Stereotactic Body Radiotherapy in Patients with Previous Pneumonectomy: Safety and Efficacy

Prognostic analysis of helical tomotherapy stereotactic body radiotherapy in multiple primary or second primary lung cancers

PURPOSE

To evaluate the safety and efficacy of Helical Tomotherapy stereotactic body radiotherapy (HT-SBRT) in treating multiple primary lung cancers (MPLCs) and second primary lung cancer (SPLC).

METHODS

From January 2010 to September 2023, 106 MPLCs and SPLC (T1-3N0M0) underwent HT-SBRT. The cumulative incidence for local recurrence (LR) was calculated using the competing risk approach and compared using Gray's test. Cancer-specific survival (CSS) and progression-free survival (PFS) were assessed using Kaplan-Meier analysis and log-rank tests.

RESULTS

After adjusting for competing risks, the LR rates for all lesions (n = 150) was 15.3%, with 2- and 4-year rates of 7.5% and 11.4%. For second primary lung nodules post-surgery, the cumulative incidence of LR was 16.1%, with 2- and 4-year rates of 6.9% and 8.7%. In MPLCs treated with HT-SBRT, the cumulative incidence of LR was 14.3%, with 2- and 4-year rates of 8.2% and 14.3%. In patients with MPLCs treated with HT-SBRT (n = 27), the CSS rates at 2, 4, and 10 years were 90.5%, 78.6%, and 53.6%, respectively, and the PFS rates were 59.5%, 32.8%, and 24.6%. In patients with SPLC who received HT-SBRT after surgery (n = 79), the CSS rates at 2, 4, and 10 years were 90.9%, 81.7%, and 61.0%, respectively, while the PFS rates were 75.4%, 64.4%, and 58.5%. Additionally, 0.9% of patients experienced grade 3 acute radiation pneumonitis, and no severe (grade 4-5) toxicities were reported.

CONCLUSIONS

HT-SBRT may be a safe and effective treatment for MPLCs and SPLC, though prospective studies are needed to confirm its efficacy.

Comparison of stereotactic body radiation therapy versus surgery for multiple primary lung cancers after prior radical resection: A multicenter retrospective study

Background

Patients who previously underwent surgical resection of initial primary lung cancer are at a high risk of developing multiple primary lung cancers (MPLCs). The purpose of this study was to compare the efficacy and safety between stereotactic body radiation therapy (SBRT) and surgery for MPLCs patients after prior radical resection for the first lung cancers.

Methods

In this multicenter retrospective study, eligible MPLC patients with tumor diameter of 5.0 cm or less at N0M0 who underwent SBRT or reoperation between January 2013 and August 2020 were enrolled. The primary endpoint was the 3-year locoregional recurrence and treatment-related toxicity. Kaplan-Meier method was used to calculate survival rates. The χ² test was adapted to assess the difference of categorical variables between the two subgroup patients.

Results

A total of 203 (73 in the SBRT group and 130 in the surgery group) patients from three academic cancer centers were evaluated with a median follow-up of 38.3 months. The cumulative 1-, 2-, and 3-year incidences of locoregional recurrence were 5.6 %, 7.0 % and 13.1 % in the SBRT group versus 3.2 %, 4.8 % and 7.4 % in the surgery group, respectively [hazard ratio (HR), 1.97; 95 % confidence interval (CI), 0.74-5.24; P = 0.14]. The cancer-specific survival rates were 95.9 %, 94.5 % and 88.1 % versus 96.9 %, 94.6 % and 93.8 % in the SBRT and surgery groups respectively (HR, 1.72; 95 % CI, 0.67-4.44; P = 0.23). In the SBRT group, two patients (2.7 %) suffered from grade 3 radiation pneumonitis, while in the surgery group, grade 3 complications occurred in four (3.1 %) patients, and four cases were expired due to pneumonia or pulmonary heart disease within 90 days after surgery.

Conclusions

SBRT is an effective therapeutic option with limited toxicity compared to surgery for patients with MPLCs after prior radical surgical resection, and it could be considered as an alternative treatment for those patients.

Drug Regimen for Patients after a Pneumonectomy

Pneumonectomy is an entire lung removal and is indicated for both malignant and benign diseases. Due to its invasiveness and postoperative complications, pneumonectomy is still associated with high mortality and morbidity. Appropriate postoperative management is crucial in pneumonectomy patients to improve quality of life and overall survival rates. Diverse drug regimens are under development to be used in adjuvant chemotherapy or to improve respiratory health after a pneumonectomy. The most common causes for a pneumonectomy are non-small cell lung cancer, malignant pleural mesothelioma, and tuberculosis; thus, an appropriate drug regimen is necessary. The uncommon incidence of pneumonectomy cases remains the major obstacle in studies of postoperative drug regimens. As the majority of current studies include post-lobectomy and post-segmentectomy patients, it is highly recommended that further research of postoperative drug regimens be focused on post-pneumonectomy patients.

Risk factors for symptomatic radiation pneumonitis after stereotactic body radiation therapy (SBRT) in patients with non-small cell lung cancer

BACKGROUND AND PURPOSE

Radiation pneumonitis (RP) can be a potential fatal toxicity of stereotactic body radiation therapy (SBRT) for medically inoperable non-small cell lung cancer (NSCLC). This study aimed to examine the risk factors that predict RP and explore dosimetric tolerance for safe practice in a large institutional series of NSCLC patients.

MATERIALS AND METHODS

Patients with early-stage and locally recurrent NSCLC who received lung SBRT between 2002 and 2015 formed the study population. The primary endpoint was grade 2 or above radiation pneumonitis (RP2). Lungs were re-contoured consistently by one radiation oncologist according to the RTOG atlas for organs at risk. Dosimetric factors were computed consistently with exclusion of gross tumor volume of either ipsilateral, contralateral, or total lungs.

RESULTS

A total of 339 patients were eligible. With a median follow-up of 47 months, RP2 was recorded in 10% patients. History of respiratory comorbidity, previous thoracic radiation, right lung location, mean lung doses of total or ipsilateral lung, and total lung volume receiving 20 Gy were all significantly associated with the risk of RP2. The dosimetric parameters of contralateral lung, including mean dose and volume receiving more than 5, 10, and 20 Gy, were not significantly associated with RP2 (ps > 0.05). A model of combining significant clinical and dosimetric factors had a predictive accuracy AUC of 0.76. According to this model, RP2 can be limited to <10% should the patient have no previous lung radiation and the mean dose of total and ipsilateral lungs be kept less than 6 Gy and 20 Gy, respectively.

CONCLUSION

Dosimetric factors of total or ipsilateral lung together with important clinical factors were significant risk factors for symptomatic radiation pneumonitis after SBRT. Constraining mean lung dose can limit clinically significant lung toxicity.

Contralateral pulmonary resection using selective bronchial blockade in postpneumonectomy patients

BACKGROUND

Pulmonary resection is occasionally performed in postpneumonectomy patients with contralateral lung lesions, such as metachronous or metastatic lung cancer. Careful intraoperative respiratory management is essential in such patients. This study evaluated the respiratory management of postpneumonectomy patients who underwent contralateral pulmonary resection with selective bronchial blockade of the lobe or segment to be resected.

METHODS

We retrospectively analyzed the surgical findings and safety of surgery in six patients who underwent contralateral pulmonary resection with selective bronchial blockade after pneumonectomy for non-small cell lung cancer (NSCLC).

RESULTS

The percutaneous oxygen saturation did not decrease in any of the patients during bronchial blockade under high oxygen concentration. The median blockade time was 57.5 minutes. The operative field was tolerable secured under conditions of partial lung collapse, and partial pulmonary resection was performed as planned. Postoperatively, one patient developed acute respiratory distress syndrome due to acute exacerbation of interstitial pneumonia; however, no patients died within one month postoperatively. Two patients underwent pulmonary resection in order to obtain adequate tissue specimens to evaluate the biomarkers of multiple lung metastases. On histopathology, one patient tested positive for anaplastic lymphoma kinase (ALK) and was subsequently administered an ALK inhibitor, which prolonged survival.

CONCLUSIONS

In all patients, intraoperative respiratory condition under partial lung collapse remained stable, and all partial pulmonary resections were safely performed. However, surgical indications should be carefully reviewed preoperatively in patients with interstitial pneumonia.

KEY POINTS

SIGNIFICANT FINDINGS OF THE STUDY: Contralateral partial pulmonary resection was performed using selective bronchial blockade in postpneumonectomy patients. Percutaneous oxygen saturation did not decrease during the bronchial blockade under high oxygen concentration, and the operative field was tolerable secured under conditions of partial lung collapse.

WHAT THIS STUDY ADDS

Oxygen concentration can be set to the minimum level, sufficient to maintain oxygenation, during contralateral partial pulmonary resection with selective bronchial blockade.

Is lung stereotactic ablative radiotherapy safe after pneumonectomy?-a systematic review

Patients treated with surgery for lung cancer are at risk of second primary lung cancers (SPLCs), which when localized, may be amenable to radical treatment. Treatment options, however, are limited due to reduced cardiopulmonary reserve and competing mortality risks. The aim of this study was to perform a systematic review of publications examining treatment planning considerations, clinical outcomes, and toxicity rates of stereotactic ablative radiotherapy (SABR) in patients who have previously undergone pneumonectomy. A systematic review of the literature was conducted in accordance with PRISMA guidelines using PubMed and EMBASE from inception to July 2018. Articles were limited to those published in the English language. Non-review articles with patients who received exclusively lung SABR post-pneumonectomy were included. Two reviewers independently performed abstract and full-text review, with discrepancies settled by a third reviewer. Of the 215 articles identified by the initial search, 6 articles comprising 53 patients who received lung SABR post-pneumonectomy met inclusion criteria. The mean age was 68, and most patients were male (73.7%). The mean time to pneumonectomy was 6.5 years. The mean biologically effective dose was 115 Gy, and the most common dose fractionation schemes were 54 Gy in 3 fractions, 48 Gy in 4 fractions, and 50 Gy in 5 fractions. The mean follow-up was 25.4 months. The mean 1-year overall survival and 2-year local control rates were 80.6% and 89.4%. Grade 3 or higher toxicity was reported in 13.2% of patients. SABR appears to be a safe and feasible option for SPLCs in patients with prior pneumonectomy. Multi-institutional and/or prospective studies would be helpful to determine the true risk and appropriateness of SABR in this high-risk patient population.

Stereotactic ablative radiotherapy of 60 Gy in eight fractions is safe for ultracentral non-small cell lung cancer

Background

There is no consensus on the definition or recommended radiotherapy treatment of ultracentral non‐small cell lung cancer (NSCLC). Here, we report our institution's experience in treating ultracentral lung cancer patients with stereotactic ablative radiotherapy (SABR) of 60 Gy in eight fractions.

Methods

We retrospectively reviewed the outcomes of 21 ultracentral NSCLC patients treated with 60 Gy SABR in eight fractions. We defined ultracentral lung cancer as the planning target volume (PTV) directly abutting or overlapping central structures, including the proximal bronchial tree, heart, and great vessels but not the esophagus. The Kaplan‐Meier method was used to estimate overall survival (OS), progression‐free survival (PFS) and local control (LC). Toxicity was scored per the CTCAE v4.03.

Results

The median follow‐up time was 15 months, and the median OS was 15 months. The one‐ and two‐year OS rates were 87.5% and 76.6%, respectively. The one‐ and two‐year PFS rates were 71.1% and 64.0%, respectively. The one‐ and two‐year LC rates were 92.9% and 92.9%, respectively. The rate of grade 2 treatment‐related toxicities was 19.1%. There was no grade ≥ 3 treatment‐related toxicity.

Conclusion

SABR of 60 Gy in eight fractions is feasible for ultracentral NSCLC.

Stereotactic ablative radiation therapy in lung cancer: an emerging standard

PURPOSE OF REVIEW

Significant advances have been made in the field of stereotactic ablative radiotherapy (SABR) for the treatment of pulmonary neoplasms in recent years. This review aims to summarize recent salient evidence on SABR for early-stage nonsmall cell lung cancer (ES-NSCLC).

RECENT FINDINGS

In medically inoperable patients, SABR remains the standard of care. The optimal SABR dosing regimen is being studied. Comparisons with non-SABR radiotherapy regimens with lower doses per fraction revealed benefit of SABR. In operable patients, no prospective clinical trial comparing SABR and surgery has been completed, although multiple trials are currently underway to address this question. SABR is generally cost-effective and safe in most patients, with preserved patient-reported quality of life. However, increased toxicity with SABR is noted in patients with disease close to, or invading the proximal tracheobronchial tree. Significant SABR-related toxicity and mortality is also reported in patients with coexisting interstitial lung disease. Considerations on pathologic confirmation, surveillance and multiple primaries are also addressed.

SUMMARY

SABR is an effective and safe treatment for inoperable ES-NSCLC. Ongoing trials and comparative effectiveness research will help to clarify SABR's role in various lung cancer indications going forward.

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.

Stereotactic body radiation therapy (SBRT) for early-stage lung cancer in the elderly

Early-stage non-small cell lung cancer (NSCLC) is on the rise due to the implementation of screening guidelines for patients at risk for developing lung cancer. It is anticipated that as the US population continues to age, there will be a higher percentage of medically inoperable early-stage lung cancer patients. For this reason, noninvasive ablative therapies are necessary. Stereotactic body radiation therapy (SBRT) is an effective modality in addressing early-stage NSCLC. SBRT consists of high-dose radiation delivered over 3-5 treatments. Several randomized trials comparing surgery to SBRT in early-stage operable patients have unfortunately closed early due to poor accrual. However, a recent pooled analysis from 2 randomized trials (StereoTActic Radiotherapy and Radiosurgery Or Surgery for operable Early-stage non-small cell Lung cancer) comparing surgery to SBRT did show comparable local control and overall survival rates between surgery and SBRT, offering a very effective, noninvasive modality for older adult patients with early-stage NSCLC. In this review, we summarize the role of SBRT in early-stage NSCLC, in particularly applied to the older adult population.

Therapeutic options following pneumonectomy in non-small cell lung cancer

INTRODUCTION

Pneumonectomy can be considered the most appropriate treatment for lung cancer that cannot be removed by lesser resection on.

AREAS COVERED

Therapeutic options following pneumonectomy may be required at least in 3 different scenarios: 1) an early approach due to acute surgical complications 2) a late approach due to chronic surgical complications 3) an integrated radio-chemotherapeutic adjuvant approach for advanced stages. In this review we focused on these three settings with particular emphasis to surgical approach as well as to alternative options. Expert commentary: Pneumonectomy itself does not preclude postoperative additional treatments, if needed, to maximize oncological results and to manage potential short or long term complications. However, as pneumonectomy puts a significant physiological stress on the respiratory and circulatory systems, the benefits and risks of pneumonectomy should be compared with those of alternative, non-resectional treatment modalities.

Efficacy and Safety of Stereotactic Ablative Radiotherapy in Patients with Previous Pneumonectomy

Background

Thoracic surgery for a newly diagnosed primary lung tumor following a previous pneumonectomy is rarely indicated. Stereotactic ablative radiotherapy (SABR) might represent a curative option. This report focuses on outcomes, toxicity and quality of life (QoL) after SABR.

Methods

Nine patients were treated with SABR between 2004 and 2011; median time since surgery was 8.4 years. In 4 cases, a histological confirmation was possible with bronchoscopy. In 5 cases, the clinical proof of malignancy was based on radiological criteria. Forced expiratory volume in 1 second (FEV1) and diffusing capacity of the lung for carbon monoxide (DLCO) were tested in all patients. A SABR biologically equivalent dose of >100 Gy was prescribed in all cases. QoL questionnaire forms were administered before SABR and during follow-up.

Results

Median follow-up was 41.8 months. We did not observe grade >3 acute toxicity, and concerning late toxicity, we registered 2 cases. QoL was decreased during the first 12 months of follow-up, followed by a progressive improvement after this time. One patient had a local relapse at 7.4 years; 1 developed a new nodule at 5.5 years, associated with metastases; and 1 developed a new nodule without any systemic disease at 3 years. There were 2 cancer-related deaths (18.2%) at 3 and 12 months after progression.

Conclusions

Data support efficacy and safety of SABR in patients with a new primary lung cancer following previous pneumonectomy, with acceptable acute, late toxicity profile and without significant impairment of QoL. Our results were comparable to those in the literature.

Stereotactic body radiation therapy for a new lung cancer arising after pneumonectomy: dosimetric evaluation and pulmonary toxicity

OBJECTIVE

To evaluate the tolerance of stereotactic body radiation therapy (SBRT) for the treatment of secondary lung tumours in patients who underwent previous pneumonectomy.

METHODS

12 patients were retrospectively analysed. The median maximum tumour diameter was 2.1 cm (1-4.5 cm). The median planning target volume was 20.7 cm(3) (2.4-101.2 cm(3)). Five patients were treated with a single fraction of 26 Gy and seven patients with fractionated schemes (3 × 10 Gy, 4 × 10 Gy, 4 × 12 Gy). Lung toxicity, correlated with volume (V) of lung receiving >5, >10 and >20 Gy, local control and survival rate were assessed. Median follow-up was 28 months.

RESULTS

None of the patients experienced pulmonary toxicity > grade 2 at the median dosimetric lung parameters of V5, V10 and V20 of 23.1% (range 10.7-56.7%), 7.3% (2.2-27.2%) and 2.7% (0.7-10.9%), respectively. No patients required oxygen or had deterioration of the performance status during follow-up if not as a result of clinical progression of disease. The local control probability at 2 years was 64.5%, and the overall survival at 2 years was 80%.

CONCLUSION

SBRT appears to be a safe and effective modality for treating patients with a second lung tumour after pneumonectomy.

ADVANCES IN KNOWLEDGE

Our results and similar literature results show that when keeping V5, V10 V20 <50%, <20% and <7%, respectively, the risk of significant lung toxicity is acceptable. Our experience also shows that biologically effective dose 10 >100 Gy, necessary for high local control rate, can be reached while complying with the dose constraints for most patients.

Continuous Positive Airway Pressure for Motion Management in Stereotactic Body Radiation Therapy to the Lung: A Controlled Pilot Study

OBJECTIVE

To determine the effect of continuous positive airway pressure (CPAP) on tumor motion, lung volume, and dose to critical organs in patients receiving stereotactic body radiation therapy (SBRT) for lung tumors.

METHODS AND MATERIALS

After institutional review board approval in December 2013, patients with primary or secondary lung tumors referred for SBRT underwent 4-dimensional computed tomographic simulation twice: with free breathing and with CPAP. Tumor excursion was calculated by subtracting the vector of the greatest dimension of the gross tumor volume (GTV) from the internal target volume (ITV). Volumetric and dosimetric determinations were compared with the Wilcoxon signed-rank test. CPAP was used during treatment if judged beneficial.

RESULTS

CPAP was tolerated well in 10 of the 11 patients enrolled. Ten patients with 18 lesions were evaluated. The use of CPAP decreased tumor excursion by 0.5 ± 0.8 cm, 0.4 ± 0.7 cm, and 0.6 ± 0.8 cm in the superior-inferior, right-left, and anterior-posterior planes, respectively (P ≤ .02). Relative to free breathing, the mean ITV reduction was 27% (95% confidence interval [CI] 16%-39%, P<.001). CPAP significantly augmented lung volume, with a mean absolute increase of 915 ± 432 cm(3) and a relative increase of 32% (95% CI 21%-42%, P=.003), contributing to a 22% relative reduction (95% CI 13%-32%, P=.001) in mean lung dose. The use of CPAP was also associated with a relative reduction in mean heart dose by 29% (95% CI 23%-36%, P=.001).

CONCLUSION

In this pilot study, CPAP significantly reduced lung tumor motion compared with free breathing. The smaller ITV, the planning target volume (PTV), and the increase in total lung volume associated with CPAP contributed to a reduction in lung and heart dose. CPAP was well tolerated, reproducible, and simple to implement in the treatment room and should be evaluated further as a novel strategy for motion management in radiation therapy.

Stereotactic ablative radiotherapy (SABR) for treatment of central and ultra-central lung tumors

OBJECTIVES

Treatment of central and ultra-central lung tumors with stereotactic ablative radiotherapy (SABR) remains controversial due to risks of treatment-related toxicities compared with peripheral tumors. Here we report our institution's experience in treating central and ultra-central lung tumor patients with SABR.

MATERIALS AND METHODS

We retrospectively reviewed outcomes in 68 patients with single lung tumors, 34 central and 34 peripheral, all treated with SABR consisting of 50 Gy in 4-5 fractions. Tumor centrality was defined per the RTOG 0813 protocol. We defined "ultra-central" tumors as those with GTV directly abutting the central airway.

RESULTS

Median follow-up time was 18.4 months and median overall survival was 38.1 months. Two-year overall survival was similar between ultra-central, central, and peripheral NSCLC (80.0% vs. 63.2% vs. 86.6%, P=0.62), as was 2-year local failure (0% vs. 10.0% vs. 16.3%, P=0.64). Toxicity rates were low and comparable between the three groups, with only two cases of grade 3 toxicity (chest wall pain), and one case of grade 4 toxicity (pneumonitis) observed. Patients with ultra-central tumors experienced no symptomatic toxicities over a median follow-up time of 23.6 months. Dosimetric analysis revealed that RTOG 0813 central airway dose constraints were frequently not achieved in central tumor treatment plans, but this did not correlate with increased toxicity rate.

CONCLUSION

Patients with central and ultra-central lung tumors treated with SABR (50 Gy in 4-5 fractions) experienced few toxicities and good outcomes, similar to patients with peripheral lung tumors.

Risk of Pneumonitis After Stereotactic Body Radiation Therapy in Patients With Previous Anatomic Lung Resection

BACKGROUND

Stereotactic body radiation therapy (SBRT) has emerged as a standard treatment of early-stage, medically inoperable lung cancer. Limited data have evaluated the radiation pneumonitis (RP) risk with SBRT after previous anatomic lung resection (ALR). We assessed the incidence of RP and all pulmonary toxicity (PT) in patients who underwent lung SBRT after ALR and compared them with those of patients without previous ALR.

MATERIALS AND METHODS

We reviewed the medical records of 84 consecutively treated patients with stage T1-T2b non-small-cell lung cancer (NSCLC) treated with 88 courses of SBRT for 94 lung tumors from January 2007 to December 2014, including 17 patients with previous ALR. The rates of RP and all PT were compared between the patients with and without previous ALR.

RESULTS

At a median follow-up duration of 18.3 months (range, 1.8-85.6 months), the crude grade 2+ RP rate was 5.9% and 2.8% for patients with and without previous ALR, respectively (P = .51). The corresponding 2-year estimates of freedom from RP were 89% and 97% (P = .51). The crude rate of all grade 2+ PT was 11.8% and 2.8% for those with and without previous ALR (P = .11), with 2-year estimates of freedom from PT of 97% and 84% (P = .11), respectively. The 2 cohorts were well matched by the mean lung dose, percentage of lung volume receiving 20 Gy (P = .86), and prescribed dose (P = .75). The 2-year estimates of local control, cause-specific survival, and overall survival were similar between the 2 cohorts.

CONCLUSION

The observed rates of PT were low among all patients, with a trend toward increased grade 2 and 3 lung toxicity among patients with previous ALR. Previous ALR did not increase the risk of grade 4 and 5 RP, and SBRT appears safe and effective in this population.

To SABR or not to SABR? Indications and contraindications for stereotactic ablative radiotherapy in the treatment of early-stage, oligometastatic, or oligoprogressive non-small cell lung cancer

Stereotactic ablative radiotherapy (SABR) is a highly effective treatment for early-stage non-small cell lung cancer. Although direct comparisons from randomized trials are not available, rates of both primary tumor control and distant metastasis are similar between SABR and surgery. Overall survival is lower after SABR compared with surgery, largely reflecting that a primary selection criterion for SABR has been medical inoperability because of decreased cardiopulmonary function and other comorbidities that lead to decreased survival independent of non-small cell lung cancer. Survival outcomes between SABR and surgery are much more similar in propensity-matched cohorts. Newer potential indications for SABR include treatment of operable patients; of oligometastatic lung cancer, in which SABR has emerged as an alternative to metastasectomy; and of oligoprogressive lung cancer, an attractive concept especially as improved personalized systemic therapies emerge, and prospective trials are currently being conducted in these settings. Although toxicity in modern series is low, SABR is clearly capable of producing fatal complications, and understanding the risk factors and approaches for mitigating them has been emerging in recent years. Thus, appropriate patient selection is a vital, evolving, and controversial topic.

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.