[Results of hypofractionated stereotactic radiotherapy for resected and intact large brain metastases]

Post-resection or isolated hypofractionated stereotactic radiotherapy (HF-SRT) is a therapeutic option for large brain metastases (>2 cm, LBMs).

OBJECTIVE

To compare the results of post-resection or isolated HF-SRT in patients with LBMs.

MATERIAL AND METHODS

A prospective study included 115 patients with 129 intact LBMs and 133 patients with 149 resected LBMs who underwent HF-SRT. Median baseline focal size was 22.5 and 28 mm, median target volume - 8.3 and 23.7 cm3, respectively.

RESULTS

Median follow-up was 13.9 months, median overall survival - 19.1 months. After 12 months, local recurrences developed in 17 and 31% of patients, respectively (p=0.0078). Local recurrence after 12 months developed in 23% of patients with residual tumor in postoperative cavity compared to 16% of patients after total resection (p=0.0073). After 12 months, incidence of leptomeningeal progression was 27 and 11%, respectively (p=0.033), incidence of symptomatic radiation-induced necrosis - 4 and 23%, respectively (p=0.0006).

CONCLUSION

Post-resection HF-SRT demonstrated better local control and less severe symptomatic radiation-induced necrosis compared to patients with intact LBMs. Incidence of leptomeningeal progression is significantly higher after resection of LBMs.

[Expression of estrogen and progesterone receptors in vestibular schwannomas]

INTRODUCTION

Stereotactic radiosurgery is one of the main treatments for vestibular schwannomas (VS). Their feature is frequent post-radiation pseudoprogression. This may be due to hormonal status of patients.

OBJECTIVE

To analyze expression of progesterone and estrogen receptors in women and men with VS.

MATERIAL AND METHODS

Immunohistochemical analysis of expression of progesterone (PR) and estrogen receptors (ER) after biopsy was performed in 240 patients with VS between 2018 and 2021. ER/PR expression was assessed in men (n=120) and women (n=120) in 3 age subgroups: young age (18-44 years), middle age (45-59 years) and old age (60-79 years). Each subgroup included 40 patients. Statistical analysis was performed using the Mann-Whitney test and MedCalc software.

RESULTS

ER expression is not typical for VS (men - 1 (0.01%), women - 3 (2.5%)). At the same time, PR expression was found in 29 (24.2%) men and 21 (17.5%) women. We found no significant difference in expression of ER and PR between men and women. However, variability in PR expression was revealed, i.e. predominance of this indicator in young women (p=0.0463) and middle-aged men (p=0.0110). Expression of PR was similar in elderly patients (p=0.2382).

CONCLUSION

The established incidence of PR expression may be one of the probable causes affecting development and duration of VS pseudoprogression after radiosurgery without clear relationship between sex and age. Further prospective research is needed to predict the risks of pseudoprogression.

[Stereotactic radiosurgery for vestibular schwannoma: early and long-term radiation-induced changes and tumor growth control]

Stereotactic radiosurgery of vestibular schwannoma is an effective and safe method of treatment. The phenomenon of schwannoma pseudo-progression (transient post-radiation enlargement) complicates assessment of the outcomes after radiosurgery.

OBJECTIVE

To investigate the changes of vestibular schwannoma in different periods after radiosurgery.

MATERIAL AND METHODS

We analyzed early and long-term radiation-induced changes in 333 patients who received Gamma Knife treatment at the Burdenko Neurosurgery Center between April 2005 and December 2015. Mean follow-up period was 60 months (range 15-167). There were 89 men (26.7%) and 244 (73.4%) women. Mean age of patients was 48.2 years. Mean baseline tumor volume was 4.1 cm³ (range 0.1-14.5). Dynamics of changes was assessed using volumetric comparison.

RESULTS

Tumor shrinkage without pseudo-progression was observed in 149 (44.7%) patients. Typical pseudo-progression in different variants was found in 131 (39.3%) patients, i.e. short-term (1 year) and long-term (≥2 years) course, complete and incomplete process. Eleven patients had atypical pseudo-progression after initial tumor shrinkage. Progression-free 5- and 10-year survival in the entire group was 87 and 81%, respectively. Progression-free 5-year survival rate was 95 and 92% in patients with and without pseudo-progression, respectively. Ten-year survival rate was 89 and 89%, respectively.

CONCLUSION

Knowledge of pseudo-progression features is essential for the most reasonable and reliable assessment of treatment results and justification of timing and frequency of subsequent MR control. Atypical course of pseudo-progression can simulate tumor recurrence. In case of tumor enlargement at any follow-up stage after radiosurgery, advisability of surgery should be determined considering clinical data and likelihood of tumor shrinkage following natural regression of post-radiation tumor enlargement.

[Investigation of the metabolic features of primary glioblastomas by Tc-MIBI SPECT/CT and evaluation of their effect on disease prognosis]

OBJECTIVE

To study the effect of metabolic characteristics of the tumor determined by 99mTc-MIBI single-photon emission computed tomography (SPECT) and various molecular genetic features on the outcomes of combination treatment of hemispheric glioblastomas.

MATERIAL AND METHODS

This single-center prospective cohort study involved 68 patients aged 25-78 years (38 males and 30 females) with primary glioblastomas. Hypermetylation of the promotor region of the MGMT gene was observed in 24 (42%) out of 57 patients. The IDH1 mutation was revealed in two (3.5%) patients. The catamnestic data were available for 66 out of 68 patients. The first SPECT/CT study was carried out before chemoradiation therapy; the second SPECT/CT study was performed after the chemoradiation therapy. In each study, quantitative measures were calculated for the early (15-30 min after the patient had received a radiopharmaceutical) and late (after 45-60 min) phases.

RESULTS

The actuarial survival rates after 12 and 24 months were 69.6 and 29.1%, respectively. The median overall survival rate was 17.5 months (95% CI 12.9-20.3). Favorable prognostic factors for overall survival included the higher uptake index (UI) in the late phase compared to UI in the early phase of the first SPECT/CT study (p=0.0444), dynamics of changes in UI during the second SPECT/CT compared to baseline over 10% (p=0.0436), MGMT hypermethylation (p=0.0003), and duration of the period between surgery and initiation of chemoradiotherapy being <1 month (p=0.0008). No statistically significant correlations were revealed between the absolute UI values in the tumor and its molecular genetic features.

CONCLUSION

The ^99mTc-MIBI SPECT/CT can be used to predict overall survival and to plan radiation therapy of glioblastoma as it is more readily available at primary healthcare facilities than amino acid PET.

[A modern strategy of combined surgical and radiation treatment in patients with brain metastases]

The treatment standards for patients with brain metastases have been developed for several decades. An important element in the evolution of approaches to the treatment of these patients is the development of microsurgery, stereotactic radiotherapy, and targeted therapy and introduction of these techniques into clinical practice. Surgery is an effective treatment option in patients having single brain metastases and/or occuring in life-threatening clinical situations. Irradiation of the whole brain after surgical treatment is a necessary step in achieving satisfactory local control of intracranial metastatic foci, but the development of neurocognitive disorders and deterioration of life quality after this irradiation necessitate the search for alternative radiotherapy techniques in this clinical situation. Currently, an alternative to postoperative irradiation of the whole brain is stereotactic radiotherapy, which is used before or after surgical treatment. Stereotactic radiotherapy improves local control of intracranial metastatic foci and reduces the risk of neurotoxicity. In this review, we analyze the literature data on outcomes of stereotactic irradiation as a component of combined treatment of patients with metastatic brain lesions.

[Overall survival and intracranial relapse in patients with brain metastases after gamma knife radiosurgery alone]

The study purpose was to evaluate the impact of gamma knife radiosurgery (GKRS) alone on the overall survival and rate of intracranial recurrences in brain metastasis patients.

MATERIAL AND METHODS

Treatment outcomes in 502 patients (211 males and 291 females with 2782 brain metastases (BMs)) were retrospectively reviewed. Most patients (n=142; 28.2%) were diagnosed with breast cancer. Multiple BMs were detected in 259 patients (51.6%). The median of the total tumor volume and ВM number was 5.9 cm3 (0.09-44.5 cm3) and 4 (1-36), respectively. The mean marginal radiation dose was 21 Gy (15-24 Gy). The mean follow-up period was 10.6 months (0.2-47.2 months).

RESULTS

The overall survival rate for 12 and 24 months was 37.6 and 19.1%, respectively. The median overall survival after GKRS was 8.6 months (95% confidence interval (CI) 7.0-10.0). Local control of metastatic lesions was achieved in 78.8% of patients. The median local recurrence-free survival was 6.8 months after radiosurgery. The development of new (distant) metastases was observed in 49.5% of patients. The median distant metastasis-free time was 8.8 months. The Karnofsky performance score (KPS) of ≥80 (HR 0.3935, 95% CI 0.2429-0.6376; p=0.0002), BM number of <3 (HR 0.6138, 95% CI 0.3993-0.9943; p=0.0269), and BMs of breast and lung cancers (HR 0.5442, 95% CI 0.3642-0.8071; p=0.0027) are predictors of better survival. In the case of intracranial metastasis recurrence, repeated radiosurgery provides the median overall survival of 19.6 months versus 9.6 months in patients without radiosurgery (HR 0.4026, 95% CI 0.2381-0.6809).

CONCLUSION

Radiosurgical treatment of patients with multiple BMs provides the median overall survival of 8.6 months. A good functional status, non-extensive metastasis of the brain, and radiosensitive morphology of the primary tumor are the predictors of better survival. Repeated radiosurgical treatment for intracranial recurrences provides longer overall survival compared to that in patients without repeated radiosurgical treatment.

[Kidney cancer with brain metastases. Prognostic factors and treatment outcome]

The aim of this study was to study the effectiveness of stereotactic radiosurgery by Gamma Knife in kidney cancer with brain metastases. There were analyzed results in 112 patients with such spread of the disease who received treatment in the Gamma Knife Center, Moscow. The median age of patients was 58 years (range, 33-77 years). Total number of metastatic lesions was 444, and the average number of brain metastases in one patient 4 (from 1 to 30). A single brain metastasis had 28 patients (25 %). Median of total volume of brain metastasis for each patient was 5. 9 cm3 (from 0. 1 to 29,1sm3). Mean marginal dose for metastatic lesion was 22 Gy (from 12 Gy to 26 Gy) and the average value of isodose, on which planning was performed - 64% (from 39% to 99%). The overall survival after radiosurgery was 37,7%, 16,4% and 9,3% for 12, 24 and 36 months, respectively, with a median overall survival of 9,1 months (95% CI = 7,1-11,8). New brain metastases after radiosurgical treatment occurred in 44 (54,3%) patients with a median of 10,1 months. (95% CI = 7-18). Local recurrences after radiosurgical treatment were detected in 19 (17%) patients with a median of 6,6 months (95% CI = 4,0-9,6). The Karnovsky index was >80. Local control was achieved in 96% of metastatic lesions in 87% of patients. Side effects of radiosurgical treatment occurred in 33. 8% of patients (6% radionecrosis and 23. 8% an increase of perifocal edema). Thus stereotactic radiosurgery by Gamma Knife is an effective treatment option for brain metastases in kidney cancer providing a high level of local control of metastatic lesions with minimal neurotoxicity. In a case of distant recurrence reuse of such treatment provides good local control and improves overall survival compared with other methods of treatment.

[Metastatic brain lesion paradigm shift in radiation therapy]

The development of methods of treatment using radiosurgery devices "Gamma Knife", "Cyber Knife" has significantly changed the results of treatment of patients with brain metastases, which allowed formulating new principles of treatment of this group of patients. Radiosurgical treatment by means of "Gamma Knife" and "Cyber Knife" provides stable reproducible results with local tumor control in the case of both single and multiple lesions. The optimal minimum dose is 18Gy. Indicators of local control were 90-94% for brain metastases from breast cancer and 81-98% for brain metastases from lung cancer. With respect to radioresistant brain metastases local tumor control after radiosurgical treatment was 73-90% for patients with melanoma and 83%-96% for patients with renal cell carcinoma. Currently there is a tendency of application of radiosurgical treatment of patients with multiple brain mertastases. Numerous studies show a high rate of local tumor control after radiosurgical treatment in this patient group. This review summarizes current literature data on radiosurgical treatment for brain metastases with an emphasis on survival, local control, distant metastasis, quality of life as well as the potential combinations of existing treatment methods.