OBJECTIVE: The treatment of cystic brain metastases is still controversial, and the purpose of this paper is to effectively investigate the role of stereotactic capsular fluid drainage combined with gamma knife in the treatment of cystic brain metastases. METHODS: From December 1996 to January 2011, 79 patients with brain metastases (84 cystic metastases), 51 men and 28 women, aged 39-79 years (mean 62.3±10.8 years), were treated with stereotactic capsular fluid drainage combined with gamma knife. The prescribed dose of gamma knife treatment was 12-28 Gy (mean 18.7 Gy). RESULTS: In 84 cystic metastases, the tumor volume was 4.5C72.3 ml (mean 25.6 ml) before cyst fluid aspiration, 3.5C45.4 ml (mean 16.2 ml) after aspiration or drainage of cyst fluid, and 1.8C30.1 ml (mean 12.3 ml) after aspiration, with a volume reduction rate of 15-68% (mean 52%). The local control rate of tumor was 93.1%. The overall survival was 16 months, with one-year and two-year survival rates of 57.1% and 32.1%, respectively. CONCLUSION: Stereotactic cyst fluid drainage combined with gamma knife for cystic metastases is feasible, and two treatments are accomplished in one operation. The drainage of cystic fluid both improves the symptoms of brain tissue compression and reduces the target volume, decreasing the possibility of dose-volume-related radionecrosis and improving the prescribed tumor dose and tumor control rate.
Stereotactic drainage and Gamma Knife radiosurgery of cystic brain metastasis Xin YU, Jianning ZHANG, Junzhao SUN, Shubing QI, Hongwei WANG, Rui LIU, Neurosurgical Department, Navy General Hospital of PLA, Beijing, China, 100048 [Abstract] Objective: Treatment options for patients with cystic brain metastasis The purpose of this study was to investigate the feasibility and efficacy of combining stereotactic drainage The purpose of this study was to investigate the feasibility and efficacy of combining stereotactic drainage and Gamma Knife radiosurgery for the treatment of cystic metastatic tumors. January 2011, 79 consecutive patients with cystic brain metastases underwent combination treatment of stereotactic drainage and Gamma Knife radiosurgery in our hospital. There were 51 males and 28 females and their mean age were 62.3±10.8 years (range 39-79 years). The mean prescription dose to the tumor margin was 18.7 Gy (range 12C28 Gy). Results: Before drainage the mean tumor volume was 25.6 ml (range 4.5C72.3 ml); before Gamma Knife the mean tumor volume was 12.3 ml (range 1.8C30.1 ml). The volume reduction was approximately 52% (range 15-68%). Local tumor control was achieved in 93.1% of the patients. Overall median patient survival was 16 months. The 1- and 2-year survival rates were57.1% and 32.1%. Conclusions: The results of this study support the use of a double stereotactic approach, with a single frame application, in treatment of patients with Stereotactic aspiration can reduce target volume and improves acute symptoms. Stereotactic aspiration can reduce target volume and improves acute symptoms. Brain metastases are the most common intracranial tumor, and the incidence of brain metastases in cancer patients is 20-40% [1-3]. In recent years, the incidence of brain metastases has been on the rise due to the prolonged survival of cancer patients and the development of neuroimaging. This feature of tumor cystic degeneration is involved in many surgically and radiosurgically treated patients, but few reports have specifically addressed this type of lesion. The purpose of this article is to investigate the feasibility and effectiveness of stereotactic cystic fluid drainage in improving gamma knife treatment.
Materials and methods From December 1996 to January 2011, a total of 1834 patients with brain metastases were treated at the Gamma Knife Treatment Center of the Naval General Hospital, of which 79 patients had cystic metastases. The diagnosis of brain metastases was based on the histopathological diagnosis of the primary focus and the typical MRI manifestation of the head. 14 patients underwent stereotactic puncture with simultaneous solid tumor biopsy to make the diagnosis of metastases directly, among which 6 patients had the diagnosis of the primary focus based on the pathological diagnosis of brain metastases.
Inclusion criteria: 1) no history of total brain radiotherapy or surgical resection of brain metastases; 2) no more than 4 tumors on MRI; 3) at least 1 of them was predominantly cystic; 4) KPS score ≥70; 5) histological diagnosis of malignant tumor. A total of 79 patients were enrolled. There were 51 male patients (64.6%) and 28 female patients (35.4%). Age was 39-79 years (mean 62.3±10.8). 37 cases (46.9%) were 65 years old. KPS score was 70-100 (mean 87). Type of primary tumor: 35 cases of lung cancer, 12 cases of breast cancer, 10 cases of kidney cancer, 8 cases of liver cancer, 4 cases of pancreatic cancer, 2 cases each of prostate and thyroid cancer, and 6 cases of unknown origin. The primary focus was not completely controlled in 52 cases (65.8%) and completely controlled in 27 cases (34.2%). Cystic metastases were located above and below the curtain in 75 cases (94.9%) and below the curtain in 4 cases (5.1%). 74 cases had one cystic metastasis and 5 cases had two cystic metastases.
Treatment procedure: Leksell G-type stereotactic head frame was installed under local anesthesia (some patients were sedated with a small amount of sedation), GE 1.5T MRI T1-weighted image enhancement scan was performed, 2-mm layer-thick axial image reconstruction was performed, stereotactic surgery planning was performed by applying the stereotactic planning system, and cyst fluid aspiration was completed in the stereotactic operating room. After the completion of cyst fluid aspiration, MRI enhancement scan was performed again (the same scan parameters as before), and the gamma knife treatment planning system was used for treatment planning and dose design. A total of 84 cystic tumors were treated in 79 patients using the domestic OUR rotary gamma-ray stereotactic therapy system (Gamma Knife).
Gamma knife treatment was performed with collimators of 4, 8, 14 and 18 mm, and multiple small diameter collimators were applied as much as possible. The isodose profile around the tumor was 35-65%, with 65 tumors (77.4%) applying a 50% isodose profile. The prescribed dose was 12-28 Gy (mean 18.7 Gy). The prescribed doses were designed according to the doses recommended in the National Radiation Oncology Collaborative Group draft 90-05, but were reduced for larger tumors, those located in important functional areas (e.g., brainstem and motor areas), and multiple metastases.
Follow-up: It was done by outpatient, telephone, and letter, and patients’ KPS scores and enhanced MRI findings were counted every 3 months after treatment. Tumor disappearance, volume reduction and stability were considered as local tumor control, while tumor increase in volume was considered as tumor progression, and the appearance of new metastatic lesions in other parts of the brain was considered as distant site progression.
Statistical analysis: Quantitative data were described by means and standard deviations, and survival was defined as the time after gamma knife treatment until the patient’s death or until the last follow-up visit.
Results Among 84 cystic metastases, the tumor volume before cyst fluid aspiration was 4.5C72.3 ml (mean 25.6 ml), with a solid volume of 0.2C22.4 ml (mean 6.2 ml) and a cystic volume of 3.7C49.9 ml (mean 18.4 ml). The volume reduction of metastases after aspiration was satisfactory (Figure 1), and 3.5C45.4 ml (mean 16.2 ml) of cystic fluid was aspirated or drained, and the tumor volume after aspiration was 1.8C30.1 ml (mean 12.3 ml), with a volume reduction rate of 15-68% (mean 52%).
Figure 1 Axial MRI T1-weighted enhanced scan showing a left parietal cystic metastasis (A) and significant tumor volume reduction after stereotactic cyst fluid aspiration (B), and CT scans at 3 months (C) and 7 months (D) after treatment showing tumor disappearance.
Tumor control rate: 11 patients died within 3 months after treatment and 12 patients were lost to follow-up. Among the 56 patients in this group who were followed up for more than 3 months, a total of 58 tumors, 54 cystic metastases had local tumor control (tumor control rate of 93.1%) and no further tumor progression during the follow-up period, 4 metastases had continued tumor progression after treatment (6.9%), and 21 patients had tumor progression in distant sites. There was no statistical difference between tumor volume and prescribed dose and tumor control rate after aspiration (see Table 1).