evidence for distinct metabolic phenotypes of metastases preferentially seeding to specific organs and their possible translation into distinct radioresistance. Finally, evidence that obesity and hyperglycemia also affect outcomes after SBRT will be presented. While delivered dose is the main determinant of a high local tumor control probability, there might be clinical scenarios when metabolic targeting could make the difference between achieving local control or not, for example when doses have to be compromised in order to spare neighboring high-risk organs, or when tumors are expected to be highly therapy-resistant due to heavy pretreatment such as chemotherapy and/or radiotherapy.

Predicting cancer relapse following lung stereotactic radiotherapy: an external validation study using real-world evidence

Purpose

For patients receiving lung stereotactic ablative radiotherapy (SABR), evidence suggests that high peritumor density predicts an increased risk of microscopic disease (MDE) and local-regional failure, but only if there is low or heterogenous incidental dose surrounding the tumor (GTV). A data-mining method (Cox-per-radius) has been developed to investigate this dose-density interaction. We apply the method to predict local relapse (LR) and regional failure (RF) in patients with non-small cell lung cancer.

Methods

199 patients treated in a routine setting were collated from a single institution for training, and 76 patients from an external institution for validation. Three density metrics (mean, 90th percentile, standard deviation (SD)) were studied in 1mm annuli between 0.5cm inside and 2cm outside the GTV boundary. Dose SD and fraction of volume receiving less than 30Gy were studied in annuli 0.5-2cm outside the GTV to describe incidental MDE dosage. Heat-maps were created that correlate with changes in LR and RF rates due to the interaction between dose heterogeneity and density at each distance combination. Regions of significant improvement were studied in Cox proportional hazards models, and explored with and without re-fitting in external data. Correlations between the dose component of the interaction and common dose metrics were reported.

Results

Local relapse occurred at a rate of 6.5% in the training cohort, and 18% in the validation cohort, which included larger and more centrally located tumors. High peritumor density in combination with high dose variability (0.5 - 1.6cm) predicts LR. No interactions predicted RF. The LR interaction improved the predictive ability compared to using clinical variables alone (optimism-adjusted C-index; 0.82 vs 0.76). Re-fitting model coefficients in external data confirmed the importance of this interaction (C-index; 0.86 vs 0.76). Dose variability in the 0.5-1.6 cm annular region strongly correlates with heterogeneity inside the target volume (SD; ρ = 0.53 training, ρ = 0.65 validation).

Conclusion

In these real-world cohorts, the combination of relatively high peritumor density and high dose variability predicts increase in LR, but not RF, following lung SABR. This external validation justifies potential use of the model to increase low-dose CTV margins for high-risk patients.

18F-FDG PET/CT for assessing heterogeneous metabolic response between primary tumor and metastases and prognosis in non-small cell lung cancer

INTRODUCTION

This study aimed to use ¹⁸F-fluorodeoxyglucose positron emission tomography and/or computed tomography (¹⁸FDG-PET/CT) imaging to evaluate the heterogeneous metabolic response between primary tumor and metastases in NSCLC after therapy and explored its correlation with prognosis.

METHODS

The data of patients with NSCLC who underwent ¹⁸FDG-PET/CT before and after treatment were retrospectively analyzed. Heterogeneous metabolic response (HR), defined as the difference in metabolic response between any metastases and primary lesion, was evaluated using ¹⁸FDG-PET/CT. And the correlation between HR and clinical prognosis was also analyzed.

RESULTS

A total of 56 patients with NSCLC including 56 primary lesions and 491 metastases were enrolled in the study. 46.4% (26/56) of patients had HR, especially in patients with stage IV disease and whose metastases with high metabolic burden. HR was significantly correlated with poorer overall survival (OS) and progression-free survival (PFS) (P < .001 and P = .045, respectively). The multivariate analysis suggested that HR was an unfavorable independent prognostic factor for OS (HR = 4.36; 95% CI, 2.00-9.49; P < .001) but not for PFS (P = .469). HR between lymph node metastases was correlated with shorter OS (P < .001) but not with PFS (P = .370).

CONCLUSION

HR was observed between primary and metastatic lesions in NSCLC after treatment using PET/CT. HR is significantly associated with poor prognosis and is an independent prognostic factor for OS.

The Combination of Radiotherapy With Immunotherapy and Potential Predictive Biomarkers for Treatment of Non-Small Cell Lung Cancer Patients

Radiotherapy is an effective local treatment modality of NSCLC. Its capabilities of eliminating tumor cells by inducing double strand DNA (dsDNA) damage and modulating anti-tumor immune response in irradiated and nonirradiated sites have been elucidated. The novel ICIs therapy has brought hope to patients resistant to traditional treatment methods, including radiotherapy. The integration of radiotherapy with immunotherapy has shown improved efficacy to control tumor progression and prolong survival in NSCLC. In this context, biomarkers that help choose the most effective treatment modality for individuals and avoid unnecessary toxicities caused by ineffective treatment are urgently needed. This article summarized the effects of radiation in the tumor immune microenvironment and the mechanisms involved. Outcomes of multiple clinical trials investigating immuno-radiotherapy were also discussed here. Furthermore, we outlined the emerging biomarkers for the efficacy of PD-1/PD-L1 blockades and radiation therapy and discussed their predictive value in NSCLC.

Current Evidence for Stereotactic Body Radiotherapy in Lung Metastases

Lung metastases are the second most common malignant neoplasms of the lung. It is estimated that 20–54% of cancer patients have lung metastases at some point during their disease course, and at least 50% of cancer-related deaths occur at this stage. Lung metastases are widely accepted to be oligometastatic when five lesions or less occur separately in up to three organs. Stereotactic body radiation therapy (SBRT) is a noninvasive, safe, and effective treatment for metastatic lung disease in carefully selected patients. There is no current consensus on the ideal dose and fractionation for SBRT in lung metastases, and it is the subject of study in ongoing clinical trials, which examines different locations in the lung (central and peripheral). This review discusses current indications, fractionations, challenges, and technical requirements for lung SBRT.

Effect of aspirin on PET parameters in primary non-small cell lung cancer and its relationship with prognosis

Background

18 F-FDG is a glucose analogue whose metabolic index SUV can effectively reflect the metabolic level of tumor microenvironment. Aspirin can affect the uptake of 18F-FDG by cancer cells, reducing the SUVmax value of primary tumors, exerting antitumor effect. This study aimed to evaluate the prognostic value of long-term aspirin and the relationship between aspirin intake and PET parameters value of primary tumor in non-small cell lung cancer (NSCLC).

Methods

Eighty-one NSCLC patients were recruited and divided into two groups: aspirin medication group and control group, who underwent surgery and had pathological diagnosis data between January 2012 and December 2016. Clinical characteristics were retrospective analyzed to evaluate the possibility of clinical prognosis, respectively. Kaplan-Meier curves and a Cox proportional hazard model were applied to evaluate the predictors of prognosis.

Results

The PET/CT SUVmax of the primary tumor in the aspirin group was lower than that in the control group (P < 0.05). Compared with the control group, the SUVmax, SUVmean and TLG of the primary tumor in aspirin group were lower, but the MTV value had no significant difference. Cox regression analysis showed that N stage and TNM stage were predictors of the prognosis. There was a significant difference in the use of aspirin in NSCLC patients.

Conclusion

Aspirin can reduce SUVmax, SUVmean and TLG in primary tumor and aspirin can improve the prognosis of patients with NSCLC.

Stereotactic body radiation therapy in the treatment of ovarian cancer

BACKGROUND

This study evaluates the outcomes and toxicity of stereotactic body radiation therapy (SBRT) in ovarian cancer.

METHODS

This retrospective analysis considered all patients treated with SBRT from 2009 to 2018 with a primary ovarian tumor. Follow-up included PET-CT and CT scans at 2-3 month intervals. Statistical analysis primarily consisted of univariate analysis, Cox proportional hazards analysis, and the Kaplan-Meier method.

RESULTS

The study included 35 patients with 98 treatments for lymph nodes (51), local recurrence (21), and de novo solid metastases (26). Median biologically effective dose (BED), gross tumor volume, and planning target volume were 38.40 Gy, 10.41 cc, and 25.21 cc, respectively. 52 lesions showed complete radiographic response, and two-year local control was 80%. Median overall survival (OS) was 35.2 months, and two-year progression-free survival (PFS) was 12%. On univariate analysis, Eastern Cooperative Oncology Group performance status > 0 was predictive of decreased OS (p = 0.0024) and PFS (p = 0.044). Factors predictive of local failure included lower BED (p = 0.016), treatment for recurrence (p = 0.029), and higher pre-treatment SUV (p = 0.026). Kaplan-Meier analysis showed BED ≤35 Gy (p < 0.005) and treatment for recurrence (p = 0.01) to be predictive of local failure. On Cox proportional hazards analysis, treatment of lymph nodes was predictive of complete radiographic response (hazard ratio (HR) = 4.95), as was higher BED (HR = 1.03). Toxicity included 27 cases of grade < 3 toxicity, and one grade 5 late toxicity of GI bleed from a radiation therapy-induced duodenal ulcer.

CONCLUSIONS

SBRT provides durable local control with minimal toxicity in ovarian cancer, especially with BED > 35 Gy and treatment for lymph nodes.

Positron emission tomography with computed tomography imaging (PET/CT) for the radiotherapy planning definition of the biological target volume: PART 1

AIM

Functional and molecular imaging, including positron emission tomography with computed tomography imaging (PET/CT) is increasing for radiotherapy (RT) definition of the target volume. This expert review summarizes existing data of functional imaging modalities and RT management, in terms of target volume delineation, for the following anatomical districts: brain (for primary and secondary tumors), head/neck and lung.

MATERIALS AND METHODS

A collection of available published data was made, by PubMed a search. Only original articles were carefully and critically revised.

RESULTS

For primary and secondary brain tumors, amino acid PET radiotracers could be useful to identify microscopic residual areas and to differ between recurrence and treatment-related alterations in case of re-irradiation. As for head and neck neoplasms may benefit from precise PET/CT-based target delineation, due to the major capability to identify high-risk RT areas. In primary and secondary lung cancer, PET/CT could be useful both to delimit a tumor and collapsed lungs and as a predictive parameter of treatment response.

CONCLUSION

Taken together, molecular and functional imaging approaches offer a major step to individualize radiotherapeutic care going forward. Nevertheless, several uncertainties remain on the standard method to properly assess the target volume definition including PET information for primary and secondary brain tumors.

Peripheral memory and naïve T cells in non-small cell lung cancer patients with lung metastases undergoing stereotactic body radiotherapy: predictors of early tumor response

Background

Further analysis of phase I trial of the KEYNOTE-001 has shown that previous radiotherapy improves the outcomes of patients with advanced non-small cell lung cancer (NSCLC) who received pembrolizumab treatment, possibly explained by the radiation-induced specific anti-cancer immunity with a memory effect. In this study, we aimed to investigate the peripheral memory and naïve T cells as predictors of early response in lung metastases post-stereotactic body radiotherapy (SBRT).

Methods

Sixty-six lung metastases patients with NSCLC who received SBRT were enrolled in this study. Analyses of peripheral memory CD4+ T, memory CD8+ T, naive CD4+ T, and naive CD8+ T in NSCLC patients were performed by flow cytometry. Evaluations of the link between immune cells and early radiation response a month after SBRT were carried out via logistic regression analyses.

Results

Higher levels of memory CD4+ T, memory CD8+ T, and lower levels of naïve CD4+ T, CD4+ naïve/memory ratio, and CD8+ naïve/memory ratio were shown in responders compared with non-responders (all P < 0.05). Logistic regression analyses of univariate and multivariate revealed that peripheral memory CD4+ T (OR: 0.14, 95% CI 0.04–0.50, P = 0.003; OR: 0.17, 95% CI 0.05–0.66, P = 0.010), memory CD8+ T (OR: 0.11, 95% CI 0.01–0.87, P = 0.037; OR: 0.11, 95% CI 0.01–0.97, P = 0.047), naïve CD4+ T (OR: 16.25, 95% CI 3.17–83.13, P = 0.001; OR: 12.67, 95% CI 2.26–71.18, P = 0.004) and CD4+ naïve/memory ratio (OR: 11.27, 95% CI 2.67–47.58, P = 0.001; OR: 8.50, 95% CI 1.90–38.14, P = 0.005) were independent predictors for tumor response to SBRT in the lung metastases of NSCLC patients.

Conclusions

The tumor response of lung metastases a month after SBRT independently correlated with peripheral memory CD4+ T, memory CD8+ T, naïve CD4+ T, and CD4+ naïve/memory ratio. These findings could be helpful in incorporating additional treatments to improve clinical outcomes in the case of poor responders.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0839-5) contains supplementary material, which is available to authorized users.

Increased CD8+CD28+ T cells independently predict better early response to stereotactic ablative radiotherapy in patients with lung metastases from non-small cell lung cancer

Background

Stereotactic ablative radiotherapy (SABR) shows a remarkable local control of non-small cell lung cancer (NSCLC) metastases, partially as a result of host immune status. However, the predictors of immune cells for tumor response after SABR are unknown. To that effect, we investigated the ability of pre-SABR immune cells in peripheral blood to predict early tumor response to SABR in patients with lung metastases from NSCLC.

Methods

This study included 70 patients with lung metastases from NSCLC who were undergoing SABR. We evaluated the early tumor response 1 month and 6 months after SABR in these patients following RECIST 1.1 guidelines. Pre-SABR peripheral CD8+ T cell count, CD8+CD28+ T-cell count, CD8+CD28− T-cell count, CD4+ T-cell count, and Treg-cell count were measured using flow cytometry.

Results

Increased CD8+CD28+ T-cell counts (14.43 ± 0.65 vs. 10.21 ± 0.66; P = 0.001) and CD4/Treg ratio (16.96 ± 1.76 vs. 11.91 ± 0.74; P = 0.011) were noted in 1-month responsive patients, compared with non-responsive patients. In univariate logistic analyses, high CD8+CD28+ T-cell counts (OR 0.12, 95% CI 0.03–0.48; P = 0.003), CD4/Treg ratio (OR 0.24, 95% CI 0.06–0.90; P = 0.035), and BED₁₀ (OR 0.91, 95% CI 0.84–0.99; P = 0.032) predicted a 1-month tumor response to SABR. According to multivariate logistic analyses, the CD8+CD28+ T-cell count predicted a 1-month tumor response to SABR (OR 0.19, 95% CI 0.04–0.90; P = 0.037) independently. Furthermore, we confirmed the independent predictive value of the CD8+CD28+ T-cell count in predicting tumor response to SABR in 41 patients 6 months after treatment (OR 0.08, 95% CI 0.01–0.85; P = 0.039).

Conclusions

A pre-SABR CD8+CD28+ T-cell count could predict early tumor response to SABR in patients with lung metastases from NSCLC. Larger, independently prospective analyses are warranted to verify our findings.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1872-9) contains supplementary material, which is available to authorized users.

Stereotactic body radiotherapy for lung oligometastases impacts on systemic treatment-free survival: a cohort study

To analyze the impact of SBRT on systemic treatment-free survival in patients affected by lung oligometastases. Inclusion criteria of the study were (a) KPS > 70, (b) 1-5 lung oligometastases underwent SBRT with a BED ≥ 100 Gy, (c) absence of extra-thoracic disease, (d) controlled primary tumor, (e) metachronous oligorecurrences for whom SBRT was adopted as primary treatment option, (f) oligoprogressive lung metastases who progressed following a disease remission after a first-line therapy, (g) oligopersistent disease after systemic therapy, and (h) at least 6 months of follow-up post-SBRT. Primary study endpoint was the systemic treatment-free survival for each group, whereas distant progression-free survival (DPFS), local failure-free survival (LFFS), and overall survival (OS) were the secondary endpoints. Seventy-eight patients and 114 lung metastases were analyzed. Of these, 32 patients were treated with SBRT in the oligorecurrence group, whereas the remaining patients underwent SBRT for oligoprogressive disease (n = 35) oligopersistent disease (n = 11). In the whole cohort of patients, the median systemic treatment-free survival was 16 months (3-46 months), the median LFFS was 18 months (12-46 months), the median DPFS was 14 months (3-43 months), and the median OS was 19.6 months (12-47 months). Oligorecurrence group had better clinical outcomes in terms of systemic treatment-free survival (log-rank test p = 0.0035) and DPFS (log-rank test p = 0.0017) compared to the other groups. In the present experience, SBRT allowed to delay the administration of systemic treatments in several settings of lung oligometastasis.

Correlation of quantified metabolic activity in nonsmall cell lung cancer with tumor size and tumor pathological characteristics

The aim of this study was to evaluate the relationship between maximum standardized uptake value (SUVmax) with tumor size and tumor pathological characteristics as well as suggesting equations between SUVmax and tumor size in patients with nonsmall cell lung cancer (NSCLC) to help differentiate between pathology types.We retrospectively analyzed the fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) findings of 98 patients with NSCLC. Statistical differences were considered significant when P < .05. Correlation between SUVmax and other variables was determined by Pearson and Spearman correlation. Both linear and nonlinear regression analysis were used to determine equations between SUVmax and tumor size to help differentiate between pathology types.The mean SUVmax in patients with squamous cell carcinoma was significantly higher than that of adenocarcinoma (21.35 ± 1.73 vs 13.75 ± 0.89, P = .000). The results of regression analysis indicated that among all equations determined with relative accuracy, the "cubic equation" has the highest accuracy when considering the relationship between SUVmax and tumor size in patients with adenocarcinoma. In patients with squamous cell carcinoma, the most accurate equation was obtained using the "quadratic equation."There was a significant correlation between SUVmax and tumor differentiation and tumor size in patients with adenocarcinoma. SUVmax of patients with squamous cell carcinoma also had a significant correlation with tumor size. Overall SUVmax of patients with NSCLC could be predicted by tumor size value. In patients with squamous cell carcinoma compared with those with adenocarcinoma, SUVmax with less accuracy can be determined by tumor size. Linear regression analysis line slope can be used as an index for distinguishing adenocarcinoma from squamous cell carcinoma.

Stereotactic body radiation therapy for liver oligometastases: predictive factors of local response by 18F-FDG-PET/CT

OBJECTIVE

To investigate metabolic parameters as predictive of local response after stereotactic body radiation therapy (SBRT) for liver-oligometastases.

METHODS

Inclusion criteria of the present retrospective study were: (a) liver oligometastases with controlled primary tumor; (b) absence of progressive disease ≥6 months; (c) metastases ≤ 3; (d) evaluation of SBRT-response by means of 18-fludeoxyglucose-PET/CT for at least two subsequent evaluations; (e) Karnofsky performance status >80; (f) life-expectancy >6 months. The following metabolic parameters were defined semi-quantitatively for each metastases: (1) standardized uptake value (SUVmax; (2) SUV-mean; (3) metabolic tumor volume (MTV), tumor volume with a SUV ≥3, threshold 40%; (4) total lesion glycolysis (TLG), i.e. the product of SUV-mean and MTV. Local control was defined as absence of recurrence in the field of irradiation.

RESULTS

41 liver metastases were analyzed. Pre-SBRT, median SUV-max was 8.7 (range, 4.5-23.59), median SUV-mean was 4.6 (range, 3-7.5), median MTV was 5.7 cc (range, 0.9-80.6) and median total lesion glycolysis was 24.1 (range, 3.6-601.5). At statistical analysis, metastases with SUV-mean >5 (p 0.04; odds ratio 4.75, sensitivity = 50%, specificity = 82.6%, area under the curve 0.66) and SUV-max >12 (p 0.02; odds ratio 5.03, sensitivity = 69%, specificity = 70%, area under the curve = 0.69) showed higher rates of infield-failure compared to the remaining lesions.

CONCLUSION

According to current findings, pre-SBRT SUV-max and SUV-mean could be predictable of local response in liver oligometastases. Advances in knowledge: Present findings could support the hypothesis that fludeoxyglucose-PET/CT may be a powerful tool to predict tumor control. Specifically, current results might be helpful for clinicians in the decision-making process regarding liver oligometastatic patient selection as well as the individual therapy stratification distinguishing between slowly local progressing patients and rapidly progressing patients.

Increased efficacy of stereotactic ablative radiation therapy after bevacizumab in lung oligometastases from colon cancer

Aim:

Metastases from colorectal cancer are poorly responsive to stereotactic ablative radiation therapy (SABR) due to intratumoral hypoxia. Intratumoral oxygenation is improved by administration of angiogenesis inhibitors. Thus, there could be a clinical synergistic effect of SABR with bevacizumab on metastases from colorectal cancer. The aim of this study was to evaluate the feasibility and efficacy of SABR after bevacizumab in lung oligometastases from colon cancer.

Methods:

The data of patients with lung metastases from colon cancer who underwent SABR were retrospectively evaluated according to the following inclusion criteria: number of metastases ≤3; lung oligometastases from colon cancer in patients who underwent SABR; patients receiving previous chemotherapy alone or in combination with bevacizumab; Karnofsky performance status >80; life expectancy >6 months; at least 6 months’ follow-up after SABR; presence of KRAS mutation. The results were compared with those of a similar cohort of patients with irradiated lung lesions from colorectal cancer in whom bevacizumab was not previously administered.

Results:

A total of 40 lung metastases were analyzed. The complete response rate after SABR was higher in patients who had received bevacizumab than in those who had not (p = 0.04). Additionally, in the bevacizumab group, a higher rate of post-SABR complete response was observed in case of oligopersistent versus oligorecurrent metastases (p = 0.001).

Conclusions:

In the setting of lung oligometastases from colon cancer the present study attested the higher efficacy of SABR after bevacizumab administration. Further studies in this field of research are strongly advocated.

Hypo-fractionated stereotactic radiation therapy for lung malignancies by means of helical tomotherapy: report of feasibility by a single-center experience

BACKGROUND

Several experiences in the literature report SBRT as an effective treatment option for medically inoperable early stage non-small cell lung cancer (NSCLC) and oligometastatic disease. The optimal fractionation schedules and total dose remain controversial. In this study, we evaluated the safety in terms of toxicity and efficacy of using of 8-10 fractions schedules with Helical Tomotherapy (HT) for primary and metastatic lung lesions.

METHODS

Between March 2014 and May 2016, a total of 39 patients (median age 72 years, range 26-91) were treated with HT-SBRT for malignant lung lesions: 22 patients with early stage NSCLC, 17 with oligometastases. Patients received 8-10 fractions with lower daily dose for central and ultracentral lesions. Treatment-related toxicity was evaluated using CTCAE v 4.0 scale. Local control (LC), overall survival (OS) and toxicity rates were prospectively collected.

RESULTS

Median duration of RT was 15 days (range 10-26 days) and no interruption occurred. With a median follow-up of 13 months (range 3-29), we reported one G2 pneumonitis (2.6%) and one G2 chest pain (2.6%); no ≥ G2 esophagitis was registered. Actuarial local control rate was 95.5% both at 12 and 24 months for early stage NSCLC and 92.9% both at 12 and 24 months for metastatic patients. OS rate was 94.4 and 92.3% at 1 year, and 94.4 and 83.9% at 2 years in primary and metastatic group, respectively.

CONCLUSIONS

The use of 8-10 fractions schedule HT-SBRT for lung malignancies results in high LC and OS rates with minimal toxicities reported.