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

Noriko Kishi,Yukinori Matsuo,Masahiro Yoneyama,Kazuhito Ueki,Takashi Mizowaki

doi:10.1016/j.adro.2022.100911

Abstract

PurposeStereotactic body radiation therapy (SBRT) can be easily used for patients with tumors in various organs and is a promising local therapy for eradicating tumors in cancer patients. There is a rising clinical need for increasing knowledge of oligometastases in the treatment of multiple pulmonary tumors. This study aimed to explore the predictive factors for symptomatic radiation pneumonitis (RP) after SBRT for multiple pulmonary oligometastases or synchronous primary lung cancer (SPLC). Methods and MaterialsA total of 38 consecutive patients who had 2 or more pulmonary oligometastases (n = 21) or SPLC (n = 17) and who were treated with SBRT were investigated. Patient characteristics, tumor characteristics, and details of radiation therapy were retrospectively collected from a clinical database. The association between RP of grade 2 or worse (grade 2+ RP) and clinical or dosimetric factors was assessed using logistic regression analyses. ResultsThe tumors presented ipsilaterally in 24 patients and bilaterally in 14 patients. During the median follow-up period of 4.9 years, grade 2+ RP, grade 2 RP, and grade 3 RP were observed in 9 patients (23.7%), 7 patients (18.4%), and 2 patients (5.3%), respectively. The mean lung dose (MLD) and the volume of the normal lung receiving ≥5 Gy (lung V5Gy) were significantly associated with grade 2+ RP (P = .023 and P = .012, respectively). The logistic model showed that 20% and 50% of the predicted probability of grade 2+ RP were 6.1 Gy and 9.1 Gy for MLD and 31.6 % and 42.8% for lung V5Gy, respectively. ConclusionAlthough further investigation is required to validate the metrics and establish reliable dose constraints, the dose-volume metrics for the normal lung could be predictive of the development of grade 2+ RP after SBRT for multiple pulmonary oligometastases or SPLCs.

Highlights

The concept of oligometastases was proposed in 1995
The indications for Stereotactic body radiotherapy (SBRT) were synchronous primary lung cancer (SPLC) in 17 patients and oligometastatic disease in 21 patients; oligometastatic disease was classified as metachronous oligorecurrence in 11, metachronous oligoprogression in one, induced oligorecurrence in six, and induced oligoprogression in three patients according to a consensus recommendation[16]
SBRT is a promising technique for the management of oligometastases and is often administered to patients with multiple pulmonary tumors

Summary

Introduction

The concept of oligometastases was proposed in 1995 It is a clinical state in which the anatomy and physiology may limit or concentrate the metastases to a single or limited number of organs.[1] The treatment strategy for patients with metastatic tumors is systemic therapy because of the spread of microscopic tumor cells. Stereotactic body radiotherapy (SBRT) is a local therapy with a precise irradiation technique that delivers high radiation doses to small, targeted tumors while decreasing the irradiated dose to organs-at-risk (OARs) surrounding the tumor. It is non-invasive and is performed in an outpatient setting with a one- or two-week treatment duration. Pulmonary toxicity is a significant issue in patients with pulmonary lesions treated with

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