A total EQD 2 greater than 85 Gy for trachea and main bronchus D 2cc being associated with severe late complications after definitive endobronchial brachytherapy

Abstract

PurposeThe endobronchial brachytherapy (EBBT) is an established treatment method for tumors of the tracheobronchial system, however, little is known about the tolerance dose for organ at risk (OAR) in EBBT. The purpose of this study is to analyze patients with superficial bronchial carcinoma treated with definitive EBBT, and to investigate a relationship between late complications and dose for OAR.Material and methodsEndobronchial brachytherapy was performed 6 Gy per fraction for three to four fractions with or without external beam radiation therapy (EBRT). For the purpose of dosimetric analysis, the wall of the lower respiratory tract (LRT: trachea, main bronchus, and lobar bronchiole), trachea, and main bronchus (TMB) was extracted. D0.5cc, D1cc, and D2cc of LRT and TMB were calculated in each EBBT session and added together. V100, V150, and V200 of LRT were also calculated.ResultsBetween March 2008 and April 2014, EBBT was performed in 14 patients for curative intent. The 2-year overall survival (OS), progression-free survival (PFS), and local recurrence free survival (LRFS) was 82.1%, 77.9%, and 91.7%, respectively. There was one patient with grade 5, one grade 4, and three grade 3 obstruction of trachea or bronchus. The mean EQD2 of LRT D2cc, TMB D2cc, D1cc, and D0.5cc of patients with or without late severe respiratory complications was significantly different between two groups (p = 0.018, 0.008, 0.009, and 0.013, respectively). The 2-year incidence rates of late severe complications in patients with TMB D2cc ≤ 85 Gy in EQD2 and > 85 Gy were 0% and 83.3%, respectively with a statistically significance (p = 0.014).ConclusionsIt was discovered that TMB D2cc > 85 Gy in EQD2 is a strong risk factor for severe late respiratory complication after EBBT.

Dosimetric impact of an air passage on intraluminal brachytherapy for bronchus cancer

“…Recently, our group investigated the late complication events for patients who underwent endobronchial brachytherapy in our institution [24, 25], and we further extracted a dosimetric parameter, such as D 2 cm 3 in equivalent dose to 2 Gy (EQD 2 ), to reveal a relation between the dosimetric parameters and the late complications rate, as reported by Murakami et al . [24].…”

“…[24]. As a result, it was discovered that D 2 cm 3  > 85 Gy in EQD 2 for the trachea and the main bronchus is a strong risk factor in relation to severe late respiratory complication.…”

Endobronchial brachytherapy with curative intent: the impact of reference points setting according to the bronchial diameter

“…Although EBB is effective for both alleviating symptoms and eliminating tumors, complications such as hemoptysis, bronchial stenosis and bronchial obstruction remain serious problems [ 14 , 17 – 25 ]. It has been suggested that these complications can be caused by eccentric locations of the source-delivering catheter in the bronchial lumen [ 19 ].…”

“…Regarding the reference dose point, it is set at 10 mm from the source axis in most studies [ 9 , 11 , 12 , 17 , 20 , 25 ]. However, the radius of the bronchus is <10 mm on the distal side of main bronchus, and this difference leads to overdosing to the bronchial mucosa.…”

Endobronchial radiotherapy in the treatment of patients with tracheal and lung cancer

“…В 1984 г. W. Schumacher реализовал лазерную реканализацию (ЛР) бронха и эндобронхиальную лучевую терапию (ЭБЛТ) [13,14]. В то же время за последние 20 лет интерес к ЭБЛТ стремительно падает, что находит отражение в уменьшении количества и масштаба публикаций по этой теме [15][16][17][18][19][20][21]. С нашей точки зрения, это может быть связано с новыми возможностями дистанционного способа подведения дозы ионизирующего излучения, которые позволяют исключить инвазивные и трудоемкие брахитерапевтические процедуры в практике лучевого лечения НМРЛ.…”