[FDG PET/CT FOR TREATMENT RESPONSE ASSESSMENT IN CANCER].

INTRODUCTION: FDG PET/CT (fluorodeoxyglucose (FDG)-positron emission tomography (PET) computed tomography (CT)) imaging reflects functional-metabolic changes occurring within the malignant process in response to therapy. Since these changes usually precede anatomic alterations, this imaging technique is highly valuable in assessing response during and after therapy and is superior to CT. FDG PET/CT following initiation of cancer therapy has a prognostic value, predicting progression free survival and overall survival. In some malignancies FDG PET/CT can guide personalized medicine by tailoring therapy in accordance with the metabolic cancer response in the individual patient. In lymphoma patients, including Hodgkin's disease (HD) and diffuse large B-cell lymphoma (DLBCL), FDG PET/CT is useful for monitoring response and guiding therapy, both after and early during therapy. Various quantitative and visual criteria systems are used for assessing cancer response to therapy by FDG PET/CT. Acquaintance with these interpretation methods and their adjustment to new anti-cancerous mechanisms such as in immunotherapy, is important for accurate imaging and meaningful interpretation. Large prospective meticulously performed studies, using standardized methodology, are required to further establish and expand the use of FDG PET/CT for the assessment of response to therapy in various malignancies.

Chemo-Radiotherapy of Oligometastases of Colorectal Cancer With Pegylated Liposomal Mitomycin-C Prodrug (Promitil): Mechanistic Basis and Preliminary Clinical Experience.

Hypo-fractionated radiotherapy and stereotactic body radiotherapy are viable options for treatment of oligometastases. A prodrug of mitomycin-C is under clinical testing as a pegylated liposomal formulation (Promitil) with an improved safety profile over mitomycin-C. Promitil was offered to two patients with oligometastases from colorectal cancer as radiosensitizer. Each derived durable clinical benefit from Promitil administered immediately prior to and following irradiation. Transient toxicity to normal tissues of moderate to severe degree was observed. Promitil appears to have potential clinical value in this setting. HIGHLIGHTS - Delivery of radio-sensitizing drugs with pegylated (long-circulating) liposomes is a pharmacologically rational approach which remains largely clinically untested.- A mitomycin-c prodrug delivered by pegylated liposomes (Promitil) is activated by thiol groups, which are produced in excess by radiation-damaged cells, thus potentiating the radio-sensitizing effect of Promitil.- Two durable clinical responses in patient with colorectal oligometastases to Promitil and radiotherapy suggest that this approach may be of value in cancer chemo-radiotherapy.

Maxillary air density measurements for differentiating between acute and chronic rhinosinusitis.

OBJECTIVE: Maxillary sinus air-fluid levels and sinus opacification may appear similar in cases of acute and chronic rhinosinusitis. Our aim was to evaluate whether air density analysis in addition to air-fluid level can be used as a metric to differentiate between cases of acute and chronic rhinosinusitis. SUBJECTS AND METHODS: A prospective study of three patient groups (n = 73) who underwent sinus CT was performed. A study group composed of 23 patients with clinical acute rhinosinusitis was compared with two different control groups (one with chronic rhinosinusitis and the other with healthy sinuses) with 25 patients in each. In each case air density within the maxillary sinus was measured using a region of interest of 1 cm(2), 0.5 cm away from the sinus wall. The mean and SD of air density of each maxillary sinus were calculated from five sequential CT slices. We compared the results of each group using a paired Student t test and analysis of variance. RESULTS: Mean air density was significantly higher in the acutely inflamed sinuses compared with chronic sinusitis and healthy aerated sinuses (-846.6 vs -980 and -975.8 HU, respectively; p < 0.05). Sinus air density SD was greater in the acutely inflamed sinus than in chronic sinusitis and healthy sinuses (78.3 vs 17.9 and 6.8 HU, respectively; p < 0.05). CONCLUSION: Increased sinus air density and heterogeneity may help differentiate acute from chronic rhinosinusitis.