Feasibility of intensity modulated radiotherapy with involved field radiotherapy for Japanese patients with locally advanced non-small cell lung cancer

Abstract

The feasibility of intensity modulated radiotherapy (IMRT) with involved field radiotherapy (IFRT) for Japanese patients with locally advanced non-small cell lung cancer (LA-NSCLC) remains unclear. Here we reviewed our initial experience of IMRT with IFRT for Japanese patients with LA-NSCLC to evaluate the feasibility of the treatment. Twenty LA-NSCLC patients who were treated with IMRT with IFRT during November 2019 to October 2020 were retrospectively analyzed. All patients received 60 Gy in 30 fractions of IMRT and were administered concurrent platinum-based chemotherapy. The median patient age was 71 years old and the group included 15 men and 5 women. The patient group included 2 patients with stage IIB, 11 patients with stage IIIA, 5 patients with stage IIIB, and 2 patients with stage IIIC disease. Histological diagnosis was squamous cell carcinoma in 14 patients, adenocarcinoma in 5 patients, and non-small cell lung cancer in 1 patient. The median follow-up period was 8 months. The incidence of grade 3 or greater pneumonitis was 5%, and grade 3 or greater esophagitis was not observed. None of the patients developed regional lymph node, with only recurrence reported so far. These findings indicate that IMRT with IFRT for Japanese patients with LA-NSCLC is feasible in terms of acute toxicity. Further study with a larger number of patients and longer follow-up to clarify the effect of treatment on patient prognosis is required.

Simple method for evaluating achievement degree of lung dose optimization in individual patients with locally advanced non‐small cell lung cancer treated with intensity modulated radiotherapy

“…Lung V5 may inevitably be higher when using IMRT than when using 3D-CRT. 6,8,11 In this study, the cutoff value for V5 IMRT /V5 3D-CRT was 1.5; however, the association with RP was not significant (p = 0.087). Further studies with greater numbers of patients are necessary to clarify the optimal cutoff value for V5 IMRT /V5 3D-CRT .…”

“…However, our patient characteristics were similar to those of other retrospective studies from Japanese facilities, as were our clinical results. [8][9][10][11][13][14][15][16] Second, the cutoff values in this study reflect our early experience with lung dose optimization. More efficient lung dose optimization would further lower the target value of ratio of dose-volume parameters.…”

“… 5 , 6 Therefore, IMRT has been increasingly administered to patients with LA‐NSCLC, especially in the Western world during the last decade. 7 Although IMRT for LA‐NSCLC is being increasingly used worldwide, 7 , 8 , 9 , 10 , 11 the proportion of the facilities where IMRT for LA‐NSCLC is performed varies widely in each region, mainly due to limited human and machine resources. 12 One of the obstacles in performing IMRT for LA‐NSCLC is the difficulty in the treatment plan optimization process because it is more complex than for 3D‐CRT.…”

“…Additionally, some researchers have expressed concern that the incidence of radiation pneumonitis (RP) may be slightly higher in specific ethnic groups after CCRT followed by durvalumab. 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 Thus, it is important to create safe and reproducible IMRT plans for treating LA‐NSCLC. However, in the absence of established means of determining clinical goals for lung dose optimization in individual patients, it is difficult to be sure that adequate optimization has been achieved or not.…”

“…However, with IMRT to the same target volume, lung dose optimization can vary widely because dose distribution can easily be modified by adjusting optimization settings. Additionally, some researchers have expressed concern that the incidence of radiation pneumonitis (RP) may be slightly higher in specific ethnic groups after CCRT followed by durvalumab 9–16 . Thus, it is important to create safe and reproducible IMRT plans for treating LA‐NSCLC.…”