Toxicity after volumetric modulated arc therapy for lung cancer: a monocentric retrospective study

Abstract

Background: Intensity-modulated radiotherapy (RT) is now widely implemented and has replaced classical three-dimensional (3D)-RT in many tumor sites, as it allows a better target dose conformity and a better sparing of organs a risk (OAR), at the expense, however, of increasing the volume of low dose to normal tissues. Clinical data on toxicities using volumetric modulated arc therapy (VMAT) in lung cancer remain scarce. We aimed to report both acute (APT) and late (LPT) pulmonary and acute (AET) and late (LET) oesophageal toxicities in such setting.Methods: All patients treated for a primary lung cancer with VMAT +/− chemotherapy (ChT) in our center from 2014 to 2018 were retrospectively included. Usual clinical, treatment and dosimetric features were collected. Univariate analysis was performed using the receiver operative characteristics approach while multivariate analysis (MVA) relied on logistic regression, calculated with Medcalc 14.8.1.Results: In total, 167 patients were included, with a median age of 66 years (39-88 years). Median radiation dose was 66 Gy (30-66 Gy); 82% patients received concomitant (32.3%), induction (25.7%) or induction followed by concomitant ChT (24%). After a median follow-up of 14.0 months, the G ≥2 APT, AET, LPT and LET rates were 22.2%, 30.0%, 16.8% and 5.4%, respectively with low grade ≥3 toxicity rates (respectively, 3%, 6.6%, 3% and 0%). On MVA, APT was significantly associated with V30 to the homolateral lung, AET with age, LPT with MEVS while no feature remained significantly correlated with LET.Conclusions: Low rates of pulmonary and esophageal toxicity were observed in our cohort. Larger prospective studies are needed to confirm these results.

Modified VMAT Plans for Locally Advanced Centrally Located Non-Small Cell Lung Cancer (NSCLC)

“…Radiation induced oesophagitis has been reported where mean dose, V30 and V60 are the predictor with threshold of 27.5 Gy, 43% and 12.4%, with V60 is the best among all [16,32]. In our study, V60 was less than 1% in all three plans, where mean dose and V30 were under the threshold suggested.…”

Predictors of high-grade radiation pneumonitis following radiochemotherapy for locally advanced non-small cell lung cancer: analysis of clinical, radiographic and radiotherapy-related factors

“…In addition, the number of patients with late RP ≥ G3 nearly doubled in the VMAT group. Other reports also did not find increased low doses to the lungs or increased toxicity with VMAT either with (lung V5 Gy < 65% and V10 Gy < 45%) 32 or without using explicit low lung dose constraints. 33 In our cohort, RP ≥ 3 occurred only after IMRT (four G3, one G4) and VMAT treatments (three G3, two G5).…”

VMAT-Based Planning Allows Sparing of a Spatial Dose Pattern Associated with Radiation Pneumonitis in Patients Treated with Radiotherapy for a Locally Advanced Lung Cancer

“…The second cohort consisted of the patients treated within the prospective trial TEFRARC (NCT03931356), evaluating the functional impact of lung radiotherapy. Characteristics of these 207 patients (165 from the retrospective and 42 from the prospective cohorts, respectively) were previously presented [ 9 , 17 ].…”

“…Indeed, the VMAT dose sculpting proved to be very useful in the treatment of challenging tumor sites, for which the sparing of strictly close or even inner OARs was the goal in addition to achieving an excellent target coverage [ 4 , 5 ]. Despite the implementation of advanced RT techniques and of stricter dose–volume constraints, acute pulmonary toxicity (APT) remains frequent, with an approximate rate of 5–25% for grade ≥ 2 APT [ 6 , 7 , 8 , 9 ]. In a population treated with adjuvant immunotherapy, the APT rate rose to 33.9% for all grades and 3.3% for grades 3–4 APT [ 10 , 11 ].…”