Applying PET-CT for predicting the efficacy of SBRT to inoperable early-stage lung adenocarcinoma: A Brazilian case-series

Fabio Y Moraes; Carlos E C V Abreu; Gabriela S M Siqueira; Cecilia K Haddad; Fabiana A M Degrande; Wilma M Hopman; Wellington F P Neves-Junior; Rafael Gadia; Heloisa A Carvalho

doi:10.1016/j.lana.2022.100241

Applying PET-CT for predicting the efficacy of SBRT to inoperable early-stage lung adenocarcinoma: A Brazilian case-series

Lancet Reg Health Am. 2022 Mar 30:11:100241. doi: 10.1016/j.lana.2022.100241. eCollection 2022 Jul.

Authors

Affiliations

¹ Instituto de Ensino e Pesquisa do Hospital Sírio Libanês, R. Prof. Daher Cutait, 69 - Bela Vista, São Paulo, SP 01308-060, Brazil.
² Department of Oncology, Queen's University, Kingston, ON, Canada.
³ Departamento de Radioterapia, Hospital Sírio Libanês, São Paulo, SP, Brazil.
⁴ Departamento de Radioterapia, Hospital Sírio Libanês, Brasília, DF, Brazil.
⁵ Departamento de Radioterapia, Hospital Santa Paula, São Paulo, SP, Brazil.
⁶ Department of Public Health Sciences, Queen's University, ON, Canada.
⁷ Departamento de Radiologia e Oncologia, Divisão de Radioterapia, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil.

Abstract

Background: Stereotactic body radiotherapy (SBRT) is a treatment option for early-stage inoperable primary lung cancer. Here we report a thorough description of the prognostic value of pre-SBRT SUVmax for predicting the efficacy of SBRT in early-stage lung adenocarcinoma.

Methods: This is a retrospective study of consecutive cases of early-stage inoperable lung adenocarcinoma, staged with PET-CT, treated with SBRT between 2007 and 17. Kaplan-Meier (KM) curves were used to assess overall survival and compare time to event between those with PET-CT SUVmax values ≤ 5.0 and those > 5. Fisher's Exact tests and the Mann-Whitney U were used to compare the patient and clinical data of those with SUVmax≤5.0 and >5.0, and those with and without any failure.

Findings: Amongst 50 lung carcinoma lesions, from 47 patients (34 (68%)-T1a or <T1b), estimated median overall survival from the KM was 44.9 months (95% confidence interval 35.5-54.3). Five experienced a local failure, which was inadequate for detecting differences between those with PET-CT SUVmax ≤5.0 and those >5 (p = 0.112). In addition, 5 experienced a regional failure and 4 a distant failure. Higher PET-CT SUVmax values before SBRT were associated with an increased risk of any failure (36% versus 0%, p = 0.0040 on Fisher's Exact test) and faster time to event (p = 0.010, log rank test). Both acute and late toxicities profile were acceptable.

Interpretation: Patients with early-stage inoperable lung adenocarcinoma present good clinical outcomes when treated with SBRT. We raised the hypothesis that the value of PET-CT SUVmax before SBRT may be an important predictive factor in disease control.

Funding: None.

Keywords: Adeno, Adenocarcinoma; Adenocarcinoma; Lung CA, lung cancer; Lung neoplasms; PET, PET-CT; Positron emission tomography computed tomography; RT, Radiotherapy; Radiosurgery/methods; Radiotherapy; SBRT, Stereotatic body radiotherapy.