TY - JOUR
T1 - Tumor volume change with stereotactic body radiotherapy (SBRT) for early-stage lung cancer
T2 - Evaluating the potential for adaptive SBRT
AU - Bhatt, Aashish D.
AU - El-Ghamry, Moataz N.
AU - Dunlap, Neal E.
AU - Bhatt, Geetika
AU - Harkenrider, Matthew M.
AU - Schuler, John C.
AU - Zacarias, Albert
AU - Civelek, Ali Cahid
AU - Pan, Jianmin
AU - Rai, Shesh N.
AU - Woo, Shiao Y.
PY - 2015/2/2
Y1 - 2015/2/2
N2 - Objectives: To quantify gross tumor volume (GTV) change during stereotactic body radiotherapy (SBRT) and on first follow-up, as well as to evaluate for any predictive prognostic risk factors related to GTV decrease. An attempt was also made to identify the potential timing for adaptive SBRT. Methods: Twenty-five tumors in 24 consecutive patients were treated with SBRT to total dose of 50 Gy in 5 fractions. Median age was 72.5 years. Tumor stage was T1, 68%; T2, 20%; and other, 12%. The GTVs of on the 5 cone-beam computed tomographies (CBCT1-5) obtained before each fraction and the first follow-up CT (CTPOST) were analyzed. Results: Median time from diagnosis to initiation of radiotherapy was 64 days. GTV on CBCT1 was the baseline for comparison. GTV decreased by a mean of 7% on CBCT2 (P=0.148), 11% on CBCT3 (P=0.364), 19% on CBCT4 (P=0.0021), and 32% on CBCT5 (P=0.0004). Univariate analyses of GTV shrinkage was significantly associated with "time from CBCT5 to CTPOST" (P=0.027) and "T-stage" (P=0.002). In multivariate analyses, "T-stage" remained significant with T1 tumors showing greater GTV shrinkage than T2 tumors. Conclusions: Significant decrease in GTV volume based on daily CBCT was demonstrated during SBRT treatment. Adaptive SBRT has the potential to minimize integral dose to the surrounding normal tissues without compromising GTV coverage.
AB - Objectives: To quantify gross tumor volume (GTV) change during stereotactic body radiotherapy (SBRT) and on first follow-up, as well as to evaluate for any predictive prognostic risk factors related to GTV decrease. An attempt was also made to identify the potential timing for adaptive SBRT. Methods: Twenty-five tumors in 24 consecutive patients were treated with SBRT to total dose of 50 Gy in 5 fractions. Median age was 72.5 years. Tumor stage was T1, 68%; T2, 20%; and other, 12%. The GTVs of on the 5 cone-beam computed tomographies (CBCT1-5) obtained before each fraction and the first follow-up CT (CTPOST) were analyzed. Results: Median time from diagnosis to initiation of radiotherapy was 64 days. GTV on CBCT1 was the baseline for comparison. GTV decreased by a mean of 7% on CBCT2 (P=0.148), 11% on CBCT3 (P=0.364), 19% on CBCT4 (P=0.0021), and 32% on CBCT5 (P=0.0004). Univariate analyses of GTV shrinkage was significantly associated with "time from CBCT5 to CTPOST" (P=0.027) and "T-stage" (P=0.002). In multivariate analyses, "T-stage" remained significant with T1 tumors showing greater GTV shrinkage than T2 tumors. Conclusions: Significant decrease in GTV volume based on daily CBCT was demonstrated during SBRT treatment. Adaptive SBRT has the potential to minimize integral dose to the surrounding normal tissues without compromising GTV coverage.
KW - Stereotactic body radiotherapy
KW - adaptive SBRT
KW - gross tumor volume change
KW - planning target volume reduction
KW - radiotherapy replanning
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UR - http://www.scopus.com/inward/citedby.url?scp=84922069471&partnerID=8YFLogxK
U2 - 10.1097/COC.0b013e318287bd7f
DO - 10.1097/COC.0b013e318287bd7f
M3 - Article
C2 - 24513663
AN - SCOPUS:84922069471
SN - 0277-3732
VL - 38
SP - 41
EP - 46
JO - American Journal of Clinical Oncology: Cancer Clinical Trials
JF - American Journal of Clinical Oncology: Cancer Clinical Trials
IS - 1
ER -