Masaya Takizawa

Usefulness of fluorine-18 fluorodeoxyglucose-positron emission tomography in management strategy for thymic epithelial tumors

BACKGROUND This study investigated the usefulness of fluorine-18 fluorodeoxyglucose-positron emission tomography (FDG-PET) during the treatment of thymic epithelial tumors in combination with Ki-67 evaluation based on surgical cases in our department. METHODS Between November 2003 and May 2011, 39 patients with thymic epithelial tumor underwent preoperative FDG-PET. The maximum standardized uptake value (SUVmax) of each category within Masaoka stage, World Health Organization classification, tumor diameter, myasthenia gravis, and Ki-67 label index were compared. To examine risk factors for relapse, SUVmax, age, sex, and surgical radicality were investigated in addition to those items. RESULTS The mean SUVmax was 4.5 (range, 1.2 to 14.6) and was significantly higher for Masaoka stage IV than for I and II (all p < 0.008) and for World Health Organization classified thymic cancer compared with all other types (all p < 0.0001). Mean SUVmax revealed significantly higher values for large tumors than for small tumors (p = 0.02). Mean SUVmax was significantly higher for high Ki-67-positive samples (p = 0.0004), indicating a strong correlation between SUVmax and the Ki-67 label index (ρ = 0.77, p = 0.0001). SUVmax accurately reflected therapeutic efficacy in patients with induction therapy. Univariate analysis revealed Masaoka stages III and IV and pathologically incomplete resection as risk factors for relapse. On multivariate analysis, independent risk factors for relapse comprised only Masaoka stages III and IV. CONCLUSIONS FDG-PET SUVmax does reflect proliferation and invasiveness of thymic epithelial tumors and can provide an index for diagnosis and treatment, although it is not a risk factor for relapse. FDG-PET is also useful for evaluating induction therapy efficacy and detecting relapse.

A novel fluorescence technique for identification of the pulmonary segments by using the photodynamic diagnosis endoscope system: An experimental study in ex vivo porcine lung

OBJECTIVE Photodynamic diagnosis is a technique that has been proposed to enhance tumor detection and resection. We modified this technique to identify pulmonary segments and examine the feasibility of this technique in ex vivo porcine lungs. METHODS The photodynamic diagnosis endoscope system consisted of the D-Light system as the excitation light source and a TRICAM camera as the fluorescence sensing endoscope (Karl Storz GmbH & Co, Tuttlingen, Germany). Vitamin B2 was used as the fluorescence substance. Two kinds of segmentectomy were performed in right porcine lung. After identification of the segmental bronchus, the fluorescent substance was injected transbronchially. The fluorescent segment was observed using the photodynamic diagnosis endoscope system, and the identified intersegmental plane was cut using scissors. The operative data collected were the success rate of accurately identifying the pulmonary segments. The duration and light intensity of fluorescence of the target segment were recorded to provide an objective measurement of success. The same parameters were also measured for the adjacent segment. RESULTS Overall, 20 segmentectomies were performed, 10 of each kind--cranial segmentectomy and L2 segmentectomy. In all procedures, it was possible to identify the target segment by its yellow-green fluorescence. No unexpected injuries of the major segmental bronchi and vessels nor incorrect recognition of target segments occurred. The success rate of accurately identifying pulmonary segments was 100%. The duration and light intensity of this fluorescence technique was enough to perform pulmonary segmentectomy. CONCLUSIONS This florescence technique using vitamin B2 and the photodynamic diagnosis endoscope system is useful to identify the target pulmonary segment easily and clearly in ex vivo porcine lung.

Myasthenia gravis complicated with lung cancer and middle mediastinal thymoma.

Myasthenia gravis complicated by lung cancer is rare, and the association between myasthenia gravis and lung cancer is unclear. Thymoma located in the middle mediastinum is very rare. We describe a case of myasthenia gravis complicated with lung cancer and middle mediastinal thymoma in a 69-year-old woman.