Radiotherapy effects on brain/bone metastatic adenocarcinoma lung cancer and the importance of EGFR mutation test.

This study proposed to retrospectively analyze the efficacy of radiotherapy on brain/bone metastases in patients with stage IV lung adenocarcinoma and to evaluate the correlation between overall survival after radiotherapy and other factors including metastatic sites and EGFR mutation status. 115 patients with Stage IV lung adenocarcinoma admitted to our center from March, 2011 to December, 2013 were enrolled. They presented with metastases to no other solid organs except the bone or brain and had received no prior treatment. 50 patients received EGFR mutation test with 32 detected as EGFR mutant and 18 wild-type. Patients with brain metastases were treated with 40 Gy whole brain irradiation (WBI) in 2 Gy fractions; patients with bone metastases were treated with 30 Gy local irradiation in 3 Gy fractions or 40 Gy in 2 Gy fractions. All the patients received systemic therapy during or after radiotherapy and 68 received targeted therapy.The median overall survival of patients with solitary brain metastases, solitary bone metastases or combined brain and bone metastases were 8.50 months, 8.50 months and 9.50 months respectively, revealing no significant difference (p=0.57). The median overall survival of patients with EGFR mutations was 10.25 months, longer than the 8.75 months of patients without EGFR mutations, revealing no significant difference (p=0.57). The median overall survival of EGFR mutant patients with solitary bone metastases, solitary brain metastases or combined brain and bone metastases were 7.50 months, 10.50 months and 11.50 months respectively, revealing no significant difference (p=0.91). 36 patients with untested EGFR mutation status received EGFR-TKI. Among EGFR mutant patients, 10 didn't receive targeted therapy; 8 were administered Erlotinib and 14 Gefitinib with median overall survival of 10.25 months and 14.5 months, showing no significant difference (p=0.11) between the two drugs. When patients with stage IV lung adenocarcinoma have been treated by early radiotherapy, the overall survival doesn't correlate with metastatic sites. Radiotherapy could extend survival for EGFR mutant patients with stage IV lung adenocarcinoma. EGFR mutation test should be performed before treatment of the disease.

Clinical dosimetric study of three radiotherapy techniques for postoperative breast cancer: Helical Tomotherapy, IMRT, and 3D-CRT.

This paper is to investigate the dosimetric characteristics of Helical Tomotherapy (HT), step-and-shoot intensity-modulated radiation therapy (SaS-IMRT) and three-dimensional conformal radiation therapy (3D-CRT) for the postoperative breast cancer as well as their dosimetric comparison of the normal tissues. CT images of 10 postoperative patients with early stage breast cancer were transferred into HT, SaS-IMRT and 3D-CRT planning systems respectively after the target region and normal tissues were outlined by the same physician to assure the contour consistency. Each prescribed dose for three different modalities of plans was given to a total of 50 Gy in 25 fractions. Doses and irradiated volumes in heart, lungs, as well as conformity index (CI) and homogeneity index (HI) were evaluated for detailed comparison. All three plans showed appropriate coverage for the prescribed target dose in the dosimetric comparison. The CI in HT and SaS-IMRT as well as 3D-CRT was 0.68 ± 0.12, 0.58 ± 0.08 and 0.40 ± 0.08, respectively. The HI were 1.10 ± 0.03, 1.14 ± 0.02 and 1.17 ± 0.04, which appeared intergroup significant differences (p < 0.05). V5, V10, as well as V20 of the heart were smallest in 3D-CRT than HT and SaS-IMRT. V5 of the ipsilateral lung was the smallest in 3D-CRT than HT and SaS-IMRT (p < 0.05); However, V20 and V30 were smaller in HT and SaS-IMRT than 3D-CRT (p < 0.05). V5 of the contralateral lung was the smallest in 3D-CRT than other groups, with V10~V30 were basically similar in numeric values with not obvious discrepancy. Comparing with SaS-IMRT and 3D-CRT, HT technique in treating breast cancer had the best conformity and homogeneity index as well as steepest dose gradient due to its highly modulated beamlets with rotational technique. The heart volume irradiated was the smallest in conventional 3D-CRT, with SaS-IMRT was the largest among the three techniques, as expected. The volume of the contralateral lung irradiated was the smallest in 3D-CRT than other groups. V5 of the ipsilateral lung was the smallest in 3D-CRT than other two groups. V10~V30 in HT and SaS-IMRT were similar and better than 3D-CRT dosimetrically. We conclude that HT technique had advantages over SaS-IMRT and 3D-CRT based on the dosimetric comparison in this study, especially in the high dose region of ipsilateral lung, target homogeneity and dose uniformity.