125I Brachytherapy Seeds Implantation for Inoperable Low-Grade Leiomyosarcoma of Inferior Vena Cava
A 60-year-old woman was admitted to our hospital with abdominal pain over the course ofthe last five days. Tenderness in the right upper abdomen was noted on physical examination. Intravenous contrast enhanced CT scan showed a mass 9 × 6 × 5.5 cm in size with almost complete obliteration of the IVC with a large extravascular component (). The mass was located in the suprarenal IVC with its epicenter outside of the IVC, and presented no extension to the renal vein. Exact diagnosis in this case was uncertain thus biopsy of the mass under CT guidance was performed. Histology revealed diffuse distribution of spindle cells with mild atypia in fibrous tissue. Immunohistochemical stains for smooth muscle desmin were positive and those for interstitialoma, endothelium and neurogenic tumors, including CD34, CD117, S100, nestin and Alkaline were negative, which were all consistent with the diagnosis of low-grade malignant leiomyosarcoma ().\nAfter informed consent from the patient and approval of the Ethics Committee of our hospital, 125I seeds implantation of the mass by posterior approach under CT guidance was performed. Three days before 125I seeds implantation, the patient underwent a detailed tumor volume study using CT scans with slice thickness of 5 mm. A radiation oncologist outlined the gross tumor volume (GTV) and marked areas at risk for subclinical disease on each transverse image. The planning target volume (PTV) included the entire GTV and 0.5-1.0 cm margins. The dose was prescribed as the minimal peripheral dose (MPD) encompassing the PTV. The distribution, MPD of 125I seeds and dose volume histogram (DVH) were calculated using computerized treatment planning system (RT-RSI, Beijing Atom and High Technique Industries Inc., Beijing, China).\nLead protective bucket, vest, apron, spectacles and gloves were used by the operator and the assistants. Puncture region was marked based on the CT image. Following local anesthesia with 0.5% lidocaine and sedation with pethidine hydrochloride and promethazine hydrochloride, eighteen-gauge needles were placed via posterior paraspinal approach or through the space between right kidney and the vertebraes. The procedure included 2-3 steps under CT guidance in a parallel array of 1.0 to 1.5 cm apart, and extended at least 0.5-1.0 cm beyond the GTV. 125I seeds (Jaco pharmaceuticals CO. LTD, Ningbo, China, t1/2: 59.6 days, energy level: 27.4-31.4. keV) were implanted using a Jaco applicator and Radiation-proof implanting needles (Hakko trading CO. LTD., Shanghai, China). The space between seeds (center to center) was kept at 1.0 cm. 30 seeds were implanted with an activity of 0.8 mCi. The distribution and uniformity of the 125Iodine seeds in the lesion and drifting seeds analysis was done under the CT scan. The total procedure lasted 60 minutes, and the dose burden of radiation was 10 mSv under CT guidance.\nAbdominal pain of the patient was relieved in one month after the procedure was performed. Three months later, a follow-up CT examination showed that the size of tumor was decreased, although a cold area was noted at the posterior margin. A second 125I seeds implantation by latero-posterior approach through the lateral space of right kidney under CT guidance was then performed and 30 0.8 mci 125I seeds were introduced into the cold area. After the 2nd session of brachytherapy the course was uneventful and the patient remained in the hospital for 5 days for observation of any unexpected complications. No procedure-related complications were observed. Three months later, CT examination showed high density 125I seeds surrounding the IVC and the previous space-occupying mass disappeared ().\nFive months after the last CT examination the patient was readmitted with lower abdominal pain and presence of lower leg edema. Inferior vena cavography showed narrowing and partial IVC obstruction at L2-3 level, with retroperitoneal collateral circulation in keeping with IVC thrombosis (). After anticoagulant and thrombolytic therapy for one week, cavoplasty was performed with balloons of 5 × 40 mm and 20 × 40 mm consecutively. After angioplasty, the diameter of IVC segment was about 20 mm (). The patient was free of symptoms five days after the procedure. 2.5 mg warfarin per day was used as anticoagulant therapy for the next 3 months.\n125I seeds implantation and balloon cavoplasty worked very well in this patient. At follow-up, the patient was free of symptoms and CT scan showed disappearance of the tumor and no recurrence for 33 months after the 2nd session of brachytherapy, with no thrombosis in the IVC ().