Local Tumor Control Rate Research Articles

Respiratory-gated proton beam therapy for intrahepatic cholangiocarcinoma without fiducial markers.

Intrahepatic cholangiocarcinoma (ICC) is a challenging primary liver cancer with a poor prognosis, especially in unresectable cases. Traditional palliative irradiation is limited in reducing liver doses. This study aimed to evaluate the efficacy and toxicity of respiratory-gated proton beam therapy without fiducial markers for intrahepatic cholangiocarcinoma. Between October 2011 and February 2022, 24 patients (median [range] age, 71 [41-88] years) were evaluated at our institution. Twelve patients were pathologically diagnosed with ICC. All patients underwent respiratory-gated proton beam therapy at a dose of 48-83.6 (relative biological effectiveness) in 20-38 fractions with four-dimensional computed tomography planning. The median follow-up period was 18.5 (range, 2.0-74.0) months. The median tumor size was 41 (range, 10-134) mm. Twenty-one patients were classified as having Child-Pugh class A, and three patients were classified as having Child-Pugh class B. Local progression was defined as any growth of the irradiated tumor. The median survival time was 28months for all patients. The Kaplan-Meier estimates of the 2-year overall survival, progression-free survival, and local tumor control rates were 51%, 26%, and 73%, respectively. Local tumor control rates were non-inferior to those reported in previous studies using fiducial markers. One patient had grade 4 pleural effusion; however, whether this was an adverse event due to the proton beam therapy was unclear. Respiratory-gated proton beam therapy without fiducial markers is an effective and less invasive treatment option for ICC, showing potential for improved local control and tolerable adverse effects.

RADT-22. EFFICACY AND SAFETY OF CYBERKNIFE STEREOTACTIC RADIOSURGERY FOR OCCIPITAL CONDYLE METASTASIS

Abstract BACKGROUND Occipital condyle metastasis (OCM) is a rare condition characterized by severe occipital pain and neurological symptoms due to lower cranial nerve deficits, stemming from its anatomical location. Despite the widespread use of stereotactic radiosurgery (SRS) for cranial metastases, its specific impact on OCM remains underexplored. OBJECTIVE This study evaluates the efficacy and safety of CyberKnife SRS in treating OCM, focusing on symptom control and local tumor control. METHOD We retrospectively analyzed cases of OCM treated with SRS at our institute from 2012 to 2023, evaluating patient demographics, presenting symptoms, treatment parameters, and outcomes. Key measures included occipital pain, dysfunctions of cranial nerves IX, X, and XII, and local tumor control. RESULTS Eighteen patients (10 females) with a median age of 64 years (range: 40-79) were treated. Common presentations included occipital pain (44%) and lower cranial nerve deficits (28%). The median target volume was 6.95 cc (range: 0.95-72.7), and the median margin dose was 20 Gy (range: 16-40). The median follow-up period was 7 months (range: 1-44). Notably, only one patient experienced tumor recurrence and subsequently died from primary cancer progression five months after treatment. SRS achieved a 93.8% local tumor control rate over three years, with a median overall survival of 13 months. Among those presenting with symptoms, 87.5% reported pain relief, and 80% observed improvements in cranial nerve function. The only patient without clinical symptom improvement also had tumor recurrence. CONCLUSION CyberKnife SRS is a promising treatment for OCM, offering significant pain relief and improvement in neurological symptoms with excellent local control rates. This non-invasive therapy provides a valuable alternative to surgery, potentially enhancing the quality of life for patients with limited treatment options due to this challenging condition.

RADT-21. EFFICACY AND SAFETY OF DONUT-SHAPED CIRCUMFERENTIAL SPINE CYBERKNIFE STEREOTACTIC BODY RADIOTHERAPY FOR METASTATIC SPINE DISEASE

Abstract BACKGROUND Spinal metastases (SM) with epidural spinal cord compression (ESCC) are challenging to manage due to the risk of radiation-induced injury. Traditional approaches often avoid circumferential stereotactic body radiotherapy (SBRT) because of these risks. The efficacy and safety of donut-shaped circumferential SBRT, which envelops the spinal column while sparing the cord, remains underexplored. OBJECTIVE This study evaluates the safety and efficacy of donut-shaped circumferential spine CyberKnife SBRT in treating spinal metastases, focusing on preventing radiation-induced myelopathy and achieving local tumor control. METHOD We retrospectively analyzed patients treated with donut-shaped circumferential spine SBRT from 2014 to 2023. We evaluated demographics, grade of ESCC (Bilsky), prior treatments, symptoms, treatment parameters, and outcomes. Key measures included SBRT dosimetric data, radiation exposure to the spinal cord or cauda equina, adherence to dose-volume constraints, occurrence of post-SBRT myelopathy, other radiation-induced complications, and local tumor control. RESULTS Forty-eight lesions from 43 patients (median age: 65 years; range: 20-78) were analyzed. Only one patient underwent separation surgery for severe ESCC (Bilsky grade 3). The median clinical target volume (CTV) was 63.77 cc (range: 20.31-270.05), and the median margin dose was 24 Gy (range: 18-30). Over a median follow-up of 8 months (range: 1-91), local tumor control rates were 91.1% at 6 months, 87.1% at 1 year, 82.8% at 3 years, and 62.1% at 5 years. Median overall survival was 17 months. Of 20 lesions exceeding dose constraints, only one patient displayed clinical myelopathy symptoms, correlating with local tumor recurrence. There was no radiographic myelopathy or other radiation-induced complications during follow-up. CONCLUSION Donut-shaped circumferential spine CyberKnife SBRT provides effective and safe treatment for spinal metastases with or without epidural involvement. It achieves substantial local tumor control and has a minimal incidence of radiation-induced myelopathy, offering a viable non-surgical option for managing this complex condition.

RADT-50. CLINICAL OUTCOME OF DAILY 5-FRACTIONATED GAMMA KNIFE RADIOSURGERY FOR LARGE BRAIN METASTASES

Abstract INTRODUCTION With the introduction of the Gamma Knife Icon, hypo-fractionated Gamma Knife radiosurgery (GKRS) for large brain metastases (LBMs) is beginning to be performed. This study aimed to assess the clinical outcome and risk of the daily 5-fractionated GKRS for LBMs. METHODS A total of 100 patients who underwent 5-fractionated GKRS for LBMs (> 14cm3) were enrolled. Forty-six were male patients, and the median age was 60 years. Most common primary cancer sites were lung (41 non-small cell cancers), breast (24), and kidney (14). The median tumor volume was 22cm3 (14 – 69cm3) and marginal dose was 35Gy (50% isodose line) in 5 fractions. Median follow-up duration was 18 months (3 – 72 months). RESULTS The last follow-up showed local tumor control in 74 cases. The cumulative 1, 2, and 3-year local tumor control rates were 73, 65, and 60%, respectively. Eighty-six tumors showed best MRI response in a year, and median tumor volume decrease rate was 80% (22 – 100%). Thirty patients experienced dramatically tumor volume decrease (> 95%). Median progression free and overall survival were 7 and 16 months, respectively. Radiation necrosis occurred in 24 patients, of which only 9 had neurological symptoms and treated with steroid and bevacizumab. CONCLUSIONS The daily 5-fractionated GKRS for very LBMs showed favorable local tumor control and acceptable radiation necrosis, but questionable survival benefit. In the future, prospective multi-center study is needed.

Oncologic Outcomes after Percutaneous Ablation for Colorectal Liver Metastases: An Updated Comprehensive Review.

Colorectal cancer is a major cause of cancer-related mortality, with liver metastases occurring in over a third of patients, and is correlated with poor prognosis. Despite surgical resection being the primary treatment option, only about 20% of patients qualify for surgery. Current guidelines recommend thermal ablation either alone or combined with surgery to treat limited hepatic metastases, provided that all visible disease can be effectively eradicated. Several ablation modalities, including radiofrequency ablation, microwave ablation, cryoablation, irreversible electroporation and histotripsy, are part of the percutaneous ablation armamentarium. Thermal ablation, including radiofrequency, microwave ablation and cryoablation, can offer local tumor control rates comparable to limited resection for selected tumors that can be ablated with margins. This review aims to encapsulate the current clinical evidence regarding the efficacy and oncologic outcomes after percutaneous ablation for the treatment of colorectal liver metastatic disease.

Correlation of Needle Biopsy–Acquired Histopathologic Grade of Hepatocellular Carcinoma with Outcomes after Thermal Ablation

PurposeTo correlate preablation needle biopsy–acquired histopathologic grade of Liver Imaging Reporting and Data System (LI-RADS) 5 hepatocellular carcinoma (HCC) with postablation local tumor control rate, intrahepatic distant tumor progression–free survival, and overall survival. Materials and MethodsThis single-center, retrospective cohort study included adult patients with LI-RADS 5 HCC who underwent a preablation core needle biopsy within 3 months prior to thermal ablation from January 2015 to December 2022. Histopathologic grade from the needle biopsy was evaluated as predictor of local tumor control rate, intrahepatic distant tumor progression–free survival, and overall survival. Kaplan-Meier survival curves were compared using the Gehan generalized Wilcoxon test. ResultsThe study group comprised 133 patients (mean age, 67 years [SD ± 10]; 107 men) with LI-RADS 5 confirmed HCC, stratified into 18 poorly differentiated tumors (median follow-up, 27.7 months; interquartile range [IQR], 15.5–55.4 months) and 115 well-differentiated/moderately differentiated tumors (median follow-up, 29.2 months; IQR, 15.4–59.9 months). No difference in local tumor control rate was noted between the 2 cohorts (hazard ratio [HR], 1.16; 95% CI, 0.32–4.23; P = .898). There was significantly lower intrahepatic distant tumor progression–free survival after thermal ablation in the poorly differentiated cohort (HR, 2.54; 95% CI, 0.92–7.05; P < .001). The overall survival in the poorly differentiated cohort was also lower, although this did not reach statistical significance (HR, 1.77; 95% CI, 0.60–5.26; P = .202). ConclusionsPatients with needle biopsy–proven poorly differentiated LI-RADS 5 HCC have significantly lower intrahepatic distant tumor progression–free survival after thermal ablation compared with those with well-differentiated/moderately differentiated HCC.

Comparison between Trans-Arterial Chemoembolization Followed by Stereotactic Body Radiation Therapy and Trans-Arterial Chemoembolization Alone in BCLC Stage B Hepatocellular Carcinoma: A Pilot Study.

Both Stereotactic Body Radiation Therapy (SBRT) and Trans-arterial Chemoembolization (TACE) are now being widely used to treat advanced hepatocellular carcinoma (HCC) and can improve tumor local control rates. We aimed at evaluating the efficacy and toxicity of combining SBRT and TACE in comparison to TACE alone in unresectable HCC. 42 unresectable Barcelona Clinic Liver Cancer (BCLC) stage B HCC Child Pugh (CP) A patients were randomized to receive either: TACE alone (Arm A) or TACE followed by SBRT (Arm B). Dose prescribed was 40Gy in 5consecutive daily fractions over 1 week . We compared the local control (LC), Progression free survival (PFS), overall survival (OS) and toxicity between the two arms. 22 patients were in arm A versus 20 patients in arm B with median follow up 20 months starting recruitment from April 2021 till January 2023. Both LC, PFS were significantly better in Arm B. Complete remission (CR) rate was 54.5% and 75% in Arm A and B, respectively. Median PFS was 16 months in Arm B compared to 11 months in Arm A (p =0.003). Median OS was not reached in both arms. Both arms had comparable toxicities. Adding SBRT to TACE in advanced HCC, is safe and feasible with better efficacy in terms of LC and PFS with comparable side effects, in comparison to TACE alone.

Managing vitreoretinal complications in uveal melanoma: Surgical treatment and practical considerations.

In the past few decades, the primary management for uveal melanoma has evolved from enucleation to eye-preservingtreatments. However, despite achieving ahigh rate of local tumour control, complications following eye-preservingtreatments still occur and are partly responsible for functional loss and secondary enucleation. A literature review by a broad international panel. We summarised the current literature on utilizing vitreoretinal (VR) surgery for managing the complications of uveal melanoma. We also provided insights from the authors' personal experience and practical recommendations for clinical care. With the advancement of VR instruments and surgical techniques and the combination of VR and ocular oncology knowledge ("Onco-VR"), it is now possible to manage or even prevent complications such as vitreous haemorrhage, retinal detachment, and toxic tumour syndrome.

Stereotactic radiosurgery for brain metastases from human epidermal receptor 2 positive breast Cancer: an international, multi-center study.

To report patient outcomes and local tumor control rates in a cohort of patients with biopsy-proven HER-2 positive breast cancer treated with stereotactic radiosurgery (SRS) for brain metastases (BM). This international, retrospective, multicenter study, included 195 female patients with 1706 SRS-treated BM. Radiologic and clinical outcomes after SRS were determined and prognostic factors identified. At SRS, median patient age was 55 years [interquartile range (IQR) 47.6-62.0], and 156 (80%) patients had KPS ≥ 80. The median tumor volume was 0.1 cm3 (IQR 0.1-0.5) and the median prescription dose was 16Gy (IQR 16-18). Local tumor control (LTC) rate was 98%, 94%, 93%, 90%, and 88% at six-, 12-, 24-, 36- and 60-months post-SRS, respectively. On multivariate analysis, tumor volume (p = < 0.001) and concurrent pertuzumab (p = 0.02) improved LTC. Overall survival (OS) rates at six-, 12-, 24-, 36-, 48-, and 60-months were 90%, 69%, 46%, 27%, 22%, and 18%, respectively. Concurrent pertuzumab improved OS (p = 0.032). In this patient subgroup, GPA scores ≥ 2.5 (p = 0.038 and p = 0.003) and rare primary tumor histologies (p = 0.01) were associated with increased and decreased OS, respectively. Asymptomatic adverse radiation events (ARE) occurred in 27 (14.0%) and symptomatic ARE in five (2.6%) patients. Invasive lobular carcinoma primary (p = 0.042) and concurrent pertuzumab (p < 0.001) conferred an increased risk for overall but not for symptomatic ARE. SRS affords effective LTC for selected patients with BM from HER-2 positive breast cancer. Concurrent pertuzumab improved LTC and OS but at the same time increased the risk for overall, but not symptomatic, ARE.

Stereotactic Radiosurgery for Residual, Recurrent, and Metastatic Hemangiopericytomas: A Single-Institution Retrospective Experience.

Hemangiopericytomas are infrequent vascular tumors originating from Zimmermann pericytes. The conventional treatment involves gross total resection, followed by adjuvant radiotherapy. Nevertheless, their tendency to infiltrate dural sinuses, high vascularity, and anatomic complexity pose challenges for radical resection, leading to a significant risk of recurrence. Stereotactic radiosurgery (SRS) has emerged as a promising adjuvant therapy to address these challenges. Our study provides the largest single-institutional retrospective, aiming to evaluate the effectiveness and safety of SRS as a treatment modality for residual, recurrent, and metastatic hemangiopericytomas. From 1998 to 2023, 27 patients with 101 tumors underwent CyberKnife SRS at Stanford University Medical Center. The median age was 51 years at the time of treatment. The median follow-up period from SRS was 103 months (range: 6-250). All patients underwent upfront surgical resection. The median tumor volume was 1.5 cc. The median single-fraction equivalent dose was 19 Gy. The SRS was administered at the 76% of the median isodose line (range: 64-89). Of the 101 treated tumors, 24 (23.8%) progressed with a median time to recurrence of 30 months. At 10 years, the rates of local tumor control (LTC), overall survival (OS), and progression-free survival (PFS) were 74.3%, 80.8%, and 67%, respectively. In patients with metastatic lesions, the LTC rates were significantly greater when compared with those with residual or recurrent tumors. There was no significant difference between patients with residual, recurrent, and metastatic hemangiopericytomas in OS and PFS. Notably, no cases of radiation-induced adverse events were detected. SRS leads to excellent LTC, PFS, and OS at 10 years with negligible risk for adverse events. Therefore, it is an effective and safe management modality for patients with residual, recurrent, and metastatic hemangiopericytomas.

Local tumour control and patient survival after ruthenium-106 brachytherapy for small choroidal melanoma

AimTo report local tumour control, metastasis and survival rates of patients with small choroidal melanoma (CM) after treatment with ruthenium-106 (Ru-106) plaque brachytherapy.MethodsRetrospective case series of 353 consecutive eyes with...

Safety of propofol sedation administered by interventional radiologists for radiofrequency ablation in patients with hepatocellular carcinoma

PurposeTo evaluate the safety of propofol sedation administered by interventional radiologists during radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC).Materials and methodsPropofol sedation was administered by interventional radiologists in 72 patients (85 procedures, 93 tumors) during RFA for HCC between August 2018 and December 2020. Interventional radiologists equipped with adequate knowledge and skills in sedation and respiratory management were responsible for sedation. Sedation was carefully assessed based on vital signs, including end-tidal carbon dioxide, consciousness status, and bispectral index. The primary endpoint was the incidence of sedation-related complications, which were evaluated separately as respiratory and cardiovascular complications. Secondary endpoints were technical success rate, ablation-related complications, and local tumor control rate. Technical success was defined as completion of ablation in the planned area. Complications were evaluated using the Clavien–Dindo classification. Sedation-related complications, technical success rate, and ablation-related complications were evaluated on a procedure basis, and local tumor control was evaluated on a tumor basis.ResultsRespiratory and cardiovascular complications were observed in eight (8/85, 9.4%) and two (2/85, 2.4%) patients, respectively. Four patients required the jaw thrust maneuver due to glossoptosis, whereas a decrease in oxygen saturation to < 90% was recorded in the other four patients. However, these were temporary, and none required manual ventilation or endotracheal intubation. Bradycardia (< 50 bpm) was detected in two patients; one recovered immediately without treatment, whereas the other rapidly improved after atropine sulfate administration. No severe hypotension (< 80 mmHg) was observed. The technical success rate was 100% (85/85). Grade 3 ablation-related complications were identified in three patients (3/85, 3.5%). The local tumor control rate was 95.7% (89/93).ConclusionPropofol sedation can be safely administered by interventional radiologists during RFA for HCC. Although it requires special safety considerations, it may be a sedation option during hepatic RFA.

The Role of CyberKnife Stereotactic Radiosurgery in Recurrent Cranial Medulloblastomas across Pediatric and Adult Populations.

Background/Objectives: Medulloblastoma is the most common malignant brain tumor in children. In recent decades, the therapeutic landscape has undergone significant changes, with stereotactic radiosurgery (SRS) emerging as a promising treatment for recurrent cases. Our study provides a comprehensive analysis of the long-term efficacy and safety of SRS in recurrent medulloblastomas across both pediatric and adult patients at a single institution. Methods: We retrospectively reviewed the clinical and radiological records of patients who underwent CyberKnife SRS for recurrent cranial medulloblastomas at our institution between 1998 and 2023. Follow-up data were available for 15 medulloblastomas in 10 patients. The cohort comprised eight pediatric patients (ages 3-18) and two adult patients (ages 19-75). The median age at the time of SRS was 13 years, the median tumor volume accounted for 1.9 cc, the median biologically equivalent dose (BED) was 126 Gy, and the single-fraction equivalent dose (SFED) was 18 Gy. The SRS was administered at 75% of the median isodose line. Results: Following a median follow-up of 39 months (range: 6-78), 53.3% of the medulloblastomas progressed, 13.3% regressed, and 33.3% remained stable. The 3-year local tumor control (LTC) rate for all medulloblastomas was 65%, with lower rates observed in the adult cohort (50%) and higher rates in pediatric patients (67%). The 3-year overall survival (OS) rate was 70%, with significantly higher rates in pediatric patients (75%) compared to adult patients (50%). The 3-year progression-free survival (PFS) rate was 58.3%, with higher rates in pediatric patients (60%) compared to adult patients (50%). Two pediatric patients developed radiation-induced edema, while two adult patients experienced radiation necrosis at the latest follow-up, with both adult patients passing away. Conclusions: Our study provides a complex perspective on the efficacy and safety of CyberKnife SRS in treating recurrent cranial medulloblastomas across pediatric and adult populations. The rarity of adverse radiation events (AREs) underscores the safety profile of SRS, reinforcing its role in enhancing treatment outcomes. The intricacies of symptomatic outcomes, intertwined with factors such as age, tumor location, and prior surgeries, emphasize the need for personalized treatment approaches. Our findings underscore the imperative for ongoing research and the development of more refined treatment strategies for recurrent medulloblastomas. Given the observed disparities in treatment outcomes, a more meticulous tailoring of treatment approaches becomes crucial.

Stereotactic Radiosurgery for Ependymoma in Pediatric and Adult Patients: A Single-Institution Experience.

Ependymoma is commonly classified as World Health Organization grade 2 with the anaplastic variant categorized as grade 3. Incomplete resection or anaplastic features can result in unfavorable outcomes. Stereotactic radiosurgery (SRS) provides a minimally invasive approach for recurrent ependymomas. Our study investigates the efficacy and safety of SRS for grade 2 and 3 ependymomas in pediatric and adult populations. We conducted a retrospective analysis on 34 patients with 75 ependymomas after CyberKnife SRS between 1998 and 2023. Fourteen were pediatric (3-18 years), and 20 were adult (19-75 years) patients. The median age was 21 years, and the median tumor volume was 0.64 cc. The median single-fraction equivalent dose was 16.6 Gy, with SRS administered at 77% of the median isodose line. After a median follow-up of 42.7 months (range: 3.8-438.3), 22.7% of ependymomas progressed. The 5-year local tumor control rate was 78.1%, varying between 59.6% and 90.2% for children and adults, with grade 2 at 85.9% compared with 58.5% for grade 3 tumors. The 5-year overall survival rate was 73.6%, notably higher in adults (94.7%) than in children (41%), and 100% for grade 2 but decreased to 35.9% for grade 3 patients. The 5-year progression-free survival rate was 68.5%, with 78.3% and 49.2% for adults and children, respectively, and a favorable 88.8% for grade 2, contrasting with 32.6% for grade 3 patients. Symptom improvement was observed in 85.3% of patients. Adverse radiation effects occurred in 21.4% of pediatric patients. Our study supports SRS as a viable modality for pediatric and adult patients with grade 2 and 3 ependymomas. Despite lower local tumor control in pediatric and grade 3 cases, integrating SRS holds promise for improved outcomes. Emphasizing careful patient selection, personalized treatment planning, and long-term follow-up is crucial for optimal neurosurgical outcomes.

Efficacy and Safety of Local Liver Radioablation in Hepatocellular Carcinoma Lesions within and beyond Limits of Thermal Ablation

Introduction: CT-guided interstitial brachytherapy (iBT) radiotherapy has been established in the treatment of liver tumors. With iBT, hepatocellular carcinoma (HCC) lesions can be treated beyond the limits of thermal ablation (i.e., size and location). However, a comprehensive analysis of the efficacy of iBT in patients within and beyond thermal ablation limits is lacking. Materials and Methods: A total of 146 patients with 216 HCC lesions have been analyzed retrospectively. Clinical and imaging follow-up data has been collected. Lesions were evaluated in terms of suitability for thermal ablation or not. The correlation between local tumor control (LTC), time to progression (TTP), overall survival (OS), and clinical and imaging parameters have been evaluated using univariable and multivariable Cox regression analyses. Results: LTC rates at 12 months, 24 months, and 36 months were 87%, 75%, and 73%, respectively. 65% of lesions (n = 141) were not suitable for radiofrequency ablation (RFA). The median TTP was 13 months, and the median OS was not reached (3-year OS rate: 70%). No significant difference in LTC, TTP, or OS regarding RFA suitability existed. However, in the overall multivariable analysis, lesion diameter >5 cm was significantly associated with lower LTC (HR: 3.65, CI [1.60–8.31], p = 0.002) and shorter TTP (HR: 2.08, CI [1.17–3.70], p = 0.013). Advanced BCLC stage, Child-Pugh Stage, and Hepatitis B were associated with shorter OS. Conclusion: iBT offers excellent LTC rates and OS in local HCC treatment regardless of the limits of thermal ablation, suggesting further evidence of its alternative role to thermal ablation in patients with early-stage HCC.

Local control and survival after stereotactic radiosurgery for colorectal cancer brain metastases: an international multicenter analysis.

The goal of this study was to characterize local tumor control (LC), overall survival (OS), and safety of stereotactic radiosurgery for colorectal brain metastasis (CRBM). Ten international institutions participating in the International Radiosurgery Research Foundation provided data for this retrospective case series. This study included 187 patients with CRBM (281 tumors), with a median age of 62 years and 56.7% being male. Most patients (53.5%) had solitary tumors, although 10.7% had > 5 tumors. The median tumor volume was 2.7 cm3 (IQR 0.22-8.1 cm3), and the median margin dose was 20 Gy (IQR 18-22 Gy). The 3-year LC and OS rates were 72% and 20%, respectively. Symptomatic adverse radiation effects occurred in 1.6% of patients. In the multivariate analysis, age > 65 years and tumor volume > 4.0 cm3 were significant predictors of tumor progression (hazard ratio [HR] 2.6, 95% CI 1.4-4.9; p = 0.003 and HR 3.4, 95% CI 1.7-6.9; p < 0.001, respectively). Better performance status (Karnofsky Performance Scale score > 80) was associated with a reduced risk of tumor progression (HR 0.38, 95% CI 0.19-0.73; p = 0.004). Patient age > 62 years (HR 1.6, 95% CI 1.1-2.3; p = 0.03) and the presence of active extracranial disease (HR 1.7, 95% CI 1.1-2.4; p = 0.009) were significantly associated with worse OS. Stereotactic radiosurgery offers a high LC rate and a low rate of symptomatic adverse radiation effects for the majority of CRBMs. The OS and LC favored younger patients with high functional performance scores and inactive extracranial disease.

Stereotactic Radiosurgery for Patients with Brain Metastases from Hepatopancreaticobiliary Cancers.

The role of stereotactic radiosurgery (SRS) for patients with brain metastases from hepatopancreaticobiliary (HPB) cancers has yet to be established. The authors present a single-institution experience of patients with HPB cancers who underwent SRS when their cancer spread to the brain. We surveyed our Gamma Knife SRS data base of 18,000 patients for the years 1987-2022. In total, 19 metastatic HPB cancer patients (13 male) with 76 brain metastases were identified. The median age at SRS was 61 years (range: 48-83). The primary cancer sites were hepatocellular carcinoma (HCC, 11 patients), cholangiocarcinoma (CCC, 2 patients), and pancreatic carcinoma (PCC, 6 patients). The median Karnofsky Performance Score (KPS) was 80 (range: 50-90). Two patients underwent pre-SRS whole-brain fractionated radiation therapy (WBRT) and eight patients underwent pre-SRS surgical resection. All SRS was delivered in single session. The median margin dose was 18 Gy (range: 15-20). The median cumulative tumor volume was 8.1 cc (range: 1.0-44.2). The median patient overall survival (OS) after SRS was 7 months (range 1-79 months). Four patients had documented local tumor progression after SRS at a median time of 8.5 months (range: 2-15) between SRS and progression. Out of 76 treated tumors, 72 tumors exhibited local control. The local tumor control rate per patient was 78.9%. The local tumor control per tumor was 94.7%. Four patients developed new brain metastases at a median of 6.5 months (range: 2-17) after SRS. No patient experienced adverse radiation effects (AREs). At the last follow-up, 18 patients had died, all from systemic disease progression. Metastatic spread to the brain from HPB cancers occurs late in the course of the primary disease. In this study, all deceased patients ultimately died from primary disease progression. SRS is a non-invasive strategy that maximally preserves quality of life, and our results reported favorable outcomes compared to the existing literature. SRS should be considered as one of the primary management strategies for patients with brain metastatic spread from HPB cancer.

Ablation of Kidney Tumors in Patients with Substantial Kidney Impairment: Current Status.

To review the current status of kidney tumor ablation in patients with substantial kidney impairment. Few reports of kidney tumor ablation in such patients have recently been published. The reported prevalence of patients with stage 4 or 5 chronic kidney disease (CKD) among patients undergoing ablation is 2.0%-10%. In patients with stage 4 or 5 CKD, local tumor control rates were 88%-100%. The effect of ablation on CKD stage is unclear, and the observed deteriorations in kidney function are consistent with both the effect of cryoablation and the natural course of advanced CKD. According to guidelines, active surveillance may be selected. The goals of treatment are complete tumor removal and maintenance of kidney function, both of which can be met by ablation. Given the limited treatment options, ablation may play a pivotal role in the management of patients with advanced CKD.

499 Silent Corticotroph Staining Pituitary Neuroendocrine Tumors: Prognostic Significance in Radiosurgery

INTRODUCTION: There is conflicting evidence on the significance of adrenocorticotrophic hormone (ACTH) staining in the prognosis of nonfunctioning pituitary neuroendocrine tumors (NFpitNETs). METHODS: This retrospective, multicenter study included patients managed with SRS for NFpitNET residuals. The patients were divided into two cohorts: 1) silent corticotroph (SC) for NFpitNETs with positive ACTH immunostaining and 2) non-SC NFpitNETs. Rates of local tumor control, as well as the incidence of post-treatment pituitary and neurological dysfunction were documented. Factors associated with radiological and clinical outcomes were also analyzed. RESULTS: The cohort included 535 patients from fourteen centers with 84 (15.7%) patients harboring silent corticotroph NFpitNETs (SCs). At last follow-up, local tumor progression occurred in 11.9% of patients in the SC compared to 8.1% of patients in the non-SC cohort (p = 0.27). No statistically significant difference was noted in new-onset hypopituitarism rates (10.7% vs 15.4%, p = 0.25) or visual deficits (3.6% vs 1.1%, p = 0.088) between the two cohorts at last follow-up. When controlling for residual tumor volume, maximum dose, and patient age and gender, positive ACTH immunostaining did not have a significant correlation with local tumor progression (HR = 1.69, 95% CI = 0.8 - 3.61, p = 0.17). CONCLUSIONS: In contemporary radiosurgical practice with a single fraction dose of 8-25 Gy (median 15 Gy), ACTH immunostaining in NFpitNETs did not appear to confer a significantly reduced rate of local tumor control after SRS.

199 Gamma Knife Radiosurgery to Treat Neurofibromatosis Type 2-Associated Meningiomas: A 35 Year Experience and Paradigm for Future Treatment

INTRODUCTION: Management of neurofibromatosis type 2 (NF2)-associated meningiomas remains a case-by-case basis, and treatment options vary. METHODS: Forty-nine patients (22 male, 44.90%) with 213 NF2-associated meningiomas treated with SRS between 1987 and 2022 were retrospectively reviewed. The median age at SRS was 56 (range: 20-79) years. Twenty-nine (59.18%) patients had pre-SRS surgical resection, and 7 (14.29%) had prior radiotherapy. The median number of meningiomas per patient was 2 (range: 1-17), the median margin dose was 13 (range: 9-16) Gy, and the median cumulative tumor volume per patient was 8.30 (range: 0.10-74.26) cm3. RESULTS: Nine patients (18.37%) had local tumor progression. The 1- and 5-year local tumor control rates were 100% and 90.54%, respectively. Tumor volume &lt; 8.30 cm3 was associated with better local tumor control (p = 0.02, HR: 1.06, 95% CI: 1.01-1.12) on multivariate analysis. Twenty-five patients (51.02%) had detection of new growing tumors (DNGT). The 1- and 5-year DNGT rates were 78.05% and 47.38%, respectively. On multivariate analysis, &gt;2 meningiomas at SRS presentation per patient (p = 0.01, HR: 1.09, 95% CI: 1.02-1.17) was significantly associated with DNGT. Neurological symptoms improved in 20 patients (40.82%), remained stable in 28 patients (57.14%), and worsened in 1 (2.04%) patient at a median follow-up time of 81 (range: 6–267) months after SRS. Seventeen (34.69%) patients were deceased at last follow-up, and 4 patients expired due to intracranial disease progression. Two (4.08%) patients developed transient adverse radiation effects; no patients developed secondary malignancies. CONCLUSIONS: Single-session SRS can effectively be used to control tumor progression and improve neurological symptoms in NF2-associated meningioma patients while limiting adverse radiation effects.