Stereotactic body radiotherapy for lung metastases as oligo-recurrence: a single institutional study

Predefined and data-driven CT radiomics predict recurrence-free and overall survival in patients with pulmonary metastases treated with stereotactic body radiotherapy

BACKGROUND

This retrospective study explores two radiomics methods combined with other clinical variables for predicting recurrence free survival (RFS) and overall survival (OS) in patients with pulmonary metastases treated with stereotactic body radiotherapy (SBRT).

METHODS

111 patients with 163 metastases treated with SBRT were included with a median follow-up time of 927 days. First-order radiomic features were extracted using two methods: 2D CT texture analysis (CTTA) using TexRAD software, and a data-driven technique: functional principal components analysis (FPCA) using segmented tumoral and peri-tumoural 3D regions.

RESULTS

Using both Kaplan-Meier analysis with its log-rank tests and multivariate Cox regression analysis, the best radiomic features of both methods were selected: CTTA-based "entropy" and the FPCA-based first mode of variation of tumoural CT density histogram: "F1." Predictive models combining radiomic variables and age showed a C-index of 0.62 95% with a CI of (0.57-0.67). "Clinical indication for SBRT" and "lung primary cancer origin" were strongly associated with RFS and improved the RFS C-index: 0.67 (0.62-0.72) when combined with the best radiomic features. The best multivariate Cox model for predicting OS combined CTTA-based features-skewness and kurtosis-with size and "lung primary cancer origin" with a C-index of 0.67 (0.61-0.74).

CONCLUSION

In conclusion, concise predictive models including CT density-radiomics of metastases, age, clinical indication, and lung primary cancer origin can help identify those patients with probable earlier recurrence or death prior to SBRT treatment so that more aggressive treatment can be applied.

Challenges related to clinical decision-making in hepatocellular carcinoma recurrence post-liver transplantation: Is there a hope?

Hepatocellular carcinoma (HCC) is a common liver malignancy and represents a serious cause of cancer-related mortality and morbidity. One of the favourable curative surgical therapeutic options for HCC is liver transplantation (LT) in selected patients fulfilling the known standard Milan/University of California San Francisco criteria which have shown better outcomes and longer-term survival. Despite careful adherence to the strict HCC selection criteria for LT in different transplant centres, the recurrence rate still occurs which could negatively affect HCC patients' survival. Hence HCC recurrence post-LT could predict patients' survival and prognosis, depending on the exact timing of recurrence after LT (early or late), and whether intra/extrahepatic HCC recurrence. Several factors may aid in such a complication, particularly tumour-related criteria including larger sizes, higher grades or poor tumour differentiation, microvascular invasion, and elevated serum alpha-fetoprotein. Therefore, managing such cases is challenging, different therapeutic options have been proposed, including curative surgical and ablative treatments that have shown better outcomes, compared to the palliative locoregional and systemic therapies, which may be helpful in those with unresectable tumour burden. To handle all these issues in our review.

Liver-Directed Combined Radiation Therapy for Downstaging Beyond-Milan Hepatocellular Carcinoma to Liver Transplantation

PURPOSE

Curative surgery involving either resection or liver transplantation (LT) is indicated only for early-stage hepatocellular carcinoma (HCC). Over the years, numerous efforts have been made to downstage advanced HCC to curative surgery using various locoregional therapies. In this study, we investigated the role of liver-directed combined radiation therapy (LD-CRT) as a downstaging strategy for converting beyond-Milan advanced HCC to LT.

METHODS AND MATERIALS

From January 2009 to February 2022, 53 patients with HCC who were initially beyond-Milan criteria were treated with LD-CRT and subsequent LT. These patients were compared with those who underwent upfront LT for within-Milan HCCs. The primary endpoint was overall survival (OS) and the secondary endpoint recurrence-free survival (RFS).

RESULTS

After LD-CRT, substantial downstaging was achieved in 35 patients (66%) who were initially beyond-Milan to within-Milan. At a median follow-up period of 47.6 months (range, 6.9-151.7 months), 5-year OS and 2-year RFS of the patients who received downstaging LD-CRT followed by LT were 66.9% and 63.2%, respectively. Patients who were successfully downstaged to within-Milan after LD-CRT had improved 5-year OS compared with their counterparts (81.9% vs 74.3%, P = .219). Recurrence after transplantation was observed in 18 patients (4 intrahepatic recurrences and 14 extrahepatic metastases).

CONCLUSIONS

LD-CRT achieved favorable oncological outcomes as a downstaging strategy for LT in patients with beyond-Milan HCC. The findings of this study suggest that the active adoption of LD-CRT needs full consideration for patients with beyond-Milan HCC, presenting the possibility of curing patients with advanced HCC.

The Clinical Efficacy of Colorectal Cancer Patients with Pulmonary Oligometastases by Sterotactic Body Ablative Radiotherapy: A Meta-Analysis

PURPOSE

There is increasing interest in the efficacy of stereotactic ablative radiotherapy (SABR) for treating colorectal cancer (CRC) patients with oligometastases (OM), recently. The purpose of this meta-analysis was to evaluate local control (LC), progression-free survival (PFS), and overall survival (OS) of CRC patients with pulmonary OM treated with SABR and toxicities.

MATERIALS AND METHODS

Studies that reported SABR for CRC patients with pulmonary OM were searched from MEDLINE and Embase. Treatment outcomes including LC, PFS, OS, and toxicities of grade 3 or higher were assessed.

RESULTS

A total of 19 studies with 1,668 patients were chosen for this meta-analysis. Pooled 1-, 2-, and 3-year LC rates were 83.1%, 69.3%, and 63.9%, respectively. PFS rates were 44.8%, 26.5%, and 21.5% at 1, 2, and 3 years, respectively. OS rates at 1-, 2-, and 3-year were 87.5%, 69.9%, and 60.5%, respectively. The toxicity rate of grade 3 or higher was 3.6%. The effect of dose escalation was meta-analyzed using available studies.

CONCLUSION

Application of SABR to CRC patients with pulmonary OM achieved modest local control with acceptable toxicity according to the present meta-analysis. Further studies establishing the clinical efficacy of SABR are guaranteed.

Stereotactic body radiotherapy takes on Lung Oligometastases: Latest breakthroughs

Lung oligometastases represent an intermediate state of cancer dissemination between localized and widespread metastases. Stereotactic body radiation therapy (SBRT) has emerged as an effective treatment option, with an efficacy comparable to that of surgical resection. This review aimed to provide a comprehensive summary of the latest advancements and controversial issues regarding SBRT for lung oligometastases. It focuses on four crucial perspectives: efficacy of SBRT, optimal patient selection criteria, technological innovations, and synergistic effects of SBRT combined with systemic therapy. Relevant clinical trials investigating SBRT for lung oligometastases have been conducted, with median 1- and 5-year local control rates of 90% and 79%, respectively. The origin of the primary tumor, size and number of lesions, and biomarker profiles were highlighted as pivotal considerations in patient selection. The precise dose delivery was enhanced using robotic SBRT and optimized dose fractionation schemes. Evidence suggests that dose escalation above 100 Gy biologically effective dose may improve tumor control. Combined immunotherapy and SBRT have demonstrated synergistic effects in prolonging progression-free survival and overall survival. This review provides valuable insights into the precise treatment of oligometastatic lung diseases using SBRT. Further multicenter randomized trials are warranted to develop definitive patient selection criteria and optimize the integration with systemic therapies.

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.

Stereotactic Body Radiotherapy for Lung Oligo-metastases: Systematic Review and International Stereotactic Radiosurgery Society Practice Guidelines

PURPOSE

A systematic review of treatment characteristics, outcomes, and treatment-related toxicities of stereotactic body radiation therapy (SBRT) for pulmonary oligometastases served as the basis for development of this International Stereotactic Radiosurgery Society (ISRS) practice guideline.

METHODS

In accordance with PRISMA guidelines, a systematic review was performed of retrospective series with ≥50 patients/lung metastases, prospective trials with ≥25 patients/lung metastases, analyses of specific high-risk situations, and all randomized trials published between 2012 and July 2022 in the MEDLINE or Embase database using the key words "lung oligometastases", "lung metastases", "pulmonary metastases", "pulmonary oligometastases", "stereotactic body radiation therapy (SBRT)" and "stereotactic ablative body radiotherapy (SBRT)". Weighted random effects models were used to calculate pooled outcomes estimates.

RESULTS

Of the 1884 articles screened, 35 analyses (27 retrospective-, 5 prospective, and 3 randomized trials) reporting on treatment of >3600 patients and >4650 metastases were included. The median local control was 90 % (Range: 57-100 %) at 1 year and 79 % (R: 70-96 %) at 5 years. Acute toxicity ≥3 was reported for 0.5 % and late toxicity ≥3 for 1.8 % of patients. A total of 21 practice recommendations covering the areas of staging & patient selection (n = 10), SBRT treatment (n = 10), and follow-up (n = 1) were developed, with agreements rates of 100 %, except for recommendation 13 (83 %).

CONCLUSION

SBRT represents an effective definitive local treatment modality combining high local control rates with low risk of radiation-induced toxicities.

Effectiveness of Stereotactic Ablative Radiotherapy for Systemic Therapy Respondents with Inoperable Pulmonary Oligometastases and Oligoprogression

Stereotactic ablative radiotherapy (SABR) may improve survival in patients with inoperable pulmonary oligometastases. However, the impact of pulmonary oligometastatic status after systemic therapy on SABR outcomes remains unclear. Hence, we investigated the outcomes of SABR in 45 patients with 77 lung tumors and the prognostic value of pulmonary oligoprogression. Eligibility criteria were pulmonary oligometastases (defined as ≤5 metastatic lung tumors), controlled extrapulmonary disease (EPD) after front-line systemic therapy, SABR as primary local treatment for inoperable pulmonary metastases, and consecutive imaging follow-up. Oligometastatic lung tumor was classified into controlled or oligoprogressive status. Overall survival (OS), in-field progression-free survival (IFPFS), out-field progression-free survival (OFPFS), and prognostic variables were evaluated. With 21.8 months median follow-up, the median OS, IFPFS, and OFPFS were 28.3, not reached, and 6.5 months, respectively. Two-year OS, IFPFS, and OFPFS rates were 56.0%, 74.2%, and 17.3%, respectively. Oligoprogressive status (p = 0.003), disease-free interval < 24 months (p = 0.041), and biologically effective dose (BED₁₀) < 100 Gy (p = 0.006) were independently associated with inferior OS. BED₁₀ ≥ 100 Gy (p = 0.029) was independently correlated with longer IFPFS. Oligoprogressive status (p = 0.017) and EPD (p = 0.019) were significantly associated with inferior OFPFS. Grade ≥ 2 radiation pneumonitis occurred in four (8.9%) patients. Conclusively, SABR with BED₁₀ ≥ 100 Gy could provide substantial in-field tumor control and longer OS for systemic therapy respondents with inoperable pulmonary oligometastases. Oligoprogressive lung tumors exhibited a higher risk of out-field treatment failure and shorter OS. Hence, systemic therapy should be tailored for patients with oligoprogression to reduce the risk of out-field treatment failure. However, in the absence of effective systemic therapy, SABR is a reasonable alternative to reduce resistant tumor burden.

Toxicity and Efficacy of Multitarget Thoracic Stereotactic Body Radiation Therapy

PURPOSE

With the increasing use of stereotactic body radiation therapy (SBRT) for primary and metastatic cancer, use of multitarget thoracic (MTT) SBRT is rising. Given the limited safety and efficacy data, we report the experience of this strategy from a large academic center.

METHODS AND MATERIALS

Between 2012 and 2021, patients who received SBRT for ≥2 thoracic targets separated by ≤1 year were retrospectively reviewed. The primary endpoint was clinically significant radiation pneumonitis (CSRP) requiring steroids, oxygen, or intubation. Secondary endpoints included local failure (LF), initiation or change of systemic therapy (ICST), progression-free survival, and overall survival. Competing risk analysis was used to evaluate the cumulative incidence of CSRP, LF, and ICST. Univariate and multivariable analyses were performed to look for clinical and dosimetric predictive factors of CSRP and LF.

RESULTS

One hundred ninety patients (481 lesions) were treated with MTT SBRT with a median follow-up of 19.7 months. Indications for SBRT were oligometastases (n = 70; 36.8%), oligoprogression (n = 62; 32.6%), curative intent in patients with primary lung cancer (n = 37; 19.5%), and control of dominant areas of metastatic progression (n = 21; 11.0%). The number of irradiated tumors ranged from 2 to 7 and the majority of SBRT courses were delivered simultaneously (88.2%). Overall, 14 patients (7.4%) had CSRP, with 5 cases requiring oxygen. The cumulative incidence of CSRP at 6 and 12 months was 5.3% and 7.6%, respectively. The cumulative incidence of LF at 2 years was 10.5%. The cumulative incidence of ICST at 2 years was 41.1%. Median progression-free survival was 11.8 months and median overall survival was 51.3 months. On multivariable analysis, a higher lung V35_Gy (hazard ratio, 2.59; P = .02) was a statistically significant predictor of CSRP and colorectal histology predicted for higher LF (hazard ratio, 2.12; P = .02).

CONCLUSIONS

In one of the largest institutional series of MTT SBRT, rates of CSRP and LF were low. Optimizing plans to lower the lung V35_Gy may decrease the risk of CSRP.

Completeness of reporting oligometastatic disease characteristics in literature and influence on oligometastatic disease classification using the ESTRO/EORTC nomenclature

BACKGROUND

There is increasing evidence for the integration of locally ablative therapy into multimodality treatment of oligometastatic disease (OMD). To support standardised data collection, analysis, and comparison, a consensus OMD classification based on fundamental disease and treatment characteristics has previously been established. This study investigated the completeness of reporting the proposed OMD characteristics in literature and evaluated whether the proposed OMD classification system can be applied to the historical data.

METHODS

A systematic literature review was performed in Medline, Embase, and Cochrane, searching for prospective and retrospective studies, where SBRT was a treatment component of OMD. Reporting of the OMD characteristics as described in the EORTC/ESTRO classification was analyzed, feasibility to retrospectively classify the proposed OMD states was investigated and the impact of the categorisation on overall survival (OS) was evaluated.

RESULTS

Our study shows incomplete reporting of the proposed OMD characteristics. The most fully reported characteristic was 'type of involved organs' (88/95 studies); 'history of cancer progression' was the least reported (not mentioned in 50/95 studies). Retrospective OMD classification of existing literature was only possible for 7/95 studies. With respect to categorization as de novo, repeat or induced OMD, homogeneous patient cohorts were observed in 21/95 studies, most frequently de novo OMD, in 20 studies. Differences in OS at 2, 3, or 5 years were not statistically significant between the different states. OS was significantly influenced by primary tumor histology, with superior OS observed for prostate cancer and worst OS observed for non-small cell lung cancer.

CONCLUSION

The largely incomplete reporting of the proposed OMD characteristics hampers a retrospective classification of existing literature. To facilitate future comparison of individual studies, as well as validation of the OMD classification, comprehensive reporting of OMD characteristics using standardised terminology is recommended, as proposed by the EORTC/ESTRO classification system and following ESTRO-ASTRO consensus.

Outcomes of SBRT for lung oligo-recurrence of non-small cell lung cancer: a retrospective analysis

The benefit of local ablative therapy (LAT) for oligo-recurrence has been investigated and integrated into the treatment framework. In recent decades, stereotactic body radiation therapy (SBRT) has been increasingly used to eliminate metastasis owing to its high rate of local control and low toxicity. This study aimed to investigate the outcomes of SBRT for patients with lung oligo-recurrence of non-small cell lung cancer (NSCLC) from our therapeutic center. Patients with lung oligo-recurrence of NSCLC treated with SBRT between December 2011 and October 2018 at Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital) were reviewed. The characteristics, treatment-related outcomes, and toxicities of the patients were analyzed. Univariable and multivariable Cox regression were performed to identify the factors associated with survival. A total of 50 patients with lung oligo-recurrence of NSCLC were enrolled. The median follow-up period was 23.6 months. The 3-year local progression-free survival (LPFS), progression-free survival (PFS) and overall survival (OS) after SBRT were 80.2%, 21.9% and 45.3%, respectively. Patients in the subgroup with LAT to all residual diseases showed significantly improved OS and PFS. No treatment-related death occurred after SBRT. SBRT is a feasible option to treat patients with lung oligo-recurrence of NSCLC, with high rates of local control and low toxicity. LAT to all residual diseases was associated with better survival outcomes. Future prospective randomized clinical trials should evaluate SBRT strategies for such patients.

Identification of novel prognostic factors focusing on clinical outcomes in patients with non-small cell lung cancer after stereotactic body radiotherapy

Stereotactic body radiotherapy (SBRT) has attracted extensive attention as an effective treatment for patients with early-stage non-small cell lung cancer. However, the factors affecting prognosis after SBRT have not been fully elucidated. The aim of the present study was to investigate the prognostic factors associated with overall survival (OS) and local control (LC) after SBRT. Between March 2003 and March 2020, 497 patients with primary or oligo-metastatic lung cancer who underwent SBRT treatment were retrospectively reviewed. Univariate analysis was performed against various factors related to patient and tumor characteristics using Kaplan-Meier method. Furthermore, the factors with statistically significant differences identified via univariate analysis underwent a stratified Cox proportional hazard regression analysis. The median follow-up period for all patients was 26.17 months (range, 0.36-194.37), and the 5-year OS and LC rates were 66.3 and 86.0%, respectively. Multivariate analysis showed that surfactant protein-D (SP-D), tumor CT values (TCTV) and iodine density values (IDV) were independent prognostic factors for OS, and histology, TCTV and IDV were for LC. Although histology was not selected as a prognostic factor related to OS, it was indicated that patients with squamous cell carcinoma were associated with the SP-D high group compared with the SP-D normal group. In addition, TCTV was correlated to water density values, which tended to decrease with increasing IDV. From these findings, SP-D and TCTV were identified as potential new candidate prognostic factors after SBRT, and it is possible that combining SP-D and histology, and TCTV and IDV may improve the accuracy of prognostic prediction.

THE MANAGEMENT OF POST-TRANSPLANTATION RECURRENCE OF HEPATOCELLULAR CARCINOMA

The annual incidence of hepatocellular carcinoma (HCC) continues to rise. Over the last two decades, liver transplantation (LT) has become the preferable treatment of HCC, when feasible and strict selection criteria are met. With the rise in HCC-related LT, compounded by downstaging techniques and expansion of transplant selection criteria, a parallel increase in number of post-transplantation HCC recurrence is expected. Additionally, in the context of an immunosuppressed transplant host, recurrences may behave aggressively and more challenging to manage, resulting in poor prognosis. Despite this, no consensus or best practice guidelines for post-transplantation cancer surveillance and recurrence management for HCC currently exist. Studies with adequate population sizes and high-level evidence are lacking, and the role of systemic and locoregional therapies for graft and extrahepatic recurrences remains under debate. This review seeks to summarize the existing literature on post-transplant HCC surveillance and recurrence management. It highlights the value of early tumour detection, re-evaluating the immunosuppression regimen, and staging to differentiate disseminated recurrence from intrahepatic or extrahepatic oligo-recurrence. This ultimately guides decision-making and maximizes treatment effect. Treatment recommendations specific to recurrence type are provided based on currently available locoregional and systemic therapies.

A single institutional experience with central lung stereotactic body radiation therapy demonstrating encouraging results with increased inter-fraction time

Background

Stereotactic body radiation therapy (SBRT) is an effective treatment modality for non-small cell lung cancer (NSCLC); however, there are concerns regarding potential toxicity for centrally located tumors.

Methods

This retrospective study considered patients with SBRT for central lung NSCLC (defined as a tumor within 2 cm of any mediastinal critical structure). The institutional protocol was that patients with central tumors received SBRT less frequently than daily—generally once or twice weekly.

Results

A total of 115 patients with 148 lesions were treated with SBRT to a median 45 [5–60] Gy in 4 [1–5] fractions over a median 5.3 [0–18] days. Many patients treated with this method presented with advanced disease: 58 treatments involved nodal targets, and 42 had stage 3 disease. 52% of patients had chronic obstructive pulmonary disease (COPD), and only 49% had a biopsy, often due to concerns regarding other medical comorbidities. Rates of prior chemotherapy, thoracic surgery, and thoracic radiotherapy were 32%, 21%, and 49%, respectively. Via the Kaplan-Meier method, 2-year overall survival was 65%, and 2-year local control was 77%. Two-year local-progression free survival was 53%, and 2-year progression-survival was 48%. Treatments for stage 3 disease had an impressive 82% 2-year local control that was comparable to early stage treatments. Patients with stage 3 disease had a 2-year overall survival of 59%, which trended towards decreased overall survival compared to early stage patients. There were 13 grade 1 (9%) and 14 grade 2 (9%) toxicities. There were no reported grade ≥3 acute or late toxicities and only 3 cases of pneumonitis.

Conclusions

Our series demonstrates encouraging local control with low rates of toxicity for central lung SBRT, including many stage 3 patients. This may be the result of the relatively large inter-fraction interval. This interval may allow for greater tumor effects (such as reoxygenation) and improved tolerance from normal tissues.

Tumor Control and Overall Survival after Stereotactic Body Radiotherapy for Pulmonary Oligometastases from Colorectal Cancer: A Meta-Analysis

PURPOSE

In pulmonary oligometastases from colorectal cancer (POM-CRC), the primarily recommended local therapy is metastasectomy. Stereotactic body radiotherapy (SBRT) is another local therapy modality that is considered as an alternative option in patients who cannot undergo surgery. The purpose of this meta-analysis is to demonstrate the effects of SBRT on POM-CRC by integrating the relevant studies.

MATERIALS AND METHODS

The authors explored MEDLINE, EMBASE, Cochrane Library, Web of Science, and SCOPUS, and selected studies including patients treated with SBRT for POM-CRC and availability of local control (LC) or overall survival (OS) rate. In this meta-analysis, the effect of SBRT was presented in the form of the LC and OS rates for 1, 2, 3, and 5 years after SBRT as pooled estimates, and the frequency of pulmonary toxicity of grade 3 or higher after SBRT (PTG3-SBRT).

RESULTS

Fourteen full texts among the searched 4,984 studies were the objects of this meta-analysis. The overall number of POM-CRC patients was 495 as per the integration of 14 studies. The pooled estimate LC rate at 1, 2, 3, and 5 years after SBRT was 81.0%, 71.5%, 56.0%, and 61.8%, and the OS rate was 86.9%, 70.1%, 57.9%, and 43.0%, respectively. The LC and OS rates gradually declined until 3 years after SBRT in a similar pattern. Among the 14 studies, only two studies reported PTG3-SBRT as 2.2% and 10.8%, respectively.

CONCLUSION

For POM-CRC, SBRT is an ablative therapy with a benefit on LC and OS rates and less adverse effects on the lung.

Radical radiotherapy for metachronous oligometastasis after initial treatment of esophageal cancer

BACKGROUND AND PURPOSE

This study aimed to evaluate the efficacy of radical radiotherapy and assess prognostic factors in metachronous oligometastatic esophageal cancer (MOEC) patients after initial treatment with curative-intent surgery and/or chemoradiotherapy.

MATERIALS AND METHODS

MOEC Patients during 2009-2018 in Mianyang Central Hospital were retrospectively analyzed. Each patient had ≤5 oligometastatic lesions, and the primary lesions were controlled in this study. Patients were devided into radiotherapy (RT) and non-radiotherapy (NRT) groups. The study endpoints were overall survival (OS) and treatment toxicities.

RESULTS

This study included 82 patients who underwent intensity-modulated radiotherapy for MOEC. Median OS were 14 (95% confidence interval [CI], 11.0-17.0) and 7 (95% CI, 4.5-9.5) months for the RT and NRT groups, respectively (P = 0.016). Median OS were 18 (95% CI, 13.6-22.4) and 10 (95% CI, 5.1-14.9) months for lung and bone metastases, respectively (P = 0.010). Median OS were 15 (95% CI, 12.4-17.6) and 10 (95% CI, 7.6-12.4) months for interval time from initial diagnosis to metastasis ≥12 and <12 months, respectively (P = 0.026). Median OS were 16 (95% CI, 12.2-19.8) and 10 (95% CI, 5.0-15.0) months for biological effective dose (BED₁₀) ≥ 60 Gy and BED₁₀ < 60 Gy, respectively (P = 0.033). Cox multivariate regression analysis showed that treatment modality (RT vs. NRT) was an independent prognostic factor for MOEC patients (hazard ratio: 1.8, 95% CI: 1.1-3.0; P = 0.022). No toxic side effects greater than grade 3 were observed in all patients.

CONCLUSIONS

Radiotherapy is a feasible and positive treatment for MOEC patients after initial treatment, a radical radiation dose with BED₁₀ ≥ 60 Gy has benefits in extending survival. Radical radiotherapy should thus be considered for MOEC patients.

Stereotactic Body Radiotherapy for Pulmonary Oligometastasis from Colorectal Cancer

BACKGROUND/AIM

A retrospective study was conducted to evaluate the safety and efficacy of stereotactic body radiotherapy (SBRT) for pulmonary oligometastasis from colorectal cancer (CRC).

PATIENTS AND METHODS

Patients with pulmonary oligometastasis from CRC who were treated with SBRT between April 2010 and October 2018 were enrolled in this study. All patients underwent SBRT using Cyberknife® with a dose of 54-60 Gy in 3 fractions to 99% of the clinical target volume. The treatment efficacy was evaluated by the local control (LC) and overall survival (OS) rates. The toxicity was evaluated using the National Cancer Institute's Common Terminology Criteria for Adverse Events version 4.0.

RESULTS

Twenty-six lesions in 20 patients were treated with SBRT. The median follow-up duration was 19 months (range=6-98 months). Local recurrence occurred in 6 of 26 lesions with a median follow-up of 12 months. The 2-year LC and OS rates were 65.8% and 88.6%, respectively. No patient developed ≥ grade 2 toxicity in the lung and other sites.

CONCLUSION

Although very high doses were delivered to the tumors with SBRT, the LC of pulmonary metastasis from CRC was not satisfactory when compared to that for stage I primary non-small cell lung cancer reported in the literature.

Modern evidence and future prospects of external body radiation therapy for lung oligometastases of breast cancer

After Hellman and Weichselbaum defined "Oligometastasis" in 1995, several local therapies for lung oligometastases including surgical resection and external body radiation therapy were reported that improved local control (LC) and progression-free survival, overall survival, and quality of life. This suggests that oligometastases is a potentially curable state. Modern advances in radiation therapy such as stereotactic body radiation therapy (SBRT) in which high dose coverage of target lesion without exposure of normal organ is possible, and are widely used to treat solitary or a limited number of primary lung cancer and metastases. Several reports showed that SBRT was a useful treatment method for lung oligometastases, and the LC rate of SBRT was 80-90% in 2 years and less invasive than surgical resection. SBRT is a safe and effective especially for small and peripheral lung metastases. However, if the metastatic lesion is big or centrally located, careful treatment is necessary to prevent radiation pneumonitis. After SBRT, it is sometimes difficult to differentiate local recurrence and pulmonary injury, especially in the early phase. However, it is important to detect local recurrence especially in patients who require further local therapy such as surgical resection and re-irradiation or systemic therapy. The diagnosis can be improved by determining the natural course after SBRT and local recurrence with computed tomography imaging and ¹⁸F-fluorodeoxyglucose positron emission tomography, respectively. Moreover, radiation therapy may have both local and systemic effects that are related to the enhancement of immune-response after radiation. Currently, several trials evaluating the benefits of SBRT for oligometastatic breast cancer are underway. However, the adaption of SBRT for lung metastases including other treatment strategies should be carefully discussed by the radiation oncologist and a multi-disciplinary team comprising a breast surgeon, medical oncologist, diagnostic radiologist, and radiation oncologist, among others.

Re-irradiation in the thorax - An analysis of efficacy and safety based on accumulated EQD2 doses

INTRODUCTION

Thoracic re-irradiation remains a challenge regarding the balance of local efficacy and acceptable toxicities. In this retrospective analysis we analyzed dosimetrical and clinical data of patients treated with thoracic re-irradiation based on accumulated EQD2Gy doses.

METHODS AND MATERIAL

We retrospectively analyzed the data of 42 consecutive single-institutional patients treated with repeated courses of thoracic radiotherapy from 12/2011 to 01/2017. Accumulated EQD2 dose distributions were calculated and dose parameters for organs at risk and target volumes were analysed.

RESULTS

The median prescription dose was 42.2 Gy (10-70.6 Gy) for all RT courses. The median Dmean of both lungs was 10.1 Gy₃ (range: 1.9 Gy₃-17.9 Gy₃) with a maximum D0.1 cc of 253.86 Gy₃. The median D0.1 cc of the esophagus was 62.2 Gy₃ with a maximum of 103.78 Gy₃. The maximum D0.1 cc for the bronchial tree was 187.33 Gy₃ (median 74.35 Gy₃) and for the Aorta 216.1 Gy₃ (median 70.9 Gy₃). Median OS after first re-irradiation was 19 months (range 1-45 months). 12-month local control after a course of re-irradiation was 52.6%. 80% of patients suffered from a G1-G2 toxicity, most frequently coughing. One patient suffered from a G5 complication probably unrelated to re-irradiation.

CONCLUSION

Even though several organs at risk received maximum accumulated doses of >100 Gy₃, thoracic reirradiation resulted in an acceptable toxicity profile. Local tumor control and overall survival remained encouraging even after multiple courses of thoracic radiotherapy.

Stereotactic robotic body radiotherapy for patients with oligorecurrent pulmonary metastases

BACKGROUND

Our aim is to report treatment efficacy and toxicity of patients treated by robotic (Cyberknife®) stereotactic body radiotherapy (SBRT) for oligorecurrent lung metastases (ORLM). Additionally we wanted to evaluate influence of tumor, patient and treatment related parameters on local control (LC), lung and distant progression free- (lung PFS/Di-PFS) and overall survival (OS).

METHODS

Consecutive patients with up to 5 ORLM (confirmed by FDG PET/CT) were included in this study. Intended dose was 60Gy in 3 fractions (prescribed to the 80% isodose volume). Patients were followed at regular intervals and tumor control and toxicity was prospectively scored. Tumor, patient and treatment data were analysed using competing risk- and Cox regression.

RESULTS

Between May 2010 and March 2016, 104 patients with 132 lesions were irradiated from primary lung carcinoma (47%), gastro-intestinal (34%) and mixed primary histologies (19%). The mean tumor volume was 7.9 cc. After a median follow up of 22 months, the 1, 2 and 3 year LC rate (per lesion) was 89.3, 80.0 and 77.8% respectively. The corresponding (per patient) 1, 2 and 3 years lung PFS were 66.3, 50.0, 42.6%, Di-PFS were 80.5, 64.4, 60.6% and OS rates were 92.2, 80.9 and 72.0% respectively. On univariable analysis, gastro-intestinal (GI) as primary tumor site showed a significant superior local control versus the other primary tumor sites. For OS, significant variables were primary histology and primary tumor site with a superior OS for patients with metastases of primary GI origin. LC was significantly affected by the tumor volume, physical and biologically effective dose coverage. Significant variables in multivariable analysis were BED prescription dose for LC and GI as primary site for OS. The vast majority of patients developed no toxicity or grade 1 acute and late toxicity. Acute and late grade 3 radiation pneumonitis (RP) was observed in 1 and 2 patients respectively. One patient with a centrally located lesion developed grade 4 RP and died due to possible RT-induced pulmonary hemorrhage.

CONCLUSIONS

SBRT is a highly effective local therapy for oligorecurrent lung metastases and could achieve long term survival in patients with favourable prognostic features.

Surgery versus stereotactic radiotherapy for treatment of pulmonary metastases. A systematic review of literature

It is not clear as to which is the best treatment among surgery and stereotactic radiotherapy (SBRT) for lung oligometastases. A systematic review of literature with a priori selection criteria was conducted on articles on the treatment of pulmonary metastases with surgery or SBRT. Only original articles with a population of patients of more than 50 were selected. After final selection, 61 articles on surgical treatment and 18 on SBRT were included. No difference was encountered in short-term survival between pulmonary metastasectomy and SBRT. In the long-term surgery seems to guarantee better survival rates. Mortality and morbidity after treatment are 0–4.7% and 0–23% for surgery, and 0–2% and 4–31% for SBRT. Surgical metastasectomy remains the treatment of choice for pulmonary oligometastases.

Patients with metastatic cancer with a limited number of deposits may benefit from surgical removal or irradiation of tumor nodules in addiction to chemotherapy. Surgical resection has been demonstrated to improve survival and, in some cases, can be curative. Stereotactic radiotherapy is emerging as a less invasive alternative to surgery, but settings and implications of the two treatments are profoundly different. The two techniques show similar results in the short-term, with lower complications rates for radiotherapy, while in the long-term surgery seems to guarantee higher survival rates.

A meta-analysis of stereotactic radiotherapy for pulmonary oligometastases from colorectal cancer

BACKGROUND

For patients with colon cancer with lung metastasis, conventional radiotherapy is commonly used, which mainly acts on the double-stranded DNA inside the tumor cells. However, many foreign studies have found that increasing the dose of radiotherapy cannot improve the prognosis of patients, and because of its side effects on normal tissues, the commonly used dose of radiotherapy is usually between 60 and 70 Gy. However, the local control of lung tumors using this dose is not good. With the rapid development of science and technology, stereotactic body radiotherapy (SBRT) technology has been widely used in patients with non-small cell lung cancer, and SBRT is also used in patients with colon cancer and lung metastasis. However, some studies have found that because there are more hypoxic cells in colon cancer tissues than in other tissues, and hypoxic cells are relatively insensitive to radiation, the efficacy of SBRT in patients with lung metastasis from colon cancer is worse than that in patients with lung metastasis from other sites. However, this conclusion is controversial. There is no definite conclusion about the optimal dose of radiotherapy. Some studies have found that increasing the dose of radiotherapy can improve the prognosis of patients with colon cancer and lung metastasis. However, this conclusion is controversial. On the basis of many studies both in China and other countries, this study made a meta-analysis on the efficacy of SBRT in the treatment of colon cancer with lung metastasis and non-colon cancer with lung metastasis, as well as a comparison of the efficacy of different radiation doses in the treatment of colon cancer with lung metastasis, in order to provide evidence-based medicine-related evidence.

AIM

To compare the efficacy of stereotactic radiotherapy for colon cancer with lung metastasis and non-colon cancer with lung metastasis (Study 1), and to compare the efficacy of different doses of radiotherapy for colon cancer with lung metastasis (Study 2).

Methods

The controlled trials including cases with pulmonary oligometastases from colon cancer published from January 2008 to December 2018 were searched according to the method of the Cochrane Collaboration, and meta-analysis was carried out by using RevMan5.3 software.

Results

Fourteen studies were included, of which nine were included in Study 1, involving 486 patients with colon cancer and 938 with non-colon cancer, and five were included in Study 2, involving 157 patients treated with high doses and 185 treated with low doses. Meta-analysis indicated that the clinical efficacy of stereotactic radiotherapy for pulmonary oligometastases from colorectal was significantly lower than that for pulmonary oligometastases from other cancers, and that the efficacy of high doses was significantly better than that of low doses (P < 0.05).

Conclusion

SBRT has worse efficacy for pulmonary oligometastases from colorectal than for those from other cancer, and better efficacy for pulmonary oligometastases from colon cancer can be achieved by dose escalation.

Stereotactic Radiotherapy for Pulmonary Oligometastases From Colorectal Cancer: A Systematic Review and Meta-Analysis

PURPOSE

The purpose of this study was to determine whether pulmonary oligometastases from colorectal cancer have greater radioresistance than that of pulmonary oligometastases from other cancers and whether good local control can be achieved by dose escalation in stereotactic body radiotherapy.

MATERIALS AND METHODS

This systematic review and meta-analysis were conducted according to the preferred reporting items for systematic reviews and meta-analyses statement and methods. Studies were obtained from a database search of PubMed, Web of Science, and Google Scholar for publications using search terms designed to identify studies on "oligometastases," "lung," "stereotactic radiotherapy," and "colorectal cancer." For meta-analysis 1, studies that showed the number of local failures after stereotactic body radiotherapy for pulmonary metastases from colorectal carcinoma and other cancers were included. For meta-analysis2, studies in which a comparison was made of local control rates of pulmonary metastases from colorectal carcinoma by stereotactic body radiotherapy with a higher dose and that with a lower dose were included. A meta-analysis was performed using Mantel-Haenszel statics with the fixed or random-effect model by Review Manager 5.3.

RESULTS

Eighteen retrospective studies with 1920 patients with pulmonary oligometastases were used in meta-analysis 1. The local control rate in patients with pulmonary oligometastases from colorectal cancer was significantly lower than that in patients with pulmonary oligometastases from other cancers (odds ratio = 3.10, P < .00001). Next, 8 retrospective studies with 478 patients were included in meta-analysis 2 for dose escalation. Better local control was achieved by a higher prescription dose than by a lower prescription dose (odds ratio = 0.16, P < .00001).

CONCLUSION

Our meta-analysis indicated that local control of pulmonary oligometastases from colorectal cancer by stereotactic body radiotherapy was significantly worse than that of pulmonary metastases from other cancers; however, our results also indicated that good local control of pulmonary oligometastases from colorectal cancer can be achieved by dose escalation.

Survival and prognostic factors of pulmonary oligometastases treated with stereotactic body radiotherapy

BACKGROUND

Stereotactic body radiotherapy (SBRT) for pulmonary oligometastatic disease achieves excellent treatment outcomes in terms of local control and toxicity. Patients treated with SBRT are often elderly and have multiple co-morbidities. This subset of patients may experience different survival as compared to young and fit patients subjected to radical metastasectomies. The purpose of this retrospective study was to evaluate OS and identify factors associated with OS for inoperable pulmonary oligometastases treated with SBRT.

MATERIAL AND METHODS

Criteria used for selection of patients with oligometastases included: metastases limited to ≤2 organs and in total ≤5 metastases at the time of treatment. Peripheral tumors were treated with 51 Gy to 60 Gy in three fractions or a single fraction of 30 Gy. Central tumors received a dose of 45-60 Gy in 5-8 fractions. Survival probabilities were estimated by means of Kaplan-Meier method and the relation between potential prognostic factors and OS was studied by means of Cox regression analyses.

RESULTS

In this study, 327 inoperable pulmonary oligometastases in 206 patients were treated with SBRT from the year 2005 to 2015. Primary sites of pulmonary oligometastases included colorectal carcinoma (n = 118), lung carcinoma (n = 36), melanoma (n = 11), sarcoma (n = 10), breast carcinoma (n = 7), and other tumors sites (n = 24). Median follow-up was 26 months. Median survival was 33 months. The 2-year and 5-year OS rates were 63% and 30%, respectively. On univariate analysis synchronous oligometastases (HR 0.59) and colorectal primary (HR 0.64) were associated with improved OS. On multivariable analysis synchronous oligometastases (HR 0.56), colorectal primary (HR 0.62) and tumor size <3 cm (HR 0.68) were independently associated with OS.

CONCLUSIONS

SBRT to pulmonary oligometastases was associated with a 2-year OS of 63%. Tumor size <3 cm and colorectal primary tumors experienced improved OS compared to tumors >3 cm and non-colorectal primary tumors.

Multidisciplinary approach for post-liver transplant recurrence of hepatocellular carcinoma: A proposed management algorithm

A large number of liver transplants have been performed for hepatocellular carcinoma (HCC), and recurrence is increasingly encountered. The recurrence of HCC after liver transplantation is notoriously difficult to manage. We hereby propose multi-disciplinary management with a systematic approach. The patient is jointly managed by the transplant surgeon, physician, oncologist and radiologist. Immunosuppressants should be tapered to the lowest effective dose to protect against rejection. The combination of a mammalian target of rapamycin inhibitor with a reduced calcineurin inhibitor could be considered with close monitoring of graft function and toxicity. Comprehensive staging can be performed by dual-tracer positron emission tomography-computed tomography or the combination of contrast computed tomography and a bone scan. In patients with disseminated recurrence, sorafenib confers survival benefits but is associated with significant drug toxicity. Oligo-recurrence encompasses recurrent disease that is limited in number and location so that loco-regional treatments convey disease control and survival benefits. Intra-hepatic recurrence can be managed with graft resection, but significant operative morbidity is expected. Radiofrequency ablation and stereotactic body radiation therapy (SBRT) are effective alternative strategies. In patients with more advanced hepatic disease, regional treatment with trans-arterial chemoembolization or intra-arterial Yttrium-90 can be considered. For patients with extra-hepatic oligo-recurrence, loco-regional treatment can be considered if practical. Patients with more than one site of recurrence are not always contraindicated for curative treatments. Surgical resection is effective for patients with pulmonary oligo-recurrence, but adequate lung function is a pre-requisite. SBRT is a non-invasive and effective modality that conveys local control to pulmonary and skeletal oligo-recurrences.

Stereotactic body radiotherapy for lung oligometastases: Literature review according to PICO criteria

Exhaustive criteria and definitive data to identify the ideal lung oligometastatic patient as a candidate for stereotactic body radiotherapy (SBRT) are lacking. Three distinct cohorts of oligometastatic patients could be distinguished: (1) patients with upfront diagnosis of oligometastases (synchronous or metachronous); (2) patients with oligorecurrent disease in terms of relapsed oligometastatic phase; (3) oligoprogressive patients after cytoreductive treatment. The aim of the present review is to analyze available data concerning the efficacy/safety of SBRT for oligometastatic/oligoprogressive/oligorecurrent lung metastases.

The role of stereotactic body radiation therapy in oligometastatic colorectal cancer: Clinical case report of a long-responder patient treated with regorafenib beyond progression

RATIONALE

Regorafenib is the new standard third-line therapy in metastatic colorectal cancer (mCRC). However, the reported 1-year overall survival rate does not exceed 25%.

PATIENT CONCERNS

A 55-year-old man affected by mCRC, treated with regorafenib combined with stereotactic body radiotherapy (SBRT), showing a durable response.

INTERVENTIONS

After 6 months of regorafenib, a PET/CT scan revealed a focal uptake in a solid lung nodule which was treated with SBRT, whereas continuing regorafenib administration. Fourteen months later, the patient had further progression in a parasternal lymph node, but treatment with regorafenib was continued. The regorafenib-associated side effects, such us the hand-foot syndrome, were favorable managed by reducing the dose from 160 to 120 mg/day.

OUTCOMES

Patient-reported outcome was characterized by a progression-free survival of approximately 3 years.

LESSONS

in presence of oligometastatic progression, a local SBRT while retaining the same systemic therapy may be a better multidisciplinary approach. Moreover, disease progression is no longer an absolute contraindication for continuing the regorafenib treatment.

Radiobiological parameters of liver and lung metastases derived from tumor control data of 3719 metastases

BACKGROUND AND PURPOSE

The radiobiological parameters for liver and lung metastases treated with stereotactic body radiation therapy (SBRT) are poorly defined. This project aimed at estimating these parameters from published tumor control probability (TCP) data, and separately for metastases with colorectal cancer (CRC) and non-CRC histology.

MATERIALS AND METHODS

A total of 62 studies with 89 different treatment prescriptions for a total of 3719 metastases were analyzed in a Bayesian framework using four different radiobiological models: The LQ, mLQ, LQ-L and the regrowth model which accounts for tumor regrowth after SBRT.

RESULTS

Depending on the particular model, α/β ratios in the range 13-23Gy for pulmonary metastases and 16-28Gy for hepatic metastases were estimated. For CRC metastases the estimated α/β ratio was 43.1±4.7Gy compared to 21.6±7.8Gy for non-CRC metastases. Typical isocenter dose prescriptions of 3×12Gy, 3×14.5Gy and 3×17Gy applied within 5days were predicted sufficient to control 90% of lung, liver and CRC metastases after 1yr, respectively.

CONCLUSIONS

α/β ratios for liver and lung metastases are higher than the usually assumed 10Gy. Differences between CRC and non-CRC histology were found. Future studies confirming these findings in individual patient data are needed.

Stereotactic Ablative Body Radiotherapy for Lung Metastases: Where is the Evidence and What are We Doing With It?

This review provides an overview of the use of stereotactic ablative body radiotherapy (SABR) for pulmonary metastases. The local control rates after SABR are generally >90%. Whether this also translates into a significant improvement in overall survival is the subject of ongoing studies. New exciting opportunities including the integration of SABR with targeted and immune therapies as well as some competing treatment strategies are discussed.

The expanding role of stereotactic body radiation therapy in oligometastatic solid tumors: What do we know and where are we going?

The spectrum hypothesis posits that there are distinct clinical states of metastatic progression. Early data suggest that aggressive treatment of more biologically indolent metastatic disease, characterized by metastases limited in number and destination organ, may offer an opportunity to alter the disease course, potentially allowing for longer survival, delay of systemic therapy, or even cure. The development of stereotactic body radiation therapy (SBRT) has opened new avenues for the treatment of oligometastatic disease. Early data support the use of SBRT for treating oligometastases in a number of organs, with promising rates of treated metastasis control and overall survival. Ongoing investigation is required to definitively establish benefit, determine the appropriate treatment regimen, refine patient selection, and incorporate SBRT with systemic therapies.

Impact of pretreatment whole-tumor perfusion computed tomography and 18F-fluorodeoxyglucose positron emission tomography/computed tomography measurements on local control of non-small cell lung cancer treated with stereotactic body radiotherapy

This study aimed to investigate the correlation between the average iodine density (AID) detected by dual-energy computed tomography (DE-CT) and the maximum standardized uptake value (SUV_max) yielded by [¹⁸F] fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) for non-small cell lung cancer (NSCLC) treated with stereotactic body radiotherapy (SBRT). Seventy-four patients with medically inoperable NSCLC who underwent both DE-CT and ¹⁸F-FDG PET/CT before SBRT (50‒60 Gy in 5‒6 fractions) were followed up after a median interval of 24.5 months. Kaplan-Meier analysis was used to determine associations between local control (LC) and variables, including AID, SUV_max, tumor size, histology, and prescribed dose. The median AID and SUV_max were 18.64 (range, 1.18-45.31) (100 µg/cm³) and 3.2 (range, 0.7-17.6), respectively. No correlation was observed between AID and SUV_max Two-year LC rates were 96.2% vs 75.0% (P = 0.039) and 72.0% vs 96.2% (P = 0.002) for patients classified according to high vs low AID or SUV_max, respectively. Two-year LC rates for patients with adenocarcinoma vs squamous cell carcinoma vs unknown cancer were 96.4% vs 67.1% vs 92.9% (P = 0.008), respectively. Multivariate analysis identified SUV_max as a significant predictor of LC. The 2-year LC rate was only 48.5% in the subgroup of lower AID and higher SUV_max vs >90% (range, 94.4-100%) in other subgroups (P = 0.000). Despite the short follow-up period, a reduction in AID and subsequent increase in SUV_max correlated significantly with local failure in SBRT-treated NSCLC patients. Further studies involving larger populations and longer follow-up periods are needed to confirm these results.