Dosimetric predictors of esophageal toxicity after stereotactic body radiotherapy for central lung tumors

Abstract

Background and Purpose Stereotactic body radiotherapy (SBRT) to central lung tumors can cause esophageal toxicity, but little is known about the incidence or risk factors. We reviewed central lung SBRT patients to identify dosimetric factors predictive of esophageal toxicity. Material and Methods We assessed esophageal toxicity in 125 SBRT patients. Using biological equivalent doses with α/β=10 Gy (BED10), dose-volume histogram variables for the esophagus (Dv and Vd) were assessed for correlation with grade ≥2 acute toxicity. Results Incidence of grade ≥2 acute toxicity was 12% (n=15). Highly significant logistic models were generated for D5cc and Dmax (p<0.001). To keep the complication rate < 20%, the model requires that D5cc ≤ 26.3 BED10. At 2 years, the probability of complication with BED10 D5cc > 14.4 Gy was 24%, compared to 1.6% if ≤14.4 Gy. Conclusions This novel analysis provides guidelines to predict acute esophageal toxicity in lung SBRT. Dose to the hottest 5cc and Dmax of the esophagus were the best predictors of toxicity. Converting the BED10 limits to physical doses, D5cc to the esophagus should be kept less than 16.8, 18.1 and 19.0 Gy for 3, 4, and 5 fractions, respectively, to keep the acute toxicity rate < 20%.

Multivariable normal-tissue complication modeling of acute esophageal toxicity in advanced stage non-small cell lung cancer patients treated with intensity-modulated (chemo-)radiotherapy

“…This is in line with an earlier report where the diverse DVH parameters were replaced by the esophageal D mean resulting in a validated AET predictive model [11]. Thus, D mean seems an adequate surrogate DVH parameter for nonstereotactic techniques, however, for modeling of AET after stereotactic radiotherapy for central lung tumors the maximum dose to the esophagus and doses to small volumes correlate best with AET [35].…”

Optimizing the flattening filter free beam selection in RapidArc®-based stereotactic body radiotherapy for Stage I lung cancer

“…Modh et al 36 reported that 12.8% patients with central lung tumour experienced $ grade 2 oesophageal toxicity after SBRT treatment. Wu et al 37 found that the incidence of grade $2 acute toxicity was 12%. In these cases, the use of 6XFFF beam will lower the incidence rate of oesophageal toxicities.…”

“…In these cases, the use of 6XFFF beam will lower the incidence rate of oesophageal toxicities. The newly introduced SBRT was reported with higher incidence of complications than conventional techniques, 4 such as pulmonary toxicity, 24,[38][39][40][41] CW pain 24,25,31,42 and oesophageal toxicity, 37 especially when the target was adjacent to the OARs. Previous studies found that V 5 , V 10 , V 20 and mean lung dose (MLD) were predictive of radiation pneumonitis (RP).…”

“…[38][39][40][41] Other studies reported that the V 30 was mostly associated with CW pain. 25,31, 42 Wu et al 37 reported the maximum dose (D max ) was the dosimetric predictors of oesophageal toxicity after SBRT for lung tumour. The dosimetric predictors mentioned above are improved with the 6XFFF beam and that may help to lower the incidence of RP, CW pain and oesophageal toxicity.…”

Clinical Evaluation Stereotactic Radiation Therapy for Recurrent or Second Primary Mediastinal Lymph Node Metastases Originating From Non-Small Cell Lung Cancer

“…Additionally, clinical studies have demonstrated that RT dose, fractionation, dosevolume histogram constraints, as well as administration of systemic therapy are related to toxicity [47][48][49]. We caution clinicians to consider lymph node station (particularly zone 7) and use of previous RT before administration of SRT for R/SP-MLNMs.…”