Cumulative intracranial tumour volume prognostic assessment: a new predicting score index for patients with brain metastases treated by stereotactic radiosurgery.

Brain metastases (BM) represent the most common intracranial malignancy in adults. Limitations of existing prognostic models reduce their predictivity and clinical applicability. The aim of this study is to validate the cumulative intracranial tumour volume prognostic assessment (CITVPA) as a new prognostic score system for patients with BM treated by Stereotactic Radiosurgery (SRS). Between January 2001 and December 2015, 1894 patients underwent Gamma Knife SRS treatment. The CITVPA model was implemented and validated as follows: the CITV cut-offs were identified thanks to a receiver-operating characteristic (ROC) curve analysis; the survival predictive factors were selected through a Cox proportional hazard model; its prognostic power was compared to RPA, SIR and GPA through the Harrel concordance index (HCI). According to the ROC curve analysis, the CITV cut-off values were set at 1.5 and 4.0 cc. Based on the multivariate analysis, the CITVPA model included: age (OR 1.010, 95% CI 1.005-1.015, p < 0.001), KPS (OR 0.960, 95% CI 0.956-0.965, p < 0.001), extracranial metastases (OR 1.287, 95% CI 1.154-1.437, p < 0.001), BM number (OR 1.193, 95% CI 1.047-1.360, p = 0.008), and CITV (OR 1.028, 95% CI 1.020-1.036, p < 0.001). A score between 0 and 1 was attributed to each prognosticator; a global CITVPA score ranging from 0 to 5 was assigned with higher results corresponding to worse outcomes. The CITVPA (HCI = 0.64) exhibited a significantly (p < 0.001) higher prognostic power compared to RPA (HCI = 0.55), SIR (HCI = 0.55) and GPA (HCI = 0.61). The CITVPA represents a reliable prognostic system for patients with BM treated by SRS. However, further prospective and multicentric studies are necessary before its applicability in clinical practice.

Stereotactic drainage and Gamma Knife radiosurgery of cystic brain metastasis.

OBJECT: Treatment options for patients with brain metastasis include tumor resection, whole-brain radiation therapy, and radiosurgery. A single treatment is not useful in cases of multiple tumors, of which at least 1 is a cystic tumor. The purpose of this study was to assess the role of stereotactic drainage and Gamma Knife surgery (GKS) in the treatment of cystic brain metastasis. METHODS: Between January 2001 and November 2005, 680 consecutive patients with brain metastases underwent GKS at our hospital, 30 of whom were included in this study (18 males and 12 females, mean age 60.6 +/- 11 years, range 38-75 years). Inclusion criteria were: 1) no prior whole-brain radiation therapy or resection procedure; 2) a maximum of 4 lesions on preoperative MR imaging; 3) at least 1 cystic lesion; 4) a Karnofsky Performance Scale score >or= 70; and 5) histological diagnosis of a malignant tumor. RESULTS: Non-small cell lung carcinoma was the primary cancer in most patients (19 patients [63.3%]). A single metastasis was present in 13 patients (43.3%). There was a total of 81 tumors, 33 of which were cystic. Ten patients (33.3%) were in recursive partitioning analysis Class I, and 20 (66.6%) were in Class II. Before drainage the mean tumor volume was 21.8 ml (range 3.8-68 ml); before GKS the mean tumor volume was 10.1 ml (range 1.2-32 ml). The mean prescription dose to the tumor margin was 19.5 Gy (range 12-25 Gy). Overall median patient survival was 15 months. The 1- and 2-year survival rates were 54.7% (95% confidence interval 45.3-64.1%) and 34.2% (95% confidence interval 23.1-45.3%). Local tumor control was achieved in 91.3% of the patients. CONCLUSIONS: The results of this study support the use of a multiple stereotactic approach in cases of multiple and cystic brain metastasis.

Radiosurgery and the prevention of regrowth of incompletely removed nonfunctioning pituitary adenomas.

OBJECT: The authors studied the efficacy of gamma knife radiosurgery (GKS) in the prevention of regrowth of nonfunctioning pituitary adenomas (NPA). METHODS: One hundred nineteen patients were included in this study and were divided into two groups. All patients had undergone surgery in our department and recurrent or residual adenoma was demonstrated on postoperative MR imaging. Group A consisted of 68 patients who were followed without additional treatment. Group B was composed of 51 patients who received GKS within 1 year after microsurgery. There was no significant demographic difference between the two groups. In Group B the mean margin dose was 16.5 +/- 0.3 Gy (range 13-21 Gy). Fifty one and one tenth percent of patients in Group A were recurrence free at 5 years and 89.8% in Group B (p < 0.001). In Group B patients, tumor volume decreased from a baseline value of 2.4 +/- 0.2 cm3 to 1.6 +/- 0.2 cm3 at last follow up (p < 0.001). CONCLUSIONS: The results of this study suggest that GKS is effective in controlling growth of residual NPA for at least 5 years following initial maximal surgical debulking compared with no radiation therapy. Thus, GKS is recommended after microsurgery when visible tumor can be detected on imaging studies.

A simplified method to integrate metabolic images in stereotactic procedures using a PET/CT scanner.

We have developed a method that needs only the computed tomography (CT) indicator box to coregister positron emission tomography (PET) images and integrates this information with magnetic resonance imaging. The study was performed using a PET/CT scanner. A standard CT bed adapter was attached to the scanner couch. Then, the patient, with the Leksell G frame fixed, was positioned into the scanner with the CT indicator box. PET images were acquired using either [18F]fluorodeoxyglucose or [11C]choline as radioisotopes. After acquisition, CT and PET images were exported in DICOM 3 standard and transferred to a dedicated workstation via data link. Homemade software was implemented for multimodal image fusion. PET images were overwritten to their corresponding CT point values using a threshold algorithm, maintaining the stereotactic CT markers. The use of a CT indicator simplifies the procedure, because there is no need for a radioactive solution filling the indicator box. This method was tested first using a phantom and then in patients. The localization accuracy of the PET images is limited only by the slice thickness.