Changes in Global Function and Regional Ventilation and Perfusion on SPECT During the Course of Radiotherapy in Patients With Non-Small-Cell Lung Cancer

Abstract

Purpose This study aimed to (1) examine changes in dyspnea, global pulmonary function test (PFT) results, and functional activity on ventilation (V)/perfusion (Q) single-photon emission computerized tomography (SPECT) scans during the course of radiation (RT), and (2) factors associated with the changes in patients with non-small-cell lung cancer (NSCLC). Methods and Materials Fifty-six stage I to III NSCLC patients treated with definitive RT with or without chemotherapy were enrolled prospectively. Dyspnea was graded according to Common Terminology Criteria for Adverse Events version 3.0 prior to and weekly during RT. V/Q SPECT-computed tomography (CT) and PFTs were performed prior to and during RT at approximately 45 Gy. Functions of V and Q activities were assessed using a semiquantitative scoring of SPECT images. Results Breathing improved significantly at the third week (mean dyspnea grade, 0.8 vs. 0.6; paired t-test p = 0.011) and worsened during the later course of RT (p > 0.05). Global PFT results did not change significantly, while regional lung function on V/Q SPECT improved significantly after ~45 Gy. The V defect score (DS) was 4.9 pre-RT versus 4.3 during RT (p = 0.01); Q DS was 4.3 pre-RT versus 4.0 during RT (p < 0.01). Improvements in V and Q functions were seen primarily in the ipsilateral lung (V DS, 1.9 pre-RT versus 1.4 during RT, p < 0.01; Q DS, 1.7 pre-RT versus 1.5 during RT, p < 0.01). Baseline primary tumor volume was significantly correlated with pre-RT V/Q DS (p < 0.01). Patients with central lung tumors had greater interval changes in V and Q than those with more peripheral tumors (p < 0.05 for both V and Q DS). Conclusions Regional ventilation and perfusion improved during RT at 45 Gy. This suggests that adaptive planning based on V/Q SPECT during RT may allow sparing of functionally recoverable lung tissue.

Effects of Definitive Chemoradiotherapy on Respiratory Function Tests and Quality of Life Scores During Treatment of Lung Cancer

“…The reduction in pulmonary function is associated with the average lung dosage, and a greater reduction in RFT was observed in patients with chronic obstructive pulmonary disease. Yuan et al (2012) investigated global and local pulmonary function disorders during radiotherapy through assessments performed before and in week 3 of treatment in 56 patients receiving thoracic radiotherapy. Although the reduction in degree of dyspnea determined by common terminology criteria for adverse event version 3 was statistically significant in week 3 of radiotherapy (p=0.01), no statistically significant change was observed during the remainder of the treatment period (p>0.05).…”

“…Thoracic radiotherapy (RT) can improve ventilation-perfusion by reducing tumor size, but also causes a reduction in pulmonary function as a result of lung damage (Borst et al, 2005;Yuan et al, 2012).…”

Functional Image-guided Radiotherapy Planning for Normal Lung Avoidance

“…Although lung function can be reduced irreversibly by radiation therapy [4,134,135], it has also been known for many years that the tumour itself can be responsible for reduced lung function [9] when bronchial obstruction and large vessel compression create regional ventilation and perfusion defects that become tempting targets for functionally-guided dose redistribution. Therefore, a potential limitation of normal lung avoidance is that lung volumes that may have received a functionally modified, amplified dose may regain some degree of function following treatment [4]; an effect noticeable on SPECT [136], PET [135], hyperpolarised gas MRI [63,137,138] and CT- [32,139] and even part way through treatment [135,140,141]. Hence, whether defects are transient [142,143], reversible [136] or persistent [134] becomes an important issue when assigning functional and non-functional planning constraints.…”

Personalized Radiation Therapy (PRT) for Lung Cancer

“…Many image modalities, including, CT, magnetic resonance image (MRI), PET, and single photon emission computed tomography (SPECT), have been used to detect normal tissue response to radiation [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]. CT has been used to measure the change of radiopacity after radiation of lung tissue, and it was found that the change of radiopacity correlated with the radiation dose and the lung toxicity (such as radiation pneumonitis, cough and dyspnea) [31,32].…”

“…Li et al reported in an abstract that in 84 patients, during-RT FDG uptake significantly correlated with RILT (p = 0.002) [48]. Yuan et al studied during-RT ventilation/perfusion (V/Q) SPECT in 56 stage I-III NSCLC patients [49]. Both studies found that both V and Q SPECT indicated improved lung function after 45 Gy of radiation treatment, especially in the ipsilateral side of lung.…”