Stereotactic radiosurgery for meningiomas

The indications for and results after meningioma radiosurgery results are discussed. Particular emphasis is placed on longer-term results, the evolution of technique, complications, and recommendations regarding the role of radiosurgery together with other management strategies.     

Stereotactic LINAC radiosurgery for incompletely resected or recurrent atypical and anaplastic meningiomas

Background  

The optimal management of subtotally resected or recurrent malignant meningiomas remains controversial. We evaluated the efficacy of linear accelerator (LINAC) radiosurgery for atypical and anaplastic meningiomas after incomplete resection or treatment of recurrences.     

Stereotactic radiosurgery of meningiomas

Stereotactic radiosurgery has an expanding role in the management of selected intracranial tumors. In an initial 30-month experience using the 201-source cobalt-60 gamma knife at the University of Pittsburgh, 50 patients with meningiomas were treated. The most frequent site of origin was the skull base. Previously, 36 patients (72%) had undergone at least one craniotomy and four patients (8%) had received fractionated external beam radiation therapy. Stereotactic radiosurgery was the primary treatment modality in 16 patients (32%) with symptomatic tumors demonstrated by neuroimaging. Computer imaging-generated isodose plans (with one to five irradiation isocenters) for single-treatment irradiation gave optimal (greater than or equal to 50% isodose line) coverage in 44 patients (88%). The proximity of cranial nerves or vascular, pituitary, and brain-stem structures to the often convoluted tumor mass was crucial to dose selection. Serial imaging studies were evaluated in all 50 patients. Twenty-four patients were examined between 12 and 36 months after treatment; 13 (54%) showed a reduction in tumor volume while nine (38%) showed no change. Of 26 patients evaluated between 6 and 12 months after treatment, four showed a decrease in tumor size while 22 showed no change. Two patients (both with large tumors that received suboptimal irradiation) had delayed tumor growth outside the radiosurgical treatment volume. The actuarial 2-year tumor growth control rate was 96%. Between 3 and 12 months after radiosurgery, three patients developed delayed neurological deficits that gradually improved, compatible with delayed radiation injury. Although extended follow-up monitoring over many years will be necessary to fully evaluate treatment, to date stereotactic radiosurgery has proved to be a relatively safe and effective therapy for selected patients with symptomatic meningiomas, including those who failed surgical resection. Radiosurgery was an effective primary treatment alternative for those patients whose advanced age, medical condition, or high-risk tumor location mitigated against surgical resection.     

Stereotactic radiosurgery for anterior foramen magnum meningiomas

BACKGROUND: Total microsurgical resection is the procedure of choice for growing and symptomatic foramen magnum meningiomas. We hypothesized that for patients with advanced age, complicating medical conditions, or residual or recurrent meningiomas at the foramen magnum, stereotactic radiosurgery would be a useful adjunctive (n = 2) or alternative (n = 3) treatment. METHODS: We report our experience in five elderly patients (73-84 years) who underwent gamma knife radiosurgery. The median tumor volume was 10.5 ml and the tumor margin dose varied from 10 to 16 Gy. Because of the irregular tumor volumes along the inferior clivus, multiple isocenters of irradiation were required (range, 2-8; mean 4.4). RESULTS: During the follow-up interval of 1-5 years (median, 3 years), one patient died of an intercurrent illness, and all remaining patients were stable without any further deterioration in their clinical condition. Follow-up imaging studies revealed a reduction in tumor volume in one patient and no further growth in the remaining four. CONCLUSION: We believe that stereotactic radiosurgery provides safe and effective management for patients who are poor candidates for resection of their foramen magnum meningiomas.     

Stereotactic radiosurgery as a salvage treatment for recurrent epipharyngeal carcinoma

Fourteen patients with recurrent epipharyngeal carcinoma (EPC) were treated by gamma knife stereotactic radiosurgery. The tumor volume ranged from 0.3 to 80 ml (median 18.9 ml). Treatment was done with a tumor margin dose of 10-27 Gy (median 15 Gy). The median follow-up period was 15 months (range 2-47 months). Ten patients were alive and 4 were dead at the end of the follow-up period. In 6 patients (43%), the tumor disappeared or decreased in size until the end of the follow-up period. In 2 (14%), the tumor remained unchanged in size. In 6 (43%), the tumor showed regression initially but was enlarged later. A second radiosurgery was performed in 4 of those 6 cases and the tumor decreased in size again in 3 of them. Thus, the overall control rate of local tumor was 79% (11/14). In selected patients with recurrent EPC, stereotactic radiosurgery can be considered as a salvage treatment producing local control.     

Stereotactic radiosurgery for locally recurrent nasopharyngeal carcinoma

BACKGROUND: Stereotactic radiosurgery has been used to treat intracranial tumors. Recently, it has also been used for the treatment of head and neck tumors involving the base of skull, including recurrent NPC. METHODS: From October 1994 to April 1999, 36 patients with recurrent NPC, were retreated by stereotactic radiosurgery. These patients received radiosurgery as a boost treatment after reirradiation for recurrence. The external RT dose ranged from 20 to 60 Gy. The tumor volume ranged from 3.58 to 24.6 cc. The target surface dose ranged from 8 to 20 Gy. The median follow-up was 22.1 months. RESULTS: The 3-year local control rate was 56%. The 5-year overall survival was 49%. Persistence after radiosurgery had a worse survival than those who had secondary recurrence. Age and gender were marginally significant. No patient had new severe complications after retreatment. Four patients (11%) had nasopharyngeal necrosis after radiosurgery, none had nasal bleeding or headache, but a foul odor was present in one patient. CONCLUSIONS: Conformal radiotherapy and stereotactic radiotherapy provide good local control and survival without severe complications for patients with recurrent NPC.     

立体定向放疗法与调强放疗对前列腺癌疗效的比较分析

目的:探究立体定向放疗法(SBRT)与普通调强放疗(IMRT)对前列腺癌患者疗效和不良反应的相关影响。方法:40例局限性前列腺腺癌患者为研究对象,患者分别接受SBRT(n=20)与IMRT(n=20)治疗;前者分为5次总计放射剂量为36.25 Gy,后者分为42次总计放射剂量为75.6 Gy;比较放疗后患者的PSA变化及相关不良反应事件,描述治疗后5年患者的免于生物化学治疗失败(FFBF)率和总生存率(OS)。结果:SBRT组患者放疗后第2年PSA最低值[0.41(0-1.25)μg/L]与第3年PSA最低值[0.22(0.1-1.4)μg/L]均显著低于IMRT组[0.62(0～2.4)、0.47(0～2.5)μg/L],差异均具有统计意义(P0.05);而IMRT组放疗后PSA到达最低值时间显著短于SBRT组[27.9(1.0～40.8)个月vs 33.6(2.7～41.6)个月,P0.05];SBRT组患者放疗后第2年与第3年PSA变化率[-0.06(-0.35,0.01)、-0.05(-0.17,0.00)μg/(L·month)]均高于IMRT组[-0.04(-0.64,0.05)、-0.02(-0.36,0.04)μg/(L·month)],差异均具有统计意义(P0.05)。5年FFBF和OS两组均无显著差异(82.2%vs 77.7%,P=0.158;91.1%vs 86.7%,P=0.158)。结论:SBRT与IMRT的疗效和毒性基本一致,考虑到前者的成本较低以及便利性,SBRT更适合局限性前列腺癌的替代性治疗。     

Stereotactic radiosurgery as a salvage treatment for recurrent skull base adenoid cystic carcinoma

Twelve patients (15 lesions) with recurrent skull base adenoid cystic carcinoma (ACC) were treated by Gamma Knife stereotactic radiosurgery (SRS). The tumor volume ranged from 2 to 103 ml (median 15 ml). Treatment was prescribed at the 40-60% isodose line and ranged from 10 to 18 Gy (median: 13.0 Gy). The median follow-up period was 18 months (range 3-55). Six patients were alive and 6 dead at the end of the follow-up period. Only 1 patient died from local tumor recurrence. Ten among 15 tumors treated by SRS decreased in size until the end of the follow-up period or the patients' death. Three remained unchanged in size. Two tumors initially regressed but then increased in size. In selected patients with recurrent skull base ACC, SRS can be considered as a salvage treatment with good local control.     

Stereotactic radiosurgery as a salvage treatment for locally persistent and recurrent nasopharyngeal carcinoma.

BACKGROUND: The purpose of this work was to study the efficacy of stereotactic radiosurgery as a salvage treatment in patients with locally persistent and recurrent nasopharyngeal carcinoma (NPC). METHODS: Between March 1996 and August 1997, 10 patients with locally persistent or recurrent NPC were treated by linac-based stereotactic radiosurgery. Four patients had radiosurgery for persistent disease after a first course of radiotherapy, 3 had radiosurgery as a boost after reirradiation for local recurrence, and 3 had radiosurgery for disease that recurred after reirradiation. The tumor volume ranged from 1.3 to 23.7 cc (median: 5.2). Treatment was prescribed at 80% isodose line and ranged from 12 to 18 Gy (median: 13.4), with a mean tumor surface dose ranged from 10-21 Gy (median: 14). The median clinical follow-up was 10.5 months (range 8-27), and the median imaging follow-up was 9.5 months (range 6-26). RESULTS: One patient had complete regression of tumor after radiosurgery, five had reduction in tumor size, three had no change, and one had progression of tumor. The overall response rate to radiosurgery was 60% (6/10), with 10% (1/10) developing in-field progression. Excluding patients receiving radiosurgery as a boost treatment after reirradiation, the response rate was 57% (4/7) and none developed in-field progression. Only one patient developed a new cranial neuropathy in the absence of disease progression. CONCLUSION: In selected patients with locally persistent or recurrent NPC, stereotactic radiosurgery can be considered as a salvage treatment with good short-term local control. The complications appear to be minimal except for treating recurrence in the cavernous sinus. Early results are encouraging although more experience and longer follow-up are still needed to better define the role of radiosurgery in the management of persistent and recurrent NPC.     

Stereotactic radiosurgery for recurrent central neurocytoma: case report

OBJECTIVE AND IMPORTANCE: Neurocytomas are typically benign tumors that have high local control rates after gross total resection. Nevertheless, tumor recurrence is possible, and some patients have aggressive tumors. CLINICAL PRESENTATION: A 26-year-old woman had a recurrent, asymptomatic neurocytoma 3 years after gross total resection. INTERVENTION: The patient underwent stereotactic radiosurgery for the tumor recurrence. Thirty-four months later, the patient remained neurologically intact, and the tumor had decreased significantly in size. CONCLUSION: Radiosurgery may be a viable treatment option for patients with recurrent neurocytomas or for patients whose tumor resections were subtotal.     

Stereotactic radiation techniques in the treatment of acoustic schwannomas. 2007

Medical decision-making is based on benefit-to-cost analysis. Optimally, treatment obtains a high degree of benefit while minimizing the physical, social, and financial costs. The goals of the treatment of acoustic schwannomas are prohibiting tumor growth and alleviation of symptoms caused by damage to local structures. These symptoms-tinnitus, ataxia, and hearing loss-secondary to eighth nerve dysfunction, as well as symptoms arising from damage to adjacent structures such as the facial nerve, trigeminal nerve, or pons, can be caused by tumor growth or treatment. Determination of optimal therapy must also take into account an understanding of the natural history of the disease, because acoustic schwannomas are slow-growing benign tumors that when left untreated, usually enlarge over time and cause problems.     

Stereotactic radiosurgery. VII. Radiosurgery versus conventionally-fractionated radiotherapy in the treatment of cavernous sinus meningiomas

Twenty-eight patients with meningiomas involving the cavernous sinus were referred to the radiosurgical service at St. Bartholomew's Hospital 1989-1998. The majority (8/13) of patients with small (< 3 cm diameter) tumours received radiosurgery whereas the majority of large tumours (> 3 cm diameter; 12/15) received conventionally-fractionated radiotherapy. Other treatment recommendations were fractionated radiosurgery (one case) and conventionally-fractionated radiotherapy to the whole meningeal base and a radiosurgery boost (three cases). Fractionated radiosurgery is optimal where the target volume is small, but abuts critically sensitive nervous system. There have been no progressions of disease at relatively early follow-up. It is argued that subtotal excision followed by appropriate dose radiation therapy is often a strong competitor to attempted radical excision given the attendant morbidity of this latter operation for meningiomas at this site. Patients referred for radiation therapy are best served by a department with both radiosurgery and conventional radiation therapy facilities.