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

Sublobar Resection, Stereotactic Body Radiation Therapy, and Percutaneous Ablation Provide Comparable Outcomes for Lung Metastasis-Directed Therapy

BACKGROUND

Prolonged survival of patients with metastatic disease has furthered interest in metastasis-directed therapy (MDT).

RESEARCH QUESTION

There is a paucity of data comparing lung MDT modalities. Do outcomes among sublobar resection (SLR), stereotactic body radiation therapy (SBRT), and percutaneous ablation (PA) for lung metastases vary in terms of local control and survival?

STUDY DESIGN AND METHODS

Medical records of patients undergoing lung MDT at a single cancer center between January 2015 and December 2020 were reviewed. Overall survival, local progression, and toxicity outcomes were collected. Patient and lesion characteristics were used to generate multivariable models with propensity weighted analysis.

RESULTS

Lung MDT courses (644 total: 243 SLR, 274 SBRT, 127 PA) delivered to 511 patients were included with a median follow-up of 22 months. There were 47 local progression events in 45 patients, and 159 patients died. Two-year overall survival and local progression were 80.3% and 63.3%, 83.8% and 9.6%, and 4.1% and 11.7% for SLR, SBRT, and PA, respectively. Lesion size per 1 cm was associated with worse overall survival (hazard ratio, 1.24; P = .003) and LP (hazard ratio, 1.50; P < .001). There was no difference in overall survival by modality. Relative to SLR, there was no difference in risk of local progression with PA; however, SBRT was associated with a decreased risk (hazard ratio, 0.26; P = .023). Rates of severe toxicity were low (2.1%-2.6%) and not different among groups.

INTERPRETATION

This study performs a propensity weighted analysis of SLR, SBRT, and PA and shows no impact of lung MDT modality on overall survival. Given excellent local control across MDT options, a multidisciplinary approach is beneficial for patient triage and longitudinal management.

Colorectal Pulmonary Metastases: Pulmonary Metastasectomy or Stereotactic Radiotherapy?

BACKGROUND

Pulmonary metastasectomy and stereotactic ablative radiotherapy (SABR) are both guideline-recommended treatments for selected patients with oligometastatic colorectal pulmonary metastases. However, there is limited evidence comparing these local treatment modalities in similar patient groups.

METHODS

We retrospectively reviewed records of consecutive patients treated for colorectal pulmonary metastases with surgical metastasectomy or SABR from 2012 to 2019 at two Dutch referral hospitals that had different approaches toward the local treatment of colorectal pulmonary metastases, one preferring surgery, the other preferring SABR. Two comparable patient groups were identified based on tumor and treatment characteristics.

RESULTS

The metastasectomy group comprised 40 patients treated for 69 metastases, and the SABR group had 60 patients who were treated for 90 metastases. Median follow-up was 38 months (IQR: 26-67) in the surgery group and 46 months (IQR: 30-79) in the SABR group. Median OS was 58 months (CI: 20-94) in the metastasectomy group and 70 months (CI: 29-111) in the SABR group (p = 0.23). Five-year local recurrence-free survival (LRFS) was 44% after metastasectomy and 30% after SABR (p = 0.16). Median progression-free survival (PFS) was 15 months (CI: 3-26) in the metastasectomy group and 10 months (CI: 6-13) in the SABR group (p = 0.049). Local recurrence rate was 12.5/7.2% of patients/metastases respectively after metastasectomy and 38.3/31.1% after SABR (p < 0.001). Lower BED Gy10 was correlated with an increased likelihood of recurrence (p = 0.025). Clavien Dindo grade III-V complication rates were 2.5% after metastasectomy and 0% after SABR (p = 0.22).

CONCLUSION

In this retrospective cohort study, pulmonary metastasectomy and SABR had comparable overall survival, local recurrence-free survival, and complication rates, despite patients in the SABR group having a significantly lower progression-free survival and local control rate. These data would support a randomized controlled trial comparing surgery and SABR in operable patients with radically resectable colorectal pulmonary metastases.

Stereotactic Body Radiation Therapy for Sarcoma Pulmonary Metastases

BACKGROUND

Lung metastases are the most common form of distant failure for patients diagnosed with sarcoma with metastasectomy considered for some patients with limited metastatic disease and good performance status. Alternatives to surgery such as stereotactic body radiation therapy (SBRT) can be considered, though data are limited. We present outcomes after SBRT for sarcoma lung metastases.

METHODS

Fifty sarcoma patients with 109 lung metastases were treated with SBRT between 2005 and 2021. Outcomes evaluated included local control (LC), overall survival (OS), and toxicity including lung pneumonitis/fibrosis, chest wall toxicity, dermatitis, brachial plexus, and esophageal toxicity. Systemic therapy receipt before and after SBRT was recorded.

RESULTS

SBRT schedules were divided into 3 cohorts: 30 to 34 Gy/1fx (n=10 [20%]), 48 to 50 Gy/4 to 5fx (n=24[48%]), and 60 Gy/5fx (n=16[32%]). With a median follow-up of 19.5 months, 1/3-year LC rates were 96%/88% and 1/3-year OS 77%/50%, respectively. There was no differences between the 3 regimens in terms of LC, OS, or toxicity. Size >4 cm was a predictor of worse LC ( P =0.031) and worse OS ( P = 0.039) on univariate analysis. The primary pattern of failure was new metastases (64%) of which the majority were in the contralateral lung (52%). One-year chemotherapy-free survival was 85%. Overall, 76% of patients did not require chemotherapy initiation or change of chemotherapy regimen after lung SBRT. Toxicity was reported in 16% of patients overall, including 25%, 20%, and 14% in the 30 to 34 Gy/1fx, 48 to 50 Gy/4 to 5fx, and 60 Gy/5fx cohorts, respectively.

CONCLUSIONS

SBRT outcomes for lung metastases from sarcoma demonstrate high rates of LC and are similar with different dose/fractionation regimens. Lung SBRT is associated with prolonged chemotherapy-free survival. Prospective validation of these results is warranted.

Stereotactic body radiation therapy (SBRT) for lung metastases from sarcoma in oligometastatic patients: a phase 2 study

PURPOSE

Lung is the most frequent site of metastasis in sarcoma patients. Pulmonary metastasectomy is the most common treatment performed. Stereotactic body radiation therapy(SBRT) has proven to be a potential alternative to resection. We aimed to assess role of SBRT for lung metastatic patients in a prospective phase 2 study.

METHODS AND MATERIALS

Adults patients with lung metastasis(LMs) up to 4, ≤5cm, unsuitable for surgery were included. Dose prescription was based on site and size: 30Gy/1fraction for peripheral lesions ≤10mm, 60 Gy/3fractions for peripheral lesions 11-20mm, 48 Gy/4fractions for peripheral lesions >20mm, and 60 Gy/8fractions for central lesions. Primary endpoint was proportion of treated lesions free from progression at 12 months. Secondary endpoints were disease free survival(DFS), overall survival(OS), and toxicity.

RESULTS

Between March 2015, and December 2020, 44 patients for 71 LMs were enrolled. Twelve-month local control was 98.5%±1.4, reaching primary aim; median DFS time,1,2,3,4,5-year PFS rates were 12 months(95%CI 8-16 months), 50%±7.5, 19.5%±6.6, 11.7%±5.8, 11.7%±5.8, and 11.7%±5.8, respectively. Median OS time,1,2,3,4,5-year OS rates were 49 months(95%CI 24-49 months), 88.6%±4.7, 66.7±7.6, 56.8%±8.4, 53.0%±8.6, and 48.2%±9.1, respectively. Prognostic factors recorded as significantly impacting survival were age, grade of primary sarcoma, interval time from diagnosis to occurrence of LMs, and number of LMs. No severe pulmonary toxicity(grade 3-4) occurred.

CONCLUSIONS

We found a local control of LMs in almost all patients treated, with negligible toxicity. Survival was also highly satisfactory. Well-designed randomized trials comparing surgery with SBRT for lung metastatic sarcoma patients are needed to confirm this preliminary data.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier XXXXXX.

Outcome of lung oligometastatic patients treated with stereotactic body irradiation

Purpose

The oligometastatic stage is an intermediate stage of cancer between the localized stage and polymetastatic stage. The prognosis of patients in this stage also appears to be intermediate. Lung stereotactic body radiotherapy is a possible tool for treating oligometastatic lung sites. The objective of our study was to evaluate the clinical outcomes in terms of local control, progression-free survival, overall survival, and toxicity of SBRT in oligometastatic patients with lung metastases from any solid primary tumor.

Materials and methods

Clinical records of consecutive lung oligometastatic patients treated between January 2010 and December 2020 for lung SBRT at 60 Gy in 3- or 8-fraction schedules and a controlled primary tumor were retrospectively analyzed.

Results

After a median follow-up of 20.3 months, local failure occurred for 14 lesions, 57 patients experienced lung progression, and 64 patients experienced disease progression. Overall survival rates at 1 and 2 years were 85.6 and 69.7%, respectively. Fifty-two patients experienced radiation pneumonitis, but only 2 patients were symptomatic and presented grade 2 late pneumonitis. No grade 3-4 toxicity was observed. ECOG 0 was the only prognostic factor for overall survival (HR = 3.5; 95% CI 3.2-3.8; p < 0.01).

Conclusion

SBRT with a 60-Gy schedule in 8 fractions is an effective and well-tolerated treatment for patients with lung oligometastases from any solid primary tumor.

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

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

Thoracic Radiotherapy for Renal Cell Carcinoma Metastases: Local Control for the Management of Lung and Mediastinal Disease in the Modern Era

INTRODUCTION/BACKGROUND

Radiotherapy (RT) is an alternative local therapy to metastasectomy in the treatment of thoracic metastases from renal cell carcinoma (RCC), including the management of life-threatening disease.

PATIENTS AND METHODS

We reviewed patients with lung and mediastinal RCC metastases treated with RT at our institution. Overall survival (OS) and metastasis control (MC) was measured from the start of RT using the Kaplan-Meier (KM) method.

RESULTS

Seventy-one patients were treated with RT for 89 lung (n = 58) or mediastinal (n = 31) metastases. Of 89 treated lesions, 11 (12%) had local tumor recurrence, at a median of 1.6 years (range 0.4-2.9). MC at 1, 3, and 5-years was 96.6%, 83.5%, and 67.9%, respectively. For the 58-lung metastasis-directed RT courses, MC rates at 1, 3, and 5-years were 95.0%, 84.5%, and 84.5%, respectively (median MC not reached). For the 31-mediastinum metastasis-directed RT courses, MC rates at 1, 3, and 5-years were 100%, 43.4%, and 43.4%, respectively (median MC 2.9 years). MC was significantly improved for lung lesions compared to mediastinal lesions (P = .046). OS for the entire cohort at 1, 3, and 5 years was 65.2%, 48.5%, and 38.0%. There was no difference in OS based on metastatic sites in the 71 patients. Nineteen patients received RT to 19 lesions with the intention of preventing an event such as airway compromise or vascular invasion. One and two-year MC for these 19 lesions were 88.9% and 71.1%, respectively (median local control 2.4 years). OS in these 19 patients at 1, 2, and 5 years were 62.1%, 48.3%, and 32.2% respectively, with median survival 1.2 years. No patients developed grade 4 or 5 acute or late toxicities.

CONCLUSION

Radiation therapy can safely achieve high metastasis control rates for lung and mediastinal metastases from RCC, including lesions at high risk for causing a life-threatening event.

Impact of tumor size and location on lung dose difference between stereotactic body radiation therapy techniques for non-small cell lung cancer

Background

To evaluate the lung dose differences between three‐dimensional conformal radiotherapy (3D‐CRT) and intensity‐modulated radiation therapy (IMRT) techniques for lung stereotactic body radiation therapy (SBRT) and the correlations with tumor characteristics, such as size and location.

Methods

Dosimetric comparisons between the two SBRT techniques in high‐ and low‐ to intermediate‐dose regions were retrospectively performed using four planning indices and lung‐dose parameters in 31 lung tumors. The magnitude of differences in these parameters was analyzed with relation to the planning target volume (PTV) and location‐related parameters.

Results

The absolute differences between the two techniques in lung‐dose parameters were small in both ipsilateral and bilateral lungs. The dosimetric differences were mainly correlated with the PTV rather than location‐related parameters, with positive and negative correlations with the high‐dose and intermediate‐dose parameters, respectively. The distances from the ipsilateral lung centroid to the PTV center were not correlated with the differences in any of the lung‐dose parameters. Additionally, the negative correlations with the MLD and V20 differences disappeared after applying a more rapid dose fall‐off in the IMRT plans for tumors with small PTVs of ≤15 cc.

Conclusions

Lung dose differences between the 3D‐CRT and IMRT techniques for lung SBRT were mainly correlated with the PTV rather than location‐related parameters. Together with the dosimetric benefit in high‐dose lung regions of IMRT for larger tumors, the relative increases in the MLD and V20 for small‐sized tumors could be reduced by applying a more rapid dose fall‐off outside the PTV.

Stereotactic Body Radiotherapy for Patients with Lung Oligometastatic Disease: A Five-Year Systematic Review

For several years, oligometastatic disease has represented an intermediate state between localized disease accessible to local treatment and multimetastatic disease requiring systemic therapy. The lung represents one of the most common metastatic locations. Stereotactic body radiation therapy (SBRT) appears to be the treatment of choice for these patients. There are few data defining the place of radiotherapy and reporting outcome after SBRT in lung metastases. This 5-year review aimed to determine areas of SBRT usefulness and methods for the management of pulmonary metastasis in oligometastatic patients. A search for articles on PubMed allowed selection of the most relevant studies. Eighteen articles were selected according to pre-established criteria for this purpose. The analysis concludes that SBRT is an effective and safe treatment in selected patients when the disease remains localized from one to three organs.

Active Surveillance in Metastatic Renal Cell Carcinoma: Results From the Canadian Kidney Cancer Information System

BACKGROUND

Active surveillance (AS) is a commonly used strategy in patients with slow-growing disease. We aimed to assess the outcomes and safety of AS in patients with metastatic renal cell carcinoma (mRCC).

PATIENTS AND METHODS

We used the Canadian Kidney Cancer information system (CKCis) to identify patients with mRCC diagnosed between January 1, 2011, and December 31, 2016. The AS strategy was defined as (1) the start of systemic therapy ≥ 6 months after diagnosis of mRCC, or (2) never receiving systemic therapy for mRCC with an overall survival (OS) of ≥1 year. Patients starting systemic treatment <6 months after diagnosis of mRCC were defined as receiving immediate systemic treatment. OS and time until first-line treatment failure (TTF) were compared between the two cohorts.

RESULTS

A total of 853 patients met the criteria for AS (cohort A). Of these, 364 started treatment >6 months after their initial diagnosis (cohort A1) and 489 never started systemic therapy (cohort A2); 827 patients received immediate systemic treatment (cohort B). The 5-year OS probability was significantly greater for cohort A than for cohort B (70% vs. 33.6%; P < .0001). After adjusting for International Metastatic RCC Database Consortium risk criteria and age, both OS (hazard ratio [HR] = 0.58; 95% confidence interval [CI], 0.47-0.70; P < .0001) and TTF (HR = 0.72; 95% CI, 0.60-0.85; P = .0002) were greater in cohort A1 compared with B. For cohort A1, the median time on AS was 14.2 months (range, 6-71).

CONCLUSIONS

Based on the largest analysis of AS in mRCC to date, our data suggest that a subset of patients may be safely observed without immediate initiation of systemic therapy.

Meta-analysis of survival outcomes following surgical and non surgical treatments for colorectal cancer metastasis to the lung

BACKGROUND

Controversy exists regarding the optimal management of colorectal lung metastases (CRLM). This meta-analysis compared surgical (Surg) versus interventional (chemotherapy and/or radiotherapy) and observational non-surgical (NSurg) management of CRLM.

METHODS

A systematic review of the major databases including Medline, Embase, SCOPUS and the Cochrane library was performed.

RESULTS

One randomized and nine observational studies including 2232 patients: 1551 (69%) comprised the Surg cohort, 521 (23%) the interventional NSurg group and 160 (7%) the observational NSurg group. A significantly higher overall survival (OS) was observed when Surg was compared to interventional NSurg at 1 year (Surg 88%, 310/352; interventional NSurg 64%, 245/383; odds ratio (OR) 2.77 (confidence interval (CI) 1.94-3.97), P = 0.001), at 3 years (Surg 59%, 857/1444; interventional NSurg 26%, 138/521; OR 2.61 (CI 1.65-4.15), P = 0.002), at 5 years (Surg 47%, 533/1144; interventional NSurg 23%, 45/196; OR 3.24 (CI 1.42-7.39), P = 0.009) and at 10 years (Surg 27%, 306/1122; interventional NSurg 1%, 2/168; OR 15.64 (CI 1.87-130.76), P = 0.031). Surg was associated with a greater OS than observational NSurg at only 1 year (Surg 92%, 98/107; observational NSurg 83%, 133/160; OR 6.69 (CI 1.33-33.58), P = 0.037) and was similar to observational NSurg at all other OS time points. Comparable survival was observed among Surg and overall NSurg cohorts at 3- and 5-year survival in articles published within the last 3 years.

CONCLUSIONS

Recent evidence suggests comparable survival with Surg and NSurg modalities for CRLM, contrasting to early evidence where Surg had an improved survival. Significant selection bias contributes to this finding, prompting the need for high powered randomized controlled trials and registry data.

Cost-Effectiveness Analysis of Stereotactic Ablative Body Radiation Therapy Compared With Surgery and Radiofrequency Ablation in Two Patient Cohorts: Metastatic Liver Cancer and Hepatocellular Carcinoma

AIMS

To compare the cost-effectiveness of stereotactic ablative body radiation therapy (SABR) with radiofrequency ablation and surgery in adult patients with metastatic liver cancer and hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Two patient cohorts were assessed: liver oligometastases and HCC. For each patient cohort, a decision analytic model was constructed to assess the cost-effectiveness of interventions over a 5-year horizon. A Markov process was embedded in the decision model to simulate the possible prognosis of cancer. Data on transition probabilities, survival, side-effects, quality of life and costs were obtained from published sources and the SABR Commissioning through Evaluation (CtE) scheme. The primary outcome was the incremental cost-effectiveness ratio with respect to quality-adjusted life-years. The robustness of the results was examined in a sensitivity analysis. Analyses were conducted from a National Health Service and Personal Social Services perspective.

RESULTS

In the base case analysis, which assumed that all three interventions were associated with the same cancer progression rates and mortality rates, SABR was the most cost-effective intervention for both patient cohorts. This conclusion was sensitive to the cancer progression rate, mortality rate and cost of interventions. Assuming a willingness-to-pay threshold of £20 000 per quality-adjusted life-year, the probability that SABR is cost-effective was 57% and 50% in liver oligometastases and HCC, respectively.

CONCLUSIONS

Our results indicate a potential for SABR to be cost-effective for patients with liver oligometastases and HCC. This finding supports further investigation in clinical trials directly comparing SABR with surgery and radiofrequency ablation.

Stereotactic Body Radiation Therapy in Oligometastatic Uterine Cancer: Clinical Outcomes and Toxicity

We report on clinical outcomes in patients with oligometastatic uterine cancer treated with stereotactic body radiation therapy (SBRT). Twenty-seven patients with 61 lesions were treated with SBRT. Median follow-up was 16.9 months. Local control was achieved in 49/61 (80.3%) lesions. One-year local-progression-free survival and overall survival were 75.9% and 65.4%. Lesions with favorable response were smaller than lesions with unfavorable response (p = .007). Liver lesions were less likely to achieve favorable response (p = .0128). There were no grade 3 or 4 events. Treatment with SBRT can provide excellent local control in oligometastatic uterine cancer with minimal toxicity.

Current Indications for Pulmonary Metastasectomy

The lung is one of the most common sites of metastatic disease. Assessing patients for pulmonary metastasectomy includes ensuring they are suitable surgical candidates for single-lung ventilation and pulmonary resection. Complete resection of metastases and control of primary tumor and oligometastatic disease are key tenets for metastasectomy. Negative prognostic factors include short disease-free interval, presence of lymphadenopathy, and multiple lesions. Primary tumors are associated with excellent outcomes. With modern high-resolution scans, minimally invasive approaches to metastasectomy are preferred. Consideration of extended resections should take place in a multidisciplinary manner. Nonoperative options include stereotactic body radiation therapy, radiofrequency ablation, and microwave ablation.

The Role of Metastasectomy in Urothelial Carcinoma: Where Are We in 2020?

Systemic therapy is the mainstay of treatment for metastatic urothelial carcinoma (UC). Responses to first-line platinum-based therapy tend to be short-lived with potential toxicity. Despite the approval of checkpoint inhibitors, the long-term prognosis for patients with metastatic UC remains dismal. Herein we report the case of a patient with a solitary pulmonary metastatic lesion of urothelial origin as the only site of metastatic disease who remained free of disease for more than 2 years without systemic therapy after metastasectomy. We review the literature discussing the role of combined surgical and medical management of oligometastatic UC. As our case illustrates, a growing body of evidence suggests a potential role for a multimodal approach in patients with oligometastatic UC.

Stereotactic Body Radiotherapy Versus Metastasectomy in Patients With Pulmonary Metastases From Soft Tissue Sarcoma

The lung is the preferred site of metastasis from soft tissue sarcoma (STS). This systematic review aims to evaluate the outcomes of stereotactic body radiotherapy (SBRT) and metastasectomy (MTS) for the treatment of lung metastases from STS. A systematic review was carried out according to the PRISMA protocol. PubMed, Medline, EMBASE, Cochrane Library, Ovid and Web of Knowledge databases were searched for English-language articles to December 2018 using a predefined strategy. Retrieved studies were independently screened and rated for relevance. Data were extracted by two researchers. In total, there were 1306 patients with STS: 1104 underwent MTS and 202 had SBRT. The mean age ranged from 40 to 55.8 years in the MTS group and from 47.9 to 64 years in the SBRT group. The cumulative death rate was 72% (95% confidence interval 59-85%) in the MTS group and 56% (38-74%) in the SBRT group. The cumulative mean overall survival time was 46.7 months (36.4-57.0%) in the MTS group and 47.6 months (33.7-61.5%) in the SBRT group. The cumulative rate of patients alive with disease was 5% (2-9%) in the MTS group and 15% (6-36%) in the SBRT group. Finally, the cumulative rate of patients alive without disease in the two groups was 19% (9-29%) and 20% (10-50%), respectively. Our study showed that local treatment of pulmonary metastases from STS with SBRT, compared with surgery, was associated with a lower cumulative overall death rate and similar overall survival time and survival rates without disease. By contrast, SBRT was associated with a higher survival rate with disease than MTS. Large randomised trials are necessary to confirm these findings and to establish whether SBRT may be a reliable option for early stage disease.

Influence of tumor characteristics on correction differences between cone-beam computed tomography-guided patient setup strategies in stereotactic body radiation therapy for lung cancer

BACKGROUND

To evaluate the correction differences between vertebra and tumor matching as cone-beam computed tomography (CBCT)-guided setup strategies in lung stereotactic body radiation therapy (SBRT), and the correlations with tumor characteristics such as size, mobility, and location.

METHODS

The manual registrations for 33 lung tumors treated with SBRT were retrospectively performed by matching thoracic vertebrae for vertebra matching and then by matching CBCT-visualized tumors within the internal target volume obtained from a four-dimensional CT dataset for tumor matching.

RESULTS

The mean correction difference between the two matching methods during the SBRT fractions was larger in the anterior-posterior direction (2.7 mm) than in the superior-inferior (2.1 mm) and left-right (1.4 mm) directions, with differences of less than 5 mm in 90% of the total 134 CBCT fractions. The X-axis and direct distances from the central axis to the tumor had significant correlations with the correction differences in all three directions, while the mobility-related parameters were correlated only in the superior-inferior direction. The absolute differences in lung-dose parameters after applying the margins (3.4-6.5 mm) required for the setup errors from vertebra matching relative to tumor matching were mild, with values of 1.95 Gy for the mean lung dose and 3.9% for V20.

CONCLUSION

The setup differences between vertebra and tumor matching in the CBCT-guided setup without rotation correction were increased in tumors located long distances from the central axis. The additional safety margins of 3.4-6.5 mm were required for the setup errors from vertebra matching.

KEY POINTS

Significant findings of the study The correction difference between the vertebra and tumor matching as CBCT-guided setup strategies was the largest in the anterior-posterior direction and significantly correlated with the X-axis and direct distances from the central axis to the tumor. What this study adds Setup differences between vertebra and tumor matching in the CBCT-guided setup were increased in tumors located long distances from the central axis. The additional safety margins of 3.4-6.5 mm were required for the setup errors from vertebra matching.

Is stereotactic radiotherapy equivalent to metastasectomy in patients with pulmonary oligometastases?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was whether stereotactic body radiotherapy (SBRT) was equivalent to metastasectomy in patients with pulmonary oligometastases arising from solid tumours. Altogether, 1612 papers were found using the reported search, of which 5 cohort studies derived from 4 patient populations represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. All 5 studies demonstrated no significant difference in post-treatment overall survival, disease-free survival or local control between SBRT and metastasectomy for pulmonary oligometastases. One of the 5 studies showed a significantly decreased rate of severe complications among the patients treated with SBRT. The other papers reported higher rates of complications in the SBRT groups, invariably due to radiation, but with uncertain clinical significance. The evidence strength of these findings may be largely attenuated due to the small sample size, heterogeneity of SBRT protocols and incomparable follow-up periods between the 2 treatment groups. The selection criteria for the choice of treatment were not stated. We conclude, based on limited evidence, that SBRT has equivalent outcomes to metastasectomy in the treatment of patients with pulmonary oligometastases.

The Past, Present and Future of Pulmonary Metastasectomy: A Review Article

Pulmonary metastases are a sign of advanced malignancy and an omen of poor prognosis. Once primary tumors metastasize, they become notoriously difficult to treat and interdisciplinary management often involves a combination of chemotherapy, radiotherapy, and surgery. Over the last 25 years, the emerging body of evidence has recognized the curative potential of pulmonary metastasectomy. Surgical resection of pulmonary metastases is now commonly considered for patients with controlled primary disease, absence of widely disseminated extrapulmonary disease, completely resectable lung metastases, sufficient cardiopulmonary reserve, and lack of a better alternative systemic therapy. Since the development of these selection criteria, other prognostic factors have been proposed to better predict survival and optimize the selection of surgical candidates. Disease-free interval (DFI), completeness of resection, surgical approach, number and laterality of lung metastases, and lymph node metastases all play a dynamic role in determining patient outcomes. There is a definite need to continue reviewing these prognosticators to identify patients who will benefit most from pulmonary metastasectomy and those who should avoid unnecessary loss of lung parenchyma. This literature review aims to explore and synthesize the last 25 years of evidence on the long-term survival, prognostic factors, and patient selection process for pulmonary metastasectomy.