Inoperable localized stage I and stage II non-small-cell lung cancer

Effective Radiation Dose from Cone-Beam Computed Tomography Guidance during Bronchoscopic Tumour Ablation

INTRODUCTION

Endobronchial radiofrequency ablation (RFA) is a novel minimally invasive approach to management of peripheral non-small-cell lung cancer (NSCLC) in medically inoperable patients. Minimally invasive ablative techniques are generally delivered with cone-beam computed tomography (CBCT) guidance. CBCT requires a significant number of two dimensional imaging projections to be acquired which is then reconstructed as a three-dimensional cone-beam image. The objective of this study was to determine the radiation dosimetry consequent to use of CBCT guidance for bronchoscopic RFA.

METHODS

Post hoc analysis of data following bronchoscopic RFA of stage I biopsy-confirmed NSCLC performed with CBCT. Effective dose estimates for these patients were calculated using PCXMC2.0 software.

RESULTS

Ten patients underwent bronchoscopic RFA, with a median 3 (range 2-4) CBCT spins per procedure. Mean dose area product (DAP) per procedure was 7,778 μGy.m2 (±4,743) with an effective dose of 11.6 mSv (±7.4). The DAP per spin for these 10 patients varied from 83.8 to 8,625.6 μGy.m2 (effective dose range 0.15-13.81 mSv).

CONCLUSION

This is the first study to report radiation dosimetry consequent to CT guidance for bronchoscopic RFA procedures. Effective doses appear comparable to other CT fluoroscopic procedures.

Effect of Histologic Type on Recurrence Pattern in Radiation Therapy for Medically Inoperable Patients with Stage I Non-Small-Cell Lung Cancer

Japanese randomized trials showed that there was a significant impact on survival from stage I adenocarcinoma (AD) of the lung by adjuvant chemotherapy with uracil-tegaful after complete resection but there was no effect for patients with squamous cell carcinoma (SQ). The purpose of this study was to examine the correlation of tumor histology and clinical outcome of radiation therapy (RT) for stage I non-small-cell lung cancer (NSCLC) and to consider the necessity of adjuvant chemotherapy after RT for these patients. The subjects were 83 patients, 54 with SQ and 29 with AD; they had received definitive RT with the total dose ranging from 60 to 80 Gy with conventional fractionation at a daily dose of 2 Gy. The differences between SQ and AD with respect to survival and recurrence pattern were investigated. The 5-year overall survival and cause-specific survival rates were 26.5% and 49.1%, respectively. No difference in survival was observed between SQ and AD patients, and the recurrence rates were almost identical (44% for SQ and 45% for AD). However, the 5-year primary control rate of SQ was significantly poorer than that of AD (SQ: 61.5%; AD: 87.6%; p = 0.03). Conversely, the 5-year metastasis-free survival rate of SQ was significantly better than that of AD (SQ: 88.2%; AD: 53.0%; p = 0.005). The different failure pattern, according to tumor histology, indicates that taking into consideration the difference in their clinical behaviors would also be important for planning RT and surgery for early lung cancer.