Univariate analysis of factors correlated with tumor control probability of three-dimensional conformal hypofractionated high-dose radiotherapy for small pulmonary or hepatic tumors.
OBJECTIVE
To show the factors correlated with tumor control probability (TCP) after three-dimensional conformal hypofractionated high-dose radiotherapy (3D-CHHRT) for small pulmonary or hepatic tumors.


METHODS
We enrolled 34 patients with 42 lesions (13 lung carcinomas, 6 hepatocellular carcinomas, and 23 lung or liver metastases) treated with 3D-CHHRT alone, with simple immobilization devices, between July 1997 and January 2002. We prescribed 45 Gy in three fractions at the 90-100% isodose line of the planning target volume. The median follow-up period was 18 months (range, 4-46 months). We calculated the TCP using the Kaplan-Meier method and univariate analysis for the following factors: age, gender, primary site, histologic type, tumor size, and previous treatment.


RESULTS
Overall, the 2-year TCP of 3D-CHHRT was 83.6%. Local recurrence was observed in 6 lesions within 1 year after treatment. We showed that tumor size was the only significant factor to correlate with the TCP in univariate analysis. The 2-year TCP for tumors <3 cm or > or =3 cm in diameter was 95.0% and 58.3%, respectively (p = 0.0022). No severe adverse effects were observed.


CONCLUSIONS
The TCP for tumors <3 cm in diameter was excellent for 3D-CHHRT.
Department of Radiology, Yamagata City Hospital Saiseikan, Japan. wadajin@rad.med.tohoku.ac.jp
Hitoshi
H
Wada
Yoshihiro
Y
Takai
Kenji
K
Nemoto
Shogo
S
Yamada
D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D020266:Radiotherapy, Conformal / Q000379:methods*; D012119:Respiration