Cancer concepts and principles: primer for the interventional oncologist-part I.

A sophisticated understanding of the rapidly changing field of oncology, including a broad knowledge of oncologic disease and the therapies available to treat them, is fundamental to the interventional radiologist providing oncologic therapies, and is necessary to affirm interventional oncology as one of the four pillars of cancer care alongside medical, surgical, and radiation oncology. The first part of this review intends to provide a concise overview of the fundamentals of oncologic clinical trials, including trial design, methods to assess therapeutic response, common statistical analyses, and the levels of evidence provided by clinical trials.

Cancer concepts and principles: primer for the interventional oncologist-part II.

This is the second of a two-part overview of the fundamentals of oncology for interventional radiologists. The first part focused on clinical trials, basic statistics, assessment of response, and overall concepts in oncology. This second part aims to review the methods of tumor characterization; principles of the oncology specialties, including medical, surgical, radiation, and interventional oncology; and current treatment paradigms for the most common cancers encountered in interventional oncology, along with the levels of evidence that guide these treatments.

Kidney neoplasms: renal halo sign after percutaneous radiofrequency ablation--incidence and clinical importance in 101 consecutive patients.

PURPOSE: To describe the incidence and clinical importance of the renal halo sign after percutaneous radiofrequency ablation (RFA) of renal neoplasms. MATERIALS AND METHODS: Institutional review board approval was obtained for this HIPAA-compliant retrospective study. The study population consisted of 101 consecutive patients with 106 solid renal neoplasms that were treated with percutaneous RFA. Postablation computed tomographic (CT) and magnetic resonance (MR) images were retrospectively reviewed by three board-certified radiologists to determine the presence of the renal halo sign. Statistical analyses were performed to determine reader agreement and assess the effect that tumor size and location, radiofrequency (RF) applicator type, RFA treatment time and success, maximum RFA treatment temperature, and number of RF applications performed had on development of the renal halo sign. RESULTS: The renal halo sign developed in 79 (75%) of the 106 ablated tumors. Average imaging follow-up lasted 25 months (range, 1-98 months). The renal halo sign appeared, on average, 6 months (range, 1 month to 3 years) after RFA. The renal halo sign resolved in five (6%) of 79 tumors treated. Interobserver agreement for the presence of the renal halo sign was high. Tumor size and location, RF applicator type, RFA treatment time and success, maximum RFA treatment temperature, and number of RF applications performed were not independent predictors of renal halo sign development. CONCLUSION: The renal halo sign is seen in 75% of patients after percutaneous RFA of renal neoplasms. It may decrease in size over time; however, it rarely disappears. It is important to recognize this sign, as it can be mistaken for recurrent tumor or angiomyolipoma by radiologists who are not familiar with RFA.

Image-guided thermal ablation of nonresectable hepatic tumors using the Cool-Tip radiofrequency ablation system.

Percutaneous thermal ablation techniques have gained considerable attention as an alternative to surgery for the treatment of malignant liver tumors in selected patients. In particular, image-guided radiofrequency ablation (RFA) is increasingly being used for the local treatment of hepatocellular carcinoma, as well as for metastases to the liver. As a minimally invasive treatment option, this technique has several advantages compared with surgical resection. Benefits include reduction in morbidity and mortality, lower cost, suitability for real-time imaging guidance, use in an outpatient setting and use in patients who are not surgical candidates. The Cool-Tip RFA system has recently received US FDA approval for use in ablating nonresectable liver tumors. This article describes the principles and application of radiofrequency ablation for the treatment of nonresectable hepatic tumors along with the unique features of the Cool-Tip RFA system. Finally, a view into the future suggests that, as the trend towards minimally invasive treatment options for hepatic malignancies continues, RFA will assume increasing clinical application.

Angiographically documented hemorrhagic conversion of a left middle cerebral artery embolic stroke during intra-arterial thrombolysis.

BACKGROUND AND PURPOSE: The clinical benefits of intra-arterial thrombolysis for ischemic stroke must be weighed against the risks, including hemorrhagic conversion. SUMMARY OF CASE: A case of angiographically documented hemorrhagic conversion of an ischemic stroke during intra-arterial thrombolysis is presented. Discussion focuses on recognition and management of risk factors for hemorrhagic conversion during performance of stroke thrombolysis. CONCLUSIONS: Recognition and modification of risk factors for hemorrhagic conversion may not prevent this complication during stroke thrombolysis. Identification of the angiographic appearance of hemorrhagic conversion should alert the interventionalist to the likelihood of a poor clinical outcome regardless of vessel patency status.

Endovenous laser ablation of the saphenous veins: bilateral versus unilateral single-session procedures.

PURPOSE: To assess the feasibility of bilateral endovenous laser ablation (EVLA) of saphenous veins in a single session with use of diluted lidocaine for tumescent anesthesia. MATERIALS AND METHODS: Among 122 consecutive EVLA procedures (112 patients; mean age, 49 years; 75% women) over a 12-month period, there were 75 unilateral procedures (n = 67) and 47 bilateral interventions (n = 45). Tumescent anesthesia consisted of lidocaine diluted to 0.10% for unilateral procedures versus 0.05% for bilateral cases (lidocaine dose <4.5 mg/kg body weight). Procedural data, immediate success rates on an intent-to-treat basis, and outcomes at 3-6-month follow-up were compared between groups with nonparametric tests. RESULTS: Bilateral procedures could be performed successfully with low lidocaine dilutions with a similar success rate (96%) as unilateral procedures (100%). No significant variation in systolic and diastolic blood pressure and heart rate was observed between bilateral and unilateral groups. No patient experienced signs of lidocaine toxicity. After adjusting for length of vein treated, there were no significant differences in the total lidocaine dose used, tumescent anesthesia volume, or procedure duration. CONCLUSIONS: Bilateral saphenous vein ablation in a single session appears safe and effective when tumescent anesthesia is given with very dilute lidocaine (0.05%). This approach may help meet patients' requests for simultaneous bilateral treatment and reduce duration of postprocedural discomfort.