IMPACT FACTORS FOR MICROINVASION IN INTRAHEPATIC CHOLANGIOCARCINOMA A POSSIBLE SYSTEM FOR DEFINING CLINICAL TARGET VOLUME

Purpose To quantify microscopic invasion of intrahepatic cholangiocarcinoma (IHC) Into nontumor tissue and define the gross tumor volume (GTV) to clinical target volume (CTV) expansion necessary for radiotherapy Methods and Materials One hundred IHC patients undergoing radical resection from January 2004 to July 2008 were enrolled in this study Pathologic and clinical data including maximum tumor diameter, tumor boundary type, TNM stage, histologic grade, tumor markers, and liver enzymes were reviewed The distance of microinvasion from the tumor boundary was measured by microscopy The contraction coefficient for tumor measurements in radiographs and slide mounted tissue was calculated SPSS15 0 was used for statistical analysis Results Sixty five patients (65%) exhibited tumor microinvasions Microinvasions ranged from 0 4-8 mm, with 96% of patients having a microinvasion distance <= 6 mm measured on slide The radiograph to-slide contraction coefficient was 82 1% The degree of microinvasion was correlated with tumor boundary type, TNM stage, histologic grade, and serum levels of carbohydrate antigen 19 9, alanine aminotransferase, aspartate aminotransferase, gamma glutamyltransferase and alkaline phosphatase To define CTV accurately, we devised a scoring system based on combination of these factors According to this system, a score <= 1 5 is associated with 96 1% sensitivity in detecting patients with a microextension <= 4 9 mm in radiographs, whereas a score >= 2 has a 95 1% sensitivity in detecting microextension <= 7 9 mm measured on radiograph Conclusions Patients with a score <= 1 5 and >= 2 require a radiographic GTV to-CTV expansions of 4 9 and 7 9 mm, respectively, to encompass >95% of microinvasions (C) 2010 Elsevier Inc