Dan Liu BMedSc, MSc, Presenter: Nothing to Disclose

Albert Chan, Abstract Co-Author: Nothing to Disclose

Daniel Fong, Abstract Co-Author: Nothing to Disclose

Bingsheng Huang, Abstract Co-Author: Nothing to Disclose

Ronnie T.P Poon, Abstract Co-Author: Nothing to Disclose

Pek Lan Khong, Abstract Co-Author: Nothing to Disclose

The purpose of our study was to develop a recurrence risk classification rule for postoperative Hepatocellular Carcinoma (HCC) patients and to propose an appropriate protocol for surveillance CT scans.

Institutional board approval was obtained for this retrospective study. We identified all consecutive HCC patients who had initial resection surgery at our institution from 8/2003 to 12/2009 and evaluated the postoperative surveillance CT scans for positive or negative findings of recurrent disease. Volume CT dose index (CTDIvol), dose length product (DLP), and effective diameter (ED) and size-specific dose estimate (SSDE) were computed. Patient age at surgery and known tumor risk factors including cirrhosis, tumor size (<5cm vs >=5cm), presence of portal or hepatic vein involvement, solitary vs multiple, presence of vascular invasion, cell differentiation and pathologic T stage were recorded. Multivariable Cox regression analysis was performed to identify risk factors, and then those factors were analyzed by Classification and Regression Tree analysis. P<0.05 was considered statistically significant. We tested the extension of scanning intervals and potential dose savings.

There were 2776 postoperative surveillance CT studies performed on 258 patients (206 male/ 52 female, 29- 82 years old (56.5±21.8 ) over a follow up period of 52.8 (±57.2) months. The mean number of surveillance CT studies per patient, DLP, CTDIvol, ED and SSDE of an individual CT were 11 (±9.9), 1627.8 (±892.3) mGy.cm , 89.6 (±42.6) mGy , 26.0 (±5.2) cm,  and 128.9 (±52.1) mGy, respectively. The new classification rule identified three risk groups of HCC recurrence. Based on these findings, extending the interval of surveillance CT scans from the current 6 monthly to 9 monthly from 2 years post-surgery will not reduce or delay the detection rate of HCC recurrence for low-risk group. This translates to a dose savings of 14.29% for a five year follow protocol.

Computed Tomography used in HCC surveillance protocol imparts significant radiation doses. Low recurrence risk patients for whom extending the CT scan interval for surveillance will reduce radiation detriment without compromising surveillance benefits.

The newly proposed surveillance CT scan protocol for postoperative Hepatocecullar carcinoma patients will reduce radiation detriment without compromising surveillance benefits.

Liu, D, Chan, A, Fong, D, Huang, B, Poon, R, Khong, P, Radiation Dose Reduction from a Newly Proposed Surveillance CT Scan Protocol for Hepatocecullar Carcinoma Patients after Resection.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13026944.html