Stereotactic ablative radiotherapy for pulmonary oligometastases and oligometastatic lung cancer

A novel lung SBRT treatment planning: Inverse VMAT plan with leaf motion limitation to ensure the irradiation reproducibility of a moving target

This study exposed the implementation of a novel technique (VMATLSL) for the planning of moving targets in lung stereotactic body radiation therapy (SBRT). This new technique has been compared to static conformal radiotherapy (3D-CRT), volumetric-modulated arc therapy (VMAT), and dynamic conformal arc (DCA). The rationale of this study was to lower geometric complexity (54.9% lower than full VMAT) and hence ensure the reproducibility of the treatment delivery by reducing the risk for interplay errors induced by respiratory motion. Dosimetry metrics were studied with a cohort of 30 patients. Our results showed that leaf speed limitation provided conformal number (CN) close to the VMAT (median CN of VMATLSL is 0.78 vs 0.82 for full VMAT) and was a significant improvement on 3D-CRT and DCA with segment-weight optimized (respectively 0.55 and 0.57). This novel technique is an alternative to VMAT or DCA for lung SBRT treatments, combining independence from the patient's breathing pattern, from the size and amplitude of the lesion, free from interplay effect, and with dosimetry metrics close to the best that could be achieved with full VMAT.

Stereotactic body radiation therapy for metastatic lung metastases

Although systemic therapy is standard management for patients with metastatic disease, several recent reports have indicated that an addition of local therapies including stereotactic body radiation therapy (SBRT) for patients with oligometastatic disease (OMD) could improve survival. The lung is the most common site of distant metastasis from many solid tumors, and the strategy of SBRT, such as dose-fraction schedules, timing, etc., would be different depending on the type of primary tumor, location, and patterns of OMD. This review describes the role of SBRT with curative-intent for patients with pulmonary OMD for each of these variables. First, differences according to the type of primary tumor, for which many studies suggest that SBRT-mediated local control (LC) for patients with pulmonary OMD from colorectal cancer (CRC) is less successful than for those from non-CRC tumors. In addition, higher dose-fraction schedules seemed to correlate with higher LC; hence, different SBRT treatment strategies may be needed for patients with pulmonary OMD from CRC relative to other tumors. Second, differences according to location, where the safety of SBRT for peripheral pulmonary tumors has been relatively well established, but safety for central pulmonary tumors including pulmonary OMD is still considered controversial. To determine the optimal dose-fraction schedules, further data from prospective studies are still needed. Third, differences according to the patterns of OMD, the number of metastases and the timing of SBRT whereby 1–5 lesions in most patients and patients with synchronous or metachronous OMD are considered good candidates for SBRT. We conclude that there are still several problems in defining suitable indications for local therapy including SBRT, and that further prospective studies are required to resolve these issues.

Application of real-time MRI-guided linear accelerator in stereotactic ablative body radiotherapy for non-small cell lung cancer: one step forward to precise targeting

PURPOSE

Tumor motion is a major challenge in stereotactic ablative body radiotherapy (SABR) for non-small cell lung cancer (NSCLC), causing excessive irradiation to compensate for this motion. Real-time tumor tracking with a magnetic resonance imaging-guided linear accelerator (MR-Linac) could address this problem. This study aimed to assess the effects and advantages of MR-Linac in SABR for the treatment of lung tumors.

METHODS

Overall, 41 patients with NSCLC treated with SABR using MR-Linac between March 2019 and December 2021 were included. For comparison, 40 patients treated with SABR using computed tomography-based modalities were also enrolled. The SABR dose ranged from 48 to 60 Gy in 3-5 fractions. The primary endpoint was a lower radiation volume compared to CT-based SABR. The secondary endpoint was the local control rate of SABR using the MR-Linac.

RESULTS

The median follow-up time was 19 months (range: 3-105 months). There was no significant difference in the gross tumor volume between the MR and CT groups (7.1 ± 9.3 cm³ vs 8.0 ± 6.8 cm³, p = 0.643), but the planning target volume was significantly smaller in the MR group (20.8 ± 18.8 cm³ vs 34.1 ± 22.9 cm³, p = 0.005). The 1-year local control rates for the MR and CT groups were 92.1 and 75.4%, respectively (p = 0.07), and the 1-year overall survival rates were 87.4 and 87.0%, respectively (p = 0.30).

CONCLUSION

Lung SABR with MR-Linac can reduce the radiation field without compromising the local control rate. Further follow-up is needed to assess the long-term effects.

Examination of the characteristics of long-term survivors among patients with gallbladder cancer with liver metastasis who underwent surgical treatment: a retrospective multicenter study (ACRoS1406)

Background

Gallbladder cancer (GBC) with liver metastasis is considered unresectable. However, there have been infrequent reports of long-term survival in patients with GBC and liver metastases. Therefore, we examined the characteristics of long-term survivors of gallbladder cancer with liver metastasis.

Methods

A retrospective multicenter study of 462 patients with GBC (mean age, 71 years; female, 51%) was performed. Although patients with pre-operatively diagnosed GBC and liver metastasis were generally excluded from resection, some cases identified during surgery were resected.

Result

In patients with resected stage III/IV GBC (n = 193), the period 2007–2013 (vs. 2000–2006, hazard ratio 0.63), pre-operative jaundice (hazard ratio 1.70), ≥ 2 liver metastases (vs. no liver metastasis, hazard ratio 2.11), and metastasis to the peritoneum (vs. no peritoneal metastasis, hazard ratio 2.08) were independent prognostic factors for overall survival, whereas one liver metastasis (vs. no liver metastasis) was not. When examining the 5-year overall survival and median survival times by liver metastasis in patients without peritoneal metastasis or pre-operative jaundice, those with one liver metastasis (63.5%, not reached) were comparable to those without liver metastasis (40.4%, 33.0 months), and was better than those with ≥ 2 liver metastases although there was no statistical difference (16.7%, 9.0 months). According to the univariate analysis of resected patients with GBC and liver metastases (n = 26), minor hepatectomy, less blood loss, less surgery time, papillary adenocarcinoma, and T2 were significantly associated with longer survival. Morbidity of Clavien–Dindo classification ≤ 2 and received adjuvant chemotherapy were marginally not significant. Long-term survivors (n = 5) had a high frequency of T2 tumors (4/5), had small liver metastases near the gallbladder during or after surgery, underwent minor hepatectomy without postoperative complications, and received postoperative adjuvant chemotherapy.

Conclusions

Although there is no surgical indication for GBC with liver metastasis diagnosed pre-operatively, minor hepatectomy and postoperative chemotherapy may be an option for selected patients with T2 GBC and liver metastasis identified during or after surgery who do not have other poor prognostic factors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02234-9.

A Comprehensive Understanding of Choroidal Metastasis from Lung Cancer

The incidence of lung cancer with intraocular metastasis is low, of which choroidal metastasis is the most painful metastatic lesion. The clinical symptoms resulting from choroidal metastasis from lung cancer easily detected although they are rarely identified prior to the diagnosis of the primary malignancy. The quality of life of patients is inevitably impaired. Some lung cancer patients complain of ocular symptoms as the first manifestation of lung cancer. Early diagnosis and treatment can significantly overcome or delay the visual impairment and improve prognosis. The main therapeutic modalities include systemic and local treatments, while observation is also a treatment option. Currently, the feasibility and effectiveness of various treatment options are controversial worldwide. Herein, we summarize the underlying mechanisms, epidemiology, clinical features, auxiliary examinations, diagnosis, and recent treatment options for intraocular metastases.

Oligometastatic Lung Cancer Defined by Biology, Science, and Secondary Growths

Breast cancer was the first malignant tumor for which TNM classification was proposed by the International Union Against Cancer. Volume and distribution of tumor burden were considered clinically important in this cancer. Lung cancer is caused by excessive cigarette smoking. Prognosis is worst in small cell lung cancer and in non-small cell lung cancer measuring over 3 cm in size and having regional lymphatic spread. Metastatic spread from lung cancer is favored by lymphatic spread to the locoregional lymph nodes and blood-borne spread to 5 sites-lung, brain, bone, liver, and adrenal-all of which are unfavorable prognostic indicators.

Artificial pneumothorax improves radiofrequency ablation of pulmonary metastases of hepatocellular carcinoma close to mediastinum

Background

To investigate the feasibility, safety and efficacy of percutaneous radiofrequency ablation (RFA) of pulmonary metastases from hepatocellular carcinoma (HCC) contiguous with the mediastinum using the artificial pneumothorax technique.

Method

A total of 40 lesions in 32 patients with pulmonary metastases from HCC contiguous with the mediastinum accepted RFA treatment from August 2014 to May 2018 via the artificial pneumothorax technique. After ablation, clinical outcomes were followed up by contrast enhanced CT. Technical success, local tumor progression (LTP), intrapulmonary distant recurrence (IDR), and adverse events were evaluated. Overall survival (OS) and local tumor progression free survival (LTPFS) were recorded for each patient.

Results

The tumor size was 1.4 ± 0.6 cm in diameter. RFA procedures were all successfully performed without intra-ablative complications. Technical success was noted in 100% of the patients. Five cases of LTP and 8 cases of IDR occurred following the secondary RFA for treatment. Slight pain was reported in all patients. No major complications were observed. The 1, 2, and 3-year LTPFS rates were 90.6, 81.2, and 71.8%, and the 1, 2, and 3-year OS rates were 100, 100 and 87.5%, respectively.

Conclusion

Artificial pneumothorax adjuvant RFA is a feasible, safe, and efficient method for treatment of pulmonary metastases from HCC contiguous with the mediastinum.

Impact of different patterns of metastasis in non-small-cell lung cancer patients

Aim: The aim of this study was to evaluate the frequency and median time for the development of metastases and prognosis by metastatic site after the diagnosis of non-small-cell lung cancer (NSCLC). Patients & methods: This cohort study was conducted with 1096 patients diagnosed with NSCLC between 2006 and 2014. Results: The most prevalent site of NSCLC metastases was the respiratory system. The nervous and adrenal systems presented the longest median time for the development of metastases. The 6-month survival varied from 68.2% for liver to 79.9% for the nervous system. Bone metastases were associated with a higher risk of death. Conclusion: The respiratory system was the most prevalent site of metastases. OS and risk of death varied according to the metastatic site.

Phase II study of concomitant radiotherapy with atezolizumab in oligometastatic soft tissue sarcomas: STEREOSARC trial protocol

INTRODUCTION

Up to 50% of soft tissue sarcoma (STS) patients develop metastases in the course of their disease. Cytotoxic therapy is a standard treatment in this setting but yields average tumour response rates of 25% at first line and ≤10% at later lines. In oligometastatic stage, stereotactic body radiation therapy (SBRT) allows reaching high control rates at treated sites (≥80%) and is potentially equally effective to surgery in term of overall survival. In order to shift the balance towards antitumour immunity by multisite irradiation, radiation could be combined with inhibitors of the immunosuppressive pathways.

METHODS AND ANALYSIS

STEREOSARC is a prospective, multicentric, randomised phase II, designed to evaluate the efficacy of SBRT associated with immunotherapy versus SBRT only. Randomisation is performed with a 2:1 ratio within two arms. The primary objective is to evaluate the efficacy, in term of progression-free survival (PFS) rate at 6 months, of immunomodulated stereotactic multisite irradiation in oligometastatic sarcoma patients. The secondary objectives include PFS by immune response criteria, overall survival, quality-of-life evaluation and developing mathematical models of tumour growth and dissemination predictive of oligometastatic versus polymetastatic evolution. Patients will be randomised in two groups: SBRT with atezolizumab and SBRT alone. The total number of included patients should be 103.

TRIAL REGISTRATION

The trial is registered on ClinicalTrials.gov (ID: NCT03548428).

ETHICS AND DISSEMINATION

This study has been approved by Comité de Protection des Personnes du sud-ouest et outre-mer 4 on 18 October 2019 (Reference CPP2019-09-076-PP) and from National Agency for Medical and Health products Safety (Reference: MEDAECNAT-2019-08-00004_2017-004239-35) on 18 September 2019.The results will be disseminated to patients upon individual request or through media release from scientific meetings. The results will be communicated through scientific meetings and publications.

Long-term toxicity and survival outcomes after stereotactic ablative radiotherapy for patients with centrally located thoracic tumors

Background

Stereotactic ablative radiotherapy (SABR) is effective for thoracic cancer and metastases; however, adverse effects are greater for central tumors. We evaluated factors affecting outcomes and toxicities after SABR for patients with primary lung and oligometastatic tumors.

Patients and methods

We retrospectively identified consecutive patients with centrally located lung tumors that were treated at our hospital from 2009-2016. The effects of patient, disease, and treatment-related parameters on local control (LC), overall survival (OS), and toxicity-free survival (TFS) were evaluated with multivariate analyses.

Results

Among 65 consecutive patients identified with 70 centrally located tumors, 20 tumors (28%) were reirradiated. Median (range) total dose for all tumors was 55 (30–60) Gy in 5 (3–10) fractions. Radiographic complete response was obtained in 43 lesions (61%). None of the analyzed factors were correlated with complete response. After a median follow-up of 57 (95% CI, 48–65) months, 10 tumors (14%) relapsed and 37 patients (57%) died; the actuarial 2- and 5-year OS rates were 52% and 28%, respectively. Median OS was significantly lower in patients with grade 3 or higher toxicity vs. lower toxicity (5 vs. 39 months; P < 0.001). Among 17 severe toxicities, 5 were grade 5, and 3 of them were reirradiated to the same field. Grade 3 to 5 TFS was lower with vs. without reirradiation (2-year TFS, 63% vs. 96%; P = 0.02).

Conclusions

Our study showed that modern SABR is effective for central lung tumors, and toxicities are acceptable. SABR for reirradiated central lung lesions and possibly for lesions abutting the tracheobronchial tree may result in higher risk of serious toxicities.

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.

The short-term outcomes of pulmonary metastasectomy or stereotactic body radiation therapy for pulmonary metastasis from epithelial tumors

Background

Stereotactic body radiation therapy (SBRT) has recently been widely performed for relatively small-volume tumors. We analyzed the short-term outcomes of pulmonary metastasectomy (PM) or SBRT for pulmonary metastases.

Methods

This study was a retrospective analysis of 82 patients with pulmonary metastasis from epithelial tumors who underwent PM or SBRT between 2013 and 2016.

Results

Fifty-nine patients underwent PM, 21 patients underwent SBRT, and 2 patients underwent combined PM and SBRT. The mean age of the PM group was significantly lower than that of the SBRT group (60.6 vs 67.4 years, p = 0.03). The most frequent types of primary tumor in the PM and SBRT groups were colorectal cancer (n = 27, 46%) and head and neck squamous cell carcinoma (n = 8, 38%), respectively. The rate of treatment-associated complications did not differ between the two groups to a statistically significant extent (20% vs 24%, p = 0.76). The 3-year local control rates of the two groups were similar (PM group, 88%; SBRT group, 92%; p = 0.48). The 3-year progression-free survival (PFS) rate of the PM group were better than that of SBRT groups (42% vs 11%, p = 0.01). The 3-year overall survival (OS) rates of the PM and SBRT groups were 77 and 52% respectively; although the rate of the PM group was higher, the difference was not statistically significant (p = 0.10).

Conclusions

SBRT provides a favorable 3-year local control rate. The 3-year OS rate of the SBRT group tended to be lower than that of the PM group, despite the difference was not statistically significant. PM and SBRT play complementary roles in patients with pulmonary metastases.

Stereotactic ablative radiotherapy and systemic treatments for extracerebral oligometastases, oligorecurrence, oligopersistence and oligoprogression from lung cancer

Background

Stereotactic irradiation (SBRT) is a standard of care for inoperable stage I lung cancer and brain oligometastases from lung cancer but is controversial for extracranial oligometastases. We assessed outcomes of lung cancer patients with extracranial metastases in oligometastatic, oligorecurrent, oligopersistent and oligoprogressive settings (“oligometastatic spectrum”) under strategies using SBRT +/− systemic treatments.

Methods

A retrospective multicentric study of consecutive lung cancer adult patients with 1–5 extracranial metastases treated with SBRT was conducted.

Results

Of 91 patients (99 metastases, median age 63, 64.8% adenocarcinomas, 19.8% molecular alterations), 11% had oligometastases, 49.5% oligorecurrence, 19.8% oligopersistence and 19.8% oligoprogression. Of 36% of patients under systemic treatments at initiation of SBRT, systemic treatment interruption was performed in 58% of them. With median follow up of 15.3 months, crude local control at irradiated metastases was 91%, while median distant progression-free survival (dPFS) and overall survival were 6.3 and 28.4 months (2-year survival 54%). Initial nodal stage and oligometastatic spectrum were prognostic factors for dPFS; age, initial primary stage and oligometastatic spectrum were prognostic factors for survival on multivariate analysis. Patients with oncogene-addicted tumors more frequently had oligoprogressive disease. Repeat ablative irradiations were preformed in 80% of patients who had oligorelapses. Worst acute toxicities consisted of 5.5% and one late toxic death occurred.

Conclusion

The oligometastatic spectrum is a strong prognosticator in patients undergoing SBRT for extracranial metastases. Median survival was over two years but dPFS was about 6 months. Continuation of systemic therapy in oligoprogressive patients should be investigated.

Individual lymph nodes: "See it and Zap it"

BACKGROUND AND PURPOSE

With magnetic resonance imaging (MRI)-guided radiotherapy systems such as the 1.5T MR-linac the daily anatomy can be visualized before, during and after radiation delivery. With these treatment systems, seeing metastatic nodes with MRI and zapping them with stereotactic body radiotherapy (SBRT) comes into reach. The purpose of this study is to investigate different online treatment planning strategies and to determine the planning target volume (PTV) margin needed for adequate target coverage when treating lymph node oligometastases with SBRT on the 1.5T MR-linac.

MATERIALS AND METHODS

Ten patients were treated for single pelvic or para-aortic lymph node metastases on the 1.5T MR-linac with a prescribed dose of 5x7Gy with a 3 mm isotropic GTV- PTV margin. Based on the daily MRI and actual contours, a completely new treatment plan was generated for each session (adapt to shape, ATS). These were compared with plans optimized on pre-treatment CT contours after correcting for the online target position (adapt to position, ATP). At the end of each treatment session, a post-radiation delivery MRI was acquired on which the GTV was delineated to evaluate the GTV coverage and PTV margins.

RESULTS

The median PTV V35Gy was 99.9% [90.7-100%] for the clinically delivered ATS plans compared to 93.6% [76.3-99.7%] when using ATP. The median GTV V35Gy during radiotherapy delivery was 100% [98-100%] on the online planning and post-delivery MRIs for ATS and 100% [93.9-100%] for ATP, respectively. The applied 3 mm isotropic PTV margin is considered adequate.

CONCLUSION

For pelvic and para-aortic metastatic lymph nodes, online MRI-guided adaptive treatment planning results in adequate PTV and GTV coverage when taking the actual patient anatomy into account (ATS). Generally, GTV coverage remained adequate throughout the treatment session for both adaptive planning strategies. "Seeing and zapping" metastatic lymph nodes comes within reach for MRI-guided SBRT.

Additional local consolidative therapy has survival benefit over EGFR tyrosine kinase inhibitors alone in bone oligometastatic lung adenocarcinoma patients

OBJECTIVES

Whether epidermal growth factor receptor tyrosine-kinase inhibitors (EGFR-TKIs) plus local consolidative therapy (LCT) has survival benefit over EGFR-TKIs alone in lung adenocarcinoma patients with EGFR mutation and bone oligometastases remains controversial.

MATERIALS AND METHODS

We conducted a retrospective study to assess the effects of LCT in lung adenocarcinoma patients with bone oligometastases and EGFR mutation. The primary endpoint was overall survival (OS); the secondary endpoints was progression-free survival (PFS).

RESULTS

A total of 127 lung adenocarcinoma patients with EGFR mutation and bone oligometastases were assessed, including 65 patients received EGFR-TKIs alone (monotherapy group) and 62 patients received EGFR-TKIs plus local consolidative therapy (LCT) (combination group). Addition of LCT was associated with significantly longer OS (36.3 vs. 21.0 months, P = 0.01; hazard ratio [HR] = 0.537, 95% confidence interval [CI]: 0.360-0.801, p = 0.01) and PFS (14.0 vs. 8.1 months, P = 0.01; HR = 0.613, 95%CI: 0.427-0.879, p = 0.01) in the whole cohort.

CONCLUSION

In lung adenocarcinoma patients with EGFR-mutation and bone oligometastases, LCT plus EGFR-TKIs therapy is associated with significantly longer OS and PFS compared with EGFR-TKIs therapy alone, indicating that LCT plus EGFR-TKIs therapy might be a better therapeutic option for this patient population.

Lymphadenectomy during pulmonary metastasectomy: Impact on survival and recurrence

Background and Objectives: Lymphadenectomy during pulmonary metastasectomy (PM) is widely carried out. We assessed the potential benefit on patient survival and tumor recurrence of this practice.

Methods: One hundred eighty‐one patients undergoing a first PM were studied. Eighty‐six patients (47.5%) underwent lymphadenectomy (L+ group) whereas 95 (52.5%) did not undergo nodal harvesting (L−group). Main outcomes were overall survival (OS) and disease‐free survival (DFS). Median follow‐up was 25 months (interquartile range [IQR], 13‐49).

Results: At follow‐up 84 patients (46.4%) died, whereas 97 (53.6%) were still alive with recurrence in 78 patients (43%). There was no difference in 5‐year survival (L+ 30.0% vs L− 43.2%; P = .87) or in the 5‐year cumulative incidence of recurrence (L + 63.2% vs L−80%; P = .07) between the two groups. Multivariable analysis indicated that disease‐free interval (DFI) less than 29 months (P < .001) and lung comorbidities (P = .003) were significant predictors of death. Metastases from non‐small–cell lung cancer increased the risk of lung comorbidities by a factor of 19.8, whereas the risk of DFI less than 29 months was increased nearly 11‐fold. Competing risk regression identified multiple metastases (P = .004), head/neck primary tumor (P = .009), and age less than 67 years (P = .024) as independent risk factors for recurrence.

Conclusion: Associated lymphadenectomy showed not to give any additional advantage in terms of survival and recurrence after PM.

Organs at Risk Considerations for Thoracic Stereotactic Body Radiation Therapy: What Is Safe for Lung Parenchyma?

PURPOSE

Stereotactic body radiation therapy (SBRT) has become the standard of care for inoperable early-stage non-small cell lung cancer and is often used for recurrent lung cancer and pulmonary metastases. Radiation-induced lung toxicity (RILT), including radiation pneumonitis and pulmonary fibrosis, is a major concern for which it is important to understand dosimetric and clinical predictors.

METHODS AND MATERIALS

This study was undertaken through the American Association of Physicists in Medicine's Working Group on Biological Effects of Stereotactic Body Radiotherapy. Data from studies of lung SBRT published through the summer of 2016 that provided detailed information about RILT were analyzed.

RESULTS

Ninety-seven studies were ultimately considered. Definitions of the risk organ and complication endpoints as well as dose-volume information presented varied among studies. The risk of RILT, including radiation pneumonitis and pulmonary fibrosis, was reported to be associated with the size and location of the tumor. Patients with interstitial lung disease appear to be especially susceptible to severe RILT. A variety of dosimetric parameters were reported to be associated with RILT. There was no apparent threshold "tolerance dose-volume" level. However, most studies noted safe treatment with a rate of symptomatic RILT of <10% to 15% after lung SBRT with a mean lung dose (MLD) of the combined lungs ≤8 Gy in 3 to 5 fractions and the percent of total lung volume receiving more than 20 Gy (V₂₀) <10% to 15%.

CONCLUSIONS

To allow more rigorous analysis of this complication, future studies should standardize reporting by including standardized endpoint and volume definitions and providing dose-volume information for all patients, with and without RILT.

Comparison of stereotactic body radiotherapy versus metastasectomy outcomes in patients with pulmonary metastases

Background

We compared the treatment outcomes of stereotactic body radiotherapy (SBRT) and metastasectomy in patients with pulmonary metastases.

Methods

Twenty‐one patients received SBRT (total radiation doses 60 Gy in 3 fractions or 48 Gy in 4 fractions) and 30 underwent metastasectomy, most (93.3%) with wedge resection. The patients were followed for a median of 13.7 months. The tumor size in the SBRT group was larger than in the metastasectomy group (median 2.5 vs. 1.25 cm; P = 0.015). Patients with synchronous metastases were more likely to be treated with SBRT than with metastasectomy (P = 0.006).

Results

There was no significant difference in the local control rates of the treatment groups (P = 0.163). Progression‐free survival (PFS) was longer in the metastasectomy than in the SBRT group (P = 0.02), with one and two‐year PFS rates of 51.1% and 46% versus 23.8% and 11.9%, respectively. The one and two‐year overall survival (OS) rates were 95% and 81.8% in the metastasectomy group and 79.5% and 68.2%, in the SBRT group, respectively. In multivariate analysis, synchronous metastasis was related to poor PFS, and tumor size was the most significant factor affecting OS. There were no significant differences in PFS and OS between treatment groups after dividing patients according to the presence or absence of synchronous metastases.

Conclusions

SBRT is considered a suitable local modality against pulmonary metastases; however, patients with synchronous metastases are only likely to obtain a small benefit from local treatment with either SBRT or surgery.

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

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

Influence of respiratory motion management technique on radiation pneumonitis risk with robotic stereotactic body radiation therapy

PURPOSE/OBJECTIVES

For lung stereotactic body radiation therapy (SBRT), real-time tumor tracking (RTT) allows for less radiation to normal lung compared to the internal target volume (ITV) method of respiratory motion management. To quantify the advantage of RTT, we examined the difference in radiation pneumonitis risk between these two techniques using a normal tissue complication probability (NTCP) model.

MATERIALS/METHOD

20 lung SBRT treatment plans using RTT were replanned with the ITV method using respiratory motion information from a 4D-CT image acquired at the original simulation. Risk of symptomatic radiation pneumonitis was calculated for both plans using a previously derived NTCP model. Features available before treatment planning that identified significant increase in NTCP with ITV versus RTT plans were identified.

RESULTS

Prescription dose to the planning target volume (PTV) ranged from 22 to 60 Gy in 1-5 fractions. The median tumor diameter was 3.5 cm (range 2.1-5.5 cm) with a median volume of 14.5 mL (range 3.6-59.9 mL). The median increase in PTV volume from RTT to ITV plans was 17.1 mL (range 3.5-72.4 mL), and the median increase in PTV/lung volume ratio was 0.46% (range 0.13-1.98%). Mean lung dose and percentage dose-volumes were significantly higher in ITV plans at all levels tested. The median NTCP was 5.1% for RTT plans and 8.9% for ITV plans, with a median difference of 1.9% (range 0.4-25.5%, pairwise P < 0.001). Increases in NTCP between plans were best predicted by increases in PTV volume and PTV/lung volume ratio.

CONCLUSIONS

The use of RTT decreased the risk of radiation pneumonitis in all plans. However, for most patients the risk reduction was minimal. Differences in plan PTV volume and PTV/lung volume ratio may identify patients who would benefit from RTT technique before completing treatment planning.

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.

Staging Lung Cancer: Metastasis

The updated eighth edition of the tumor, node, metastasis (TNM) classification for lung cancer includes revisions to T and M descriptors. In terms of the M descriptor, the classification of intrathoracic metastatic disease as M1a is unchanged from TNM-7. Extrathoracic metastatic disease, which was classified as M1b in TNM-7, is now subdivided into M1b (single metastasis, single organ) and M1c (multiple metastases in one or multiple organs) descriptors. In this article, the rationale for changes in the M descriptors, the utility of preoperative staging with PET/computed tomography, and the treatment options available for patients with oligometastatic disease are discussed.

Patterns of initial and intracranial failure in metastatic EGFR-mutant non-small cell lung cancer treated with erlotinib

OBJECTIVES

Patients with metastatic EGFR-mutant (mEGFRmt) NSCLC have favorable survival when treated with erlotinib. We hypothesized that treatment failure in most patients is limited to initial sites of disease, in which case incorporating local therapy such as radiation might further delay progression. We therefore analyzed patterns and predictors of failure in a large cohort of such patients.

MATERIALS AND METHODS

We reviewed 189 patients treated with erlotinib for mEGFRmt NSCLC. We classified first pattern of failure as involving initial sites only (ISF), new sites only (NSF), or the combination (CSF), and used competing-risks regression to identify factors associated with ISF, progression and overall survival (OS). We also separately analyzed intracranial and intrathoracic failure.

RESULTS

Of 171 patients who progressed, 103 (60.2%) had ISF, 30 (17.5%) had NSF, and 38 (22.2%) had CSF. Younger age and lack of initial CNS involvement independently correlated with ISF, with a trend for higher T and N stage. Higher T and N stage was also a significant predictor of progression. Factors predicting shorter OS were female gender, weight loss, initial intracranial involvement, and ≥4 extracranial metastases. Intrathoracic progression was a component of first failure in 61%, and three-year cumulative incidence of brain metastasis was 30%.

CONCLUSION

The main pattern of progression in mEGFRmt NSCLC on erlotinib is in the initial sites of disease. Younger patients and those without brain involvement are particularly likely to develop ISF. This suggests a role for incorporating local therapy into treatment of selected patients with mEGFRmt NSCLC.

Role of stereotactic body radiation therapy for lung metastases from radio-resistant primary tumours

OBJECTIVES

A retrospective analysis was performed on patients treated for lung oligo-metastatic disease from radio-resistant histology groups.

METHODS

The primary end point was local control (LC), secondary end points were overall survival (OS) and progression free survival (PFS). Toxicity was scored according to CTCAE 4.03.

RESULTS

200 patients were analyzed: 49.5% of the cases derived from colorectal primary tumors, 20.5% from sarcomas, 12.0% from renal cell carcinoma and the rest from other mixed origin. The mean follow-up was 24.2 months. LC at 1 and 2 years was 91, 84.9%. Primary histology and the presence of extra-pulmonary disease had a significant impact on LC. OS at 1 and 2 years was 88.7, 65.4%. Primary histology, disease free interval, presence of extra-pulmonary disease, number of irradiated lung lesions and age showed a correlation with prognosis at univariate analysis. PFS at 1 and 2 years was 84, 57.7%. The presence of extra-pulmonary disease and the number of irradiated lung lesions correlated with prognosis. Treatment was well tolerated with no G3-4 acute or late toxicity recorded.

CONCLUSION

Colorectal metastases showed a higher rate of local relapse. However, the factors mostly influencing prognosis were the presence of extra-pulmonary disease and the number of lung lesions.

What do radiation oncologists require for future advancements in lung SBRT?

Stereotactic Body Radiotherapy (SBRT) is a well established therapeutic option for patients affected with peripheral early stage non-small cell lung cancer (NSCLC), given the positive clinical evidence accumulated so far on its efficacy and safety. SBRT is regarded as the best choice for inoperable patients, and could also be offered as an alternative to surgery to selected operable patients. More recently, its use for lung metastases progressively increased, and SBRT is now regarded as a low toxic and highly effective local therapy for lung oligometastases from different primary tumors, especially colorectal cancer. Improved planning and delivery techniques have facilitated over the years its use on large and/or centrally located primary tumors, and multiple nodules. Given the successful applications and the current wide dissemination of this technique, clinicians are now faced with an increasingly complex and multi-variable decision process. Some clinically relevant factors are still uncertain, and strategies are needed to reduce the risk of both local and distant failures. Secondly, aspects related to target delineation, dose prescription, image guidance and treatment planning still need to be fully addressed; this may hamper, at least for now, the standardization of SBRT procedures through different Institutions making any kind of direct outcomes comparison difficult. We here aim to provide a perspective on the current role of lung SBRT and its critical aspects, highlighting the potential future developments.

Surgery in oligometastatic NSCLC patients in the targeted therapy era

More than 50% of NSCLC patients present with metastatic disease at first diagnosis, with a median survival of 8-11 months. However, selected patients with oligometastatic disease who receive appropriate local therapy for both the primary lesion and metastases enjoy long-term survival or are even cured. The new (eighth) edition of the tumor, node and metastasis classification of lung cancer suggests that patients with a single metastatic lesion in one distant organ should be placed into a new category, M1b, which will certainly lead to more applications of local therapy in such subpopulations. Moreover, as the applications of targeted therapy increase, surgery will play an evermore critical role in eliminating drug-resistant cancer clones of patients who exhibit mixed responses to tyrosine kinase inhibitors. The lung, brain and adrenal gland are the most common oligometastatic organs, and are reviewed separately.

Role of Local Ablative Therapy in Patients with Oligometastatic and Oligoprogressive Non-Small Cell Lung Cancer

Because of an improved understanding of lung cancer biology and improvement in systemic treatment, an oligometastatic state in which metastatic disease is present at a limited number of anatomic sites is being increasingly recognized. An oligoprogressive state, which is a similar but distinct entity, refers to disease progression at a limited number of anatomic sites, with continued response or stable disease at other sites of disease. Such an oligoprogressive state is best described in patients with NSCLC treated with molecular targeted therapy. Possible explanations for development of the oligoprogressive state include the presence of underlying clonal heterogeneity and extrinsic selection pressure due to the use of targeted therapy. Traditionally, local ablative therapy (LAT) has been limited to symptom palliation in patients with advanced NSCLC, but the presence of oligometastatic or oligoprogressive disease provides a unique opportunity to evaluate the role of LAT such as surgery, radiation therapy, radiofrequency ablation, or cryoablation. There is increasing evidence to support the clinical benefit of LAT in patients with NSCLC with limited metastatic disease and in selected individuals in whom resistance to targeted therapies develops. In the latter instance, adequate treatment of drug-resistant clones by LAT could potentially help in avoiding switching systemic therapy prematurely. This review focuses on the biology of oligometastatic and oligoprogressive NSCLC and describes the role of LAT in the treatment of these conditions.

[Radiotherapy for intrathoracic metastases]

Indication, doses, and technique of radiotherapy, for intrathoracic metastases are presented. The recommendations for delineation of the target volumes and organs at risk are detailed.

Clinical applications of stereotactic radiation therapy for oligometastatic cancer patients: a disease-oriented approach

Oligometastases from solid tumors are currently recognized as a distinct clinical entity, corresponding to an intermediate state between local and widespread disease. It has been suggested that local ablative therapies (including surgery, radiofrequency ablation and radiation therapy) play an important role in this setting, in combination or not with systemic therapies, particularly in delaying disease progression and hopefully in increasing the median survival time. Stereotactic body radiation therapy (SBRT) rapidly emerged in recent years as one of the most effective and less toxic local treatment modalities for lung, liver, adrenal, brain and bone metastases. The aim of this review was to focus on its clinical role for oligometastatic disease in four major cancer subtypes: lung, breast, colorectal and prostate. On the basis of the available evidence, SBRT is able to provide high rates of local tumor control without significant toxicity. Its global impact on survival is uncertain; however, in specific subpopulations of oligometastatic patients there is a trend towards a significant improvement in progression-free and overall survival rates; these important data might be used as a platform for clinical decision-making and establish the basis for the current and future prospective trials investigating its role with or without systemic treatments.

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.

Emerging Treatment Paradigms in Radiation Oncology

Rapid advancements in radiotherapy and molecularly targeted therapies have resulted in the development of potential paradigm-shifting use of radiotherapy in the treatment of cancer. In this review, we discuss some of the most promising therapeutic approaches in the field of radiation oncology. These strategies include the use of highly targeted stereotactic radiotherapy and particle therapy as well as combining radiotherapy with agents that modulate the DNA damage response, augment the immune response, or protect normal tissues.

Complete Disappearance of Choroidal Metastasis from Lung Adenocarcinoma Treated with Bevacizumab and Chemotherapy

Choroidal metastasis from lung cancer is uncommon. We report a case of choroidal metastasis as an inaugural manifestation of lung adenocarcinoma, successfully treated by docetaxel, cisplatinum, and intravenous bevacizumab as an antiangiogenesis therapy. A complete remission was obtained after 4 cycles and maintained after six cycles. This case report demonstrates the importance of the systemic bevacizumab and chemotherapy in the treatment of choroidal metastasis from adenocarcinoma of the lung.

Available evidence on re-irradiation with stereotactic ablative radiotherapy following high-dose previous thoracic radiotherapy for lung malignancies

Patients affected with intra-thoracic recurrences of primary or secondary lung malignancies after a first course of definitive radiotherapy have limited therapeutic options, and they are often treated with a palliative intent. Re-irradiation with stereotactic ablative radiotherapy (SABR) represents an appealing approach, due to the optimized dose distribution that allows for high-dose delivery with better sparing of organs at risk. This strategy has the goal of long-term control and even cure. Aim of this review is to report and discuss published data on re-irradiation with SABR in terms of efficacy and toxicity. Results indicate that thoracic re-irradiation may offer satisfactory disease control, however the data on outcome and toxicity are derived from low quality retrospective studies, and results should be cautiously interpreted. As SABR may be associated with serious toxicity, attention should be paid for an accurate patients' selection.

Colorectal Histology Is Associated With an Increased Risk of Local Failure in Lung Metastases Treated With Stereotactic Ablative Radiation Therapy

PURPOSE

Stereotactic ablative radiation therapy (SABR) is increasingly used to treat lung oligometastases. We set out to determine the safety and efficacy of this approach and to identify factors associated with outcomes.

METHODS AND MATERIALS

We conducted a retrospective study of patients treated with SABR for metastatic lung tumors at our institution from 2003 to 2014. We assessed the association between various patient and treatment factors with local failure (LF), progression, subsequent treatment, systemic treatment, and overall survival (OS), using univariate and multivariate analyses.

RESULTS

We identified 122 tumors in 77 patients meeting inclusion criteria for this study. Median follow-up was 22 months. The 12- and 24-month cumulative incidence rates of LF were 8.7% and 16.2%, respectively; the 24-month cumulative incidence rates of progression, subsequent treatment, and subsequent systemic treatment were 75.2%, 64.5%, and 35.1%, respectively. Twenty-four-month OS was 74.6%, and median OS was 36 months. Colorectal metastases had a significantly higher cumulative incidence of LF at 12 and 24 months (25.5% and 42.2%, respectively), than all other histologies (4.4% and 9.9%, respectively; P<.0004). The 24-month cumulative incidences of LF for colorectal metastases treated with a biologically effective dose at α/β = 10 (BED10) of <100 Gy versus BED10 of ≥100 Gy were 62.5% and 16.7%, respectively (P=.08). Toxicity was minimal, with only a single grade 3 or higher event observed.

CONCLUSIONS

SABR for metastatic lung tumors appears to be safe and effective with excellent local control, treatment-free intervals, and OS. An exception is metastases from colorectal cancer, which have a high LF rate consistent with a radioresistant phenotype, suggesting a potential role for dose escalation.