Background & Aims It is not clear whether survival times of patients with hepatocellular carcinoma (HCC) are associated with their response to therapy. We analyzed the association between tumor response and survival times of patients with HCC who were treated with locoregional therapies (LRTs; chemoembolization and radioembolization). Methods Patients received LRTs over a 9-year period (n=463). Patients with metastases, portal venous thrombosis, or who had received transplants were excluded; 159 patients with Child-Pugh≤B7 were analyzed. Response (based on European Association for Study of the Liver [EASL] or World Health Organization [WHO] criteria) was associated with survival times using the landmark, risk-of-death, and Mantel-Byar methodologies. In a subanalysis, survival times of responders were compared to those of patients with stable disease (SD) and progressive disease (PD). Results Based on 6-month data, in landmark analysis, responders survived longer than nonresponders (based on EASL but not WHO criteria: P=0.002 and 0.0694). The risk of death was also lower for responders (based on EASL but not WHO criteria: P=0.0463 and 0.707). Landmark analysis of 12-month data showed that responders survived longer than nonresponders (P=<0.0001 and 0.004, based on EASL and WHO criteria, respectively). The risk of death was lower for responders (P=0.0132 and 0.010, based on EASL and WHO criteria, respectively). By the Mantel-Byar method, responders had longer survival than nonresponders, based on EASL criteria (P<0.0001; P=0.596 with WHO criteria). In the subanalysis, responders lived longer than patients with SD or PD. Conclusion Radiographic response to LRTs predicts survival time. EASL criteria for response more consistently predicted survival times than WHO criteria. The goal of LRT should be to achieve a radiologic response, rather than to stabilize disease.

Radioembolization with 90 Y microspheres represents a novel transarterial radiation treatment for liver tumors. The purpose of this pilot study was to evaluate the findings of postimplantation PET/CT of 90 Y glass microspheres. Methods: Three patients with hepatocellular carcinoma and 2 patients with liver metastases (1 neuroendocrine, 1 colorectal) underwent PET/CT after radioembolization. Four patients underwent imaging at 1 mo to assess response and confirm PET/CT findings; 1 patient underwent PET/CT at 4 d after 90 The tracer 90 Y is traditionally thought of as a pure b-emitter. Thus, current clinical practice involves determining the distribution of the microspheres through bremsstrahlung imaging combined with anatomic imaging via SPECT/CT (1). Because bremsstrahlung imaging is based on a SPECT acquisition that uses either a wide imaging window or multiple energy windows due to the continuum, the scattered photon cannot easily be distinguished from true photons. Consequently, bremsstrahlung imaging is not quantifiable, and thus accurate dose distribution cannot be obtained (2).In an effort to improve pretreatment evaluation and follow-up, microspheres containing radionuclides that emit both b-and g-radiations have been proposed, and treatment with microspheres includes the use of 166 Ho and 186 Re/ 188 Re. At the time of this article's publication, glass and poly (L-lactic acid) (PLLA) microspheres incorporating 186 Re/ 188 Re had not been tested in human subjects with liver tumors. However, 188 Re human serum albumin microspheres ( 188 Re-HSAM) have been tested in a small cohort of patients at a single institution (3). The maximum b-particle energy of 188 Re (2.12 MeV) is lower than that of 90 Y (2.28 MeV), thus necessitating 4-to 5-fold-higher activities to obtain an absorbed dose equivalent to that of 90 Y. Because the g-energy (155 keV) is comparable to other nuclear medicine imaging agents, 188 Re-HSAM seems to be a good candidate for radioembolization of liver tumors. However, no conclusive effects could be derived from the study performed by Liepe et al. because of the small cohort size and heterogeneity of the patients' primary disease (3). To properly evaluate the effect of radioembolization of hepatic malignancies with 188 Re-HSAM, more studies and a larger patient cohort are warranted.Another promising radionuclide proposed for radioembolization of hepatic tumors is 166 Ho (maximum energy of the b-particle, 1.77 [48.7%] and 1.85 [50.5%] MeV and energy of the g-ray, 81 keV [6.7%]). 166 Ho PLLA microspheres are currently being used in patients with hepatic malignancies under a phase I clinical trial (4,5). Similar to the 188 Re HSAM dosimetry, the absorbed radiation dose per activity of 166 Ho (8.7 mGy/MBq) is lower than that of 90 Y (28 mGy/MBq). As a result, with 166 Ho 3 times the radioactivity will be required for radioembolization to achieve a dosimetry equivalent to that of 90 Y. The greatest advantage of 166 Ho is that it represents a multimodality imaging agent (6). The paramagnetic pro...

In this largest metastatic CRC series published to date, Y90 radioembolization was found to be safe; survival varied by prior therapy. Further studies are required to further refine the role of Y90 in metastatic CRC.

This study demonstrated the feasibility of same-day Y evaluation and treatment while maintaining the principles of safe and effectiveY infusion including tumoricidal dosimetry (lobar, segmentectomy), minimization of nontarget flow, and minimization of lung dose. This paradigm translates into expeditious cancer care and significant cost savings.

No abstract