Long-term clinical outcomes of stereotactic radiotherapy for bilateral vestibular schwannomas in neurofibromatosis type 2 patients.

PURPOSE: The evidence for treating patients with neurofibromatosis 2-related vestibular schwannoma (VS-NF2) using hypofractionated stereotactic radiation therapy (HSRT) is limited. This study aimed to investigate clinical outcomes in patients with VS-NF2 treated with Robotic HSRT. METHODS: We retrospectively analyzed 25 NF2 patients with 48 VSs who were treated using Robotic HSRT at Ramathibodi Hospital from January 2009 to January 2020. RESULTS: Median follow-up was 98 months (range, 24-155 months). Median tumor volume was 2.3 cm3 (range, 0.4-28.3 cm3). Median prescribed dose was 18 Gy (range, 18-25 Gy) in three fractions (range, 3-5). The 5- and 10-year local control rates were 87% and 80%, respectively. The 5- and 10-year hearing preservation rates were 59% and 35%, respectively. Three patients developed new symptoms associated with transient volume expansion after treatment: hydrocephalus in one, facial weakness in one, and ataxia in one. No patient developed worsening of trigeminal nerve function. No histologically confirmed of radiation induced malignancy was reported in the study. CONCLUSIONS: Robotic HSRT demonstrated excellent long-term tumor control with a low non-auditory complication rate in patients with VS-NF2. However, preservation of hearing remains a major concern.

Long-term treatment outcomes of pediatric low-grade gliomas treated at a university-based hospital.

PURPOSE: A multimodality approach is generally considered for pediatric low-grade gliomas (LGG); however, the optimal management remains uncertain. The objective of the study was to evaluate treatment outcomes of pediatric LGG, focusing on long-term survival and factors related to outcomes. METHODS: A retrospective review of 77 pediatric LGG cases treated at Ramathibodi Hospital, Thailand between 2000 and 2018 was performed. The inclusion criteria were all pediatric LGG cases aged ≤ 15 years. Diffuse intrinsic pontine gliomas and spinal cord tumors were excluded. RESULTS: The median follow-up time was 8.2 years (range, 0.6-19.7). The median age at diagnosis was 6.2 years (interquartile range, 3.6-11.4). Treatments modality included tumor surgery (93%), chemotherapy (40%), and radiation therapy (14%). The 10-year overall survival (OS) and 10-year progression-free survival were 94% and 59%, respectively, for the entire cohort. The 10-year OS was 100% in three subgroups of patients: pilocytic subtype, WHO grade 1 tumors, and recipient of gross total resection. After multivariable analysis, no tumor surgery had a significantly unfavorable influence on overall survival. CONCLUSIONS: With a multimodality approach, pediatric LGGs had excellent outcome. Gross total resection is the standard primary treatment. Chemotherapy is the alternative standard treatment in incomplete resection cases, unresectable patients, or patients with progressive disease. Radiation therapy should be reserved as a salvage treatment option because of late complications that usually affect patients' quality of life.

High-dose Intensity-modulated proton therapy versus Standard-dose Intensity-modulated RadIation therapy for esophageal squamous cell carcinoma (HI-SIRI): study protocol for a randomized controlled clinical trial.

BACKGROUND: Chemoradiotherapy is the standard of care for esophageal cancer as a neoadjuvant treatment before surgery, or as a definitive treatment for unresectable disease. Intensity-modulated radiotherapy (IMRT) has been considered the standard radiation technique. However, patients suffer from treatment-related toxicities, and most die from disease progression or recurrence. With emerging technological advancement, proton therapy has theoretical advantages over IMRT because it offers apparent dosimetric benefits to allow dose escalation to the target while better sparing surrounding tissues such as the lungs, heart, liver, and spinal cord. The purpose of this study protocol is to investigate the survival benefit of proton therapy using modern intensity-modulated proton therapy (IMPT) compared to standard IMRT for esophageal cancer. METHODS: This is a two-arm open phase II/III multi-institution randomized controlled trial. Eligible patients will have histologically confirmed squamous cell carcinoma of the thoracic esophagus with no evidence of tracheoesophageal/esophagobronchial fistula or distant metastasis. After stratification according to resectability status (resectable vs. borderline resectable/unresectable), a total of 232 patients will be randomized to receive IMPT or IMRT using a 1:1 allocation ratio. In resectable cases, surgical resection following concurrent chemoradiation will be attempted for the patients who are medically fit at the time of surgery. In those with initially borderline resectable/unresectable disease, definitive concurrent chemoradiation will be performed. The phase II study will assess safety (toxicity and postoperative complications) and feasibility (recruitment rate and chemoradiation dose modification) in 40 patients into each arm. The study will then continue into phase III, further recruit 76 patients into each arm, and compare progression-free survival between IMPT vs IMRT groups. The secondary endpoints will be overall survival, local and distant control, toxicities, health-related quality of life, and cost-utility. This protocol describes a detailed radiotherapy and chemotherapy. DISCUSSION: This randomized clinical trial will demonstrate the clinical benefit of IMPT in esophageal cancer treatment in terms of survival and toxicity outcomes which will further establish high-level evidence for radiation modality in squamous cell carcinoma of the thoracic esophagus. TRIAL REGISTRATION: TCTR20200310006 . Registered 10 March 2020.

Long-Term Visual Function After Fractionated Stereotactic Radiotherapy for Primary Optic Nerve Sheath Meningioma: A Retrospective Analysis of 34 Subjects.

Objective: To evaluate long-term visual function after fractionated stereotactic radiotherapy (FSRT) for primary optic nerve sheath meningioma (PONSM). Methods: This 22-year retrospective study included 34 subjects (34 affected eyes) with PONSM who were treated with FSRT exclusively. Subjects with a history of biopsy/resection were excluded. Visual function, including visual acuity (VA) and visual field mean deviation (VF MD), was evaluated at presentation (pre-radiotherapy; pre-RT) and at the final follow-up (post-radiotherapy; post-RT); treatment complications were also evaluated. Treatment success was defined as either stabilization or improvement of visual function. Results: The median pre-RT VA and pre-RT VF MD were 0.70 logarithm of the minimum angle of resolution (logMAR; range: 0.0-2.9 logMAR) and -15.4 decibels (dB) (range: -31.4 to -3.2 dB), respectively. The median total dose of FSRT was 50 Gy (range: 45-54 Gy) and the median number of fractions was 25 (range: 25-30). The median follow-up interval was 89 months (range: 6-251 months). The median post-RT VA and post-RT VF MD were 0.48 logMAR (range: 0.0-2.9 logMAR) (p = 0.010) and -6.8 dB (range: -20.6 to -1.6 dB) (p = 0.005), respectively. Among the 34 included eyes, VA was successfully treated in 29 eyes (85.3%) and worsened in 5 eyes (14.7%). Of the 14 eyes with both VA and reliable VF MD at pre-RT and post-RT time points, VF MD was successfully treated in 13 eyes (92.8%) and worsened in one (7.2%); overall visual function was successfully treated in 13 eyes (92.8%) and worsened in 1 eye (7.2%). Complications occurred in one subject (2.9%; radiation retinopathy). Conclusion: Approximately 90% of PONSM subjects exhibited long-term treatment success in terms of VA, VF MD, and overall visual function after FSRT. Additionally, the incidence of complications was low. Therefore, FSRT is effective and safe treatment for PONSM.

Long-term clinical outcomes of stereotactic radiosurgery and hypofractionated stereotactic radiotherapy using the CyberKnife® robotic radiosurgery system for vestibular schwannoma.

AIM: The study aimed to evaluate the long-term clinical outcomes of patients with vestibular schwannoma (VS) treated with stereotactic radiosurgery (SRS) and hypofractionated stereotactic radiotherapy (HSRT) with frameless robotic whole-body radiosurgery system (CyberKnife® ). METHODS: This retrospective analysis of prospectively collected data included 123 consecutive patients with VS treated at the Radiosurgery center, Ramathibodi Hospital, Bangkok, Thailand. SRS was recommended for patients with unserviceable hearing and Koos grade I-III tumors, and HSRT for patients with serviceable hearing or Koos grade III-IV tumors. Between March 2009 and December 2015, 23 patients (19%) were treated with SRS, whereas 100 (81%) received HSRT. The commonly used regimen was 12 Gy in one fraction for SRS and 18 Gy in three fractions for HSRT. RESULTS: After a median follow-up of 72 months (range: 12-123 months), the 5-year and 8-year progression-free survival (PFS) rates for the whole cohort were 96% and 92%, respectively. The PFS was not significantly different between the SRS and HSRT groups (p = 0.23). Among 28 patients with serviceable hearing in the HSRT group, the 5-year and 8-year hearing preservation rates were 87% and 65%, respectively. The rate of nonauditory complications was 14%. Koos grade III/IV was a predictor of disease progression and was associated with nonauditory complications. CONCLUSION: SRS and HSRT with the CyberKnife® system provided excellent long-term tumor control with a low rate of nonauditory complications. HSRT may result in acceptable hearing preservation rates.

Carboplatin-based regimen in pediatric intracranial germ-cell tumors (IC-GCTs): effectiveness and ototoxicity.

BACKGROUND: Induction chemotherapy with carboplatin followed by radiotherapy has been used for many years for treating intracranial germ-cell tumors (IC-GCTs) in Thailand. The objective of this study was to assess treatment outcomes, focusing on survival and ototoxicity. METHODS: The outcomes of all patients with IC-GCT treated at Ramathibodi Hospital and the Prasat Neurological Institute between 2000 and 2017 were reviewed and analyzed, including all patient characteristics and treatment modalities. Five-year overall survival (OS) and event-free survival (EFS) were analyzed using the Kaplan-Meier method, and factors affecting survival were compared using the log-rank test. RESULTS: Fifty-three patients age 1-14 years (median, 11 years) were included in this study. The median follow-up time was 63 months. The 5-year EFS and OS rates were 94.3% and 96.2% for all patients, respectively. No statistical difference in OS or EFS was observed between the data of recipients in the carboplatin-based and historical cisplatin-based therapies in our institutes. Concerning radiotherapy, omission of radiotherapy or focal irradiation results in worse long-term survival outcomes, but reduction in dose of radiotherapy to less than 40 Gy did not cause any negative impact on survival rates. Furthermore, carboplatin was associated with lower rates of hearing loss than cisplatin (5.7% vs 87.5%). CONCLUSIONS: Induction chemotherapy with carboplatin-based regimens was associated with excellent survival rates and low ototoxicity in patients with IC-GCT. Radiotherapy should be given to all patients with a minimal volume equivalent to whole-ventricular radiotherapy, during which doses of lower than 40 Gy can be effectively used.

Outcome of postoperative radiation therapy for pediatric intracranial ependymoma: a single-institution review.

PURPOSE: To report outcome of postoperative radiotherapy (RT) in both new and recurrent grade II and III intracranial ependymomas in children treated at Ramathibodi Hospital. MATERIALS AND METHODS: Between 2006 and 2017, 24 pediatric intracranial ependymomas treated with postoperative RT were retrospectively reviewed. The median age at diagnosis was 44.5 months (range, 4-165 months). There were 14 (58%) males. Fourteen (58%) patients had infratentorial tumor. The median maximal diameter of tumor at diagnosis was 4.45 cm (range, 2.2-10 cm). Fourteen (58%) patients had anaplastic tumor. Gross total resections were performed in 14 (58%) patients. The median prescribed dose was 54 Gy (range, 45-60 Gy). The median total treatment time was 43 days (range, 37-78 days). RESULTS: The median clinical follow-up time was 44.5 months (range, 1-146 months). There were nine recurrences, five of which occurred at the primary tumor site. The estimated 5-year progression-free survival rate was 56%. The estimated 5-year overall survival rate was 75%. Extent of resection was the only factor associated with improved progression-free survival and overall survival after univariate testing. Six from nine patients with recurrent diseases underwent further surgery or further RT. These six patients had better median overall survival than the three who did not. Acute complication was mostly transient and tolerable. No late radiation effect was found. CONCLUSIONS: Postoperative radiation is an effective treatment. GTR is associated with better PFS and OS. Aggressive salvage local treatments for recurrent patients can result in good overall survival. Longer follow-up is needed in account for late relapse.

Clinical outcomes of perioptic tumors treated with hypofractionated stereotactic radiotherapy using CyberKnife® stereotactic radiosurgery.

INTRODUCTION: Stereotactic radiation technique is widely reported as an effective treatment for various types of benign intracranial tumors. However, single fraction radiosurgery (SRS) is not recommended for tumors located close to the optic apparatus due to the restricted radiation tolerance dose of the optic pathway. Recent advances in radiotherapy include advanced frameless radiosurgery using hypofractionated stereotactic radiotherapy (HSRT), and this has become an attractive treatment option for perioptic tumors within 2-3 mm of the optic pathway. Accordingly, the aim of this study was to investigate the clinical outcomes of perioptic tumors treated with HSRT using CyberKnife® (CK) robotic radiosurgery system relative to tumor control, vision preservation and toxicity. METHODS: This retrospective analysis of prospectively collected data included consecutive 100 patients that were diagnosed with and treated for perioptic tumor at the Radiosurgery center, Ramathibodi Hospital during the January 2009 to December 2012 study period. RESULTS: The median tumor volume was 6.81 cm3 (range 0.37-51.6), and the median prescribed dose was 25 Gy (range 20-35) in 5 fractions (range 3-5). After the median follow-up time of 37.5 months (range 21-103), two patients developed tumor progression at 6 and 34 months post-HSRT. The 5-year overall survival was 97%, and the 5-year local control was 97.5%. At the last follow-up, no vision deterioration or newly developed hypopituitarism was detected in our study. CONCLUSIONS: Although a longer follow-up is needed, HSRT yields a high level of local control and vision preservation, and should be considered a treatment of choice for perioptic tumor located close to the optic apparatus.

Clinical Outcomes of Intracranial Nonvestibular Schwannomas Treated with LinacBased Stereotactic Radiosurgery and Radiotherapy.

BACKGROUND: Intracranial nonvestibular schwannomas arising from various cranial nerves excluding CN VIII are uncommon. Recently, stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (SRT) have been widely reported as effective treatment modalities for nonvestibular schwannomas. The purpose of this study was to study the long term clinical outcome for nonvestibular schwannomas treated with both XKnife and CyberKnife (CK) radiosurgery at one institution. MATERIALS AND METHODS: From 2004 to 2013, fiftytwo nonvestibular schwannoma patients were included in this study, 33 patients (63%) were treated with CK, and 19 (37%) were treated with XKnife. The majority of the tumors were jugular foramen schwannomas (38%) and trigeminal schwannomas (27%). HSRT was given for 45 patients (86%), whereas CSRT was for 6 (12%) and SRS for 1 (2%). RESULTS: The median pretreatment volume was 9.4 cm3 (range, 0.5752 cm3). With the median follow up time of 36 months (range, 3135), the 3 and 5 year progression free survival was 94 % and 88%, respectively. Tumor size was decreased in 13 (25%), stable in 29 (56%), and increased in 10 (19%). Among the latter, 3 (30%) required additional treatment because of neurologic deterioration. No patient was found to develop any new cranial nerve deficit after SRS/SRT. CONCLUSIONS: These data confirmed that SRS/ SRT provide high tumor control rates with low complications. Large volume tumors and cystic expansion after radiation should be carefully followed up with neurological examination and MRI, because it may frequently cause neurological deterioration requiring further surgery.

The Clinical Outcome of Hypofractionated Stereotactic Radiotherapy With CyberKnife Robotic Radiosurgery for Perioptic Pituitary Adenoma.

Stereotactic radiation technique including single fraction radiosurgery and conventional fractionated stereotactic radiotherapy is widely reported as an effective treatment of pituitary adenomas. Because of the restricted radiation tolerance dose of the optic pathway, single fraction radiosurgery has been accepted for small tumor located far away from the optic apparatus, while fractionated stereotactic radiotherapy may be suitable for larger tumor located close to the optic pathway. More recently, hypofractionated stereotactic radiotherapy has become an alternative treatment option that provides high rate of tumor control and visual preservation for the perioptic lesions within 2 to 3 mm of the optic pathway. The objective of the study was to analyze the clinical outcomes of perioptic pituitary adenomas treated with hypofractionated stereotactic radiotherapy. From 2009 to 2012, 40 patients with perioptic pituitary adenoma were treated with CyberKnife robotic radiosurgery. The median tumor volume was 3.35 cm3 (range, 0.82-25.86 cm3). The median prescribed dose was 25 Gy (range, 20-28 Gy) in 5 fractions (range, 3-5). After the median follow-up time of 38.5 months (range, 14-71 months), 1 (2.5%) patient with prolactinoma had tumor enlargement, 31 (77.5%) were stable, and the remaining 8 (20%) tumors were smaller in size. No patient's vision deteriorated after hypofractionated stereotactic radiotherapy. Hormone normalization was observed in 7 (54%) of 13 patients. No newly developed hypopituitarism was detected in our study. These data confirmed that hypofractionated stereotactic radiotherapy achieved high rates of tumor control and visual preservation. Because of the shorter duration of treatment, it may be preferable to use hypofractionated stereotactic radiotherapy over fractionated stereotactic radiotherapy for selected pituitary adenomas immediately adjacent to the optic apparatus.

Long Term Outcomes of Preoperative versus Postoperative Concurrent Chemoradiation for Locally Advanced Rectal Cancer: Experience from Ramathibodi Medical School in Thailand.

OBJECTIVES: The study analyzed and compared the long term outcome in locally advanced rectal cancer treated with preoperative and postoperative concurrent chemoradiation (CCRT). MATERIALS AND METHODS: A retrospective review of 105 patients with stage T3-T4 or regional lymph node positive adenocarcinoma of rectum treated with preoperative or postoperative CCRT at Ramathibodi Hospital during 2005 to 2010 was performed. The results of treatment were reported with 5-year overall survival (OS), 5- year locoregional recurrence free survival (LRFS), and toxicity according to preoperative versus postoperative concurrent chemoradiation (CCRT) groups. RESULTS: Among 105 patients, 34 (32%) were treated with preoperative CCRT and 71 (68%) with postoperative CCRT. At the median follow-up time of 50.5 months (range 2-114 months), five-year OS and LRFS of all patients were 87% and 91.6%, respectively. The study found no difference in 5-year OS (81.7% vs 89.2 %) or LRFS (83.4% vs 95.1%) between preoperative versus postoperative CCRT. Seven cases of loco-regional recurrence were diagnosed, 4 (11.8%) after preoperative CCRT and 3 (4.2%) after postoperative CCRT. The recurrent sites were anastomosis in all patients. There was no significant factor associated with outcome after univariate and multivariate testing. Grade 3 or 4 acute and late complications were low in both preoperative and postoperative CCRT groups. CONCLUSIONS: Locally advanced rectum cancer patients experience good results with surgery and adjuvant concurrent chemoradiation.

Outcomes for Pituitary Adenoma Patients Treated with Linac- Based Stereotactic Radiosurgery and Radiotherapy: a Long Term Experience in Thailand.

BACKGROUND: The study analyzed the long term clinical outcomes of pituitary adenoma cases treated with the first Thailand installation of a dedicated Linac-based stereotactic radiation machine (X-Knife). MATERIALS AND METHODS: A retrospective review of 115 consecutive pituitary adenoma patients treated with X-Knife at the Faculty of Medicine, Ramathibodi Hospital, Bangkok, Thailand from 1997 to 2003 was performed. Stereotactic radiosurgery (SRS) was selected for 21 patients (18%) including those with small tumors (≤3 cm) located ≥5 mm. from the optic apparatus, whereas the remaining 94 patients (82%) were treated with fractionated stereotactic radiotherapy (FSRT). RESULTS: With a median follow-up time of 62 months (range, 21-179), the six-year progression free survival was 95% (93% for SRS and 95% for FSRT). The overall hormone normalization at 3 and 5 years was 20% and 30%, respectively, with average time required for normalization of approximately 16 months for SRS and 20 months for FSRT. The incidence of new hypopituitarism was 10% in the SRS group and 9% in the FSRT group. Four patients (5%) developed optic neuropathy (1 in the SRS group and 3 in the FSRT group). CONCLUSIONS: Linac-based SRS and FSRT achieved similar high local control rates with few complications in pituitary adenoma cases. However, further well designed, randomized comparative studies between SRS versus FSRT particularly focusing on hormone normalization rates are required.

Clinical outcome of postoperative radiotherapy with or without chemotherapy in adult glioblastoma multiforme in Ramathibodi Hospital: a retrospective study.

OBJECTIVE: To identify the treatment outcome of glioblastoma multiforme (GBM) in Ramathibodi Hospital from overall survival rate and related prognostic factors. MATERIAL AND METHOD: Medical records of patients with histological diagnosis of GBM treated at Radiation Oncology Division, Radiology Department, Ramathibodi Hospital between 2000 and 2010 were reviewed and available data extracted for evaluation of treatment outcome. RESULTS: There were 47 patients with mean age at diagnosis of 51.9 years (range from 18 to 82 years). Surgery (partial 76.6%, total 12.8%, and biopsy 10.6%) followed by postoperative radiotherapy (mean dose 52 gray) was the treatment of choice with or without concurrent and adjuvant Temozolomide (TMZ). With median follow-up time of 0.9 years, the median survival of the patients was 2.1 years (95% CI 1.08-7.36), whereas one and two-year overall survival rates were 78.0% and 57.8%, respectively. In univariate analysis, persistent neurological deficit after surgery and presenting symptom of visual disturbance were identified to lower overall survival while multivariate analysis, younger age, and higher radiation dose were identified as favorable prognostic factors to improve overall survival. Re-surgery or re-irradiation in some selected cases of recurrent or progressive disease was considered as a choice for palliative treatment. CONCLUSION: Proper management of GBM patient was surgical removal and postoperative radiotherapy with or without chemotherapy. Proper palliative treatment modality was considered in selected cases of recurrent or progressive disease.

The clinical outcome of intracranial hemangioblastomas treated with linac-based stereotactic radiosurgery and radiotherapy.

Recent publications have reported stereotactic radiosurgery as an effective and safe treatment for intracranial hemangioblastomas. However, because of the low incidence of these particular tumors, reports on large patient number studies have not yet been available. The objective of this study was to analyze the clinical results of 14 patients with 56 intracranial hemangioblastomas treated with linear accelerator (linac)-based stereotactic radiosurgery (SRS) and radiotherapy (SRT) in the same institute. The median age of patients was 41 years (range, 28-73 years). Nine of the patients (64%) had von Hippel-Lindau disease. A total of 39 lesions (70%) were treated with CyberKnife (CK), and 17 lesions (30%) were treated with X-Knife. The median pretreatment volume was 0.26 cm(3) (range, 0.026-20.4 cm(3)). The median marginal dose was 20 Gy (range, 10-32 Gy) in 1 fraction (range, 1-10 fractions). The median follow-up time was 24 months (range, 11-89 months). At the last follow-up, 47 tumors (84%) were stable, 7 (13%) decreased and 2 (4%) increased. The 1-, 2- and 6-year local control rates were 98%, 88% and 73%, respectively. No radiation complications were observed in this study. There was a trend toward local failure only in cystic tumors, but this trend was not found to be statistically significant. SRS/SRT achieved a high local control rate in intracranial hemangioblastomas without radiation-induced complications.

Linac-based stereotactic radiosurgery and fractionated stereotactic radiotherapy for vestibular schwannomas: comparative observations of 139 patients treated at a single institution.

Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (SRT) have been recognized as an alternative to surgery for small to medium sized vestibular schwannoma (VS). This study analysed and compared the outcomes of VS treated with the first Thailand installation of a dedicated Linac-based stereotactic radiation machine using single-fraction radiosurgery (SRS), hypofraction stereotactic radiotherapy (HSRT) and conventional fraction stereotactic radiotherapy (CSRT). From 1997 to 2010, a total of 139 consecutive patients with 146 lesions of VS were treated with X-Knife at Ramathibodi hospital, Bangkok, Thailand. SRS was selected for 39 lesions (in patients with small tumors ≤3 cm and non-serviceable hearing function), whereas HSRT (79 lesions) and CSRT (28 lesions) were given for the remaining lesions that were not suitable for SRS. With a median follow-up time of 61 months (range, 12-143), the 5-year local control rate was 95, 100 and 95% in the SRS, HSRT and CSRT groups, respectively. Hearing preservation was observed after SRS in 75%, after HSRT in 87% and after CSRT in 63% of the patients. Cranial nerve complications were low in all groups. There were no statistically significant differences in local control, hearing preservation or complication between the treatment schedules. In view of our results, it may be preferable to use HSRT over CSRT for patients with serviceable hearing because of the shorter duration of treatment.

Preliminary experience of CyberKnife treatment of lung metastasis: the question about real clinical benefit.

OBJECTIVE: Evaluate the effectiveness of radiotherapy plan and physical parameters including local tumor response and clinical outcome of lung metastasis in patients who received CyberKnife treatment at Ramathibodi Hospital. MATERIAL AND METHOD: Six cases with twenty lesions of lung metastasis patients were evaluated for tumor response after having received CyberKnife treatment. The prescribed radiation dose was calculated approximately to biological equivalent dose (BED) around 60 to 100 gray (Gyz). The response of each lesion to treatment was evaluated from roentgenographic study during follow-up period along with adverse event, status of patients, and disease. RESULTS: At the third month after treatment, roentgenographic partial response (PR, 50% decrease in size) was demonstrated in eight lesions and stable disease (SD, unchanged size) in eight lesions with no complete response (CR, disappearance of tumor) detected. Progressive disease (PD, 25% increase in size) of six treated lesions was detected during the follow-up period. At the time of report, two patients were alive and still received palliative chemotherapy, two patients died from uncontrolled progressive metastases and failed palliative chemotherapy, and two patients lost follow-up after progressive metastases with unknown surviving status. No severe adverse event was observed. The treatment planning parameters demonstrated borderline of radiation dose homogeneity, and conformality coverage of the target volume. CONCLUSION: This preliminary report aimed to provide the idea of choosing the appropriate lung metastasis patient to receive CyberKnife treatment that must strictly clarify the real clinical benefit of each selected case to achieve the best outcome from this special treatment procedure.

The clinical results of pediatric brain tumors treated with Linac-based stereotactic radiosurgery and radiotherapy.

OBJECTIVE: Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) for brain tumor is increasingly acceptable worldwide. In Thailand, the first Linac-based stereotactic radiation machine was implemented at the Radiosurgery Center, Ramathibodi Hospital since 1997. This is the first study in Thailand to report the results of pediatric brain tumor patients treated with SRS and FSRT MATERIAL AND METHOD: The clinical outcome of 39 pediatric patients treated with SRS/FSRT between 1998 and 2010 was retrospectively reviewed. RESULTS: The median follow-up time was 26 months (range, 1 to 154 months). The local progression free survival (LPFS) at one and five years after SRS/FSRT for all patients was 87.5% and 54.2%, respectively. The 5-year LPFS by tumor histology was as follow, pituitary adenoma 100%, meningioma 100%, ependymoma, and low-grade astrocytoma 75%, and craniopharyngioma 68.6%. High-grade tumor had the worst LPFS and the median LPFS of this group was only 12 months. On univariate analysis, low-grade tumor (pituitary adenoma and menigioma) and small tumor volume (< 10 ml) were the factors that correlated significantly with good local control. After multivariate analysis, small tumor volume was the only factor associated with good LPFS (HR = 2.35, p = 0.042). No other radiation complication except panhypopituitarism was reported. CONCLUSION: SRS/FSRT in pediatric brain tumor is technically feasible, with minimal acute side effects. SRS/FSRT plays an important role for the small low-grade tumor

Preliminary experience of CyberKnife treatment of primary non-small cell lung cancer.

OBJECTIVE: Provide the effectiveness of treatment protocol, radiotherapy plan, technique, and early clinical results of inoperable primary non-small cell lung cancer (NSCLC) in patients who received CyberKnife treatment at Ramathibodi Hospital. MATERIAL AND METHOD: Six cases of inoperable primary NSCLC patients were evaluated for tumor response after having received CyberKnife treatment. The prescribed radiation dose was 45 gray (Gy) in three consecutive fractions for peripherally located tumor and 50 Gy in five fractions within two weeks for centrally located tumor (biological equivalent dose, BED, 112.5 Gy 10, and 100 Gy 10, respectively). The response to treatment was evaluated from roentgenographic study during follow-up period along with clinical outcome and adverse event. RESULTS: Overall response after the treatment was demonstrated in five cases with roentgenographic complete response (CR, disappearance of tumor) and partial response (PR, 50% decrease in size) in two and three cases, respectively without any severe adverse event. The treatment planning parameters demonstrated the effectiveness of radiation dose homogeneity and conformity coverage of the target volume. CONCLUSION: This preliminary report has provided the effectiveness of treatment plan and local tumor controlled without severe adverse event for primary inoperable NSCLC patients receiving CyberKnife treatment.

Radiation-induced peripheral malignant nerve sheath tumor arising from vestibular schwannoma after linac-based stereotactic radiation therapy: a case report and review of literatures.

In recent years the use of stereotactic radiation for vestibular schwannomas has increased worldwide. However, malignant transformation associated with radiation, although uncommon, has been reported in recent publications. We present a case of the 34 year-old female who had left vestibular schwannoma and who underwent surgery and postoperative stereotactic radiotherapy (SRT), hypofraction in 2005. At 6 years after SRT, the patient came with left facial palsy and severe headache. CT brain revealed progression in size with cystic and hemorrhagic changes of the preexisting tumor at left CPA with new obstructive hydrocephalus. Partial tumor removal was done, and the pathological report was malignant peripheral nerve sheath tumor (MPNST). Regarding the uncertainty of carcinogenesis risk, we should still practice radiation therapy with caution, especially in the young patient with tumor predisposition syndrome. Because of low incidence of MPNST after radiation, it should not be a major decision about giving radiotherapy. However, with the poor prognosis of MPNST, this possibility should be explained to the patient before radiation treatment option.