Pulmonary oligometastases treated by stereotactic body radiation therapy (SBRT): a single institution’s experience

Abstract

Background: To investigate the effect of stereotactic body radiation therapy (SBRT) on pulmonary oligometastases and to analyze the clinical factors and dose parameters affecting local recurrence-free survival (LRFS) and overall survival (OS). Methods: This study retrospectively enrolled a total of 84 patients (148 lesions) treated in our department from May 2015 to November 2018. Pulmonary oligometastases was defined as up to 5 metastatic lesions in the lung and with both the primary tumor and any extra-thoracic metastases being controlled. Patients receiving a BED 10 (biological effective dose, α/β =10) of SBRT ≥75 Gy and a dose/fraction ≥4 Gy were enrolled. The patient group consisted of 52 men (61.9%) and 32 women (38.1%), with a median age 56 years (range, 29-80 years). Median tumor diameter was 1.71cm (range, 1.2-5.0 cm). The BED 10 was 75-119 Gy in 4-15 fractions. Univariate and multivariate Cox regression analyses were performed on factors predicting the outcomes. Results: All patients completed the treatment as planned, and the median follow-up time was 20.3 months.The median OS for the entire group was 34.3 months, with an actuarial 1-, 2-, 3-and 5-year OS of 74.7%, 59.4%, 49.7%, and 36.8%, respectively. Among the 148 lesions in the whole group, 19 (12.8%) lesions had local recurrence (LR). The median LRFS time for all patients was 56.9 months. The LRFS rate was 93.6%, 83.5%, 81.4%, and 76.6% at 1, 2, 3, and 5 years, respectively. No patient developed acute grade 3 or 4 toxicity.On univariate analysis, age ≥63 years old, primary site of colorectal cancer, BED 10 <85.2 Gy, pathological type of adenocarcinoma, planning target volume (PTV) min BED 10 <76.6 Gy, and gross tumor volume (GTV) ≥8.8 cc, were significantly associated with poorer LRFS. Multivariate analysis showed that age ≥63 years old, primary site of colorectal cancer, and PTV min BED 10 <76.6 Gy were significant risk factors affecting LRFS.Conclusions: SBRT is feasible for pulmonary oligometastasis with favorable local control and minimal toxicity. Multiple dose parameters, instead of a prescription dose only, in combination with clinical parameters, should be considered for optimal local control.

Symptomatic Radiation Pneumonitis After Stereotactic Body Radiation Therapy for Multiple Pulmonary Oligometastases or Synchronous Primary Lung Cancer

“…The local control (LC) rate of SBRT for pulmonary lesions is high, although slightly different rates are shown depending on the histology: the LC rate at 3 years was >85% in solitary primary lung cancer, 14 and the LC rate at 2 to 3 years was 59% to 80% in oligometastatic pulmonary tumors. 23 , 24 , 25 , 26 , 27 A biological effective dose with an α/β ratio of 10 Gy (BED 10 ) < 100 Gy to the target volume and pulmonary metastasis that originates from tumors less responsive to radiation therapy, such as colorectal cancer, are associated with a poor LC rate. 24 , 25 , 28 , 29 As for OS, previous reports on oligometastatic pulmonary tumors showed widely ranging OS rates of 50% to 70% at 2 to 3 years.…”

“… 24 , 25 , 28 , 29 As for OS, previous reports on oligometastatic pulmonary tumors showed widely ranging OS rates of 50% to 70% at 2 to 3 years. 23 , 24 , 26 In this study, 6 patients (15%) were treated with 8 fractions (BED 10 < 100 Gy) owing to the central location, and 8 patients (21%) with pulmonary metastasis that originated from tumors less responsive to radiation therapy (colorectal cancer and renal cancer) were included. Although a direct comparison between the studies is difficult owing to the different patient backgrounds and treatment, the incidence of LR in this study was relatively low compared with these previous reports, and the OS was comparable.…”

Survival and Prognostic Factors of 40 Patients with Pulmonary Oligometastases Treated with Tomotherapy Hypofractionated Radiotherapy

“…Chai et al discussed the therapeutic effects of SBRT on pulmonary metastatic tumors. Univariate analysis showed that age ≥ 63 years, primary colorectal cancer, BED10 < 85.2 Gy, adenocarcinomas, PTV min BED10 < 76.6 Gy, and GTV ≥ 8.8 cc were signi cantly correlated with local recurrence-free survival (LRFS) (23). This study found that patients who were younger than 57 years of age (p = 0.037, HR = 3.35, 95% CI = 1.08-10.41) and those whose metastatic organs were the lungs (p = 0.046, HR = 3.15, 95% CI = 1.02-9.76) had a better overall survival time, which is consistent with the ndings of previous reports.…”

Oligometastatic Adenocarcinoma of the Esophagus: Current Understanding, Diagnosis, and Therapeutic Strategies

“…Inderson et al's report an endoscopic ultrasound guided radiofrequency ablation for left adrenal oligometastasis following EA with acceptable outcome [49]. Pulmonary oligometastases treated with SBRT also appear to be safe and feasible for local control with minimal toxicity [50]. Larger SBRT studies that include synchronous metastasis or oligorecurrence of esophageal carcinoma have demonstrated the safety and efficacy of this treatment strategy [51].…”