A lot to a little or a little to a lot-which dose-volume relationship ensures the best clinical outcome in the high dose radiation therapy of thoracic tumors? A prospective approach.
BACKGROUND
The purpose of this prospective randomized trial is to determine which constellation of dose and corresponding volume of the lung tissue-either a lot to a little or a little to a lot-should be preferred to ensure the best possible outcome for patients with thoracic carcinomas.


METHODS
From Apr 2012 to Oct 2015, 81 patients with NSCLC, SCLC or esophageal carcinoma were randomized and treated with either a 4-field-IMRT or a VMAT technique with or without additional chemotherapy. Data regarding clinical outcome, pulmonary function tests (PFT) and quality of life (QoL) was collected before RT, 6 weeks, 12 weeks and 6 months after treatment, QoL data additionally 1 year post RT. Follow up CTs were done 12 weeks and 6 months after RT.


RESULTS
There is no significant difference regarding the local (P=0.954) and distant (P=0.206) outcome, side effects (all P>0.05) or survival (P=0.633) at any follow-up appointment. The comparison of the PFT shows a statistically significant difference for the DLCO 6 weeks post RT (P=0.028). All other parameters do not differ significantly at any follow up appointment. Regarding the QoL there is no statistically significant difference at any follow up appointment (P>0.1). There is a statistically significant difference between the mean density of the lung parenchyma at 12 weeks (P<0.0005) and 6 months post RT (P<0.0005).


CONCLUSIONS
Since there is no significant and relevant difference between both treatment arms regarding PFT, clinical outcome and QoL it does not seem to relevant how the DVH is shaped exactly as long as established dose constraints for the organs at risk are respected. As to whether the difference between the CT density changes is clinically relevant further analysis is needed.
Clinic for Radiotherapy and Radiation Oncology, University Clinic Giessen and Marburg, Marburg, Germany;; Clinic for Radiotherapy and Radiation Oncology, Ruppiner Kliniken GmbH, Neuruppin, Germany.
Christina
C
Schröder
Clinic for Radiotherapy and Radiation Oncology, University Clinic Giessen and Marburg, Marburg, Germany ;
Rita
R
Engenhart-Cabillic
Clinic for Radiotherapy and Radiation Oncology, University Clinic Giessen and Marburg, Marburg, Germany ;
Hilke
H
Vorwerk
Clinic for Radiotherapy and Radiation Oncology, Ruppiner Kliniken GmbH, Neuruppin, Germany.
Michael
M
Schmidt
Clinic for Radiotherapy and Radiation Oncology, Ruppiner Kliniken GmbH, Neuruppin, Germany.
Winfried
W
Huhnt
Clinic for Radiotherapy and Radiation Oncology, Ruppiner Kliniken GmbH, Neuruppin, Germany.
Eyck
E
Blank
Clinic for Radiotherapy and Radiation Oncology, Ruppiner Kliniken GmbH, Neuruppin, Germany.
Dietrich
D
Sidow
Clinic for Radiotherapy and Radiation Oncology, Ruppiner Kliniken GmbH, Neuruppin, Germany.
André
A
Buchali
Lung neoplasms; intensity modulated radiotherapy (IMRT); quality of life (QoL); radiation pneumonitis (RP); respiratory function tests