Omer Sager

Linear accelerator-based stereotactic radiosurgery in recurrent glioblastoma: a single center experience.

BACKGROUND/AIM Management of patients with recurrent glioblastoma (GB) comprises a therapeutic challenge in neurooncology owing to the aggressive nature of the disease with poor local control despite a combined modality treatment. The majority of cases recur within the high-dose radiotherapy field limiting the use of conventional techniques for re-irradiation due to potential toxicity. Stereotactic radiosurgery (SRS) offers a viable noninvasive therapeutic option in palliative treatment of recurrent GB as a sophisticated modality with improved setup accuracy allowing the administration of high-dose, precise radiotherapy. The aim of the study was to, we report our experience with single-dose linear accelerator (LINAC) based SRS in the management of patients with recurrent GB. METHODS Between 1998 and 2010 a total of 19 patients with recurrent GB were treated using single-dose LINAC-based SRS. The median age was 47 (23-65) years at primary diagnosis. Karnofsky Performance Score was > or = 70 for all the patients. The median planning target volume (PTV) was 13 (7-19) cc. The median marginal dose was 16 (10-19) Gy prescribed to the 80%-95% isodose line encompassing the planning target volume. The median follow-up time was 13 (2-59) months. RESULTS The median survival was 21 months and 9.3 months from the initial GB diagnosis and from SRS, respectively. The median progression-free survival from SRS was 5.7 months. All the patients tolerated radiosurgical treatment well without any Common Toxicity Criteria (CTC) grade > 2 acute side effects. CONCLUSION Single-dose LINAC-based SRS is a safe and well- tolerated palliative therapeutic option in the management of patients with recurrent GB.

Management of patients with recurrent glioblastoma using hypofractionated stereotactic radiotherapy.

Background Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. The chance of cure is very limited due to treatment-refractory disease course with frequent recurrences despite aggressive multimodality management. In this retrospective study, we evaluated treatment outcomes of hypofractionated stereotactic radiotherapy (HFSRT) in the management of recurrent GBM and report our single-center experience. Methods Twenty-eight patients receiving HFSRT for recurrent GBM between September 2008 and February 2014 were retrospectively assessed. Total radiotherapy dose was 25 Gy delivered in 5 fractions over 5 consecutive days for all patients. High-precision, image-guided volumetric modulated arc therapy was delivered with a linear accelerator using 6-MV photons using the frameless technique. Analyzed prognostic factors were age, gender, Karnofsky performance status (KPS), tumor location, planning target volume (PTV) size, overall survival (OS), progression-free survival (PFS), time interval between completion of treatment with Stupp protocol at primary diagnosis and recurrence. Results Median follow-up time was 42 months (range 2–68). Median time interval between primary chemoradiotherapy and HFSRT was 11.2 months (range 4–57.9). Median OS and PFS calculated from reirradiation was 10.3 months and 5.8 months, respectively. Longer interval between initial treatment and recurrence (p = 0.01), smaller PTV size (p = 0.001), KPS ≥70 (p = 0.005) and younger age (p = 0.004) were associated with longer OS on statistical analysis. Conclusion HFSRT offers a feasible and effective salvage treatment option for recurrent GBM management. Prognostic factors associated with longer OS in our study were longer interval between initial treatment and recurrence, smaller PTV size, KPS ≥70 and younger age.

Evaluation of linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) for cerebral cavernous malformations: a 15-year single-center experience.

BACKGROUND AND OBJECTIVES Surgery is the principal treatment for safely accessible hemorrhagic and symptomatic cavernous malformations. Nevertheless, the role of linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) in the management of high-risk, symptomatic cavernoma lesions warrants further refinement. In this study, we evaluate the use of LINAC-based SRS for cerebral cavernous malformations (CMs) and report our 15-year single-center experience. DESIGN AND SETTINGS A retrospective study from the Department of Radiation Oncology and the Department of Neurosurgery at Gulhane Military Medical Academy and Medical Faculty, Ankara from April 1998 to June 2013. PATIENTS AND METHODS Fifty-two patients (22 females and 30 males) with cerebral CM referred to our department underwent high-precision single-dose SRS using a LINAC with 6-MV photons. All patients had at least 1 bleeding episode prior to radiosurgery along with related symptoms. Median dose prescribed to the 85% to 95% isodose line encompassing the target volume was 15 Gy (range, 10–20). RESULTS Out of the total 52 patients, follow-up data were available for 47 patients (90.4%). Median age was 35 years (range, 19–63). Median follow-up time was 5.17 years (range, 0.08–9.5) after SRS. Three hemorrhages were identified in the post-SRS period. Statistically significant decrease was observed in the annual hemorrhage rate after radiosurgical treatment (pre-SRS 39% vs post-SRS 1.21, P<.0001). Overall, there were no radiosurgery-related complications resulting in mortality. CONCLUSION LINAC-based SRS may be considered as a treatment option for high-risk, symptomatic cerebral CM of selected patients with prior bleeding from lesions located at surgically inaccessible or eloquent brain areas.

Evaluation of stereotactic body radiation therapy in the management of adrenal metastases from non-small cell lung cancer.

Aims and Background In this retrospective analysis, we evaluated the use of stereotactic body radiation therapy in the management of adrenal metastases from non-small cell lung cancer and report our single center experience. Methods and Study design Fifteen non-small cell lung cancer patients (9 male, 6 female) with 17 adrenal metastases referred to Gulhane Military Medical Academy Radiation Oncology Department were treated using active breathing control-guided stereotactic body radiation therapy between December 2009 and October 2013. Dose per fraction was 10 Gy to deliver a total dose of 30 Gy over 3 consecutive days for all metastatic adrenal lesions. The mean gross tumor volume was 28.4 cc (range 6.6-101.5) and mean planning target volume was 57.4 cc (range 16.5-143.8). Results At a median follow-up of 16 months, local control was 86.7% and overall survival was 33.3%. Median disease-free survival was 10 months. Treatment response according to RECIST was categorized as complete response in 3 patients (20%), partial response in 5 patients (33.3%), stable disease in 5 patients (33.3%), and progressive disease in 2 patients (13.3%). Most common acute toxicity was grade 1 nausea (n = 7) and grade 1 fatigue (n = 12). There was no case of grade ≥3 acute or late toxicity. Conclusions Stereotactic body radiation therapy offers a safe and efficacious management strategy for adrenal metastases from non-small cell lung cancer by providing excellent local control with negligible treatment related toxicity.

Stereotactic radiosurgery of glomus jugulare tumors: current concepts, recent advances and future perspectives

Stereotactic radiosurgery (SRS), a very highly focused form of therapeutic irradiation, has been widely recognized as a viable treatment option in the management of intracranial pathologies including benign tumors, malign tumors, vascular malformations and functional disorders. The applications of SRS are continuously expanding thanks to the ever-increasing advances and corresponding improvements in neuroimaging, radiation treatment techniques, equipment, treatment planning and delivery systems. In the context of glomus jugulare tumors (GJT), SRS is being more increasingly used both as the upfront management modality or as a complementary or salvage treatment option. As its safety and efficacy is being evident with compiling data from studies with longer follow-up durations, SRS appears to take the lead in the management of most patients with GJT. Herein, we address current concepts, recent advances and future perspectives in SRS of GJT in light of the literature.

Management of patients with ≥4 brain metastases using stereotactic radiosurgery boost after whole brain irradiation.

Aims and Background Brain metastases are a prevalent consequence of systemic cancer, and patients suffering from brain metastases usually present with multiple metastatic lesions. An overwhelming majority of the available literature assessing the role of stereotactic radiosurgery in brain metastasis management includes patients with up to 4 metastases. Given the significant benefit of stereotactic radiosurgery for the treatment of 1 to 3 brain metastases, we evaluated the use of stereotactic radiosurgery boost after whole brain irradiation in the management of patients with ≥4 brain metastases. Methods In this retrospective analysis, outcomes of 50 patients who underwent linear accelerator-based stereotactic radiosurgery boost within 4 to 6 weeks of whole brain irradiation for ≥4 brain metastases were assessed in terms of local control, overall survival, primary involved organ, recursive partitioning analysis class and Karnofsky performance status at the time of stereotactic radiosurgery, number of lesions, age, status of the primary cancer (controlled vs uncontrolled), presence of extracranial disease and toxicity. Results Fifty patients with ≥4 brain metastases were treated using linear accelerator-based stereotactic radiosurgery boost after whole brain irradiation between April 1998 and April 2013. Mean and median number of intracranial lesions was 6.02 and 6, respectively. Median lesion volume was 10.9 cc (range, 0.05–32.6). Median survival time after radiosurgery was 10.1 months (range, 1–25). Status of the primary cancer (controlled vs uncontrolled), recursive partitioning analysis class, Karnofsky performance status, and extracranial metastasis showed statistically significant correlations with overall survival (P <0.001). Treatment-related side effects after stereotactic radiosurgery included temporary edema (n = 14, 28%), hemiparesis (n = 1, 2%), seizure (n = 1, 2%), leukoencephalopathy (n = 2, 4%), and radiation necrosis (n = 6, 12%). Conclusions Linear accelerator-based stereotactic radiosurgery boost within 4 to 6 weeks after whole brain irradiation proved to be an efficacious and well-tolerated treatment strategy for the management of patients with ≥4 brain metastases in our study.

Evaluation of linear accelerator-based stereotactic radiosurgery in the management of glomus jugulare tumors.

AIMS AND BACKGROUND Although mostly benign and slow-growing, glomus jugulare tumors have a high propensity for local invasion of adjacent vascular structures, lower cranial nerves and the inner ear, which may result in substantial morbidity and even mortality. Treatment strategies for glomus jugulare tumors include surgery, preoperative embolization followed by surgical resection, conventionally fractionated external beam radiotherapy, radiosurgery in the form of stereotactic radiosurgery or fractionated stereotactic radiation therapy, and combinations of these modalities. In the present study, we evaluate the use of linear accelerator (LINAC)-based stereotactic radiosurgery in the management of glomus jugulare tumors and report our 15-year single center experience. METHODS AND STUDY DESIGN Between May 1998 and May 2013, 21 patients (15 females, 6 males) with glomus jugulare tumors were treated using LINAC-based stereotactic radiosurgery at the Department of Radiation Oncology, Gulhane Military Medical Academy. The indication for stereotactic radiosurgery was the presence of residual or recurrent tumor after surgery for 5 patients, whereas 16 patients having growing tumors with symptoms received stereotactic radiosurgery as the primary treatment. RESULTS Median follow-up was 49 months (range, 3-98). Median age was 55 years (range, 24-77). Of the 21 lesions treated, 13 (61.9%) were left-sided and 8 (38.1%) were right-sided. Median dose was 15 Gy (range, 10-20) prescribed to the 85%-100% isodose line encompassing the target volume. Local control defined as either tumor shrinkage or the absence of tumor growth on periodical follow-up neuroimaging was 100%. CONCLUSIONS LINAC-based stereotactic radiosurgery offers a safe and efficacious management strategy for glomus jugulare tumors by providing excellent tumor growth control with few complications.

Automatic Segmentation of Anatomical Structures from CT Scans of Thorax for RTP

Modern radiotherapy techniques are vulnerable to delineation inaccuracies owing to the steep dose gradient around the target. In this aspect, accurate contouring comprises an indispensable part of optimal radiation treatment planning (RTP). We suggest a fully automated method to segment the lungs, trachea/main bronchi, and spinal canal accurately from computed tomography (CT) scans of patients with lung cancer to use for RTP. For this purpose, we developed a new algorithm for inclusion of excluded pathological areas into the segmented lungs and a modified version of the fuzzy segmentation by morphological reconstruction for spinal canal segmentation and implemented some image processing algorithms along with them. To assess the accuracy, we performed two comparisons between the automatically obtained results and the results obtained manually by an expert. The average volume overlap ratio values range between 94.30 ± 3.93% and 99.11 ± 0.26% on the two different datasets. We obtained the average symmetric surface distance values between the ranges of 0.28 ± 0.21 mm and 0.89 ± 0.32 mm by using the same datasets. Our method provides favorable results in the segmentation of CT scans of patients with lung cancer and can avoid heavy computational load and might offer expedited segmentation that can be used in RTP.

Dosimetric evaluation of critical organs at risk in mastectomized left-sided breast cancer radiotherapy using breath-hold technique

AIMS AND BACKGROUND The aim of the study was to evaluate the dosimetric impact of the active breathing control-moderate deep inspiration breath-hold (ABC-mDIBH) technique on normal tissue sparing in locally advanced left-sided breast cancer radiotherapy. METHODS AND STUDY DESIGN Twenty-seven consecutive patients with left-sided locally advanced breast cancer referred to our department for adjuvant radiotherapy were enrolled in the study. Each patient was scanned at free breathing and ABC-mDIBH for radiation treatment planning. Two separate radiotherapy treatment plans were generated with and without ABC-mDIBH to investigate the dosimetric impact of ABC-mDIBH in breast cancer radiotherapy. RESULTS Between June 2011 and February 2012, 27 consecutive patients with left-sided locally advanced breast cancer referred to our department for adjuvant radiotherapy were enrolled in the study. Dose-volume parameters of left anterior descending coronary artery, lungs, heart, contralateral breast, esophagus and spinal cord were significantly reduced with the use of ABC-mDIBH (P <0.001). CONCLUSIONS Our study revealed that the use of ABC-mDIBH in the practice of locally advanced mastectomized left-sided breast cancer radiotherapy improves normal tissue sparing with the expected potential of decreasing treatment-related morbidity and mortality. Moreover, the resultant reduction achieved with ABC in doses to the left anterior descending coronary artery, which plays a central role in cardiac perfusion, may have implications for decreasing the potential of radiation-induced cardiac morbidity and mortality.

Adaptive splenic radiotherapy for symptomatic splenomegaly management in myeloproliferative disorders.

Aims and Background Symptomatic, massive splenomegaly is a debilitating complication of myeloproliferative disorders. In the study, we evaluated the use of a contemporary, individualized radiotherapeutic approach for splenic irradiation, including 3-dimensional computed tomography-based treatment planning, individualized treatment margins based on splenic motion assessment, online setup verification with volumetric image guidance at each fraction, and adaptive radiation treatment planning to account for changes in splenic size during the fractionated radiotherapy course. Methods and Study design Between December 2008 and January 2014, 18 patients (13 males, 5 females) with myeloproliferative disorders referred to Gulhane Military Medical Academy Radiation Oncology Department underwent 22 courses of splenic irradiation using 3-dimensional computed tomography-based treatment planning and volumetric image guidance for palliation of symptomatic splenomegaly. Results Median age was 64 years (range 28-79). Significant pain relief was achieved in 20 of the 22 splenic irradiation courses (90.9%). Improvement in hematological parameters was achieved in 8 of the 11 splenic irradiation courses applied for cytopenia (72.7%). At least a 50% reduction in splenic size was achieved in 18 of the 22 splenic irradiation courses (81.8%). Toxicity was manageable with supportive treatment including antiemetics and platelet or red blood cell transfusions. Conclusions Splenic irradiation with a contemporary radiotherapeutic approach offers safe and effective palliation of symptomatic splenomegaly in myeloproliferative disorders.