Evaluation of anatomical landmark position differences between respiration-gated MRI and four-dimensional CT for radiation therapy in patients with hepatocellular carcinoma

OBJECTIVE

To measure the accuracy of position differences in anatomical landmarks in gated MRI and four-dimensional CT (4D-CT) fusion planning for radiation therapy in patients with hepatocellular carcinoma (HCC).

METHODS

From April to December 2009, gated MR and planning 4D-CT images were obtained from 53 inoperable HCC patients accrued to this study. Gated MRI and planning 4D-CT were conducted on the same day. Manual image fusions were performed by matching the vertebral bodies. Liver volumes and three specific anatomical landmarks (portal vein conjunction, superior mesenteric artery bifurcation, and other noticeable points) were contoured from each modality. The points chosen nearest the centre of the four landmark points were compared to measure the accuracy of fusion.

RESULTS

The average distance differences (±standard deviation) of four validation points were 5.1 mm (±4.6 mm), 5.6 mm (±6.2 mm), 5.4 mm (±4.5 mm) and 5.1 mm (±4.8 mm). Patients who had ascites or pulmonary disease showed larger discrepancies. MRI-CT fusion discrepancy was significantly correlated with positive radiation response (p<0.05).

CONCLUSIONS

Approximately 5-mm anatomical landmark positional differences in all directions were found between gated MRI and 4D-CT fusion planning for HCC patients; the gap was larger in patients with ascites or pulmonary disease.

ADVANCES IN KNOWLEDGE

There were discrepancies of approximately 5 mm in gated MRI-CT fusion planning for HCC patients.

Diagnosis, Staging, and Treatment of Cholangiocarcinoma

Attention has to be focused on earlier detection of cholangiocarcinoma, especially in high-risk patients such as those with primary sclerosing cholangitis (PSC). Enhanced techniques for diagnosing this disease include imaging studies such as positron emission tomography (PET) scanning, and cytologic analysis including digital image analysis (DIA) and fluorescent in situ hybridization (FISH). Magnetic resonance imaging and endoscopic ultrasonography have also improved and simplified preoperative staging. Despite recent advances in the endoscopic management of cholangiocarcinoma, this neoplastic disease is still fatal in the majority of patients. Surgical resection or liver transplantation offers the only possibility for curing this disease in its early stages. However, most patients present with advanced disease that is not amenable to such therapy. For those patients presenting with unresectable carcinoma above the cystic duct without intrahepatic or extrahepatic metastases, orthotopic liver transplantation combined with preoperative irradiation and chemotherapy is available and demonstrates improved survival on the basis of a recent study conducted at the Mayo Clinic. In the future, chemopreventive strategies aimed at blocking the links between inflammation (eg, nitric oxide synthase and cylcooxygenase 2 inhibitors) and carcinogenesis may help prevent this often fatal disease in high-risk patients (eg, patients with PSC).

Preliminary experience with liver transplantation in selected patients with unresectable hilar cholangiocarcinoma

Previous experience with OLT for hilar CCA has been discouraging, and survival was dismal. This study demonstrates that carefully selected patients with unresectable hilar CCA can achieve long-term survival after OLT. The survival rate obtained with this protocol (5-year actuarial survival of 87%) is comparable with the overall survival rate of liver-transplant recipients at the authors' institution. In comparison, the best survival rate after OLT for hilar CCA reported in the literature is 64.8% at 5 years in a subset of nine patients with negative lymph nodes. In the absence of a control group, it is difficult to assess with certainty the role of a combination of chemotherapy and radiotherapy, but in some patients it seems to prevent or slow progression of the disease while waiting for an available organ. Treatment-related morbidity, although significant, is not prohibitive. Nevertheless, a considerable proportion of treated patients ultimately was found to have advanced disease precluding transplantation. This finding confirms the importance of the staging laparotomy as an essential component of the protocol.

Cell transplantation after oxidative hepatic preconditioning with radiation and ischemia-reperfusion leads to extensive liver repopulation

The inability of transplanted cells to proliferate in the normal liver hampers cell therapy. We considered that oxidative hepatic DNA damage would impair the survival of native cells and promote proliferation in transplanted cells. Dipeptidyl peptidase-deficient F344 rats were preconditioned with whole liver radiation and warm ischemia-reperfusion followed by intrasplenic transplantation of syngeneic F344 rat hepatocytes. The preconditioning was well tolerated, although serum aminotransferase levels rose transiently and hepatic injury was observed histologically, along with decreased catalase activity and 8-hydroxy adducts of guanine, indicating oxidative DNA damage. Transplanted cells did not proliferate in the liver over 3 months in control animals and animals preconditioned with ischemia-reperfusion alone. Animals treated with radiation alone showed some transplanted cell proliferation. In contrast, the liver of animals preconditioned with radiation plus ischemia-reperfusion was replaced virtually completely over 3 months. Transplanted cells integrated in the liver parenchyma and liver architecture were preserved normally. These findings offer a paradigm for repopulating the liver with transplanted cells. Progressive loss of cells experiencing oxidative DNA damage after radiation and ischemia-reperfusion injury could be of significance for epithelial renewal in additional organs.

Treatment of cholangiocarcinoma complicating primary sclerosing cholangitis: the Mayo Clinic experience

OBJECTIVES

The aims of this retrospective study were to assess the frequency with which we used different treatment modalities for patients with primary sclerosing cholangitis (PSC) and cholangiocellular carcinoma (CCA).

METHODS

A total of 41 patients with known CCA complicating PSC with a median age of 49 yr (range, 27-75 yr) were identified from a group of 1009 patients (4%) with PSC seen over 10 yr at the Mayo Clinic.

RESULTS

These patients received mainly five forms of treatment: 10 patients were treated with radiation therapy (RT) with or without 5-fluorouracil (5-FU) (seven with palliative and three with curative intent), nine with stent placement for cholestasis, 12 with conservative treatment, four with surgical resection (one of four received RT and 5-FU), and three patients with orthotopic liver transplantation and RT, with or without 5-FU. One patient was treated with 5-FU alone, one with photodynamic therapy, and one patient with somatostatin analog. A total of 36 patients died, whereas four (10%) patients survived (two with surgical resection, one with orthotopic liver transplantation and RT, and one with stent placement) during a median follow-up of 5.5 months (range, 1-75 months). One patient was lost to follow-up.

CONCLUSIONS

In highly selective cases, resective surgery seems to be of benefit in PSC patients with CCA. However, these therapies are rarely applied to these patients because of the advanced nature of the disease at the time of diagnosis. Efforts should be directed at earlier identification of potential surgical candidates.

Postoperative endoscopic retrograde high dose-rate brachytherapy for cholangiocarcinoma

Cholangiocarcinoma typically presents with disease unlikely to be completely resected, and prognosis remains poor. Improvements in imaging, endoscopy, and stenting have given rise to renewed interest in brachytherapy. Several recent retrospective series suggest a benefit to intraluminal brachytherapy, most commonly delivered by the transhepatic route. We describe a case in which brachytherapy was delivered via the nasobiliary route to address positive margins at the common bile duct stump. A custom catheter was manufactured to make the procedure feasible. Pertinent literature is reviewed, which supports the view that these malignancies benefit from high doses of radiation, if this can be achieved respecting normal tissue tolerance.