Analysis of patients with oligometastases undergoing two or more curative-intent stereotactic radiotherapy courses

Correlation Between Oligometastatic Tumor in Two Other Visceral Organs and Prognosis in Patients With Brain Metastases

Background and Objective: A recent report indicated that metastases to other body organs commonly develop after stereotactic body radiation treatment for cure in patients with oligometastases (OGM) confined to one organ. This study was undertaken to determine if the presence of metastatic disease in two other visceral organs (TVO) in patients with conventionally treated brain metastases (BRM) was associated with poorer prognosis. Methods: This retrospective clinical investigation included 26 patients treated for palliation of OGM-BRM between May 1996 and February 2020. These individuals were classified according to the presence (13 patients) or absence (13 patients) of metastases in TVO. Results: With an overall mean follow-up of 16 months, 20 patients were deceased, and 6 patients were alive. The median survivals for the OGM-BRM-TVO and non-OGM-BRM-TVO subsets were 4 and 12 months, respectively; the corresponding crude survival rates at 12 months were 0% and 46% (p < 0.01). Subgroup analysis correlating prognosis to the number of BRM (single vs. multiple) and OGM-BRM categories (synchronous vs. metachronous) failed to reveal a survival advantage favoring a certain subgroup. Conclusion: Although the evidence is speculative, we believe that an aggressive disease condition is more likely present in patients with OGM-BRM-TVO. With the notion of an overall poor survival, we suggest a more tailored, less or nonharmful management approach (i.e., palliative therapy or hospice) for this particular patient cohort.

Repeat stereotactic body radiotherapy for oligometastatic disease

BACKGROUND

Patients with oligometastatic disease (OMD) treated with metastasis-directed definitive local therapy such as stereotactic body radiotherapy (SBRT) are at risk of developing new metastases. Here, we compare characteristics and outcomes of patients treated with a single course and repeat SBRT.

MATERIALS/METHODS

OMD patients treated with SBRT to 1-5 metastases were included in this retrospective study, and classified as single course or repeat SBRT. Progression-free survival (PFS), widespread failure-free survival (WFFS), overall survival (OS), systemic therapy-free survival (STFS) and cumulative incidence of different first failures were analyzed. Patient and treatment characteristics predicting the use of repeat SBRT were investigated using univariable and multivariable logistic regression.

RESULTS

Among the 385 patients included, 129 and 256 received repeat or single course SBRT, respectively. The most common primary tumor and OMD state in both groups were lung cancer and metachronous oligorecurrence. Patients treated with repeat SBRT had shorter PFS (p<0.0001), while WFFS (p=0.47) and STFS (p=0.22) were comparable. Distant failure, particularly with a single metastasis, was more frequently observed in repeat SBRT patients. Repeat SBRT patients had longer median OS (p=0.01). On multivariable logistic regression, low distant metastases velocity and more previous lines of systemic therapy significantly predicted the use of repeat SBRT.

CONCLUSION

Despite shorter PFS and comparable WFFS and STFS, repeat SBRT patients had longer OS. The role of repeat SBRT for OMD patients warrants further prospective investigation, focussing on predictive factors to select patients that might derive a benefit.

SEOR SBRT-SG stereotactic body radiation therapy consensus guidelines for non-spine bone metastasis

The use of stereotactic body radiation therapy (SBRT) to treat non-spine bone metastases (NSBM) is becoming increasingly common in clinical practice. The clinical advantages of SBRT include good pain control and high local control rates, although only limited data are available. The Spanish Society of Radiation Oncology (SEOR) SBRT group recently convened a task force of experts in the field to address key questions related to SBRT for NSBM, including treatment indications, planning, techniques, and dose fractionation. The task force reviewed the available literature to develop evidence-based recommendations for the safe application of NSBM SBRT and to standardize and optimize SBRT processes. The present document provides a comprehensive analysis of the available data, including ongoing clinical trials and controversies, providing clinically applicable recommendations.

Non-surgical Treatments for Lung Metastases in Patients with Soft Tissue Sarcoma: Stereotactic Body Radiation Therapy (SBRT) and Radiofrequency Ablation (RFA)

BACKGROUND

Radio-frequency ablation (RFA) and Stereotactic Body Radiation Therapy (SBRT) are two emerging therapies for lung metastases.

INTRODUCTION

Aliterature review was performed to evaluate the outcomes and complications of these procedures in patients with lung metastases from soft tissue sarcoma (STS).

METHODS

After selection, seven studies were included for each treatment encompassing a total of 424 patients: 218 in the SBRT group and 206 in the RFA group.

RESULTS

The mean age ranged from 47.9 to 64 years in the SBRT group and from 48 to 62.7 years in the RFA group. The most common histologic subtype was, in both groups, leiomyosarcoma. In the SBRT group, median overall survival ranged from 25.2 to 69 months and median disease- free interval was from 8.4 to 45 months. Two out of seven studies reported G3 and one G3 toxicity, respectively. In RFA patients, overall survival ranged from 15 to 50 months. The most frequent complication was pneumothorax. Local control showed a high percentage for both procedures.

CONCLUSION

SBRT is recommended in patients unsuitable to surgery, in synchronous bilateral pulmonary metastases, in case of deep lesions and patients receiving high-risk systemic therapies. RFA is indicated in case of a long disease-free interval, in oligometastatic disease, when only the lung is involved, in small size lesions far from large vessels. Further large randomized studies are necessary to establish whether these treatments may also represent a reliable alternative to surgery.

Disease course of lung oligometastatic colorectal cancer treated with stereotactic body radiotherapy

PURPOSE

Stereotactic body radiotherapy (SBRT) or stereotactic ablative radiotherapy (SABR) has been shown to increase survival rates in oligometastatic disease (OMD), but local control of colorectal metastases remains poor. We aimed to explore the natural course of oligometastatic colorectal cancer and to investigate how SBRT of lung metastases can delay the progression to polymetastatic disease (PMD).

METHODS

107 lung oligometastases in 38 patients were treated with SBRT at a single institution. The median number of treated lesions was 2 (range 1-5). Time to PMD (ttPMD) was defined as the time from SBRT to the occurrence of >5 new metastases. Genetic biomarkers such as EGFR, KRAS, NRAS, BRAF, and microsatellite instability were investigated as predictive factors for response rates.

RESULTS

Median follow-up was 28 months. At median follow-up, 7 patients were free from disease and 31 had progression: 18 patients had sequential oligometastatic disease (SOMD) and 13 polymetastatic progression. All SOMD cases received a second SBRT course. Median progression-free survival (PFS) was 7 months (range 4-9 months); median ttPMD was 25.8 months (range 12-39 months) with 1‑ and 2‑year PFS rates of 62.5% and 53.4%, respectively. 1‑ and 2‑year local PFS (LPFS) rates were 91.5% and 80%, respectively. At univariate analysis, BRAF wildtype correlated with better LPFS (p = 0.003), SOMD after primary SBRT was associated with longer cancer-specific survival (p = 0.031). Median overall survival (OS) was 39.5 months (range 26-64 months) and 2‑year OS was 71.1%.

CONCLUSION

The present results support local ablative treatment of lung metastases using SBRT in oligometastatic colorectal cancer patients, as it can delay the transition to PMD. Patients who progressed as SOMD maintained a survival advantage compared to those who developed PMD.

Stereotactic body radiotherapy (SBRT) can delay polymetastatic conversion in patients affected by liver oligometastases

PURPOSE

SBRT demonstrated to increase survival in oligometastatic patients. Nevertheless, little is known regarding the natural history of oligometastatic disease (OMD) and how SBRT may impact the transition to the polymetastatic disease (PMD).

METHODS

97 liver metastases in 61 oligometastatic patients were treated with SBRT. Twenty patients (33%) had synchronous oligometastases, 41 (67%) presented with metachronous oligometastases. Median number of treated metastases was 2 (range 1-5).

RESULTS

Median follow-up was 24 months. Median tPMC was 11 months (range 4-17 months). Median overall survival (OS) was 23 months (range 16-29 months). Cancer-specific survival predictive factors were having further OMD after SBRT (21 months versus 15 months; p = 0.00), and local control of treated metastases (27 months versus 18 months; p = 0.031). Median PFS was 7 months (range 4-12 months). Patients with 1 metastasis had longer median PFS as compared to those with 2-3 and 4-5 metastases (14.7 months versus 5.3 months versus 6.5 months; p = 0.041). At the last follow-up, 50/61 patients (82%) progressed, 16 of which (26.6%) again as oligometastatic and 34 (56%) as polymetastatic.

CONCLUSION

In the setting of oligometastatic disease, SBRT is able to delay the transition to the PMD. A proportion of patients relapse as oligometastatic and can be eventually evaluated for a further SBRT course. Interestingly, those patients retain a survival benefit as compared to those who had PMD. Further studies are needed to explore the role of SBRT in OMD and to identify treatment strategies able to maintain the oligometastatic state.

Treatment outcomes of stereotactic ablative radiation therapy for non-spinal bone metastases: focus on response assessment and treatment indication

OBJECTIVE

To report treatment outcomes of stereotactic ablative radiation therapy (SABR) for non-spinal bone metastases in a single institution, and to compare assessments of Response Evaluation Criteria in Solid Tumors (RECIST) v. 1.1 and the University of Texas MD Anderson Cancer Center (MDA) criteria.

METHODS

From July 2011 to January 2017, 33 patients with 38 non-spinal bone metastatic lesions were treated using SABR. Treatment intent was categorized as follows: single metastasis or oligo-metastases; oligo-progression; and dominant areas of progression. Tumor responses were evaluated according to the RECIST and MDA criteria. Local control (LC) was defined as lesions that were not classified as progressive disease on both criteria.

RESULTS

The median follow-up period was 10.4 months (range, 2.5-47.4). Both 1- and 2 year LC rates were 94.2 %. The median overall survival (OS) was 20.2 months, and the median progression-free survival (PFS) was 6.9 months. Treatment intent was a significant factor for OS in multivariate analysis. The 1 year OS rates for single metastasis or oligo-metastasis, for oligo-progression, and for dominant areas of progression were 84.2%, 66.7%, and 0.0%, respectively ( p < 0.001). Overall response rate was 86.8 % according to MDA criteria, and 75.7 % according to RECIST criteria. When using MDA criteria, there appeared to be significant associations both between response and PFS (median 7.6 months for responders vs 2.5 months for non-responders; p = 0.036) and between response and OS. In contrast, when using RECIST criteria, the associations were significant neither between response and PFS (median 5.8 months for responders vs 9.3 months for non-responders; p = 0.522) nor between response and OS (25.7 months for responders vs 18.5 months for non-responders; p = 0.811).

CONCLUSION

SABR for non-spinal bone metastases demonstrated high LC rates with acceptable toxicity. The MDA criteria demonstrated advantages in predicting survival outcomes.

ADVANCES IN KNOWLEDGE

SABR for non-spinal bone metastases is a promising treatment option to achieve good local control. The MDA criteria, which is a newly proposed response evaluation criteria for bone metastases, has advantages in predicting survival outcomes compared to other established criteria.

Carbon-ion radiotherapy for lymph node oligo-recurrence: a multi-institutional study by the Japan Carbon-Ion Radiation Oncology Study Group (J-CROS)

Background

The efficacy of carbon-ion radiotherapy (C-ion RT) for lymph node (LN) oligo-recurrence has only been evaluated in limited single-center studies. We aimed to investigate the benefit of C-ion RT for LN oligo-recurrence in a large multi-center study.

Methods

Patients who received C-ion RT between December 1996 and December 2015 at 4 participating facilities and who met the following eligibility criteria were included: (i) histological or clinical diagnosis of LN recurrence; (ii) controlled primary lesion; (iii) no recurrence other than LN; (iv) LN recurrence involved in a single lymphatic site; and (v) age ≥ 20 years.

Results

A total of 323 patients were enrolled. Median follow-up period was 34 months for surviving patients. The most common dose fractionation of C-ion RT was 48.0 Gy (relative biological effectiveness) in 12 fractions. Forty-seven patients had a history of RT at the recurrent site. The 2-year local control (LC) and overall survival (OS) rates after C-ion RT were 85% and 63%, respectively. Only 1 patient developed grade-3 toxicity. Factors such as LN diameter, histology, and history of previous RT did not correlate with LC. Smaller diameters (< 30 mm) and numbers (≤ 3) of LN metastases as well as longer disease-free intervals post-primary therapy (≥ 16 months) were associated with significantly better OS.

Conclusions

C-ion RT for LN oligo-recurrence appeared to be effective and safe. C-ion RT may provide a survival benefit to patients with LN oligo-recurrence, particularly to those with few LN metastases, smaller LN diameters, and longer disease-free intervals.

Electronic supplementary material

The online version of this article (10.1007/s10147-019-01440-y) contains supplementary material, which is available to authorized users.

Hypofractionated Stereotactic Radiotherapy for Non-breast or Prostate Cancer Oligometastases: A Tail of Survival Beyond 10 Years

Purpose and Objective(s): We sought to analyze the long-term follow-up of patients treated with hypofractionated, stereotactic radiotherapy (HSRT) for oligometastases from malignancies other than breast or prostate cancer. Materials and Methods: From 2001 to 2006, 82 cancer patients with 1-5 radiographically apparent metastatic lesions (in 1-3 organs) from primary sites other than breast or prostate cancer, were enrolled on a prospective study of HSRT. Freedom from widespread metastasis (FFWM) was defined from date of enrollment until death, an event (i.e., widespread distant metastasis not amenable to local therapy), or last radiographic study. Local recurrence was scored as an event if pathologically confirmed or if a treated lesion increased by ≥20% using RECIST criteria. Prognostic variables were assessed using Cox regression analysis. Results: The mean age was 61 ± 11 years, with a male to female ratio of 46:36. The most common metastatic sites were liver (50%), lung (48%), thoracic lymph nodes (18%), and bone (5%). Sixty-one patients (74%) had 1 involved organ and 18 (22%) had 1 lesion treated. The preferred dose-fractionation scheduled was 50 Gy in 10 fractions (52 patients). The median follow-up was 1.7 years. Eleven patients lived >5 years, and 6 lived >10 years. The 5-year OS, PFS, FFWM, and LC rates were 13.4, 7.3, 18.3, and 63.4%, and the 10-years OS, PFS, FFWM, and patient LC rates were 7.3, 6.1, 13.4, and 62.2%, respectively. A greater net gross tumor volume (GTV) was significantly adverse for OS (p < 0.01) and LC (p < 0.01). For FFWM, net GTV was not a significant factor (p = 0.14). Four patients remain alive at >13 years from enrollment and treatment, without evidence of active disease. Conclusion: A small subset of select non-breast, non-prostate cancer patients with limited metastasis treated with HSRT are long-term survivors. Net GTV is a significant factor for tumor control and survival. Further research is needed to help better select patients most likely to benefit from local therapy for metastatic disease.

Role of radiotherapy in the treatment of metastatic head and neck cancer

In metastatic or locally advanced head and neck tumors that present in frail patients or after chemotherapy progression, radiotherapy is normally used as a palliative treatment, with a high rate of symptom palliation and improvement in quality of life. However, there is controversy about what the optimal regimen is. Moreover, despite the poor prognosis of metastatic head and neck cancer, different retrospective studies have shown that a minority of patients with oligometastatic disease experience prolonged disease-free survival after adding curative radiotherapy treatment to the metastatic disease and/or primary tumor. Different retrospective studies have identified clinical prognostic factors that may be used to select candidate patients with metastatic head and neck cancer for a radical approach with radiotherapy. The purpose of this manuscript is to review the role of radiotherapy in metastatic and locally advanced head and neck tumors.

Curative-intent radiotherapy in patients with oligometastatic lesions from colorectal cancer: A single-center study

The purpose of the present study was to investigate the efficacy and safety of radiotherapy for patients with oligometastases from colorectal cancer (CRC).This was a retrospective cross-sectional study. Patients with liver and/or lung oligometastatic lesions from CRC treated with curative-intent radiotherapy in West China Hospital, Sichuan University, between 2009 and 2013 were included. Radiotherapy modality included 3-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and stereotactic body radiation therapy (SBRT); simultaneous chemotherapies along with radiotherapy of metastasis were allowed. Overall survival (OS) and progression-free survival (PFS) were calculated using the Kaplan-Meier method. Local control (LC) rates, toxicities, and factors of prognostic significance were also assessed.A total of 40 CRC patients with 57 liver and/or lung oligometastatic lesions were included. Most of the patients (95%) had received at least 1 line of previous systemic chemotherapy. Among them, 19 patients with 26 lesions received 3D-CRT with a median dose of 51.5 Gy in 16.1 fractions, 7 patients with 11 lesions received IMRT with a median dose of 49.3 Gy in 10.4 fractions, and 14 patients with 20 lesions received SBRT with a median dose of 56.4 Gy in 6.7 fractions, respectively. The median follow-up time was 34 months (range, 9-86 months). Median OS and PFS for patients were 30.0 months [95% confidence interval (95% CI), 21.3-38.7] and 11.0 months (95% CI, 9-13), respectively. One, 3, and 5 years' LC rates for metastasis were 63.2%, 24.6%, and 16.9%, respectively. In subgroup analysis, patients with metachronous metastases had longer OS (median, 41.0 months; 95% CI, 33.3-48.7) than patients with synchronous lesions (median, 17.0 months; 95% CI, 7.4-26.6, P = .001). All patients tolerated the radiation treatment well, and there was no treatment-related death. Multivariate analysis showed that number of metastasis lesions and simultaneous liver and lung metastases were potential survival predictors.The study demonstrated that curative radiotherapy might be a tolerable and potential alternative for the treatment of patients with liver and/or lung oligometastases from CRC, and patients with metachronous lesions might have better survival than those with synchronous lesions when treated with curative-intent radiotherapy.

Hypofractionated stereotactic radiotherapy for oligometastatic patients: developing of a response predictive model

OBJECTIVES

Treatment of oligometastatic patients is a current challenge in radiation oncology. Aim of this study is to define a dose-response relationship for hypofractionated radiotherapy of oligometastases.

METHODS

Retrospective analysis of metastases treated by hypofractionated stereotactic radiotherapy was performed. Delivered dose was calculated both as biological effective dose (BED₁₀), and as ratio between BED₁₀ and the logarithm of metastasis volume (BED₁₀ logVolume Ratio, BVR). Two dose-response models were defined by logistic regression. The fitted outcome was the Metastases Complete Response (MCR). Performances of the models were assessed by area under the receiver operating curve (AUC) and by bootstrap calibration of original data. BED₁₀ and BVR impact on survival outcomes has been evaluated.

RESULTS

Fifty-three patients with 79 metastases were analyzed. AUC and calibration of BVR-based logistic model showed better accuracy in predicting MCR with respect to BED₁₀-based model. No significant difference between the two ROCs was observed (De Long test p value > 0.05), but significant discordance in calibration resulted in the BED₁₀ model (p value < 0.05 in Hosmer-Lemeshow Goodness of fit test). BVR returned also better results in multivariate analyses for survival outcomes.

CONCLUSIONS

The ratio between BED₁₀ and the logarithm of metastasis volume (BVR), as a corrective factor for fitting the probability of metastases response to stereotactic radiotherapy, could be a tool for evaluating and prescribing treatments for oligometastatic disease. BVR can be useful for producing more reliable survival statistics too.

Locoregional control and survival after lymph node SBRT in oligometastatic disease

Stereotactic body radiotherapy (SBRT) has emerged as an effective option in oligo-metastatic cancer patients affected by lymph node metastases, but its use might be questioned due to risk of regional and distant dissemination through the lymph node chain. The primary aim of our study was to assess the loco-regional control following SBRT in this setting. Ninety-one patients undergoing SBRT for at least one lymph node metastasis from miscellaneous primary tumors were retrospectively evaluated for patterns of failure and toxicity. locoregional relapse-free survival (LRRFS) and distant metastasis-free survival (DMFS) at 4 years were 79 and 44%. Repeated use of local therapy after progression resulted in a median interval of 17 months until allocation to systemic therapy or supportive care. Forty-three percent of patients were alive at 4 years. Local failure, occurring in 15% of patients, was the only predictor of poor survival (HR: 3.06). Tumor diameter ≥ 30 mm and urothelial primary tumor predicted for impaired local control (HR: 4.59 and 5.43, respectively). Metastases from pulmonary cancer showed a significant earlier distant dissemination (HR: 3.53). Only acute and late grade 1–2 toxicities were reported except for 1 case of G3 dysphagia. Loco-regional failure risk is low (18%) and justifies the use of local therapies for patients with oligometastatic disease. Durable disease remission can be achieved by iterative use of local approaches. Local control is correlated to improved OS. Diameter and primary tumor type may affect response to SBRT and risk for early metastatic dissemination.

Second course of stereotactic radiosurgery for locally recurrent brain metastases: Safety and efficacy

In the present study, we have evaluated the efficacy and toxicity of repeated brain metastases (BM) stereotactic radiosurgery (SRS2) following local failure of a prior radiosurgical procedure (SRS1). Between December 1996 and August 2015, 30 patients with 36 BM underwent SRS2 with a median dose of 18Gy. All BM were located outside critical structures. Following SRS2, local control at 6 months and one year were respectively 82.9% (IC 95%: 67.6–91.9) and 67.8% (IC 95%: 51–81). On multivariate analysis, planning target volume (PTV) < 3cc (HR: 0.19 (0.1–0.52)) and whole brain radiotherapy (WBRT) prior to SRS2 (HR: 0.25 (0.1–0.64)) were significantly associated with a better local control. One- and two-year overall survival rates after SRS2 were respectively 65.5% (IC 95%: 47.3–80%) and 27.6% (IC 95%: 14.7–45.7). Median overall survival following SRS2 was 14.2 months (range 1–106). Nineteen (63%) patients died from progressive systemic disease. Three (10%) patients died from out-field progressive brain disease and 8 (27%) in-field. Concerning toxicities, edema, radionecrosis, and hemorrhages were identified in 5 (12.8%), 4 (10.2%), and 5 (12.8%) patients respectively. No toxicity resulted in a neurological deficit. On univariate analysis, toxicities were significantly associated with PTV > 7cc (p = 0.02) and all patients had a WBRT before SRS2. A second course of SRS for locally recurrent brain metastases showed encouraging rates of local control. This treatment led to acceptable toxicities, especially for brain metastases smaller than 7cc, in our selected cohort of patients with BM located outside critical structures. Further studies are needed.

Stereotactic Body Radiotherapy for Lung Metastases from Colorectal Cancer: Prognostic Factors for Disease Control and Survival

OBJECTIVES

To evaluate disease control and survival after stereotactic body radiotherapy (SBRT) for lung metastases from colorectal cancer and to identify prognostic factors after treatment.

METHODS

Patients with metastatic colorectal cancer to the lungs treated with SBRT from 2002 to 2013 were identified from a prospectively maintained database. Patients may have received prior systemic therapy, radiotherapy to nonthoracic sites and/or resection of thoracic and/or nonthoracic metastases. Endpoints were timed from end of SBRT and included overall survival (OS), progression-free survival, distant metastases-free survival, and local failure-free survival. Univariate and multivariate analysis using Cox proportional hazard modeling was used to identify prognostic factors.

RESULTS

Sixty-five patients were identified. Before SBRT, 69.2% and 33.8% of patients received systemic therapy and lung-directed local therapy, respectively, for metastatic disease. At the time of SBRT, 64.6% had lung-only involvement. Median survivals were: OS of 20.3 months (95% confidence intervals [CI], 15.9-27.0 mo), progression-free survival of 5.7 months (95% CI, 3.2-7.0 mo), distant metastases-free survival of 5.8 months (95% CI, 3.2-7.6 mo), and local failure-free survival of 15.4 months (95% CI, 8.5-21.1 mo). Nearly all (98%) patients developed distant progression. Extra lung and liver involvement at the time of initial metastases (hazard ratios [HR] 2.10) and extra lung involvement at SBRT (HR 2.67) were the only independent predictors of OS. Net gross target volume of >14.1 mL (HR 2.49) was the only independent predictor of local failure-free survival.

CONCLUSIONS

Reasonable survival and local control can be achieved with SBRT. We identified several prognostic factors testable in future prospective trials that may help improve patient selection.

Robotic Radiosurgery for Adrenal Gland Metastases

Introduction

The purpose of this study was to investigate the safety and efficacy of CyberKnife (CK) robotic radiosurgery for treatment of adrenal metastases.

Methods

We performed a retrospective analysis of 23 patients with adrenal metastases who had been treated with CK between October 2006 and December 2015. Fifteen patients received chemotherapy prior to radiosurgery, all patients underwent computer tomography (CT) fluoroscopically guided percutaneous placement of one to three gold fiducials into the adrenal gland. Nineteen patients were selected for single-fraction radiosurgery with a median dose of 22 Gy, four patients were treated in three fractions with a median dose of 13.5 Gy.

Results

Median follow-up time was 23.6 months. Four patients (17%) experienced local relapse during the evaluation period with a mean time of 19 months to tumor progression. The actuarial local tumor control rate was 95% after one year and 81% after two years. Three of the four patients with local recurrence were retreated with CK radiosurgery. Dynamic tumor tracking enabled accurate treatment with correlation errors less than 2 mm, despite extensive respiration-induced target motion up to 22 mm. Apart from nausea directly after treatment in five patients, we observed no early or late treatment-related side effects.

Conclusions

Single fraction robotic radiosurgery for adrenal gland metastases is a safe and effective treatment option for patients who are not eligible for surgical resection.

Stereotactic ablative body radiosurgery (SABR) or Stereotactic body radiation therapy (SBRT)

While conventional treatment relies on protracted courses of therapy using relatively small dose-per-fraction sizes of 1.8-2Gy, there is substantial evidence gathered over decades that this may not be the optimal approach for all targetable disease. Stereotactic ablative body radiosurgery (SABR) or stereotactic body radiation therapy (SBRT) is a technique which uses precise targeting to deliver high doses of radiation capable of ablating tumors directly. In this review, we will discuss the justification for and techniques used to deliver ablative doses to improve treatment outcomes, interactions with biological and immunologic therapy, and special procedures to spare normal tissue, which have facilitated the expanding role for these techniques in the management of a wide range of malignant histologies and disease states.

Local Therapy for Limited Metastatic Non-Small Cell Lung Cancer: What Are the Options and Is There a Benefit?

Distant metastasis is common in non-small cell lung cancer (NSCLC) and typically associated with poor prognosis. Aggressive local therapy including surgery and/or radiation for limited metastatic disease from colorectal cancer and sarcoma is associated with survival benefit and has become part of the standard of care. In this article, we review the literature and ongoing studies concerning surgery, radiation, and radiofrequency ablation for oligometastatic NSCLC.

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OLIGOMETASTASIS AND OLIGOPROGRESSION

Oligometastic progression (or solitary metastases) can justify ablative treatment for metastatic treatment. When such a strategy is discussed, it is important to notice that definition of oligometastases is not consensual both in terms of clinical presentation than on the biological basis. Does a specific biological background truly exist and are there markers that could predict for additional occult disease and its oligo or polymetastatic profile in individuals with demonstrated oligometastasis. This article provides a summary of the state of the art in this field and highlights some current areas of controversies.

Ablative Approaches for Pulmonary Metastases

Pulmonary metastases are common in patients with cancer for which surgery is considered a standard approach in appropriately selected patients. A number of patients are not candidates for surgery due to a medical comorbidities or the extent of surgery required. For these patients, noninvasive or minimally invasive approaches to ablate pulmonary metastases are potential treatment strategies. This article summarizes the rationale and outcomes for non-surgical treatment approaches, including radiotherapy, radiofrequency and microwave ablation, for pulmonary metastases.

Exploratory Analysis on Overall Survival after Either Surgery or Stereotactic Radiotherapy for Lung Oligometastases from Colorectal Cancer

AIMS

Lung metastasectomy and, more recently, stereotactic body radiotherapy (SBRT), are frequently proposed to stage IV oligometastatic colorectal cancer (CRC) patients. In the absence of a randomised comparison between the two treatments, we aimed to retrospectively explore the effect on overall survival and progression-free survival (PFS) in a comparative cohort study.

MATERIALS AND METHODS

We included patients who consecutively underwent surgery (n = 142) or SBRT (n = 28) as first local therapy at the time of lung progression, between 2005 and 2012. Both overall survival and PFS functions according to treatment were calculated using the Kaplan-Meier method and compared using the Log-rank test. The effect of treatment on overall survival and PFS was estimated by Cox models using different adjustment methods.

RESULTS

Patients receiving SBRT were older and were treated more recently, whereas the two cohorts were similar for most baseline prognostic factors. Overall survival at 1 and 2 years was 0.89 and 0.77 for SBRT and 0.96 and 0.82 for surgery (P = 0.134), respectively. Multivariable analyses did not highlight a clear treatment effect on overall survival (adjusted hazard ratioSBRT versus surgery = 1.71; 95% confidence interval 0.82-3.54; P = 0.149) and even smaller differences using the inverse probability treatment weighting method (hazard ratioSBRT versus surgery = 1.28, 95% confidence interval 0.58-2.82; P = 0.547). The results of PFS were unreliable because different follow-up protocols were applied in the two cohorts.

CONCLUSION

With limitations consisting in the retrospective observational design and different sample sizes, the results of this explorative analysis indicate that overall survival probability after SBRT is similar to surgery for the first 2 years from treatment. This finding supports the need for high-quality trials comparing different treatment modalities for lung oligometastases from CRC.

Stereotactic Body Radiotherapy for Recurrent Unresectable Head and Neck Cancers

Background

Treatment of locoregional, recurrent head and neck cancers following definitive radiotherapy has evolved during the past 30 years. Brachytherapy as well as protracted courses of systemic therapy and chemoradiotherapy result in 12-month survival rates of 40% to 50% but have high rates of severe toxicity. Given the advancements in radiotherapy targeting and delivery, stereotactic body radiotherapy (SBRT) has been investigated as an alternative treatment option with the potential advantages of reduced treatment time and rates of toxicity.

Methods

The authors reviewed prospective trials and retrospective reports from the past decade addressing the management of locoregional, recurrent, previously radiated head and neck cancers, focusing on SBRT.

Results

The body of evidence is growing in support of reirradiation using SBRT for the treatment of recurrent head and neck cancers. The 1-year survival rates associated with SBRT are promising and similar to those seen with chemotherapy alone and concurrent, conventionally fractionated radiotherapy and chemotherapy. Treatment-related adverse events of reirradiation using SBRT are also similar to other palliative therapies. Late carotid rupture is a relatively rare but concerning late toxicity associated with reirradiation using SBRT.

Conclusions

SBRT is a promising treatment for locoregional recurrent head and neck cancers. It also offers a logistical advantage over other palliative treatments, as it only requires 1 to 2 weeks of treatment.

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

The purpose of this study was to investigate clinical outcomes following stereotactic body radiotherapy (SBRT) for lung metastases as oligo-recurrence. From May 2003 to June 2014, records for 66 patients with 76 oligo-recurrences in the lungs treated with SBRT were retrospectively reviewed. Oligo-recurrence primary sites and patient numbers were as follows: lungs, 31; colorectal, 13; head and neck, 10; esophagus, 3; uterus, 3; and others, 6. The median SBRT dose was 50 Gy (range, 45-60 Gy) administered in a median of 5 (range, 5-9) fractions. All patients received SBRT, with no acute toxicity. Surviving patients had a median follow-up time of 36.5 months. The 3-year rates of local control, overall survival and disease-free survival were 90.6%, 76.0% and 53.7%, respectively. Longer disease-free interval from initial treatment to SBRT, and non-colorectal cancer were both associated with favorable outcomes. Disease progression after SBRT occurred in 31 patients, most with distant metastases (n = 24) [among whom, 87.5% (n = 21) had new lung metastases]. Among these 21 patients, 12 were judged as having a second oligo-recurrence. Additional SBRT was performed for these 12 patients, and all 12 tumors were controlled without disease progression. Three patients (4.5%) developed Grade 2 radiation pneumonitis. No other late adverse events of Grade ≥2 were identified. Thus, SBRT for oligo-recurrence achieved acceptable tumor control, with additional SBRT also effective for selected patients with a second oligo-recurrence after primary SBRT.

Initial UK Experience of Stereotactic Body Radiotherapy for Extracranial Oligometastases: Can We Change the Therapeutic Paradigm?

AIMS

To retrospectively review the toxicity and early outcome data from patients who have received stereotactic body radiotherapy (SBRT) for extracranial oligometastases at a single UK institution.

MATERIALS AND METHODS

Eligible patients had ≤3 extracranial metastases and performance status ≤2. Prior systemic therapy and radical treatment of oligometastastic relapse with any standard treatment modality was permitted. Patients with synchronous metastatic disease were excluded unless they had evidence of controlled primary disease after radical therapy. Follow-up consisted of clinical examination, biochemical and radiological assessments in accordance with standard clinical care. Progression events were defined using RECIST. Toxicity was evaluated using CTCAE v4.0. Local control, progression-free survival (PFS), freedom from widespread distant metastasis (defined as disease not amenable to further radical salvage therapy) and overall survival were calculated.

RESULTS

Between July 2011 and April 2014, 73 patients with 87 metastases received SBRT (range 1-3 per patient). The median follow-up was 14.5 months (range 0-26.4). The median PFS was 14.5 months (1 year PFS 57%, 2 year 28%); 1 year overall survival 96%, 2 year 79.8%; 2 year local control 88%. At 2 years, 46% of patients were free from widespread distant metastases. No ≥ grade 3 acute or late toxicity was observed.

CONCLUSION

At this time point, observed toxicity is minimal with excellent local control rates. This promising treatment paradigm requires further investigation in the context of a randomised controlled trial to establish if the addition of SBRT to standard care improves survival outcomes.

A case of long term survival with skeletal only metastatic breast cancer

INTRODUCTION

The prognosis of patients with metastatic breast cancer is very poor. Because of this, treatment of skeletal metastasis is often palliative with limited goals rather than cure. However, there are those patients, such as presented here, who survive for an extended time.

PRESENTATION OF CASE

This thirty-six year old female presented with lytic lesions to one ulna and rib five years after mastectomy for breast cancer. Despite radiation and chemotherapy, the ulnar lesion expanded and resulted in an elbow dislocation. The rib lesion was resected and the arm amputated above the elbow. She developed local recurrence in both her above elbow amputation stump and chest wall and a more proximal below shoulder amputation was performed with resection of chest wall lesion. Even though she had locally aggressive disease, she has survived for 31 years after diagnosis without any evidence of disease.

DISCUSSION

Reports of metastatic breast cancer survival indicate the five year survival to be 15%. There have been few reports indicating that those patients with skeletal only or oligometastatic disease have improved prognosis. It is not clear what biological properties of these tumors results in the improved survival.

CONCLUSION

This case highlights the challenges of giving patients the optimal treatment in the light of limited ability to predict prognosis. It also highlights the need to further investigate the phenotypes of breast cancer that can, despite metastatic disease and with modern treatment go on to long survival. In addition this case demonstrates the importance of long term followup.

Is Stereotactic Body Radiotherapy (SBRT) in lymph node oligometastatic patients feasible and effective?

OBJECTIVES

To review the available data about stereotactic body-radiotherapy (SBRT) for oligometastatic lymph node cancer recurrence.

METHODS

The inclusion criteria for this study were as follows: Medline search for the (1) English language (2) full paper (abstracts were excluded) on (3) adult oligometastatic solid cancer recurrence limited to lymph node that underwent SBRT (4) outcome data available and (5) published up to the 30th April 2014.

RESULTS

38 papers fulfilling the inclusion criteria have been found: 7 review articles and 31 patient series (20 and 11 retrospective and prospective studies, respectively) including between 1 and 69 patients (636 lymph nodes). Twelve articles reported only lymph node SBRT while in 19 - all types of SBRT including lymph node SBRT were presented. Two-year local control, 4-year progression free survival and overall survival was of up to 100%, 30% and 50%, respectively. The progression was mainly out-field (10-30% of patients had a recurrence in another lymph node/nodes). The toxicity was low with mainly mild acute events and single grade 3-4 late events. When compared to SBRT for any oligometastatic cancer, SBRT for lymph node recurrence carried better prognosis and showed lower toxicity.

CONCLUSIONS

SBRT is a feasible approach for oligometastatic lymph node recurrence, offering excellent in-field tumor control with low toxicity profile. The potential abscopal effect has been hypothesized as a basis of these findings. Future studies are warranted to identify the patients that benefit most from this treatment. The optimal combination with systemic treatment should also be defined.

Phase II trial of stereotactic body radiation therapy combined with erlotinib for patients with limited but progressive metastatic non-small-cell lung cancer

PURPOSE

Patients with stage IV non-small-cell lung cancer (NSCLC) who progress through first-line therapy have poor progression-free survival (PFS) and overall survival (OS), most commonly failing in original sites of gross disease. Cytoreduction with stereotactic body radiation therapy (SBRT) may help systemic agents delay relapse.

PATIENTS AND METHODS

Patients in our single arm phase II study had stage IV NSCLC with no more than six sites of extracranial disease who failed early systemic chemotherapy and were able to receive SBRT and concurrent erlotinib until disease progression. After erlotinib commencement, SBRT with equipotent fractionation was delivered to all sites of disease. PFS, OS, and other end points were evaluated.

RESULTS

Twenty-four patients (13 men and 11 women) with a median age of 67 years (range, 56-86 years) were enrolled with median follow-up of 11.6 months. All patients had progressed through platinum-based chemotherapy. A total of 52 sites were treated with 16 of 24 patients receiving SBRT to more than one site. Lung parenchyma was most often irradiated. Median PFS was 14.7 months, and median OS was 20.4 months. Most patients progressed in new distant sites with only three of 47 measurable lesions recurring within the SBRT field. Two grade 3 toxicities were radiation related. Zero of 13 patients tested were positive for an EGFR mutation.

CONCLUSION

Use of SBRT with erlotinib for unselected patients with stage IV NSCLC as a second- or subsequent line therapy resulted in dramatic changes in patterns of failure, was well tolerated, and resulted in high PFS and OS, substantially greater than historical values for patients who only received systemic agents.

Stereotactic body radiation therapy for post-pulmonary lobectomy isolated lung metastasis of thoracic tumor: survival and side effects

BACKGROUND

Stereotactic body radiation therapy (SBRT) has emerged as an alternative treatment for patients with early stage non-small cell lung cancer (NSCLC) or metastatic pulmonary tumors. However, for isolated lung metastasis (ILM) of thoracic malignances after pulmonary lobectomy, reported outcomes of SBRT have been limited. This study evaluates the role of SBRT in the treatment of such patients.

METHODS

A retrospective search of the SBRT database was conducted in three hospitals. The parameters analyzed in the treated patients were local control, progression-free survival (PFS), overall survival (OS), and the treatment-related side-effects.

RESULTS

In total, 23 patients with single ILM after pulmonary lobectomy treated with SBRT were identified and the median follow-up time was 14 months (range: 6.0-47.0 months). Local recurrences were observed in two patients during follow-up and the 1-year local control rate was 91.3%. Median PFS and OS for the studied cohort were 10.0 months [95% confidence interval (CI) 5.1-14.9 months] and 21.0 months (95% CI 11.4-30.6 months), respectively. Acute radiation pneumonitis (RP) of grade 2 or worse was observed in five (21.7%) and three (13.0%) patients, respectively. Other treatment-related toxicities included chest wall pain in one patient (4.3%) and acute esophagitis in two patients (8.7%). By Pearson correlation analysis, the planning target volume (PTV) volume and the volume of the ipsilateral lung exposed to a minimum dose of 5 Gy (IpV5) were significantly related to the acute RP of grade 2 or worse in present study (p < 0.05). The optimal thresholds of the PTV and IpV5 to predict RP of acute grade 2 or worse RP were 59 cm3 and 51% respectively, according to the receiver-operating characteristics curve analysis, with sensitivity/specificity of 75.0%/80.0% and 62.5%/80.0%.

CONCLUSIONS

SBRT for post-lobectomy ILM was effective and well tolerated. The major reason for disease progression was distant failure but not local recurrence. The PTV and IpV5 are potential predictors of acute RP of grade 2 or higher and should be considered in treatment planning for such patients.

Stereotactic Ablative Radiotherapy (SABR) in inoperable oligometastatic disease from colorectal cancer: a safe and effective approach

Background

To assess the safety and efficacy of Stereotactic Ablative Radiotherapy (SABR) in oligometastatic patients from colorectal cancer.

Methods

82 patients with 1–3 inoperable metastases confined to one organ (liver or lung), were treated with SABR for a total of 112 lesions in an observational study. Prescription dose ranged between 48 and 75Gy in 3 or 4 consecutive fractions. Primary end-points were local control (LC), overall survival (OS) and progression-free survival (PFS). Secondary end-point was toxicity.

Results

Median follow-up was 24 months (range 3–47). One, two and three years LC rate was 90%,80% and 75% (85%,75% and 70% for lung and 95%, 90% and 85% for liver metastases; no statistically significance was found). The difference in LC between the subgroup of lesions treated with ≥60 Gy (n = 58) and those irradiated with <60 Gy (n = 52) was statistically significant, with a 1, 2 and 3 yrs LC of 97%,92% and 83% for the higher dose, compared to 85%,70% and 70% for the lower dose (p < 0.04). Median OS was 32 months. Actuarial OS rate at 1, 2 and 3 yrs was 85%,65% and 43%. Univariate analysis showed a correlation only between OS and cumulative GTV > 3 cm (p < 0.02). Median PFS was 14 months, with a PFS rate of 56% at 1 yr and 40% at 2-3 yrs, without correlation with the site and prescription dose (p < 0.48 and p < 0.56). No patients experienced radiation-induced liver disease or grade >3 toxicity.

Conclusions

SABR is a safe and feasible alternative treatment of oligometastatic colorectal liver and lung metastases in patients not amenable to surgery or other ablative treatments.

Radical irradiation of extracranial oligometastases

Advances in radiotherapy planning and delivery have been used to treat patients with limited metastatic disease. With these techniques, high rates of treated metastasis control and low toxicity have been reported. Some patients have long disease-free intervals after radiotherapy similar to those seen after surgical resection. Ongoing studies will determine the benefit of these irradiation techniques to treat limited metastases, identify appropriate candidates, and assist in integrating these treatments into management strategies for specific diseases.

The oligometastatic state - separating truth from wishful thinking

The oligometastatic paradigm implies that patients who develop a small number of metastatic lesions might achieve long-term survival if all these lesions are ablated with surgery or stereotactic radiotherapy. Clinical data indicate that the number of patients with oligometastatic disease receiving aggressive treatment is increasing rapidly. We examine the key evidence supporting or refuting the existence of an oligometastatic state. Numerous single-arm studies suggest that long-term survival is 'better-than-expected' after ablative treatment. However, the few studies with adequate controls raise the possibility that this long-term survival might not be due to the treatments themselves, but rather to the selection of patients based on favourable inclusion criteria. Furthermore, ablative treatments carry a risk of harming healthy tissue, yet the risk-benefit ratio cannot be quantified if the benefits are unmeasured. If the strategy of treating oligometastases is to gain widespread acceptance as routine clinical practice, there should be stronger evidence supporting its efficacy.

[Stereotactic body radiation therapy and oligometastases]

In stage IV cancers, locoregional management of primitive tumours as surgery and/or radiotherapy improved both progression-free survival and overall survival. Among metastatic cancer patients, some of them are considered as oligometastatic stage as they present few metastatic sites associated with low tumor aggressiveness. For those patients, metastatic local control, and therefore prolonged time to progression should be reached through local treatments as surgery and/or radiofrequency ablation and/or stereotactic radiotherapy. Here we propose a review of oligometastatic stage and results from extracranial stereotactic radiotherapy in terms of efficacy and tolerance.

Local control rates with five-fraction stereotactic body radiotherapy for oligometastatic cancer to the lung

OBJECTIVE

To report our institutional experience with five fractions of daily 8-12 Gy stereotactic body radiotherapy (SBRT) for the treatment of oligometastatic cancer to the lung.

METHODS

Thirty-four consecutive patients with oligometastatic cancers to the lung were treated with image-guided SBRT between 2008 and 2011. Patient age ranged from 38 to 81 years. There were 17 males and 17 females. Lung metastases were from the following primary cancer types: colon cancer (n=13 patients), head and neck cancer (n=6), breast cancer (n=4), melanoma (n=4), sarcoma (n=4) and renal cell carcinoma (n=3). The median prescription dose was 50 Gy in five fractions (range, 40-60 Gy) to the isocenter, with the 80% isodose line encompassing the planning target volume (PTV) [defined as gross tumor volume (GTV) + 7-11 mm volumetric expansion]. The follow-up interval ranged from 2.4-54 months, with a median of 16.7 months.

RESULTS

The 1-, 2-, and 3-year patient local control (LC) rates for all patients were 93%, 88%, and 80% respectively. The 1-, 2-, and 3-year overall survival (OS) rates were 62%, 44%, and 23% respectively. The 1- and 2-year patient LC rates were 95% and 88% for tumor size 1-2 cm (n=25), and 86% for tumor size 2-3 cm (n=7). The majority (n=4) of local failures occurred within 12 months. No patient experienced local failure after 12 months except for one patient with colon cancer whose tumors progressed locally at 26 months. All five patients with local recurrences had colorectal cancer. Statistical analyses showed that age, gender, previous chemotherapy, previous surgery or radiation had no significant effect on LC rates. No patient was reported to have any symptomatic pneumonitis at any time point.

CONCLUSIONS

SBRT for oligometastatic disease to the lung using 8-12 Gy daily fractions over five treatments resulted in excellent 1- and 2-year LC rates. Most local failures occurred within the first 12 months, with five local failures associated with colorectal cancer. The treatment is safe using this radiation fractionation schedule with no therapy-related pneumonitis.

Stereotactic radiotherapy for pulmonary metastases

The most common treatment of pulmonary metastasis for solid tumors employs systemic chemotherapy, hormonal therapy, or biologic agents. Some series have suggested that aggressive surgical resection of pulmonary metastasis may improve patient outcomes in terms of quality of life and overall survival. Recently, data from clinical trials and retrospective series support the use of aggressive local control with high conformal dose radiotherapy (stereotactic body radiation therapy) in patients with limited metastases or oligometastases. Further evidence suggests that these patients represent a distinct clinical and biological class of patients. This review focuses on the role of ablative doses of radiotherapy in the treatment of pulmonary metastases. Specifically we discuss the rationale, treatment delivery, and local control that have led to the ongoing randomized clinical trials attempting to demonstrate a benefit over the current palliative standard of care.

Stereotactic body radiotherapy for metachronous multisite oligo-recurrence: a long-surviving case with sequential oligo-recurrence in four different organs treated using locally radical radiotherapy and a review of the literature

Stereotactic body radiotherapy (SBRT) for oligometastases represents a recent trend in radiation oncology. While abundant data are available regarding the use of SBRT for the treatment of lung or liver oligometastases from various retrospective series and prospective trials, relatively little information has been accumulated for the treatment of oligometastases at sites other than the lungs and liver, particularly for sequential oligometastases in multiple organs. Oligometastases with primary lesions controlled is called “oligo-recurrence.” We describe herein the case of a lung cancer patient who developed repeated oligo-recurrence at multiple sites that were each controlled by radical radiotherapy and achieved long-term survival and discuss the merits of locally aggressive radiotherapy for this type of disease condition with reviewing the literature. Although further investigation should be undertaken to clarify the benefits, objectives, and methods of SBRT for the treatment of oligometastases, we believe utilization of SBRT may be worthwhile for patients with remote metastases who hope for treatment to acquire better local control and possible longer survival.

Feasibility and toxicity of hypofractionated image guided radiation therapy for large volume limited metastatic disease

PURPOSE

Hypofractionated image guided radiation therapy (HIGRT) is increasingly used for limited metastases. Reported studies have mostly treated small volume tumors. Here, we report the toxicity and oncologic outcomes following treatment of large volume metastases.

METHODS AND MATERIALS

HIGRT patients treated from October 2005 to March 2010 were reviewed. Gross tumor volumes (GTV) and planning target volumes (PTV) were obtained from planning software. A metastasis was considered large volume if the treated PTV exceeded 50 cc. Patients were treated with either 10-fraction (4-5 Gy per fraction) or 3-5 fraction (8-14 Gy per fraction) regimens. Toxicity was obtained from both prospectively collected databases and retrospectively from patient charts.

RESULTS

Sixty-four patients with 93 treated lesions >50 cc were identified. The median GTV and PTV volumes were 41 and 119 cc, respectively. The median number of treated large volume lesions was 1, and a maximum of 3 large volume lesions were treated in a single patient. Primary malignancies included non-small cell lung cancer, renal cell, colorectal, breast, bladder, pituitary, small cell lung cancer, sarcoma, head-and-neck cancer, and hepatocellular cancer. Treated sites included lung (n = 33), regional lymph nodes (n = 20), bone (n = 17), adrenal (n = 9), and liver (n = 6). The most frequently used treatment regimen was 50 Gy in 5 Gy fractions. The median follow-up was 27 months for surviving patients. Treated lesion control was 78%. Low rates of acute and late grade 3 or higher toxicity were reported, with 3 and 5 patients experiencing each, respectively.

CONCLUSIONS

HIGRT to large volume oligometastatic disease is tolerable and feasible with promising tumor control. Local radiation therapy should be considered in patients with large volume, limited metastatic disease.

Stereotactic body radiotherapy treatment of extracranial metastases

Radiotherapy is an integral treatment for patients with metastatic cancer, although it is usually reserved for palliation of pain, dyspnoea, oedema, bleeding and neurological symptoms. However, the administration of high-precision radiotherapy, termed stereotactic body radiotherapy (SBRT), has the potential to significantly affect the disease course for some patients with metastatic cancer by delivering high doses of radiation to the secondary tumours with limited high-dose delivery to adjacent healthy tissues. Indeed, such accurate delivery has been firmly established as a therapy for medically inoperable early-stage non-small-cell lung cancer. To date, the technique has demonstrated improvements in controlling metastasis and, in some cases, improved palliation compared with conventionally fractionated radiotherapy. Active areas of research in SBRT include patient selection for curative intent, optimization of SBRT planning techniques, dosing schema and integration of SBRT into systemic therapies. Given the improvements in cytotoxic and targeted therapies over the past decade, studies testing the careful integration of SBRT into standard systemic therapy regimens are needed. Further investigations are also needed to understand the basic biological mechanisms underlying SBRT because they are likely to be different to those mechanisms in conventional radiotherapy.

Salvage stereotactic body radiotherapy for patients with limited prostate cancer metastases: deferring androgen deprivation therapy

BACKGROUND

We investigated whether repeated stereotactic body radiotherapy (SBRT) of oligometastatic disease is able to defer the initiation of palliative androgen deprivation therapy (ADT) in patients with low-volume bone and lymph node metastases.

PATIENTS AND METHODS

Patients with up to 3 synchronous metastases (bone and/or lymph nodes) diagnosed on positron emission tomography, following biochemical recurrence after local curative treatment, were treated with (repeated) SBRT to a dose of 50 Gy in 10 fractions. Androgen deprivation therapy-free survival (ADT-FS) defined as the time interval between the first day of SBRT and the initiation of ADT was the primary end point. ADT was initiated if more than 3 metastases were detected during follow-up even when patients were still asymptomatic or in case of a prostate specific antigen elevation above 50 ng/mL in the absence of metastases. Secondary end points were local control, clinical progression-free survival, and toxicity. Toxicity was scored using the Common Terminology Criteria for Adverse Events.

RESULTS

We treated 24 patients with a median follow-up of 24 months. Ten patients started with ADT resulting in a median ADT-FS of 38 months. The 2-year local control and clinical progression-free survival was 100% and 42%, respectively. Eleven and 3 patients, respectively, required a second and third salvage treatment for metachronous low-volume metastatic disease. No grade 3 toxicity was observed.

CONCLUSION

Repeated salvage SBRT is feasible, well tolerated and defers palliative ADT with a median of 38 months in patients with limited bone or lymph node PCa metastases.