Tumor Volume Changes Assessed With High Quality kVCT in Lung Cancer Patients Undergoing Concurrent Chemoradiation Therapy

Abstract

Purpose/Objective(s)We evaluated tumor volume changes in lung cancer patients undergoing concurrent chemoradiation therapy, during image guided radiation therapy (IGRT).Materials/MethodsKilovoltage computed tomography (KVCT) of CT on rail was obtained, for each five fractions. The gross tumor volumes (GTVs), including the primary tumor and lymph node (LN), were contoured for analysis of timing and degree of gross tumor regression.ResultsA total of 46 patients, including 32 patients with NSCLC and 14 patients with SCLC were included. A total of 281 CT scans and 82 sites of GTVs were evaluated. The significant volume changes occurred during RT in both the NSCLC and SCLC group (p<0.001 and 0.002, respectively), and average GTV change compared to baseline was 49.85 ± 28.01% and 65.95 ± 22.05% for each group. The difference in degree of volume reduction, between the primary tumor and LN, was observed in only NSCLC (P<0.0001), but not in SCLC (P = 0.735). The maximal volume regression occurred between 15 and 20 fractions for NSCLC, while 5 and 10 fractions for SCLC. The initial larger volume of the primary tumor and LN, in NSCLC, had a greater rate of regression than that of the smaller volume. (p = 0.002 for primary tumor and p<0.0001 for LN, respectively).ConclusionsBoth primary tumor and LN were well defined, using KVCT of CT on rail. The tumor regression was noted in the majority of patients, and there was difference in volume reduction between NSCLC and SCLC regarding the degree and timing of tumor reduction for primary tumor and LN subgroup. Purpose/Objective(s)We evaluated tumor volume changes in lung cancer patients undergoing concurrent chemoradiation therapy, during image guided radiation therapy (IGRT). We evaluated tumor volume changes in lung cancer patients undergoing concurrent chemoradiation therapy, during image guided radiation therapy (IGRT). Materials/MethodsKilovoltage computed tomography (KVCT) of CT on rail was obtained, for each five fractions. The gross tumor volumes (GTVs), including the primary tumor and lymph node (LN), were contoured for analysis of timing and degree of gross tumor regression. Kilovoltage computed tomography (KVCT) of CT on rail was obtained, for each five fractions. The gross tumor volumes (GTVs), including the primary tumor and lymph node (LN), were contoured for analysis of timing and degree of gross tumor regression. ResultsA total of 46 patients, including 32 patients with NSCLC and 14 patients with SCLC were included. A total of 281 CT scans and 82 sites of GTVs were evaluated. The significant volume changes occurred during RT in both the NSCLC and SCLC group (p<0.001 and 0.002, respectively), and average GTV change compared to baseline was 49.85 ± 28.01% and 65.95 ± 22.05% for each group. The difference in degree of volume reduction, between the primary tumor and LN, was observed in only NSCLC (P<0.0001), but not in SCLC (P = 0.735). The maximal volume regression occurred between 15 and 20 fractions for NSCLC, while 5 and 10 fractions for SCLC. The initial larger volume of the primary tumor and LN, in NSCLC, had a greater rate of regression than that of the smaller volume. (p = 0.002 for primary tumor and p<0.0001 for LN, respectively). A total of 46 patients, including 32 patients with NSCLC and 14 patients with SCLC were included. A total of 281 CT scans and 82 sites of GTVs were evaluated. The significant volume changes occurred during RT in both the NSCLC and SCLC group (p<0.001 and 0.002, respectively), and average GTV change compared to baseline was 49.85 ± 28.01% and 65.95 ± 22.05% for each group. The difference in degree of volume reduction, between the primary tumor and LN, was observed in only NSCLC (P<0.0001), but not in SCLC (P = 0.735). The maximal volume regression occurred between 15 and 20 fractions for NSCLC, while 5 and 10 fractions for SCLC. The initial larger volume of the primary tumor and LN, in NSCLC, had a greater rate of regression than that of the smaller volume. (p = 0.002 for primary tumor and p<0.0001 for LN, respectively). ConclusionsBoth primary tumor and LN were well defined, using KVCT of CT on rail. The tumor regression was noted in the majority of patients, and there was difference in volume reduction between NSCLC and SCLC regarding the degree and timing of tumor reduction for primary tumor and LN subgroup. Both primary tumor and LN were well defined, using KVCT of CT on rail. The tumor regression was noted in the majority of patients, and there was difference in volume reduction between NSCLC and SCLC regarding the degree and timing of tumor reduction for primary tumor and LN subgroup.