Improved outcomes for triple negative breast cancer brain metastases patients after stereotactic radiosurgery and new systemic approaches

PURPOSE

Although ongoing studies are assessing the efficacy of new systemic therapies for patients with triple negative breast cancer (TNBC), the overwhelming majority have excluded patients with brain metastases (BM). Therefore, we aim to characterize systemic therapies and outcomes in a cohort of patients with TNBC and BM managed with stereotactic radiosurgery (SRS) and delineate predictors of increased survival.

METHODS

We used our prospective patient registry to evaluate data from 2012 to 2023. We included patients who received SRS for TNBC-BM. A competing risk analysis was conducted to assess local and distant control.

RESULTS

Forty-three patients with 262 tumors were included. The median overall survival (OS) was 16 months (95% CI 13-19 months). Predictors of increased OS after initial SRS include Breast GPA score > 1 (p < 0.001) and use of immunotherapy such as pembrolizumab (p = 0.011). The median time on immunotherapy was 8 months (IQR 4.4, 11.2). The median time to new CNS lesions after the first SRS treatment was 17 months (95% CI 12-22). The cumulative rate for development of new CNS metastases after initial SRS at 6 months, 1 year, and 2 years was 23%, 40%, and 70%, respectively. Thirty patients (70%) underwent multiple SRS treatments, with a median time of 5 months (95% CI 0.59-9.4 months) for the appearance of new CNS metastases after second SRS treatment.

CONCLUSIONS

TNBC patients with BM can achieve longer survival than might have been previously anticipated with median survival now surpassing one year. The use of immunotherapy is associated with increased median OS of 23 months.

Evaluation of the SSTR2-targeted Radiopharmaceutical 177Lu-DOTATATE and SSTR2-specific 68Ga-DOTATATE PET as Imaging Biomarker in Patients with Intracranial Meningioma

PURPOSE

There are no effective medical therapies for patients with meningioma who progress beyond surgical and radiotherapeutic interventions. Somatostatin receptor type 2 (SSTR2) represents a promising treatment target in meningiomas. In this multicenter, single-arm phase II clinical study (NCT03971461), the SSTR2-targeting radiopharmaceutical 177Lu-DOTATATE is evaluated for its feasibility, safety, and therapeutic efficacy in these patients.

PATIENTS AND METHODS

Adult patients with progressive intracranial meningiomas received 177Lu-DOTATATE at a dose of 7.4 GBq (200 mCi) every eight weeks for four cycles. 68Ga-DOTATATE PET-MRI was performed before and six months after the start of the treatment. The primary endpoint was progression-free survival (PFS) at 6 months (PFS-6). Secondary endpoints were safety and tolerability, overall survival (OS) at 12 months (OS-12), median PFS, and median OS.

RESULTS

Fourteen patients (female = 11, male = 3) with progressive meningiomas (WHO 1 = 3, 2 = 10, 3 = 1) were enrolled. Median age was 63.1 (range 49.7-78) years. All patients previously underwent tumor resection and at least one course of radiation. Treatment with 177Lu-DOTATATE was well tolerated. Seven patients (50%) achieved PFS-6. Best radiographic response by modified Macdonald criteria was stable disease (SD) in all seven patients. A >25% reduction in 68Ga-DOTATATE uptake (PET) was observed in five meningiomas and two patients. In one lesion, this corresponded to >50% reduction in bidirectional tumor measurements (MRI).

CONCLUSIONS

Treatment with 177Lu-DOTATATE was well tolerated. The predefined PFS-6 threshold was met in this interim analysis, thereby allowing this multicenter clinical trial to continue enrollment. 68Ga-DOTATATE PET may be a useful imaging biomarker to assess therapeutic outcome in patients with meningioma.

Long-term Survival From Breast Cancer Brain Metastases in the Era of Modern Systemic Therapies

BACKGROUND AND OBJECTIVES

Median survival for all patients with breast cancer with brain metastases (BCBMs) has increased in the era of targeted therapy (TT) and with improved local control of intracranial tumors using stereotactic radiosurgery (SRS) and surgical resection. However, detailed characterization of the patients with long-term survival in the past 5 years remains sparse. The aim of this article is to characterize patients with BCBM who achieved long-term survival and identify factors associated with the uniquely better outcomes and to find predictors of mortality for patients with BCBM.

METHODS

We reviewed 190 patients with breast cancer with 931 brain tumors receiving SRS who were followed at our institution with prospective data collection between 2012 and 2022. We analyzed clinical, molecular, and imaging data to assess relationship to outcomes and tumor control.

RESULTS

The median overall survival from initial SRS and from breast cancer diagnosis was 25 months (95% CI 19-31 months) and 130 months (95% CI 100-160 months), respectively. Sixteen patients (17%) achieved long-term survival (survival ≥5 years from SRS), 9 of whom are still alive. Predictors of long-term survival included HER2+ status ( P = .041) and treatment with TT ( P = .046). A limited number of patients (11%) died of central nervous system (CNS) causes. A predictor of CNS-related death was the development of leptomeningeal disease after SRS ( P = .025), whereas predictors of non-CNS death included extracranial metastases at first SRS ( P = .017), triple-negative breast cancer ( P = .002), a Karnofsky Performance Status of <80 at first SRS ( P = .002), and active systemic disease at last follow-up ( P = .001). Only 13% of patients eventually needed whole brain radiotherapy. Among the long-term survivors, none died of CNS progression.

CONCLUSION

Patients with BCBM can achieve long-term survival. The use of TT and HER2+ disease are associated with long-term survival. The primary cause of death was extracranial disease progression, and none of the patients living ≥5 years died of CNS-related disease.

Volumetric growth rate of incidentally found meningiomas on immunotherapy

PURPOSE

The expression of PD-L1 in high-grade meningiomas made it a potential target for immunotherapy research in refractory cases. Several prospective studies in this field are still on going. We sought to retrospectively investigate the effects of check-point inhibitors (CI) on meningiomas that had been naïve to either surgical or radiation approaches by following incidental meningiomas found during treatment with CI for various primary metastatic cancers.

METHODS

We used the NYU Perlmutter Cancer Center Data Hub to find patients treated by CI for various cancers, who also had serial computerized-tomography (CT) or magnetic-resonance imaging (MRI) reports of intracranial meningiomas. Meningioma volumetric measurements were compared between the beginning and end of the CI treatment period. Patients treated with chemotherapy during this period were excluded.

RESULTS

Twenty-five patients were included in our study, of which 14 (56%) were on CI for melanoma, 5 (20%) for non-small-cell lung cancer and others. CI therapies included nivolumab (n = 15, 60%), ipilimumab (n = 11, 44%) and pembrolizumab (n = 9, %36), while 9 (36%) were on ipilimumab/nivolumab combination. We did not find any significant difference between tumor volumes before and after treatment with CI (1.31 ± 0.46 vs. 1.34 ± 0.46, p=0.8, respectively). Among patients beyond 1 year of follow-up (n = 13), annual growth was 0.011 ± 0.011 cm3/year. Five patients showed minor volume reduction of 0.12 ± 0.10 cm3 (21 ± 6% from baseline). We did not find significant predictors of tumor volume reduction.

CONCLUSION

Check-point inhibitors may impact the natural history of meningiomas. Additional research is needed to define potential clinical indications and treatment goals.

Quantitative Analysis of Parenchymal Effects and Flow of Large Arteriovenous Malformations Managed With Stereotactic Radiosurgery

BACKGROUND AND OBJECTIVES

Stereotactic radiosurgery (SRS) of larger arteriovenous malformations (AVM) is associated with an elevated incidence of adverse radiation effects (ARE). To date, volume-response and dose-response models have been used to predict such effects. To understand radiological outcomes and their hemodynamic effects on the regional brain.

METHODS

A retrospective analysis was conducted at our institution using a prospective registry of patients managed between 2014 and 2020. We included patients with AVM with a nidus larger than 5 cc who received either single-session or volume-staged Gamma Knife radiosurgery. AVM volume changes, volumes of parenchymal response, and obliteration were analyzed and correlated with transit times and diameters of feeding arteries and draining veins.

RESULTS

Sixteen patients underwent single-session SRS, and 9 patients underwent volume-staged SRS. The average AVM volume was 12.6 cc (5.5-23). The AVM locations were predominantly lobar (80%) and 17 (68%) were in critical locations. The mean margin dose was 17.2 Gy (15-21), and the median V12Gy was 25.5 cc. Fourteen (56%) AVMs had a transit time shorter than 1 second. The median vein-artery ratio (sum diameter of the veins/sum diameter of feeding arteries) was 1.63 (range, 0.60-4.19). Asymptomatic parenchymal effects were detected in 13 (52%) patients and were symptomatic in 4 (16%) patients. The median time to ARE was 12 months (95% CI 7.6-16.4). On univariate analysis, significant predictors of ARE were lower vein-artery ratio ( P = .024), longer transit time ( P = .05), higher mean dose ( P = .028), and higher D95 ( P = .036).

CONCLUSION

Transit times and vessel diameters are valuable predictors of the subsequent parenchymal response after SRS. A more quantitative understanding of blood flow is critical for predicting the effects on the regional brain after AVM radiosurgery.

Low-Dose Radiosurgery for Brain Metastases in the Era of Modern Systemic Therapy

BACKGROUND AND OBJECTIVES

Dose selection for brain metastases stereotactic radiosurgery (SRS) classically has been based on tumor diameter with a reduction of dose in the settings of prior brain irradiation, larger tumor volumes, and critical brain location. However, retrospective series have shown local control rates to be suboptimal with reduced doses. We hypothesized that lower doses could be effective for specific tumor biologies with concomitant systemic therapies. This study aims to report the local control (LC) and toxicity when using low-dose SRS in the era of modern systemic therapy.

METHODS

We reviewed 102 patients with 688 tumors managed between 2014 and 2021 who had low-margin dose radiosurgery, defined as ≤14 Gy. Tumor control was correlated with demographic, clinical, and dosimetric data.

RESULTS

The main primary cancer types were lung in 48 (47.1%), breast in 31 (30.4%), melanoma in 8 (7.8%), and others in 15 patients (11.7%). The median tumor volume was 0.037cc (0.002-26.31 cm 3 ), and the median margin dose was 14 Gy (range 10-14). The local failure (LF) cumulative incidence at 1 and 2 years was 6% and 12%, respectively. On competing risk regression analysis, larger volume, melanoma histology, and margin dose were predictors of LF. The 1-year and 2-year cumulative incidence of adverse radiation effects (ARE: an adverse imaging-defined response includes increased enhancement and peritumoral edema) was 0.8% and 2%.

CONCLUSION

It is feasible to achieve acceptable LC in BMs with low-dose SRS. Volume, melanoma histology, and margin dose seem to be predictors for LF. The value of a low-dose approach may be in the management of patients with higher numbers of small or adjacent tumors with a history of whole brain radio therapy or multiple SRS sessions and in tumors in critical locations with the aim of LC and preservation of neurological function.

EGFR-mutated non-small lung cancer brain metastases and radiosurgery outcomes with a focus on leptomeningeal disease

PURPOSE

Patients with EGFR-mutated NSCLC represent a unique subset of lung cancer patients with distinct clinical and molecular characteristics. Previous studies have shown a higher incidence of brain metastases (BM) in this subgroup of patients, and neurologic death has been reported to be as high as 40% and correlates with leptomeningeal disease (LMD).

METHODS

Between 2012 and 2021, a retrospective review of our prospective registry identified 606 patients with BM from NSCLC, with 170 patients having an EGFR mutation. Demographic, clinical, radiographic, and treatment characteristics were correlated to the incidence of LMD and survival.

RESULTS

LMD was identified in 22.3% of patients (n = 38) at a median follow-up of 19 (2-98) months from initial SRS. Multivariate regression analysis showed targeted therapy and a cumulative number of metastases as significant predictors of LMD (p = 0.034, HR = 0.44), (p = .04, HR = 1.02). The median survival time after SRS of the 170 patients was 24 months (CI 95% 19.1-28.1). In a multivariate Cox regression analysis, RPA, exon 19 deletion, and osimertinib treatment were significant predictors of overall survival. The cumulative incidence of neurological death at 2 and 4 years post initial stereotactic radiosurgery (SRS) was 8% and 11%, respectively, and correlated with LMD.

CONCLUSION

The study shows that current-generation targeted therapy for EGFR-mutated NSCLC patients may prevent the development and progression of LMD, leading to improved survival outcomes. Nevertheless, LMD is associated with poor outcomes and neurologic death, making innovative strategies to treat LMD essential.

Extended Survival in Patients With Non-Small-Cell Lung Cancer-Associated Brain Metastases in the Modern Era

BACKGROUND

Brain metastases (BM) have long been considered a terminal diagnosis with management mainly aimed at palliation and little hope for extended survival. Use of brain stereotactic radiosurgery (SRS) and/or resection, in addition to novel systemic therapies, has enabled improvements in overall and progression-free (PFS) survival.

OBJECTIVE

To explore the possibility of extended survival in patients with non-small-cell lung cancer (NSCLC) BM in the current era.

METHODS

During the years 2008 to 2020, 606 patients with NSCLC underwent their first Gamma Knife SRS for BM at our institution with point-of-care data collection. We reviewed clinical, molecular, imaging, and treatment parameters to explore the relationship of such factors with survival.

RESULTS

The median overall survival was 17 months (95% CI, 13-40). Predictors of increased survival in a multivariable analysis included age <65 years ( P < .001), KPS ≥80 ( P < .001), absence of extracranial metastases ( P < .001), fewer BM at first SRS (≤3, P = .003), and targeted therapy ( P = .005), whereas chemotherapy alone was associated with shorter survival ( P = .04). In a subgroup of patients managed before 2016 (n = 264), 38 (14%) were long-term survivors (≥5 years), of which 16% required no active cancer treatment (systemic or brain) for ≥3 years by the end of their follow-up.

CONCLUSION

Long-term survival in patients with brain metastases from NSCLC is feasible in the current era of SRS when combined with the use of effective targeted therapeutics. Of those living ≥5 years, the chance for living with stable disease without the need for active treatment for ≥3 years was 16%.

How many brain metastases can be treated with stereotactic radiosurgery before the radiation dose delivered to normal brain tissue rivals that associated with standard whole brain radiotherapy?

INTRODUCTION

Clinical trial data comparing outcomes after administration of stereotactic radiosurgery (SRS) or whole-brain radiotherapy (WBRT) to patients with brain metastases (BM) suggest that SRS better preserves cognitive function and quality of life without negatively impacting overall survival. Here, we estimate the maximum number of BM that can be treated using single and multi-session SRS while limiting the dose of radiation delivered to normal brain tissue to that associated with WBRT.

METHODS

Multiple-tumor SRS was simulated using a Monte Carlo - type approach and a pre-calculated dose kernel method. Tumors with diameters ≤36 mm were randomly placed throughout the contoured brain parenchyma until the brain mean dose reached 3 Gy, equivalent to the radiation dose delivered during a single fraction of a standard course of WBRT (a total dose of 30 Gy in 10 daily fractions of 3 Gy). Distribution of tumor sizes, dose coverage, selectivity, normalization, and maximum dose data used in the simulations were based on institutional clinical metastases data.

RESULTS

The mean number of tumors treated, mean volume of healthy brain tissue receiving > 12 Gy (V12) per tumor, and total tumor volume treated using mixed tumor size distributions were 12.7 ± 4.2, 2.2 cc, and 12.9 cc, respectively. Thus, we estimate that treating 12-13 tumors per day over 10 days would deliver the dose of radiation to healthy brain tissue typically associated with a standard course of WBRT.

CONCLUSION

Although in clinical practice, treatment with SRS is often limited to patients with ≤15 BM, our findings suggest that many more lesions could be targeted while still minimizing the negative impacts on quality of life and neurocognition often associated with WBRT. Results from this in silico analysis require clinical validation.

Modern Hearing Preservation Outcomes After Vestibular Schwannoma Stereotactic Radiosurgery

BACKGROUND

For patients with vestibular schwannoma (VS), stereotactic radiosurgery (SRS) has proven effective in controlling tumor growth while hearing preservation remains a key goal.

OBJECTIVE

To evaluate hearing outcomes in the modern era of cochlear dose restriction.

METHODS

During the years 2013 to 2018, 353 patients underwent Gamma knife surgery for VS at our institution. We followed 175 patients with pre-SRS serviceable hearing (Gardner-Robertson Score, GR 1 and 2). Volumetric and dosimetry data were collected, including biological effective dose, integral doses of total and intracanalicular tumor components, and hearing outcomes.

RESULTS

The mean age was 56 years, 74 patients (42%) had a baseline GR of 2, and the mean cochlear dose was 3.5 Gy. The time to serviceable hearing loss (GR 3-4) was 38 months (95% CI 26-46), with 77% and 62% hearing preservation in the first and second years, respectively. Patients optimal for best hearing outcomes were younger than 58 years with a baseline GR of 1, free canal space ≥0.041 cc (diameter of 4.5 mm), and mean cochlear dose <3.1 Gy. For such patients, hearing preservation rates were 92% by 12 months and 81% by 2 years, staying stable for >5 years post-SRS, significantly higher than the rest of the population.

CONCLUSION

Hearing preservation after SRS for patients with VS with serviceable hearing is correlated to the specific baseline GR score (1 or 2), age, cochlear dose, and biological effective dose. Increased tumor-free canal space correlates with better outcomes. The most durable hearing preservation correlates with factors commonly associated with smaller tumors away from the cochlea.

Preoperative flow analysis of arteriovenous malformations and obliteration response after stereotactic radiosurgery

OBJECTIVE

Morphological and angioarchitectural features of cerebral arteriovenous malformations (AVMs) have been widely described and associated with outcomes; however, few studies have conducted a quantitative analysis of AVM flow. The authors examined brain AVM flow and transit time on angiograms using direct visual analysis and a computer-based method and correlated these factors with the obliteration response after Gamma Knife radiosurgery.

METHODS

A retrospective analysis was conducted at a single institution using a prospective registry of patients managed from January 2013 to December 2019: 71 patients were analyzed using a visual method of flow determination and 38 were analyzed using a computer-based method. After comparison and validation of the two methods, obliteration response was correlated to flow analysis, demographic, angioarchitectural, and dosimetric data.

RESULTS

The mean AVM volume was 3.84 cm3 (range 0.64-19.8 cm3), 32 AVMs (45%) were in critical functional locations, and the mean margin radiosurgical dose was 18.8 Gy (range 16-22 Gy). Twenty-seven AVMs (38%) were classified as high flow, 37 (52%) as moderate flow, and 7 (10%) as low flow. Complete obliteration was achieved in 44 patients (62%) at the time of the study; the mean time to obliteration was 28 months for low-flow, 34 months for moderate-flow, and 47 months for high-flow AVMs. Univariate and multivariate analyses of factors predicting obliteration included AVM nidus volume, age, and flow. Adverse radiation effects were identified in 5 patients (7%), and 67 patients (94%) remained free of any functional deterioration during follow-up.

CONCLUSIONS

AVM flow analysis and categorization in terms of transit time are useful predictors of the probability of and the time to obliteration. The authors believe that a more quantitative understanding of flow can help to guide stereotactic radiosurgery treatment and set accurate outcome expectations.

Stereotactic body radiation therapy for an unresectable FGF23-secreting tumor of the cervical spine: A case report and literature review

We present the case of a 65-year-old male with tumor-induced osteomalacia (TIO) caused by an FGF23-secreting phosphaturic tumor of C2 treated definitively with stereotactic body radiation therapy (SBRT) and kyphoplasty. The patient exhibited notable reduction in FGF23 6 weeks following radiotherapy. He also received a dose of the FGF23 monoclonal antibody, burosumab. We discuss the case with emphasis on radiation in the management of TIO. This case demonstrates SBRT as a well-tolerated local treatment option for the management of unresectable FGF23-producing tumors.

The incidence and predictors of new brain metastases in patients with non-small cell lung cancer following discontinuation of systemic therapy

OBJECTIVE

Patients with non-small cell lung cancer (NSCLC) metastatic to the brain are living longer. The risk of new brain metastases when these patients stop systemic therapy is unknown. The authors hypothesized that the risk of new brain metastases remains constant for as long as patients are off systemic therapy.

METHODS

A prospectively collected registry of patients undergoing radiosurgery for brain metastases was analyzed. Of 606 patients with NSCLC, 63 met the inclusion criteria of discontinuing systemic therapy for at least 90 days and undergoing active surveillance. The risk factors for the development of new tumors were determined using Cox proportional hazards and recurrent events models.

RESULTS

The median duration to new brain metastases off systemic therapy was 16.0 months. The probability of developing an additional new tumor at 6, 12, and 18 months was 26%, 40%, and 53%, respectively. There were no additional new tumors 22 months after stopping therapy. Patients who discontinued therapy due to intolerance or progression of the disease and those with mutations in RAS or receptor tyrosine kinase (RTK) pathways (e.g., KRAS, EGFR) were more likely to develop new tumors (hazard ratio [HR] 2.25, 95% confidence interval [CI] 1.33-3.81, p = 2.5 × 10-3; HR 2.51, 95% CI 1.45-4.34, p = 9.8 × 10-4, respectively).

CONCLUSIONS

The rate of new brain metastases from NSCLC in patients off systemic therapy decreases over time and is uncommon 2 years after cessation of cancer therapy. Patients who stop therapy due to toxicity or who have RAS or RTK pathway mutations have a higher rate of new metastases and should be followed more closely.

Predicting local failure of brain metastases after stereotactic radiosurgery with radiomics on planning MR images and dose maps

PURPOSE

Stereotactic radiosurgery (SRS) has become an important modality in the treatment of brain metastases. The purpose of this study is to investigate the potential of radiomic features from planning magnetic resonance (MR) images and dose maps to predict local failure after SRS for brain metastases.

MATERIALS/METHODS

Twenty-eight patients who received Gamma Knife (GK) radiosurgery for brain metastases were retrospectively reviewed in this IRB-approved study. 179 irradiated tumors included 42 that locally failed within one-year follow-up. Using SRS tumor volumes, radiomic features were calculated on T1-weighted contrast-enhanced MR images acquired for treatment planning and planned dose maps. 125 radiomic features regarding tumor shape, dose distribution, MR intensities and textures were extracted for each tumor. Logistic regression with automatic feature selection was built to predict tumor progression from local control after SRS. Feature selection and model evaluation using receiver operating characteristic (ROC) curves were performed in a nested cross validation (CV) scheme. The associations between selected radiomic features and treatment outcomes were statistically assessed by univariate analysis.

RESULTS

The logistic model with feature selection achieved ROC AUC of 0.82 ± 0.09 on 5-fold CV, providing 83% sensitivity and 70% specificity for predicting local failure. A total of 10 radiomic features including 1 shape feature, 6 MR images and 3 dose distribution features were selected. These features were significantly associated with treatment outcomes (p < 0.05). The model was validated on independent holdout data with an AUC of 0.78.

CONCLUSIONS

Radiomic features from planning MR images and dose maps provided prognostic information in SRS for brain metastases. A model built on the radiomic features shows promise for early prediction of tumor local failure after treatment, potentially aiding in personalized care for brain metastases.

Hippocampal sparing in patients receiving radiosurgery for ≥25 brain metastases

PURPOSE/OBJECTIVES

To report our dosimetric analysis of the hippocampi (HC) and the incidence of perihippocampal tumor location in patients with ≥25 brain metastases who received stereotactic radiosurgery (SRS) in single or multiple sessions.

MATERIALS/METHODS

Analysis of our prospective registry identified 89 patients treated with SRS for ≥25 brain metastases. HC avoidance regions (HA-region) were created on treatment planning MRIs by 5 mm expansion of HC. Doses from each session were summed to calculate HC dose. The distribution of metastases relative to the HA-region and the HC was analyzed.

RESULTS

Median number of tumors irradiated per patient was 33 (range 25-116) in a median of 3 (range1-12) sessions. Median bilateral HC D_min (D₁₀₀), D₄₀, D₅₀, D_max, and D_mean (Gy) was 1.88, 3.94, 3.62, 16.6, and 3.97 for all patients, and 1.43, 2.99, 2.88, 5.64, and 3.07 for patients with tumors outside the HA-region. Multivariate linear regression showed that the median HC D₄₀, D₅₀, and D_min were significantly correlated with the tumor number and tumor volume (p < 0.001). Of the total 3059 treated tumors, 83 (2.7%) were located in the HA-region in 57% evaluable patients; 38 tumors (1.2%) abutted or involved the HC itself.

CONCLUSIONS

Hippocampal dose is higher in patients with tumors in the HA-region; however, even for patients with a high burden of intracranial disease and tumors located in the HA-regions, SRS affords hippocampal sparing. This is particularly relevant in light of our finding of eventual perihippocampal metastases in more than half of our patients.

Evaluation of First-line Radiosurgery vs Whole-Brain Radiotherapy for Small Cell Lung Cancer Brain Metastases: The FIRE-SCLC Cohort Study

Importance

Although stereotactic radiosurgery (SRS) is preferred for limited brain metastases from most histologies, whole-brain radiotherapy (WBRT) has remained the standard of care for patients with small cell lung cancer. Data on SRS are limited.

Objective

To characterize and compare first-line SRS outcomes (without prior WBRT or prophylactic cranial irradiation) with those of first-line WBRT.

Design, Setting, and Participants

FIRE-SCLC (First-line Radiosurgery for Small-Cell Lung Cancer) was a multicenter cohort study that analyzed SRS outcomes from 28 centers and a single-arm trial and compared these data with outcomes from a first-line WBRT cohort. Data were collected from October 26, 2017, to August 15, 2019, and analyzed from August 16, 2019, to November 6, 2019.

Interventions

SRS and WBRT for small cell lung cancer brain metastases.

Main Outcomes and Measures

Overall survival, time to central nervous system progression (TTCP), and central nervous system (CNS) progression-free survival (PFS) after SRS were evaluated and compared with WBRT outcomes, with adjustment for performance status, number of brain metastases, synchronicity, age, sex, and treatment year in multivariable and propensity score-matched analyses.

Results

In total, 710 patients (median [interquartile range] age, 68.5 [62-74] years; 531 men [74.8%]) who received SRS between 1994 and 2018 were analyzed. The median overall survival was 8.5 months, the median TTCP was 8.1 months, and the median CNS PFS was 5.0 months. When stratified by the number of brain metastases treated, the median overall survival was 11.0 months (95% CI, 8.9-13.4) for 1 lesion, 8.7 months (95% CI, 7.7-10.4) for 2 to 4 lesions, 8.0 months (95% CI, 6.4-9.6) for 5 to 10 lesions, and 5.5 months (95% CI, 4.3-7.6) for 11 or more lesions. Competing risk estimates were 7.0% (95% CI, 4.9%-9.2%) for local failures at 12 months and 41.6% (95% CI, 37.6%-45.7%) for distant CNS failures at 12 months. Leptomeningeal progression (46 of 425 patients [10.8%] with available data) and neurological mortality (80 of 647 patients [12.4%] with available data) were uncommon. On propensity score-matched analyses comparing SRS with WBRT, WBRT was associated with improved TTCP (hazard ratio, 0.38; 95% CI, 0.26-0.55; P < .001), without an improvement in overall survival (median, 6.5 months [95% CI, 5.5-8.0] for SRS vs 5.2 months [95% CI, 4.4-6.7] for WBRT; P = .003) or CNS PFS (median, 4.0 months for SRS vs 3.8 months for WBRT; P = .79). Multivariable analyses comparing SRS and WBRT, including subset analyses controlling for extracranial metastases and extracranial disease control status, demonstrated similar results.

Conclusions and Relevance

Results of this study suggest that the primary trade-offs associated with SRS without WBRT, including a shorter TTCP without a decrease in overall survival, are similar to those observed in settings in which SRS is already established.

RADT-10. SURVIVAL IN PATIENTS FULFILLING CCTG CE.7 ELIGIBILITY CRITERIA: EVALUATING INITIAL STEREOTACTIC RADIOSURGERY FOR 5-15 BRAIN METASTASES

INTRODUCTION

The suitability of stereotactic radiosurgery (SRS) in patients with 5-15 brain metastases (BM) is being evaluated in the ongoing CCTG CE.7 randomized trial testing SRS against HA-WBRT. Our study examines the survival of patients with 5-15 BM treated at initial SRS.

METHODS

Review of our Gamma Knife registry identified 163 patients who fulfilled CCTG CE.7 eligibility criteria.

RESULTS

92 females (56%) and 71 males (44%) with median age of 51.6 years (23-98.9) and primary diagnoses of lung (n = 108, 28 EGFR/ALK mutations), breast (n =14, 1 Her2+), melanoma (n = 27, 9 BRAF+), and 14 other were identified. 145 had active extracranial disease (89%); median KPS was 90 (50-100). Median number of tumors at first SRS was 8.2; 114 patients (70%) had 5-9 and 49 (30%) had 10-15 tumors. 73 patients (45%) had subsequent SRS to a median of 19 (6-84) cumulative subsequent tumors at a median time to 2nd treatment of 3.9 months (0.7-30.3). 32 patients (20%) had a 3rd SRS and 24 patients (15%) had 4 or more treatments. 16 patients (10%) received WBRT after initial SRS. 73 patients (45%) were alive at time of data analysis. Median OS from initial SRS for all patients was 15.5 months and was 15, 17.6, 13.4, and 8.7 months, for breast, lung, melanoma, and other respectively. Median OS with 5-9 metastases vs 10-15 metastases was 17.5 vs. 13.3 months (p=.15). Median OS with vs without subsequent SRS was 21.8 vs 8 months (p=.0013).

CONCLUSION

Patients with 5-15 BM treated with initial SRS can achieve survivals that compare favorably with or better than those of WBRT. These findings potentially challenge the assumption that such patients may be better candidates for HA-WBRT than upfront SRS. Our experience supports the ongoing efforts to prospectively evaluate upfront SRS in these patients.

Full automation of spinal stereotactic radiosurgery and stereotactic body radiation therapy treatment planning using Varian Eclipse scripting

The purpose of this feasibility study is to develop a fully automated procedure capable of generating treatment plans with multiple fractionation schemes to improve speed, robustness, and standardization of plan quality. A fully automated script was implemented for spinal stereotactic radiosurgery/stereotactic body radiation therapy (SRS/SBRT) plan generation using Eclipse v15.6 API. The script interface allows multiple dose/fractionation plan requests, planning target volume (PTV) expansions, as well as information regarding distance/overlap between spinal cord and targets to drive decision‐making. For each requested plan, the script creates the course, plans, field arrangements, and automatically optimizes and calculates dose. The script was retrospectively applied to ten computed tomography (CT) scans of previous cervical, thoracic, and lumbar spine SBRT patients. Three plans were generated for each patient — simultaneous integrated boost (SIB) 1800/1600 cGy to gross tumor volume (GTV)/PTV in one fraction; SIB 2700/2100 cGy to GTV/PTV in three fractions; and 3000 cGy to PTV in five fractions. Plan complexity and deliverability patient‐specific quality assurance (QA) was performed using ArcCHECK with an Exradin A16 chamber inserted. Dose objectives were met for all organs at risk (OARs) for each treatment plan. Median target coverage was GTV V100% = 87.3%, clinical target volume (CTV) V100% = 95.7% and PTV V100% = 88.0% for single fraction plans; GTV V100% = 95.6, CTV V100% = 99.6% and PTV V100% = 97.2% for three fraction plans; and GTV V100% = 99.6%, CTV V100% = 99.1% and PTV V100% = 97.2% for five fraction plans. All plans (n = 30) passed patient‐specific QA (>90%) at 2%/2 mm global gamma. A16 chamber dose measured at isocenter agreed with planned dose within 3% for all cases. Automatic planning for spine SRS/SBRT through scripting increases efficiency, standardizes plan quality and approach, and provides a tool for target coverage comparison of different fractionation schemes without the need for additional resources.

Stereotactic Radiation for Treating Primary and Metastatic Neoplasms of the Spinal Cord

Stereotactic radiation treatment can be used to treat spinal cord neoplasms in patients with either unresectable lesions or residual disease after surgical resection. While treatment guidelines have been suggested for epidural lesions, the utility of stereotactic radiation for intradural and intramedullary malignancies is still debated. Prior reports have suggested that stereotactic radiation approaches can be used for effective tumor control and symptom management. Treatment-related toxicity has been documented in rare subsets of patients, though the incidences of injury are not directly correlated with higher radiation doses. Further studies are needed to assess the factors that influence the risk of radiation-induced myelopathy when treating spinal cord neoplasms with stereotactic radiation, which can include, but may not be limited to, maximum dose, dose-fractionation, irradiated volume, tumor location, histology and treatment history. This review will discuss evidence for current treatment approaches.

Abstract A65: Longitudinal detection of TERT-mutant plasma cell-free circulating tumor DNA in newly diagnosed glioblastoma patients

Introduction: Liquid biopsies, especially plasma cell-free circulating tumor DNA (ctDNA), provide a potential opportunity to be a noninvasive biomarker for the diagnosis and monitoring of glioblastoma (GBM) patients. Previously, we detected TERT promoter hotspot mutations (C228T and C250T) in ctDNA of IDH wild-type (IDHwt) TERT promoter mutant GBM patients with 100% specificity using mutation-specific droplet digital PCR (ddPCR) assays. Here, we examine the association between mutant TERT ctDNA levels and clinical outcomes in newly diagnosed GBM patients undergoing chemoradiation.

Methods: We analyzed 76 serially collected plasma samples from 17 patients with suspected IDHwt GBM based on MRI before surgery. Twenty mL of whole blood was collected in EDTA tubes at predetermined times: pre- and postoperatively, at the end of chemoradiation, and 1, 3, and 6 months from the end of chemoradiation. TERT promoter mutations C228T or C250T were identified in FFPE tumor samples using ddPCR assays specific for these mutations. Plasma samples were analyzed for the patient’s tumor TERT mutation using the ddPCR assays. The analytically validated thresholds for positive ctDNA detection were 1.5 and 1.7 copies/mL for C228T and C250T, respectively.

Results: Sixteen of 17 (94%) IDHwt tumors had TERT mutations (10 C228T, 6 C250T) with MGMT methylated, unmethylated, or unknown status in 10, 5, and 1, respectively. Fourteen of the 16 patients (87.5%) had detectable mutant ctDNA at one or more time points (range 1.66 to 22.13 copies/mL). Of the 2 patients with undetectable ctDNA, one had diffuse and non-avidly enhancing disease and the other only had pre/postop plasma samples collected. Six patients had detectable ctDNA preop, and most had a dominant rim-enhancing mass with additional nonenhancing or enhancing lesion(s). Ten patients had detectable ctDNA up to 4 days postop, half of whom had undergone gross total resection. For 3 of 5 patients for whom there was a question of pseudoprogression versus true progression, ctDNA kinetics matched the clinical outcome. One patient with MGMT unmethylated multifocal GBM achieved ctDNA zeroconversion at 6 months post radiation (RT), and did not progress for another five months. Another patient was negative at all time points until their 3-month post RT follow-up, at which time they developed a recurrence. Another patient achieved zeroconversion at the end of RT but developed a borderline positive ctDNA at 6 months after RT, 2 months before documented radiographic progression.

Conclusions: In this pilot, prospective ctDNA monitoring study of IDHwt GBM, TERT mutant ctDNA was detected at one or more time points in the majority of patients. ctDNA kinetics were associated with clinical outcomes for some patients. These data suggest that additional, larger studies could refine how ctDNA monitoring may be used to enhance the clinical management of IDHwt GBM patients.

Citation Format: Christine Cordova, Mahrukh M. Syeda, Broderick Corless, Jennifer M. Wiggins, Amie Patel, Sylvia C. Kurz, Malcolm Delara, Zacharia Sawaged, Minerva Utate, Dimitris Placantonakis, John Golfinos, Jessica Schafrick, Joshua S. Silverman, Rajan Jain, Matija Snuderl, David Zagzag, George Karlin-Neumann, David Polsky, Andrew S. Chi. Longitudinal detection of TERT-mutant plasma cell-free circulating tumor DNA in newly diagnosed glioblastoma patients [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr A65.

The relationship of dose to nerve volume in predicting pain recurrence after stereotactic radiosurgery in trigeminal neuralgia

OBJECTIVE Approximately 75%-92% of patients with trigeminal neuralgia (TN) achieve pain relief after Gamma Knife surgery (GKS), although a proportion of these patients will experience recurrence of their pain. To evaluate the reasons for durability or recurrence, this study determined the impact of trigeminal nerve length and volume, the nerve dose-volume relationship, and the presence of neurovascular compression (NVC) on pain outcomes after GKS for TN. METHODS Fifty-eight patients with 60 symptomatic nerves underwent GKS for TN between 2013 and 2015, including 15 symptomatic nerves secondary to multiple sclerosis (MS). High-resolution MRI was acquired the day of GKS. The median maximum dose was 80 Gy for initial GKS and 65 Gy for repeat GKS. NVC, length and volume of the trigeminal nerve within the subarachnoid space of the posterior fossa, and the ratio of dose to nerve volume were assessed as predictors of recurrence. RESULTS Follow-up was available on 55 patients. Forty-nine patients (89.1%) reported pain relief (Barrow Neurological Institute [BNI] Grades I-IIIb) after GKS at a median duration of 1.9 months. The probability of maintaining pain relief (BNI Grades I-IIIb) without requiring resumption or an increase in medication was 93% at 1 year and 84% at 2 years for patients without MS, and 68% at 1 year and 51% at 2 years for all patients. The nerve length, nerve volume, target distance from the brainstem, and presence of NVC were not predictive of pain recurrence. Patients with a smaller volume of nerve (< 35% of the total nerve volume) that received a high dose (≥ 80% isodose) were less likely to experience recurrence of their TN pain after 1 year (mean time to recurrence: < 35%, 32.2 ± 4.0 months; > 35%, 17.9 ± 2.8 months, log-rank test, χ² = 4.3, p = 0.039). CONCLUSIONS The ratio of dose to nerve volume may predict recurrence of TN pain after GKS. Prospective studies are needed to determine the optimal dose to nerve volume ratio and whether this will result in longer pain-free outcomes.

INTRAVITREAL BEVACIZUMAB IN THE MANAGEMENT OF BREAST CANCER IRIS METASTASIS

PURPOSE

To report a case of neovascular and angle closure glaucoma secondary to breast cancer metastatic to the iris that was successfully treated with injections of intravitreal bevacizumab (Avastin) 1.25 mg/0.05 mL.

METHODS

Case report.

PATIENTS

A 47-year-old woman with metastatic breast cancer presented to The New York Eye Cancer Center with left ocular pain, photosensitivity, vision loss, and multiple iris nodules. Her intraocular pressure was uncontrolled. Gonioscopy revealed neovascularization of the iris and angle; no choroidal neovascularization was noted. Ultrasound biomicroscopy demonstrated tumor invasion of iris stroma with marked anterior uveal thickening and narrowed angles.

RESULTS

Three monthly injections of intravitreal bevacizumab resulted in nearly complete resolution of iris neovascularization, reduction of intraocular pressure, and control of tumor (although a small amount of residual tumor remained).

CONCLUSION

Intravitreal anti-vascular endothelial growth factor therapy for breast cancer metastatic to the iris with secondary neovascular glaucoma provided good local control for a limited follow-up period, because the patient died because of systemic complications of her disease.

Relapsed or refractory primary central nervous system lymphoma radiosurgery: Report of the International Gamma Knife Research Foundation

Stereotactic radiosurgery (SRS) can be used as part of multimodality management for patients with primary central nervous system lymphoma (PCNSL). The objective of this study is to evaluate outcomes of SRS for this disease. The International Gamma Knife Research Foundation identified 23 PCNSL patients who underwent SRS for either relapsed (intracerebral in-field or out-of-field tumor recurrences) or refractory disease from 1995-2014. All 23 patients presented with RPA Class I or II PCNSL, and were initially treated with a median of 7 cycles of methotrexate-based chemotherapy regimens (range, 3-26 cycles). Ten received prior whole brain radiation (WBRT) to a median dose of 43 Gy (range, 24-55 Gy). Sixteen presented with relapsed PCNSL, and seven presented with refractory disease. Twenty-three received 26 procedures of SRS. The median tumor volume was 4 cm³ (range, 0.1-26 cm³), and the median margin dose was 15 Gy (range, 8-20 Gy). Median follow-up from SRS was 11 months (interquartile range, 5.7-33.2 months). Twenty presented with treatment response to twenty-three tumors (12 complete, 11 partial). Fourteen patients relapsed or were refractory to salvage SRS, and local control was 95%, 91%, and 75% at 3, 6, and 12 months post SRS. Intracranial (in-field and out-of-field) and distant (systemic) PFS was 86%, 81%, and 55% at 3, 6, and 12 months post SRS. Toxicity of SRS was low, with one developing an adverse radiation effect requiring no additional intervention. Although methotrexate-based chemotherapy regimens with or without WBRT is the first-line management option for PCNSL, SRS may be used as an alternative option in properly selected patients with smaller relapsed or refractory PCNSL tumors.

Weekly versus every-three-weeks platinum-based chemoradiation regimens for head and neck cancer

Background

The majority of chemoradiation (CRT) trials for locally advanced head and neck squamous cell carcinoma (HNSCC) have relied on platinum-based chemotherapy regimens administered every-3-weeks. However, given the increased utilization of weekly platinum regimens, it remains unclear how different chemotherapy schedules compare regarding efficacy and toxicity.

Methods

We retrospectively identified 212 patients with HNSCC who were treated at a single academic medical center with concurrent platinum-based CRT given weekly (N = 68) or every-three-weeks (N = 144). JMP version 10 (SAS Institute) was used for statistical analysis. Discrete variables were compared with the chi-square test and differences in the medians were assessed using the Wilcoxon test. Survival curves were constructed using the Kaplan-Meier method and significance was assessed using the log rank test. For univariate analysis and multivariate analysis, we used Cox proportional hazard or logistic regression models to compare differences in survival or differences in categorical variables, respectively.

Results

Patients receiving weekly platinum regimens were more likely to be older (median age 61.4 vs. 55.5 y; P < .001), have high or very high Charlson comorbidity index (45.6% vs. 27.8%; P = .01), and receive carboplatin-based chemotherapy (6.3% vs. 76.5%; P < .001). Weekly and every-3-week platinum regimens had similar locoregional control (HR 1.10; 95% CI 0.63–1.88; P = .72), progression-free survival (HR 1.13; 95% CI 0.75–1.69; P = .55), and overall survival (HR 1.11; 95% CI 0.64–1.86; P = .71). Every-3-weeks platinum regimens were associated with increased days of hospitalization (median: 3 days vs. 0 days; P = .03) and acute kidney injury (AKI) during radiotherapy (50.0% vs. 22.1%; P < .001). On multivariate analysis, AKI was significantly associated with every-3-weeks regimens (OR: 24.38; 95% CI 3.00–198.03; P = .003) and high comorbidity scores (OR: 2.74; 95% CI 2.15–5.99; P = .01).

Conclusions

Our results suggest that every-3-weeks and weekly platinum-containing CRT regimens have similar disease control but weekly platinum regimens are associated with less acute toxicity.

Electronic supplementary material

The online version of this article (doi:10.1186/s40463-016-0175-x) contains supplementary material, which is available to authorized users.

The biology of radiosurgery and its clinical applications for brain tumors

Stereotactic radiosurgery (SRS) was developed decades ago but only began to impact brain tumor care when it was coupled with high-resolution brain imaging techniques such as computed tomography and magnetic resonance imaging. The technique has played a key role in the management of virtually all forms of brain tumor. We reviewed the radiobiological principles of SRS on tissue and how they pertain to different brain tumor disorders. We reviewed the clinical outcomes on the most common indications. This review found that outcomes are well documented for safety and efficacy and show increasing long-term outcomes for benign tumors. Brain metastases SRS is common, and its clinical utility remains in evolution. The role of SRS in brain tumor care is established. Together with surgical resection, conventional radiotherapy, and medical therapies, patients have an expanding list of options for their care. Clinicians should be familiar with radiosurgical principles and expected outcomes that may pertain to different brain tumor scenarios.

SCF ubiquitin ligases in the maintenance of genome stability

In response to genotoxic stress, eukaryotic cells activate the DNA damage response (DDR), a series of pathways that coordinate cell cycle arrest and DNA repair to prevent deleterious mutations. In addition, cells possess checkpoint mechanisms that prevent aneuploidy by regulating the number of centrosomes and spindle assembly. Among these mechanisms, ubiquitin-mediated degradation of key proteins has an important role in the regulation of the DDR, centrosome duplication and chromosome segregation. This review discusses the functions of a group of ubiquitin ligases, the SCF (SKP1-CUL1-F-box protein) family, in the maintenance of genome stability. Given that general proteasome inhibitors are currently used as anticancer agents, a better understanding of the ubiquitylation of specific targets by specific ubiquitin ligases may result in improved cancer therapeutics.

Decreased Posttreatment SUV on PET Scan Is Associated With Improved Local Control in Medically Inoperable Esophageal Cancer

BACKGROUND

The relationship between local, regional, or distant disease control (LC, RC, DC) and maximal posttreatment standardized uptake value (SUV(max)) in patients with esophageal cancer has not been elucidated. This study was initiated to explore whether a decrease in SUV on positron emission tomography-computed tomography (PET-CT) scan is associated with LC, RC, or DC in patients with esophageal carcinoma treated with definitive chemoradiotherapy.

METHODS

Medical records of 40 patients with inoperable esophageal cancer treated with definitive intent and who underwent pre- and posttreatment PET-CT scans were reviewed. The histology, nodal status, tumor location, and radiotherapy (RT) dose were investigated as variables to determine a relationship between SUV(max) and LC, RC, and DC as well as disease-free survival (DFS).

RESULTS

Decreased posttreatment SUV(max) on PET scan (P = .02) and increased RT dose (P = .009) were the only significant predictors of improved LC on univariate analysis. Mean RT doses in patients with no evidence of disease or with local, regional, or distant recurrences were 5,244, 4,580, 5,094, and 4,968, respectively. Decreased posttreatment SUV (P = .03) and increased RT dose (P = .008) were also associated with an improvement in DFS. Furthermore, decreased posttreatment SUV(max) correlated with an improvement in LC (hazard ratio [HR] = 1.3, 95% confidence interval [CI] = 1.03-1.6, P = .03) as well as DFS (HR = 1.3, 95% CI = 1.03-1.6, P = .03). These findings were maintained on multivariate analysis.

CONCLUSIONS

Posttreatment decrease in SUV is associated with LC and DFS in esophageal cancer patients receiving definitive chemoradiotherapy. RT dose was also associated with both LC and DFS. The prognostic significance of these findings warrants prospective confirmation.

Synthetic lethal screen of an EGFR-centered network to improve targeted therapies

Intrinsic and acquired cellular resistance factors limit the efficacy of most targeted cancer therapeutics. Synthetic lethal screens in lower eukaryotes suggest that networks of genes closely linked to therapeutic targets would be enriched for determinants of drug resistance. We developed a protein network centered on the epidermal growth factor receptor (EGFR), which is a validated cancer therapeutic target, and used small interfering RNA screening to comparatively probe this network for proteins that regulate the effectiveness of both EGFR-targeted agents and nonspecific cytotoxic agents. We identified subnetworks of proteins influencing resistance, with putative resistance determinants enriched among proteins that interacted with proteins at the core of the network. We found that clinically relevant drugs targeting proteins connected in the EGFR network, such as protein kinase C or Aurora kinase A, or the transcriptional regulator signal transducer and activator of transcription 3 (STAT3), synergized with EGFR antagonists to reduce cell viability and tumor size, suggesting the potential for a direct path to clinical exploitation. Such a focused approach can potentially improve the coherent design of combination cancer therapies.

Targeting EGFR resistance networks in head and neck cancer

A core set of oncoproteins is overexpressed or functionally activated in many types of cancer, and members of this group have attracted significant interest as subjects for development of targeted therapeutics. For some oncoproteins such as EGFR/ErbB1, both small molecule and antibody agents have been developed and applied in the clinic for over a decade. Analysis of clinical outcomes has revealed an initially unexpected complexity in the response of patients to these agents. Diverse factors, including developmental lineage of the tumor progenitor cell, co-mutation or epigenetic modulation of genes encoding proteins in an extended EGFR signaling network or regulating core survival responses in individual tumors, and environmental factors including inflammatory agents and viral infection, all have been identified as modulating response to treatment with EGFR-targeted drugs. Second and third generation therapeutic strategies increasingly incorporate knowledge of cancer type-specific signaling environments, in a more personalized treatment approach. This review takes squamous cell carcinoma of the head and neck (SCCHN) as a specific example of an EGFR-involved cancer with idiosyncratic biological features that influence design of treatment modalities, with particular emphasis on commonalities and differences with other cancer types.

A case of cutaneous low-grade myofibroblastic sarcoma

A 28-year-old woman presented with a recurrent nodule on the lower margin of her left nostril after laser surgery. Histologically, the nodule had an indistinct margin and was composed of interlacing fascicles of plump, spindled or stellate tumor cells with mild cytologic atypia. The tumor cells were revealed to be myofibroblasts by positivity to smooth muscle actin and negativity to desmin. A diagnosis of low grade myofibroblastic sarcoma (LGMS) was made.

Benign recurring lipoblastoma in an adult versus well differentiated subcutaneous myxoid liposarcoma: clinicopathologic, immunohistochemical and molecular analysis of a unique case

Subcutaneous myxoid liposarcoma (ML) is exceedingly rare, with only two or three cases having been reported. Lipoblastoma (LB), a rare fatty tumor that arises in infants and children, is unknown after adolescence. In contrast to ML, LB is often superficial. The two tumors can be difficult to distinguish due to many histologic similarities. We examined a 0.9 cm superficial subcutaneous nodule from the dorsal neck of a 48 year old man that had been growing slowly. Three and one half years later, a 0.4 cm palpable recurrent nodule was excised from the scar. The patient is now free of disease at 7.5 years. Because of these unusual features, we performed clinicopathologic, immunohistochemical and molecular analysis of this unusual tumor to decide if this represented a rare cutaneous ML or an unprecedented example of LB in an adult. The primary featured a thick fibrous pseudocapsule with foci of lymphocytes and infiltrating nests of semi-mature fetal-appearing adipocytic tissue. This surrounded a more immature cellular-but-cytologically-bland myxoid tissue featuring stellate cells and signet lipoblasts. There were fibrous sep at the periphery and the vasculature was rather inconspicuous. The 0.4 cm diameter recurrence was distinctly lobular and had minute satellite nodules. It was composed of uniform fetal-appearing bland myxoid lipoblastic tissue featuring signet ring lipoblasts surrounded by a few spindle cells. In both tumors, lipoblasts expressed S-100 protein. In the primary, 5% of the lesional cells were FXIIIa+ dendritic stromal histiocytes while in the recurrence, 15% of the lesional cells were FXIIIa+ dendritic cells. CD34 stained only scattered small capillaries. The Ki67 proliferation index was 1% in the primary and 3% in the recurrence. RT-PCR assay for TLS/FUS-CHOP fusion transcripts was negative despite three repeat tests performed on paraffin sections of the primary tumor in the presence of good m-RNA internal controls. We reviewed the clinicopathologic and cytogenetic features of ML and LB. Based on this review and on the growth pattern, anatomic features and molecular data from the present case, we conclude that this tumor may represent the first reported case of adult LB.

A cutaneous case of giant cell angiofibroma occurring with dermatofibrosarcoma protuberans and showing bimodal CD34+ fibroblastic and FXIIIa+ histiocytic immunophenotype

Dei Tos and colleagues in 1995 reported a series of seven distinctive orbital tumors in adults which they named giant cell angiofibroma (GCA). The morphologic features are intermediate between giant cell fibroblastoma and solitary fibrous tumor with a richly vascularized, patternless spindle cell proliferation forming a collagenous or myxoid stroma with pseudovascular angiectoid spaces. The spindled tumor cells have large, rounded nuclei, sometimes with complex folded shape and pseudoinclusions. There also are multi- or mononuclear giant cells, and these tumor cells partly line so-called angiectoid spaces. Cells express human progenitor cell antigen CD34 and vimentin. One case in the buccinator fascia was also noted by the authors, but similar cutaneous lesions are thus far unknown. We report our experience with a polypoid tumor that ocurred on the thigh of a 49-year-old woman that conforms to the description of GCA. The tumor has variegated vessels admixed with patternless spindle and giant cell stroma with angiectoid spaces as well as areas of dermatofibrosarcoma protuberans (DFSP). Most tumor cells express vimentin and CD34, including giant and spindle cells lining angiectoid spaces. Focally up to 40% of the lesional cells express coagulation factor XIIIa with histiocytoid to highly dendritic cytosomes. The DFSP component is composed of admixed CD34+ and FXIIIa+ dendritic cells arranged in a storiform pattern. Tumor cells are negative for actin, desmin, S-100, and cytokeratin. The Ki67 proliferation index is 1% in GCA areas and 3% in DFSP areas; Ki 67 stains mainly fibroblasts. We conclude that this cutaneous GCA is a fibrohistiocytic tumor closely related to and representing a more organoid angioformative analog of GCF, with both being related histogenetically also to DFSP. These lesions represent part of a greater spectrum of fibrovascular tissue patterns, all probably derived from proliferations of interactive microvascular CD34+ fibroblasts and FXIIIa+ histiocytes.

Comparison of angiomyofibroblastoma and aggressive angiomyxoma in both sexes: four cases composed of bimodal CD34 and factor XIIIa positive dendritic cell subsets

Aggressive angiomyxoma (AA) is a distinctive, locally aggressive, fibromyxoid tumor of the pelvic and genital soft tissues. AA is of unknown histogenesis but the cytologically bland spindled tumor cells, which surround characteristic variegated blood vessels, show fibroblastic or myofibroblastic features. AA may be related to angiomyofibroblastoma (AMF), another cytologically bland fibromyxoid genital spindle cell tumor with variable myoid differentiation that does not, as a rule, recur. Recently, CD34+ primitive fibroblasts and factor XIIIa+ dendritic histiocytes have been found in varying combination in many fibrovascular, fibrohistiocytic, and myxoid soft tissue tumors. Both cells belong to the microvascular unit, a tissue responsible for stromal repair and remodeling and angiogenesis. To determine if these ubiquitous stromal cells participate in the histogenesis of AA and AMF, we examined two scrotal tumors, one AA with multiple recurrences and one AMF, for the presence of CD34+ and FXIIIa+ dendritic cell subsets. For comparison, a vaginal AMF and a pararectal AA in a woman were included. We also studied actins and desmin to detect myofibroblastic differentiation, and, through double labeling studies, assessed hormone receptors and the cell cycle marker Ki 67 in the different cell subsets. The AA showed unusual cytologic atypia and was initially diagnosed as liposarcoma. It massively recurred four times over 12 years, the first time after seven years. The histologic appearance was fairly constant over the years. The scrotal AMF was a circumscribed 6 cm mass in a 37 year old man. In both cases, most tumor cells were wavy and fibrillar, spindled, stellate, or polygonal fibroblast-like CD34+ dendritic cells. Depending on the area examined, a 20-50% subset of dendritic cells showed both nuclear and cytoplasmic staining for FXIIIa. Actin+ cells were rare but vessels had actin+ myopericytes, although a small focus of the initial male AA was desmin positive. The recurring AA expressed androgen receptors and had Ki 67 index of 10-20% in "hot spots" of the primary and up to 30% in recurrent tumors. The scrotal AMF widely expressed androgen and progesterone receptors with focal estrogen receptor positivity and the Ki 67 index was 10%. Both CD34+ fibroblasts and FXIIIa+ histiocytes were present in the Ki 67+ cycling fraction in both the male AA and AMF and both cell types expressed androgen receptors. The female pararectal AA had more focal CD34 reactivity, particularly in perivascular fibroblasts and these cells were admixed with small FXIIIa+ cells. The vaginal AMF was strongly desmin+ and variably to weakly CD34+ with 20% FXIIIa+ dendritic cells and Ki 67 index of 2%. The vaginal AMF strongly expressed estrogen, progesterone, and androgen receptors. In conclusion our data suggest that at least some AA and AMF are myxoid fibrohistiocytic tumors composed of CD34+ fibroblasts and FXIIIa+ dendritic histiocytes. In our tumors, neoplastic CD34+ dendritic fibroblasts showed predominantly myxo-collagenous differentiation with prominent myofibroblastic differentiation in only one desmin+ vaginal AMF. Our results support the notion that AMF and AA are part of a morphologic and histogenetic continuum of myxofibrous and myoid tumors that may arise due to interactions between microvascular CD34+ fibroblasts and FXIIIa+ histiocytes. CD34 and FXIIIa reactivity may be underappreciated in these tumors and is more important when considered histogenetically and biologically rather than in classifying individual neoplasms. Hormonal stimulation of proliferating pelvico-gential microvascular dendritic cells appears to play a role in the morphogenesis of both tumors.

Fibrohistiocytic differentiation in subcutaneous fatty tumors. Study of spindle cell, pleomorphic, myxoid, and atypical lipoma and dedifferentiated liposarcoma cases composed in part of CD34+ fibroblasts and FXIIIa+ histiocytes

Subsets of dendritic cells, fibroblasts which express the human progenitor cell antigen CD34 or histiocytes which express coagulation factor XIIIa (FXIIIa), are present in fat and in collagenous connective tissue. As components of the microvascular unit, these fibrohistiocytic cell subsets may interact during stromal remodeling, repair, and neoplasia. We studied white fat and subcutaneous fatty tumors to determine if CD34 and/or FXIIIa+ "fibrohistiocytic" dendritic cell subsets are involved in their morphogenesis. Three lipomas (L), 1 intramuscular lipoma (IL), 1 myxoid lipoma (ML), 2 pleomorphic lipomas (PL), 2 spindle cell lipomas (SCL), 8 angiolipomas (AN) in 4 patients, 1 atypical lipoma/well-differentiated liposarcoma (AL), 1 de novo dedifferentiated liposarcoma (DL), and 1 recurring atypical myxoid signet ring lipomatous tumor were examined for CD34, FXIIIa and in some cases for CD31, desmin, Ki 67, or S-100. Normal fat has scattered CD34+ dendritic cells and small FXIIIa+ dendritic histiocytes among variably S-100+ adipocytes. The CD34 and FXIIIa+ dendritic cells are more numerous near vessels and within fibrovascular septae. In L and IL, CD34 and FXIIIa+ dendritic cells are activated and some adipocytes express CD34. Mesenchymal areas of SCL, PL, ML, and AL and DL are composed of CD34+ dendritic cells with CD34+ but FXIIIa-negative floret cells in PL or atypical cells in AL and DL. FXIIIa+ dendritic cells are numerous in these lesions, comprising 30-40% of cells in SCL and PL, and 50% in ML, AL, and DL. AN have focal CD34+ interstitial cells and plump FXIIIa+ cells that in one case resembled multivacuolated lipoblasts. The myxoid signet ring lipomatous tumor was CD34 negative with few FXIIIa+ cells. We conclude that subsets of CD34+ and FXIIIa+ dendritic microvascular cells are present in normal fat and proliferate together in various types of lipomas and in at least some dedifferentiated liposarcomas.

Pleomorphic hyalinizing angiectatic tumor of soft parts: immunohistochemical case study shows cellular composition by CD34+ fibroblasts and factor XIIIa+ dendrophages

We report immunomorphologic observations on a pleomorphic hyalinizing angiectatic tumor of soft parts (PHAT), a rare tumor recently described by Smith, Fisher, and Weiss. A 2 cm skin-covered, grossly lobulated, firm, yellow-tan, focally hemorrhagic tumor was excised from the dorsum of a 59-year-old woman's right foot. It infiltrated dermis and subcutis and entrapped skin adnexae. The tumor microscopically resembled both a pleomorphic malignant fibrous histiocytoma and a neurilemoma with fascicular spindle cell pattern, pleomorphic tumor giant cells, and focal congeries of ectatic, fibrinous, and slightly hyalinized vessels. Tumour cells produced abundant reticulin but collagenous sclerosis was minimal. Mast cells were numerous. Pleomorphic cells, some phagocytic, had intranuclear vacuolar inclusions and many cells had large pale cytoplasmic globular inclusions. Most tumor cells expressed vimentin and CD34, including pleomorphic cells. Factor XIIIa stained focally 20-40% of the spindle cells. S-100 and cytokeratin were negative and actin and desmin stained only vessel myopericytes. The Ki 67 index was 3% with mostly large CD34+ cells and a few smaller FXIIIa+ cells in the cycling fraction. We conclude that PHAT is a fibrohistiocytic tumor probably derived from proliferating microvascular CD34+ dendritic cells and FXIIIa+ dendrophage cell subsets. Possible interactions between these cell types deserve further study in PHAT and other fibrohistiocytic tumors.