Background. We investigated the radiographic and pathologic response rate of esophageal adenocarcinoma treated with neoadjuvant chemoradiation in patients taking metformin. Material and methods. Two hundred eighty-fi ve patients with esophageal adenocarcinoma treated with concurrent chemoradiation (CRT) followed by esophagectomy from 1997 to 2012 were included in the study, including 29 diabetics taking metformin, 21 diabetics not taking metformin and 235 non-diabetics. Pre-and post-treatment positron emission tomography (PET) scans were available for 204 patients. Pathologic response was graded at the time of surgery. Response rates were compared using both the χ 2 statistic as well as ANOVA with post-hoc LSD analysis. Multivariate logistic regression analysis was performed to control for predictors of pathologic complete response (CR) after CRT. Results. The overall rate of pathologic CR for the study population was 20%. The pathologic CR rate was higher in patients taking metformin (34.5%), compared to diabetic patients not taking metformin (4.8%, p ϭ 0.01) and non-diabetic patients (19.6%, p ϭ 0.05). Pathologic CR was related to metformin dose, with Ն 1500 mg/d associated with a higher CR rate. No signifi cant difference seen in pre-CRT maximum tumor SUV (p ϭ 0.93), however post-CRT maximum SUV was signifi cantly decreased in patients taking metformin (p ϭ 0.05). On multivariate logistic regression, metformin use was independently associated with pathologic CR (p ϭ 0.04). Metformin use was also associated with decreased in fi eld loco-regional failure following radiation (p ϭ 0.05). Conclusion. Metformin use is associated with a dose-dependent increased response to CRT in esophageal cancer and may be a sensitizer to this therapy.

In veteran patients with early-stage non-small cell lung cancer, video-assisted thoracoscopic lobectomy resulted in better disease control and survival than stereotactic body radiotherapy. Although prior reports suggest that stereotactic body radiotherapy is a suitable alternative to surgery in early-stage lung cancer, a prospective randomized trial is needed. Nevertheless, stereotactic body radiotherapy remains a suitable option for medically inoperable patients.

Purpose This study quantifies pulmonary radiation toxicity in patients who received proton therapy for esophagus cancer. Materials/methods We retrospectively studied 100 esophagus cancer patients treated with proton therapy. The linearity of the enhanced FDG uptake vs. proton dose was evaluated using the Akaike Information Criterion (AIC). Pneumonitis symptoms (RP) were assessed using the Common Toxicity Criteria for Adverse Events version 4.0 (CTCAEv4). The interaction of the imaging response with dosimetric parameters and symptoms was evaluated. Results The RP scores were: 0 grade 4/5, 7 grade 3, 20 grade 2, 37 grade 1, and 36 grade 0. Each dosimetric parameter was significantly higher for the symptomatic group. The AIC winning models were 30 linear, 52 linear quadratic, and 18 linear logarithmic. There was no significant difference in the linear coefficient between models. The slope of the FDG vs. proton dose response was 0.022 for the symptomatic and 0.012 for the asymptomatic (p = 0.014). Combining dosimetric parameters with the slope did not improve the sensitivity or accuracy in identifying symptomatic cases. Conclusions The proton radiation dose response on FDG PET/CT imaging exhibited a predominantly linear dose response on modeling. Symptomatic patients had a higher dose response slope.