Gross tumor and intracranial control benefits with fractionated radiotherapy compared to stereotactic radiosurgery for patients with WHO grade 2 meningioma

OBJECTIVE

Surgical resection is the mainstay of treatment for WHO grade 2 meningioma. Fractionated radiation therapy (RT) is frequently employed following surgery, though many centers utilize stereotactic radiosurgery (SRS) for recurrence or progression. Herein, we report disease control outcomes from an institutional cohort with adjuvant fractionated RT versus salvage SRS.

METHODS

We identified 32 patients from an institutional database with WHO grade 2 meningioma and residual/recurrent tumor treated with either SRS or fractionated RT. Patients were treated between 2007 and 2021 and had at least 1 year of follow-up. Kaplan-Meier estimators were used to determine gross tumor control (GTC) and intracranial control (IC). Univariate Cox proportional hazards models using biologically effective dose (BED) as a continuous parameter were used to assess for dose responses.

RESULTS

With a median follow-up of 5.5 years, 13 patients (41%) received SRS to a recurrent or progressive nodule, 2 (6%) fractionated radiation to a recurrent or progressive nodule, and 17 (53%) adjuvant fractionated radiation following subtotal resection. 5-year GTC was higher with fractionated RT versus SRS (82% vs. 38%, p=0.03). 5-year IC was also better with fractionated RT versus SRS (82% vs. 11%, p<0.001). On univariate analysis, increasing BED10 was significantly associated with better GTC (p=0.039); increasing BED3 was not (p=0.82).

CONCLUSIONS

In this patient cohort, GTC and IC were significantly higher in patients treated with adjuvant fractionated RT compared to salvage SRS. Increasing BED10 was associated with better GTC. Fractionated RT may provide a better therapeutic ratio than SRS for grade 2 meningiomas.

Patterns of failure after radiosurgery for WHO grade 1 or imaging defined meningiomas: Long-term outcomes and implications for management

BACKGROUND

We analyzed long-term control and patterns of failure in patients with World Health Organization Grade 1 meningiomas treated with definitive or postoperative stereotactic radiosurgery at the authors' affiliated institution.

METHODS

96 patients were treated between 2004 and 2019 with definitive (n = 57) or postoperative (n = 39) stereotactic radiosurgery. Of the postoperative patients, 17 were treated adjuvantly following subtotal resection and 22 were treated as salvage at time of progression. Patients were treated to the gross tumor alone without margin or coverage of the dural tail to a median dose of 15 Gy. Median follow up was 7.4 years (inter-quartile range 4.8-11.3). Local control, marginal control, regional control, and progression-free survival were analyzed.

RESULTS

Local control at 5 and 10 years was 97 % and 95 %. PFS at 5 and 10 years was 94 % and 90 % with no failures reported after 6 years. Definitive and postoperative local control were similar at 5 (95 % [82-99 %] vs. 100 %) and 10 years (92 % [82-99 %] vs. 100 %). Patients treated with postoperative SRS did not have an increased marginal failure rate (p = 0.83) and only 2/39 (5 %) experienced recurrence elsewhere in the cavity.

CONCLUSIONS

Stereotactic radiosurgery targeting the gross tumor alone provides excellent local control and progression free survival in patients treated definitively and postoperatively. As in the definitive setting, patients treated postoperatively can be treated to gross tumor alone without need for additional margin or dural tail coverage.

The importance of considering competing risks in recurrence analysis of intracranial meningioma

BACKGROUND

The risk of recurrence is overestimated by the Kaplan-Meier method when competing events, such as death without recurrence, are present. Such overestimation can be avoided by using the Aalen-Johansen method, which is a direct extension of Kaplan-Meier that accounts for competing events. Meningiomas commonly occur in older individuals and have slow-growing properties, thereby warranting competing risk analysis. The extent to which competing events are considered in meningioma literature is unknown, and the consequences of using incorrect methodologies in meningioma recurrence risk analysis have not been investigated.

METHODS

We surveyed articles indexed on PubMed since 2020 to assess the usage of competing risk analysis in recent meningioma literature. To compare recurrence risk estimates obtained through Kaplan-Meier and Aalen-Johansen methods, we applied our international database comprising ~ 8,000 patients with a primary meningioma collected from 42 institutions.

RESULTS

Of 513 articles, 169 were eligible for full-text screening. There were 6,537 eligible cases from our PERNS database. The discrepancy between the results obtained by Kaplan-Meier and Aalen-Johansen was negligible among low-grade lesions and younger individuals. The discrepancy increased substantially in the patient groups associated with higher rates of competing events (older patients with high-grade lesions).

CONCLUSION

The importance of considering competing events in recurrence risk analysis is poorly recognized as only 6% of the studies we surveyed employed Aalen-Johansen analyses. Consequently, most of the previous literature has overestimated the risk of recurrence. The overestimation was negligible for studies involving low-grade lesions in younger individuals; however, overestimation might have been substantial for studies on high-grade lesions.

Mutations of Rad6 E2 ubiquitin-conjugating enzymes at alanine-126 affect ubiquitination activity and decrease enzyme stability

Rad6, an E2 ubiquitin-conjugating enzyme conserved from yeast to humans, functions in transcription, genome maintenance, and proteostasis. The contributions of many conserved secondary structures of Rad6 and its human homologs UBE2A and UBE2B to their biological functions are not understood. A mutant RAD6 allele with a missense substitution at alanine-126 (A126) of helix-3 that causes defects in telomeric gene silencing, DNA repair, and protein degradation was reported over 2 decades ago. Here, using a combination of genetics, biochemical, biophysical, and computational approaches, we discovered that helix-3 A126 mutations compromise the ability of Rad6 to ubiquitinate target proteins without disrupting interactions with partner E3 ubiquitin-ligases that are required for their various biological functions in vivo. Explaining the defective in vitro or in vivo ubiquitination activities, molecular dynamics simulations and NMR showed that helix-3 A126 mutations cause local disorder of the catalytic pocket of Rad6 in addition to disorganizing the global structure of the protein to decrease its stability in vivo. We also show that helix-3 A126 mutations deform the structures of UBE2A and UBE2B, the human Rad6 homologs, and compromise the in vitro ubiquitination activity and folding of UBE2B. Providing insights into their ubiquitination defects, we determined helix-3 A126 mutations impair the initial ubiquitin charging and the final discharging steps during substrate ubiquitination by Rad6. In summary, our studies reveal that the conserved helix-3 is a crucial structural constituent that controls the organization of catalytic pockets, enzymatic activities, and biological functions of the Rad6-family E2 ubiquitin-conjugating enzymes.

Outcomes using linear accelerator stereotactic radiosurgery for the treatment of trigeminal neuralgia: A single-center, retrospective study

Background:

Linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) treatment of trigeminal neuralgia (TN) may have similar efficacy to Gamma Knife SRS (GK-SRS), but the preponderance of data comes from patients treated with GK-SRS. Our objective was to analyze the outcomes for LINAC-based treatment of TN in patients at our institution.

Methods:

We retrospectively analyzed data for patients who underwent LINAC-based SRS for TN from 2006 to 2018. Data were collected from the patients’ medical records. Nonparametric statistics were used for the analysis.

Results:

Of the 41 patients treated with LINAC-based SRS (typically 90 Gy dosed using a 4 mm collimator for one fraction) during that time, follow-up data of >3 weeks post-SRS were available for 32 patients. The median pretreatment Barrow Neurological Institute (BNI) pain score was 5 (range 4–5). The follow-up period ranged from 0.9 to 113.2 months (median 5 months). There was significant improvement in postradiation BNI pain score (P < 0.001), with 23 (72%) patients who improved to a BNI pain score of 1–3. One patient had bothersome hypoesthesia postradiation. Approximately 38% of patients who had initial pain control had recurrence of symptoms (BNI > 3). Survival analysis showed a median time to pain recurrence of 30 months. There was no relationship between prior microvascular decompression (MVD) surgery and change in BNI pain score pre- to posttreatment.

Conclusion:

The results demonstrate that LINAC-based SRS is an effective means to treat TN. Prior MVD surgery did not affect efficacy of SRS in lowering the BNI score from pre- to posttreatment in this patient cohort.

Low-risk meningioma: Initial outcomes from NRG Oncology/RTOG 0539

BACKGROUND

Three- and five-year progression-free survival (PFS) for low-risk meningioma managed with surgery and observation reportedly exceeds 90%. Herewith we summarize outcomes for low-risk meningioma patients enrolled on NRG/RTOG 0539.

METHODS

This phase II trial allocated patients to one of three groups per World Health Organization grade, recurrence status, and resection extent. Low-risk patients had either gross total (GTR) or subtotal resection (STR) for a newly diagnosed grade 1 meningioma and were observed after surgery. The primary endpoint was 3-year PFS. Adverse events (AEs) were scored using Common Terminology Criteria for Adverse Events (CTCAE) version 3.

RESULTS

Among 60 evaluable patients, the median follow-up was 9.1 years. The 3-, 5-, and 10-year rates were 91.4% (95% CI, 84.2 to 98.6), 89.4% (95% CI, 81.3 to 97.5), 85.0% (95% CI, 75.3 to 94.7) for PFS and 98.3% (95% CI, 94.9 to 100), 98.3%, (95% CI, 94.9 to 100), 93.8% (95% CI, 87.0 to 100) for overall survival (OS), respectively. With centrally confirmed GTR, 3/5/10y PFS and OS rates were 94.3/94.3/87.6% and 97.1/97.1/90.4%. With STR, 3/5/10y PFS rates were 83.1/72.7/72.7% and 10y OS 100%. Five patients reported one grade 3, four grade 2, and five grade 1 AEs. There were no grade 4 or 5 AEs.

CONCLUSIONS

These results prospectively validate high PFS and OS for low-risk meningioma managed surgically but raise questions regarding optimal management following STR, a subcohort that could potentially benefit from adjuvant therapy.

Central Nervous System Cancers, Version 3.2020, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Central Nervous System (CNS) Cancers focus on management of adult CNS cancers ranging from noninvasive and surgically curable pilocytic astrocytomas to metastatic brain disease. The involvement of an interdisciplinary team, including neurosurgeons, radiation therapists, oncologists, neurologists, and neuroradiologists, is a key factor in the appropriate management of CNS cancers. Integrated histopathologic and molecular characterization of brain tumors such as gliomas should be standard practice. This article describes NCCN Guidelines recommendations for WHO grade I, II, III, and IV gliomas. Treatment of brain metastases, the most common intracranial tumors in adults, is also described.

Repeat radiation with bevacizumab and minocycline in bevacizumab-refractory high grade gliomas: a prospective phase 1 trial

Introduction

There are no effective treatments for gliomas after progression on radiation, temozolomide, and bevacizumab. Microglia activation may be involved in radiation resistance and can be inhibited by the brain penetrating antibiotic minocycline. In this phase 1 trial, we examined the safety and effect on survival, symptom burden, and neurocognitive function of reirradiation, minocycline, and bevacizumab.

Methods

The trial used a 3 + 3 design for dose escalation followed by a ten person dose expansion. Patients received reirradiation with dosing based on radiation oncologist judgment, bevacizumab 10 mg/kg IV every two weeks, and oral minocycline twice a day. Symptom burden was measured using MDASI-BT. Neurocognitive function was measured using the COGSTATE battery.

Results

The maximum tolerated dose of minocycline was 400 mg twice a day with no unexpected toxicities. The PFS3 was 64.6%, and median overall survival was 6.4 months. Symptom burden and neurocognitive function did not decline in the interval between treatment completion and tumor progression.

Conclusions

Minocycline 400 mg orally twice a day with bevacizumab and reirradiation is well tolerated by physician and patient reported outcomes in people with gliomas that progress on bevacizumab.

Short delay in initiation of radiotherapy for patients with glioblastoma-effect of concurrent chemotherapy: a secondary analysis from the NRG Oncology/Radiation Therapy Oncology Group database

Background

We previously reported the unexpected finding of significantly improved survival for newly diagnosed glioblastoma in patients when radiation therapy (RT) was initiated later (>4 wk post-op) compared with earlier (≤2 wk post-op). In that analysis, data were analyzed from 2855 patients from 16 NRG Oncology/Radiotherapy Oncology Group (RTOG) trials conducted prior to the era of concurrent temozolomide (TMZ) with RT. We now report on 1395 newly diagnosed glioblastomas from 2 studies, treated with RT and concurrent TMZ followed by adjuvant TMZ. Our hypothesis was that concurrent TMZ has a synergistic/radiosensitizing mechanism, making RT timing less significant.

Methods

Data from patients treated with TMZ-based chemoradiation from NRG Oncology/RTOG 0525 and 0825 were analyzed. An analysis comparable to our prior study was performed to determine whether there was still an impact on survival by delaying RT. Overall survival (OS) was investigated using the Kaplan-Meier method and Cox proportional hazards model. Early progression (during time of diagnosis to 30 days after RT completion) was analyzed using the chi-square test.

Results

Given the small number of patients who started RT early following surgery, comparisons were made between >4 and ≤4 weeks delay of radiation from time of operation. There was no statistically significant difference in OS (hazard ratio = 0.93; P = 0.29; 95% CI: 0.80-1.07) after adjusting for known prognostic factors (recursive partitioning analysis and O6-methylguanine-DNA methyltransferase methylation status). Similarly, the rate of early progression did not differ significantly (P = 0.63).

Conclusions

We did not observe a significant prognostic influence of delaying radiation when given concurrently with TMZ for newly diagnosed glioblastoma. The effects of early (1-3 wk post-op) or late (>5 wk) initiation of radiation tested in our prior study could not be replicated.

Esthesioneuroblastoma: A Patterns-of-Care and Outcomes Analysis of the National Cancer Database

BACKGROUND

The available literature to guide treatment decision making in esthesioneuroblastoma (ENB) is limited.

OBJECTIVE

To define treatment patterns and outcomes in ENB according to treatment modality using a large national cancer registry.

METHODS

This study is a retrospective cohort analysis of 931 patients with a diagnosis of ENB who were treated with surgery, radiation therapy, and/or chemotherapy in the United States between the years of 2004 and 2012. Log-rank statistics were used to compare overall survival by primary treatment modality. Logistic regression modeling was used to identify predictors of receipt of postoperative radiotherapy (PORT). Cox proportional hazards modeling was used to determine the survival benefit of PORT. Subgroup analyses identified subgroups that derived the greatest benefit of PORT.

RESULTS

Primary surgery was the most common treatment modality (90%) and resulted in superior survival compared to radiation (P < .01) or chemotherapy (P < .01). On multivariate analysis, PORT was associated with decreased risk of death (hazard ratio [HR] 0.53, P < .01). PORT showed a survival benefit in Kadish stage C (HR 0.42, P < .01) and D (HR 0.09, P = .01), but not Kadish A (HR 1.17, P = .74) and B (HR 1.37, P = .80). Patients who received chemotherapy derived greater benefit from PORT (HR 0.22, P < .01) compared with those who did not (HR 0.68, P = .13). Predictors of PORT included stage, grade, extent of resection, and chemotherapy use.

CONCLUSION

Best outcomes were obtained in patients undergoing primary surgery. The benefit of PORT was driven by patients with stages C and D disease, and by those also receiving chemotherapy.

Snapshot of a Specialty: Results of the ABR 2016 Radiation Oncology Clinical Practice Analysis

PURPOSE

Beginning in 2010, the ABR has administered triennial clinical practice analysis surveys to inform examination development volunteers and staff about the actual state of radiation oncology practice.

METHODS AND MATERIALS

As reported here, the 2016 survey was designed to provide objective data regarding actual patient volumes of specific disease sites and subjective insight as to the importance and relevance of site-specific therapy to individual practices.

RESULTS

The survey instrument was circulated to 4,075 radiation oncologists listed in the membership database of the American Society for Radiation Oncology, and responses were received from 690 (16.9%); a total of 287 (41.5%) self-identified as being in academic practice. Even in the academic setting, a majority (216 of 287, or 75.3%) indicated that they spend most of their time in clinical practice.

CONCLUSIONS

Data from the survey are informative regarding changes in the practice of radiation oncology over the past 6 years.

Demographics, stage distribution, and relative roles of surgery and radiotherapy on survival of persons with primary prostate sarcomas

Background

Primary prostate sarcomas (PPS) are rare. Outcomes for this cancer have not been well characterized.

Materials and Methods

Subjects with a PPS diagnosed between 1973 and 2014 were identified in the SEER database. Subjects were stratified by disease stage and types of therapies received. Disease‐specific survival (DSS) and Overall survival (OS) was estimated by Kaplan‐Meier analysis and cohorts were compared with a univariate and multivariable Cox regression.

Results

The incidence of PPS among all prostate cancer diagnoses was 0.02%. Subjects younger than age 26 years at diagnosis represented 29% of cases, and 32% of primary prostate sarcomas were rhabdomyosarcoma histology.

Rhabdomyosarcoma Histologies

The median age at diagnosis was 9 years. Between age 0‐25 years rhabdomyosarcoma accounted for 96.4% of primary prostate sarcoma diagnoses, after age 25 rhabdomyosarcoma represented 15% of new diagnoses. The 10‐year DSS and OS for rhabdomyosarcoma was 47% and 44%.

Non‐Rhabdomyosarcoma Histologies

The median age at diagnosis was 71 years. The most common diagnoses were leiomyosarcoma (33%) and carcinosarcoma (28%). Localized, regional, or distant disease occurred in 40%, 34%, and 26% of cases. The 10‐year DSS and OS were 26% and 14%. In locally advanced cases, RT added to surgery trended toward improved DSS (P = 0.10).

Conclusions

Disease‐specific survival and OS for non‐rhabdomyosarcoma histologies appear inferior to those of rhabdomyosarcoma. The addition of RT to surgical resection may improve DSS in locally advanced non‐rhabdomyosarcoma. This is the largest report of the incidence, stage distribution, and survival for this extremely rare urologic malignancy providing valuable prognostic information.

NCCN Guidelines Insights: Central Nervous System Cancers, Version 1.2017

For many years, the diagnosis and classification of gliomas have been based on histology. Although studies including large populations of patients demonstrated the prognostic value of histologic phenotype, variability in outcomes within histologic groups limited the utility of this system. Nonetheless, histology was the only proven and widely accessible tool available at the time, thus it was used for clinical trial entry criteria, and therefore determined the recommended treatment options. Research to identify molecular changes that underlie glioma progression has led to the discovery of molecular features that have greater diagnostic and prognostic value than histology. Analyses of these molecular markers across populations from randomized clinical trials have shown that some of these markers are also predictive of response to specific types of treatment, which has prompted significant changes to the recommended treatment options for grade III (anaplastic) gliomas.

Anaplastic meningioma: an analysis of the National Cancer Database from 2004 to 2012

OBJECTIVE

Anaplastic meningiomas represent 1%–2% of meningioma diagnoses and portend a poor prognosis. Limited information is available on practice patterns and optimal management. The purpose of this study was to define treatment patterns and outcomes by treatment modality using a large national cancer registry.

METHODS

The National Cancer Database was used to identify patients diagnosed with anaplastic meningioma from 2004 to 2012. Log-rank statistics were used to compare survival outcomes by extent of resection, use of adjuvant radiotherapy (RT), and use of adjuvant chemotherapy. Least-squares linear regression was used to evaluate the utilization of RT over time. Logistic regression modeling was used to identify predictors of receipt of RT. Cox proportional hazards modeling was used to evaluate the effect of RT, gross-total resection (GTR), and chemotherapy on survival.

RESULTS

A total of 755 adults with anaplastic meningioma were identified. The 5-year overall survival rate was 41.4%. Fifty-two percent of patients received RT, 7% received chemotherapy, and 58% underwent GTR. Older patients were less likely to receive RT (OR 0.98, p < 0.01). Older age (HR 1.04, p < 0.01), high comorbidity score (HR 1.33, p = 0.02), and subtotal resection (HR 1.57, p = 0.02) were associated with increased risk of death on multivariate modeling, while RT receipt was associated with decreased risk of death (HR 0.79, p = 0.04). Chemotherapy did not have a demonstrable effect on survival (HR 1.33, p = 0.18).

CONCLUSIONS

Anaplastic meningioma portends a poor prognosis. Gross-total resection and RT are associated with improved survival, but utilization of RT is low. Unless medically contraindicated, patients with anaplastic meningioma should be offered RT.

Factors influencing prostate cancer patterns of care: An analysis of treatment variation using the SEER database

PURPOSE

The aim of this study is to describe the trends and factors that influence the initial treatment of men with localized prostate cancer (PC) in the United States between 2004 and 2014.

METHODS AND MATERIALS

The National Cancer Institute's Surveillance, Epidemiology and End Results database was used to identify patients with primary prostate adenocarcinoma between 2004 and 2014. Patients were staged in accordance with the American Joint Committee on Cancer 7th edition criteria and stratified according to the National Comprehensive Cancer Network guidelines risk group classification. Descriptive statistics describing treatment patterns by year of diagnosis, age, risk group, insurance status, and region were performed.

RESULTS

A total of 460,311 male patients were identified with sufficient information to be categorized into National Comprehensive Cancer Network risk groups. Overall, 30.9% of patients had low-risk disease, 38.1% were intermediate risk, 20.2% were high risk, 4.4% were very high risk, 1.6% were node-positive, and 4.7% had metastatic disease. During the study period, there was a 60% decrease in brachytherapy monotherapy utilization for patients with PC, and no definitive treatment increased from 20.3% in 2004 to 26.3% in 2014. There were regional treatment variations and discrepancies in treatment by age. Radical prostatectomy was performed on a greater proportion of insured patients than patients with Medicaid or those who were uninsured, but radiation therapy and no definitive treatment was administered to a greater proportion of uninsured and Medicaid patients.

CONCLUSIONS

PC treatment shows declining trends in brachytherapy utilization, increases in conservative management, and stability of surgical procedures over time. There is wide variation by geographical region, age, and insurance status.

The radiosurgery fractionation quandary: single fraction or hypofractionation?

Stereotactic radiosurgery (SRS), typically administered in a single session, is widely employed to safely, efficiently, and effectively treat small intracranial lesions. However, for large lesions or those in close proximity to critical structures, it can be difficult to obtain an acceptable balance of tumor control while avoiding damage to normal tissue when single-fraction SRS is utilized. Treating a lesion in 2 to 5 fractions of SRS (termed "hypofractionated SRS" [HF-SRS]) potentially provides the ability to treat a lesion with a total dose of radiation that provides both adequate tumor control and acceptable toxicity. Indeed, studies of HF-SRS in large brain metastases, vestibular schwannomas, meningiomas, and gliomas suggest that a superior balance of tumor control and toxicity is observed compared with single-fraction SRS. Nonetheless, a great deal of effort remains to understand radiobiologic mechanisms for HF-SRS driving the dose-volume response relationship for tumors and normal tissues and to utilize this fundamental knowledge and the results of clinic studies to optimize HF-SRS. In particular, the application of HF-SRS in the setting of immunomodulatory cancer therapies offers special challenges and opportunities.

Patterns of care and outcomes in gliosarcoma: an analysis of the National Cancer Database

OBJECTIVE The authors compared presenting characteristics and survival for patients with gliosarcoma (GS) and glioblastoma (GBM). Additionally, they performed a survival analysis for patients who underwent GS treatments with the hypothesis that trimodality therapy (surgery followed by radiation and chemotherapy) would be superior to nontrimodality therapy (surgery alone or surgery followed by chemotherapy or radiation). METHODS Adults diagnosed with GS and GBM between the years 2004 and 2013 were queried from the National Cancer Database. Chi-square analysis was used to compare presenting characteristics. Kaplan-Meier, Cox regression, and propensity score analyses were employed for survival analyses. RESULTS In total, data from 1102 patients with GS and 36,658 patients with GBM were analyzed. Gliosarcoma had an increased rate of gross-total resection (GTR) compared with GBM (19% vs 15%, p < 0.001). Survival was not different for patients with GBM (p = 0.068) compared with those with GS. After propensity score analysis for GS, patients receiving trimodality therapy (surgery followed by radiation and chemotherapy) had improved survival (12.9 months) compared with those not receiving trimodality therapy (5.5 months). In multivariate analysis, GTR, female sex, fewer comorbidities, trimodality therapy, and age < 65 years were associated with improved survival. There was a trend toward improved survival with MGMT promoter methylation (p = 0.117). CONCLUSIONS In this large registry study, there was no difference in survival in patients with GBM compared with GS. Among GS patients, trimodality therapy significantly improved survival compared with nontrimodality therapy. Gross-total resection also improved survival, and there was a trend toward increased survival with MGMT promoter methylation in GS. The major potential confounder in this study is that patients with poor functional status may not have received aggressive radiation or chemotherapy treatments, leading to the observed outcome. This study should be considered hypothesis-generating; however, due to its rarity, conducting a clinical trial with GS patients alone may prove difficult.

HDAC1,2 inhibition and doxorubicin impair Mre11-dependent DNA repair and DISC to override BCR-ABL1-driven DSB repair in Philadelphia chromosome-positive B-cell precursor acute lymphoblastic leukemia

Philadelphia chromosome-positive (Ph+) B-cell precursor acute lymphoblastic leukemia (ALL) expressing BCR-ABL1 oncoprotein is a major subclass of ALL with poor prognosis. BCR-ABL1-expressing leukemic cells are highly dependent on double-strand break (DSB) repair signals for their survival. Here we report that a first-in-class HDAC1,2 selective inhibitor and doxorubicin (a hyper-CVAD chemotherapy regimen component) impair DSB repair networks in Ph+ B-cell precursor ALL cells using common as well as distinct mechanisms. The HDAC1,2 inhibitor but not doxorubicin alters nucleosomal occupancy to impact chromatin structure, as revealed by MNase-Seq. Quantitative mass spectrometry of the chromatin proteome along with functional assays showed that the HDAC1,2 inhibitor and doxorubicin either alone or in combination impair the central hub of DNA repair, the Mre11–Rad51–DNA ligase 1 axis, involved in BCR-ABL1-specific DSB repair signaling in Ph+ B-cell precursor ALL cells. HDAC1,2 inhibitor and doxorubicin interfere with DISC (DNA damage-induced transcriptional silencing in cis)) or transcriptional silencing program in cis around DSB sites via chromatin remodeler-dependent and -independent mechanisms, respectively, to further impair DSB repair. HDAC1,2 inhibitor either alone or when combined with doxorubicin decreases leukemia burden in vivo in refractory Ph+ B-cell precursor ALL patient-derived xenograft mouse models. Overall, our novel mechanistic and preclinical studies together demonstrate that HDAC1,2 selective inhibition can overcome DSB repair ‘addiction’ and provide an effective therapeutic option for Ph+ B-cell precursor ALL.

Adjuvant radiotherapy for atypical meningiomas

OBJECTIVE

The aim of this paper was to evaluate outcomes in patients with atypical meningiomas (AMs) treated with surgery alone compared with surgery and radiotherapy at initial diagnosis, or at the time of first recurrence.

METHODS

Patients with pathologically confirmed AMs treated at the University of Utah from 1991 to 2014 were retrospectively reviewed. Local control (LC), overall survival (OS), Karnofsky Performance Status (KPS), and toxicity were assessed. Outcomes for patients receiving adjuvant radiotherapy were compared with those for patients treated with surgery alone. Kaplan-Meier and the log-rank test for significance were used for LC and OS analyses.

RESULTS

Fifty-nine patients with 63 tumors were reviewed. Fifty-two patients were alive at the time of analysis with a median follow-up of 42 months. LC for all tumors was 57% with a median time to local failure (TTLF) of 48 months. The median TTLF following surgery and radiotherapy was 180 months, compared with 46 months following surgery alone (p = 0.02). Excluding Simpson Grade IV (subtotal) resections, there remained an LC benefit with the addition of radiotherapy for Simpson Grade I, II, and III resected tumors (median TTLF 180 months after surgery and radiotherapy compared with 46 months with surgery alone [p = 0.002]). Patients treated at first recurrence following any initial therapy (either surgery alone or surgery and adjuvant radiotherapy) had a median TTLF of 26 months compared with 48 months for tumors treated at first diagnosis (p = 0.007). There were 2 Grade 3 toxicities and 1 Grade 4 toxicity associated with radiotherapy.

CONCLUSIONS

Adjuvant radiotherapy improves LC for AMs. The addition of adjuvant radiotherapy following even a Simpson Grade I, II, or III resection was found to confer an LC benefit. Recurrent disease is difficult to control, underscoring the importance of aggressive initial treatment.

Central Nervous System Cancers, Version 1.2015

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Central Nervous System (CNS) Cancers provide interdisciplinary recommendations for managing adult CNS cancers. Primary and metastatic brain tumors are a heterogeneous group of neoplasms with varied outcomes and management strategies. These NCCN Guidelines Insights summarize the NCCN CNS Cancers Panel's discussion and highlight notable changes in the 2015 update. This article outlines the data and provides insight into panel decisions regarding adjuvant radiation and chemotherapy treatment options for high-risk newly diagnosed low-grade gliomas and glioblastomas. Additionally, it describes the panel's assessment of new data and the ongoing debate regarding the use of alternating electric field therapy for high-grade gliomas.

Planned Neck Dissection after Definitive Radiotherapy or Chemoradiation for Base of Tongue Cancers

OBJECTIVES: The study goal was to analyze the role of planned neck dissection for squamous cell carcinoma of the base of the tongue treated with definitive radiotherapy or chemoradiation.

STUDY DESIGN, SETTING: We conducted a retrospective study of patients with squamous cell carcinoma of the base of the tongue undergoing planned neck dissection after definitive radiotherapy or chemoradiation.

RESULTS: Twenty-two of 41 (53.7%) patients had one to six positive residual lymph nodes after receiving definitive radiotherapy or chemoradiation. Neck control rates were 92.3% and 88.3% at two and five years, respectively. Three of 22 (13.6%) patients with pathological residual nodal disease had regional or locore-gional failures, compared with 1 of 19 (5.3%) patients with a pathologically complete response ( P = 0.39).

CONCLUSIONS: We observed a high incidence of pathologically residual lymph nodes after definitive radiotherapy or chemoradiation.

SIGNIFICANCE: Planned neck dissection following definitive radiotherapy or chemoradiation is highly effective in achieving regional control of squamous cell carcinoma of the base of the tongue.

Time Course and Accumulated Risk of Severe Urinary Adverse Events After High- Versus Low-Dose-Rate Prostate Brachytherapy With or Without External Beam Radiation Therapy

PURPOSE

Severe urinary adverse events (UAEs) include surgical treatment of urethral stricture, urinary incontinence, and radiation cystitis. We compared the incidence of grade 3 UAEs, according to the Common Terminology Criteria for Adverse Events, after low-dose-rate (LDR) and high-dose-rate (HDR) brachytherapy, as well as after LDR plus external beam radiation therapy (EBRT) and HDR plus EBRT.

METHODS AND MATERIALS

Men aged >65 years with nonmetastatic prostate cancer were identified from the Surveillance, Epidemiology, and End Results-Medicare database who were treated with LDR (n=12,801), HDR (n=685), LDR plus EBRT (n=8518), or HDR plus EBRT (n=2392). The populations were balanced by propensity weighting, and the Kaplan-Meier incidence of severe UAEs was compared. Propensity-weighted Cox proportional hazards models were used to compare the adjusted hazard of UAEs. These UAEs were compared with those in a cohort of men not treated for prostate cancer.

RESULTS

Median follow-up was 4.3 years. At 8 years, the propensity-weighted cumulative UAE incidence was highest after HDR plus EBRT (26.6% [95% confidence interval, 23.8%-29.7%]) and lowest after LDR (15.7% [95% confidence interval, 14.8%-16.6%]). The absolute excess risk over nontreated controls at 8 years was 1.9%, 3.8%, 8.4%, and 12.9% for LDR, HDR, LDR plus EBRT, and HDR plus EBRT, respectively. These represent numbers needed to harm of 53, 26, 12, and 8 persons, respectively. The additional risk of development of a UAE related to treatment for LDR, LDR plus EBRT, and HDR plus EBRT was greatest within the 2 years after treatment and then continued to decline over time. Beyond 4 years, the risk of development of a new severe UAE matched the baseline risk of the control population for all treatments.

CONCLUSIONS

Toxicity differences were observed between LDR and HDR, but the differences did not meet statistical significance. However, combination radiation therapy (either HDR plus EBRT or LDR plus EBRT) increases the risk of severe UAEs compared with HDR alone or LDR alone. The highest increased risk of urinary toxicity occurs within the 2 years after therapy and then declines to an approximately 1% increase in incidence per year.

Long-term comparative toxicity of LDR versus HDR prostate brachytherapy ± EBRT and evaluation of risk hazard over time: A SEER-Medicare analysis

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Background: Severe urinary adverse events (UAEs) include surgical treatment of urethral stricture, urinary incontinence and radiation cystitis. Our objective is to compare the incidence of late UAEs after low dose rate BT (LDR) and high dose rate BT (HDR) as well as LDR+EBRT and HDR+EBRT. Methods: We identified men treated with LDR (n=12,801), HDR (n=685), LDR+EBRT (8,518) and HDR+EBRT (n=2,392) from the SEER-Medicare Database. The populations were balanced by propensity weighting and the Kaplan-Meier incidence of severe UAEs was compared. Propensity-weighted Cox proportional hazards models were used to compare the adjusted hazard of UAEs. These UAEs were compared to a cohort of men not treated for prostate cancer. Results: Median follow-up was 4.3 years. At 8 years, the propensity weighted cumulative UAE incidence was highest after HDR+EBRT (28%) and lowest after LDR (17%; see Figure). The absolute excess risk over non-treated controls of a UAE at 8 years was 1.9%, 3.8%, 8.4% and 12.9% for the LDR, HDR, LDR + EBRT, and HDR + EBRT respectively. This translates into a number needed to harm of 53, 26, 12, and 8 persons. There is no statistical difference in severe UAE risk between HDR vs. LDR or between HDR+EBRT vs. LDR+EBRT. The additional risk for developing a UAE related to treatment for LDR, LDR+EBRT, and HDR+EBRT, was greatest within the 2 years following treatment, and continued to decline over time. For HDR monotherapy, the risk was greatest within the first 4 years, and then declined. The risk of developing a severe UAE matched the baseline risk of the control population for all treatments at 4 years following therapy. Conclusions: LDR and HDR brachytherapy are statistically indistinguishable for late severe urinary adverse events. However, combination radiotherapy (either HDR+EBRT or LDR+EBRT) increases the risk of severe UAEs compared to HDR alone or LDR alone. In the 8 years following brachytherapy treatment, the increased risk of urinary toxicity occurs almost exclusively within the 2 years following therapy, and then declines to a baseline hazard. The hypothesis that late urinary radiation toxicity accelerates over time is not supported by this study.

Local control of melanoma brain metastases treated with stereotactic radiosurgery

PURPOSE

To examine the effectiveness of stereotactic radiosurgery (SRS) for melanoma brain metastases, as the optimal management is unknown.

MATERIALS AND METHODS

Patients with melanoma brain metastases treated between 1999 and 2013 with SRS as initial management were reviewed. Local control (LC), intracranial progression free survival, and overall survival were evaluated using the Kaplan Meier analysis and logistic regression.

RESULTS

185 patients were identified with 435 treated brain metastases. 76% of metastases were controlled, with a median freedom from local failure of 23.4 months. Higher SRS dose (p=0.001) and smaller tumor volume (p=0.0007) were associated with improved LC on univariate analysis, but on multivariate analysis only smaller tumor volume remained significant (p=0.047). At analysis, 7.6% of patients were alive and the median time to death after SRS was 7.8 months.

CONCLUSIONS

SRS is an effective primary treatment for melanoma brain metastases. There was no benefit combining SRS and surgery or whole brain radiotherapy.

Long-term life expectancy for children with ependymoma and medulloblastoma

OBJECTIVES

There is a paucity of long-term follow-up data for children with intracranial ependymoma (IE) and medulloblastoma (MB). What happens to these children 20, 30, or 40 years after diagnosis? Do they have potential for a normal lifespan? The purpose of this study was to ascertain the long-term survival potential in children with MB or IE who have survived 5 years from diagnosis.

METHODS

A retrospective analysis was conducted using the SEER Program. Children (ages 0-19 years) from 1973 to 2011 with a diagnosis of MB or IE were identified. A cohort was created of potentially cured patients who survived 5 years from diagnosis. Cox proportional hazards models and Kaplan-Meier estimates were utilized to analyze long-term survival.

RESULTS

We identified 876 patients with MB and 474 patients with IE who were alive 5 years from diagnosis. Patients with MB had a 30-year overall survival (OS) and cancer-specific survival (CSS) of 70.2% and 80.1%, respectively. Patients with IE had a 30-year OS and CSS of 57.3% and 68.8%, respectively. When comparing MB with IE, MB had improved CSS (P = 0.04) and trended toward increased OS (P = 0.10).

CONCLUSIONS

A significant number of deaths due to disease occur for several decades after treatment for both IE and MB. Despite this, the potential for long-term survival exists in 5-year survivors of both histologies. If alive at 5 years from diagnosis, patients with MB tend to have a lower risk of death from disease compared to those with IE.

Central nervous system cancers, version 2.2014. Featured updates to the NCCN Guidelines

The NCCN Guidelines for Central Nervous System Cancers provide multidisciplinary recommendations for the clinical management of patients with cancers of the central nervous system. These NCCN Guidelines Insights highlight recent updates regarding the management of metastatic brain tumors using radiation therapy. Use of stereotactic radiosurgery (SRS) is no longer limited to patients with 3 or fewer lesions, because data suggest that total disease burden, rather than number of lesions, is predictive of survival benefits associated with the technique. SRS is increasingly becoming an integral part of management of patients with controlled, low-volume brain metastases.

Phase II trial of pre-irradiation and concurrent temozolomide in patients with newly diagnosed anaplastic oligodendrogliomas and mixed anaplastic oligoastrocytomas: long term results of RTOG BR0131

We report on the long-term results of a phase II study of pre-irradiation temozolomide followed by concurrent temozolomide and radiotherapy (RT) in patients with newly diagnosed anaplastic oligodendroglioma (AO) and mixed anaplastic oligoastrocytoma. Pre-RT temozolomide was given for up to 6 cycles. RT with concurrent temozolomide was administered to patients with less than a complete radiographic response. Forty eligible patients were entered and 32 completed protocol treatment. With a median follow-up time of 8.7 years (range 1.1-10.1), median progression-free survival (PFS) is 5.8 years (95 % CI 2.0, NR) and median overall survival (OS) has not been reached (5.9, NR). 1p/19q data are available in 37 cases; 23 tumors had codeletion while 14 tumors had no loss or loss of only 1p or 19q (non-codeleted). In codeleted patients, 9 patients have progressed and 4 have died; neither median PFS nor OS have been reached and two patients who received only pre-RT temozolomide and no RT have remained progression-free for over 7 years. 3-year PFS and 6-year OS are 78 % (95 % CI 61-95 %) and 83 % (95 % CI 67-98 %), respectively. Codeleted patients show a trend towards improved 6-year survival when compared to the codeleted procarbazine/CCNU/vincristrine (PCV) and RT cohort in RTOG 9402 (67 %, 95 % CI 55-79 %). For non-codeleted patients, median PFS and OS are 1.3 and 5.8 years, respectively. These updated results suggest that the regimen of dose intense, pre-RT temozolomide followed by concurrent RT/temozolomide has significant activity, particularly in patients with 1p/19q codeleted AOs and MAOs.

Local control after stereotactic radiosurgery for brain metastases in patients with melanoma with and without BRAF mutation and treatment

OBJECT

BRAF inhibitors improve progression-free and overall survival in patients with metastatic melanoma. Brain metastases are common, and stereotactic radiosurgery (SRS) has been used, resulting in excellent local control. Because BRAF inhibitors are associated with intracranial responses, the authors hypothesized that BRAF inhibitors would improve local control in patients with melanoma who are receiving SRS for brain metastases.

METHODS

The authors retrospectively identified patients with metastatic melanoma who had been tested for BRAF mutation and treated with SRS for brain metastases. Patients with previous resection, multiple brain metastases, or multiple courses of SRS were eligible. SRS was delivered in a single fraction to a median dose of 2000 cGy. Patients with a BRAF mutation were treated with a BRAF inhibitor on the basis of physician preference.

RESULTS

The authors identified 52 patients who were treated in 82 treatment sessions for 185 brain metastases and 13 tumor beds. At a median follow-up of 10.5 months, the 1-year local control rate was 69.2%. At 1 year, the local control rate for brain metastases in patients with BRAF mutation with BRAF treatment was 85.0%, and the local control rate for brain metastases in those without BRAF treatment was 51.5% (p = 0.0077). The rates of distant brain failure, freedom from whole-brain radiation, and overall survival were not different on the basis of BRAF mutation status or inhibitor therapy. The number of new intratumoral hemorrhages after SRS was increased significantly in patients with BRAF treatment.

CONCLUSIONS

Treatment with BRAF inhibitors was associated with improved local control after SRS in patients with melanoma and brain metastases. An increased number of intratumoral hemorrhages was associated with BRAF inhibitor therapy.

Grade 3 or higher morbidity requiring urologic surgical management following curative-intent radiotherapy of localized prostate cancer: Patient characteristics

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Background: Although there are prospective data reporting the incidence of grade 3 morbidity after treatment of prostate cancer (PCA), little has been reported on the specific morbidities, latency period and surgical management of these patients. We retrospectively evaluated the characteristics of patients treated for grade 3 or higher complications at the University of Utah. Methods: We identified patients with PCA from our institutional database who were treated with definitive or postoperative radiation between the years 1995 and 2012 with at least 1 CTCAE defined Grade 3 or higher adverse event (AE). We evaluated the details of surgery and/or radiation, time course to development of AE’s, and procedures performed to manage the AE’s. Descriptive statistics were performed. GI toxicities were not evaluated. Results: There were 208 Grade 3 events reported in 44 patients. Five had a single event, 8 had 2 events, and 31 patients had 3 or more. Following radiotherapy, 21 patients initially presented with a grade 3 toxicity, whereas 12 presented with a grade 1 and 11 presented with a grade 2 that progressed to grade 3. One subject had a grade 4 toxicity. There were 9 subjects who reported baseline grade 1 to 3 toxicity prior to curative-intent treatment. The most common Grade 3 events were: obstruction (100 events), incontinence (40 events) and fistula (21 events). Fourteen patients had surgery and EBRT, and at least 16 patients had HDR brachytherapy. The average latency period to the first grade 3 event was 76.8 months (range 0 to 195 months). Between 2005 and 2010 an average of 531 and 92 patients with PCA were treated with radiation in the state of Utah (SEER) and the University of Utah annually, respectively. Conclusions: Grade 3 or higher urologic morbidity is uncommon following prostate cancer radiation treatment. Combinations of radiation therapies and HDR brachytherapy appear to increase the risk of an adverse event. Outcome studies reporting late toxicity with median follow up of less than 5 years may significantly under-report the incidence.

Prostate patterns of care

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Background: The aim of this study is to describe initial treatment of men diagnosed with prostate cancer in the United States (US) between 2004 and 2011. Methods: Subjects with adenocarcinoma of the prostate were identified using the National Cancer Institute’s (NCI) Surveillance, Epidemiology and End Results (SEER) Program between 2004 and 2011. Subjects were staged according the American Joint Committee on Cancer (AJCC) 7th edition criteria. The National Comprehensive Cancer Network (NCCN) risk group classifications were used to stratify subjects into low risk (LR) including very low risk, intermediate risk (IR), high risk (HR) and very high (VHR) groups. Surgical intervention was grouped into no surgery, prostatectomy or other which included cyroablative therapy, hyperthermia, laser ablation, TURP, etc. Descriptive statistics and analysis were performed using Microsoft Office 2013 Excel. Results: There were 306,694 PC subjects with sufficient data to be risk categorized. Overall, 35.0% of subjects had LR, 36.1% had IR, 22.5% had HR, 1.2% had VHR, 0.6% had node positive and 4.6% had metastatic disease. Table 1 reveals the surgical and radiation treatment distribution for each risk group. Between 2004 and 2011 the use of prostatectomy, no treatment and external beam RT (EBRT) increased and the use of brachy including brachy monotherapy and brachytherapy in combination with EBRT decreased. Age is a strong influence on treatment delivered. Conclusions: This patterns of care study shows the heterogeneity of therapy for PC stratified by risk group in a contemporary series. Trends in treatment may reflect the development of new technology and findings from randomized trials. [Table: see text]

Definitive treatment of localized prostate cancer: Time and geographic trends

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Background: Numerous definitive treatment options exist for localized prostate cancer. We evaluated how the distribution of treatments varied by geographic location and over time in a contemporary US population database. Methods: All subjects with NCCN clinical risk-stratifiable localized prostate cancer between the years 2004 and 2011 were identified in the Surveillance Epidemiology and End-Results Database. Descriptive statistics evaluating the relative distribution of therapies by geographic region and over time were performed. Results: There were 290,631 evaluable subjects identified. The Table shows trends in treatment over time for combined low, intermediate, high, and very high risk prostate cancer. The use of brachytherapy has been significantly declining between 2004 and 2011, and no definitive therapy has been increasing. In 2010-2011, regional prostatectomy use varied from a low of 18% (Rural Georgia) to a high of 57% (Iowa). No definitive therapy rates varied between 12% (Hawaii) and 35% (Rural Georgia). Analyses of regional variation at the State County level reveals significant variability in the ratio of subjects receiving surgery to radiation (e.g., State of Utah surgery:radiation ratio 0.25 (Beaver County) versus 3.06 (Toole County). Conclusions: There is marked regional variation of practice at both the county and state levels for localized prostate cancer definitive therapy. The use of radiotherapy has been declining between the years 2004 and 2011, and appears to be offset by increases in no definitive therapy. Prostatectomy rates remained stable. [Table: see text]

Clinical outcomes associated with evolving treatment modalities and radiation techniques for base-of-tongue carcinoma: thirty years of institutional experience

Curative treatment for base-of-tongue squamous cell carcinoma (BOT SCC) has evolved over time; however, comparative outcomes analysis for various treatment strategies is lacking. The authors reviewed the evolution of treatment modality and radiotherapy (RT) technique for 231 consecutive BOT SCC patients at our institution between 1981 and 2011. Treatment modalities included definitive chemoradiotherapy (chemoRT) (42%), definitive RT (33%), surgery followed by RT (20%), and surgery alone (5%). RT techniques included external beam plus interstitial brachytherapy (EBRT + IB) (37%), conventional EBRT (29%), intensity-modulated radiation therapy ± simultaneous integrated boost (IMRT ± SIB) (34%). Clinical characteristics and outcomes were stratified by modality or RT technique. Treatment modality evolved from definitive RT (1980s–1990s) to definitive chemoRT (1990s–2000s). RT technique evolved from EBRT + IB (1980s–1990s) to conventional EBRT (1990s–2000s) to IMRT + SIB (2000s). With median alive follow-up of 6 years (0.3–28 years), the 5-year LC, LRC, and OS rates were 80%, 73%, and 51%. There was no difference in distribution of gender, age, stage among treatment modalities. Definitive chemoRT had improved LRC (HR 1.6) and OS (HR 1.7) compared to definitive RT. IMRT + SIB had improved LRC (HR 3.2), DFS (HR 3.4), and OS (HR 3.0) compared to conventional EBRT. Over the past 30 years, BOT SCC treatment has undergone major paradigm shifts that incorporate nonsurgical functional preservation, concurrent chemotherapy, and advanced RT techniques. Excellent locoregional control and survival outcomes are associated with accelerated IMRT with chemotherapy.

Central nervous system cancers

Primary and metastatic tumors of the central nervous system are a heterogeneous group of neoplasms with varied outcomes and management strategies. Recently, improved survival observed in 2 randomized clinical trials established combined chemotherapy and radiation as the new standard for treating patients with pure or mixed anaplastic oligodendroglioma harboring the 1p/19q codeletion. For metastatic disease, increasing evidence supports the efficacy of stereotactic radiosurgery in treating patients with multiple metastatic lesions but low overall tumor volume. These guidelines provide recommendations on the diagnosis and management of this group of diseases based on clinical evidence and panel consensus. This version includes expert advice on the management of low-grade infiltrative astrocytomas, oligodendrogliomas, anaplastic gliomas, glioblastomas, medulloblastomas, supratentorial primitive neuroectodermal tumors, and brain metastases. The full online version, available at NCCN. org, contains recommendations on additional subtypes.

Patterns of failure and predictors of outcome in cutaneous malignant melanoma of the scalp

BACKGROUND

Patients with melanoma of the scalp may have higher failure (recurrence) rates than melanoma of other body sites.

OBJECTIVE

We sought to characterize survival and patterns of failure for patients with scalp melanoma.

METHODS

Between 1998 and 2010, 250 nonmetastatic patients underwent wide local excision of a primary scalp melanoma. Kaplan-Meier analyses were performed to evaluate overall survival, scalp control, regional neck control, distant metastases-free survival, and disease-free survival.

RESULTS

Five-year overall survival was 86%, 57%, and 45% for stages I, II, and III, respectively, and 5-year scalp control rates were 92%, 75%, and 63%, respectively. Five-year distant metastases-free survival for these stages were 92%, 65%, and 45%, respectively. Of the 74 patients who recurred, the site of first recurrence included distant disease in 47%, although 31% recurred in the scalp alone.

LIMITATIONS

This is a retrospective review.

CONCLUSION

Distant metastases-free survival and overall survival for stage II and III patients with scalp melanoma are poor, and stage III patients experience relatively high rates of scalp failure suggesting that these patients may benefit from additional adjuvant systemic and local therapy. Further research is needed to characterize the environmental, microenvironmental, and genetic causes of the increased aggressiveness of scalp melanoma and to identify more effective treatment and surveillance methods.

Stereotactic radiosurgery for a single brain metastasis: factors impacting control

OBJECT

Stereotactic radiosurgery (SRS) is well established in the treatment of brain metastases, however it's exact role remains unclear. A single metastasis at presentation raises additional challenges, however there is minimal outcome data within this subgroup. We sought to evaluate the outcomes of treatment in patients with a single brain metastasis, as well as factors impacting local control.

METHODS

All patients treated with SRS for a single brain metastasis were evaluated. Data was collected regarding patient demographics, treatment characteristics, and treatment outcomes. Univariate analyses were performed to evaluate the impact of treatment and patient variables on these outcomes. Emphasis was placed on analyses of factors impacting LC.

RESULTS

Between 1998 and 2011, a total of 141 patients underwent SRS for a single brain metastasis; in addition 31 had surgical resection, 15 received whole brain radiotherapy (WBRT), and 2 underwent both. There was no statistical impact on local control (LC) or distant intracranial control (DIC) with the addition of WBRT or surgery (LC 74%, 100%, and 58%, and DIC 37%, 67%, and 49% for SRS alone, SRS + WBRT, and SRS + surgery, respectively, smallest p = 0.17). Local control was decreased with larger tumors, doses <20Gy, and tight overtreatment ratios (i.e. conformity) (largest p = 0.02), although the independence of these factors could not be established. Long term freedom from requiring future whole brain radiotherapy was 73%.

CONCLUSIONS

SRS alone for patients with single brain metastases demonstrates acceptable intracranial outcomes. Further evaluation into factors impacting LC are warranted.

Tumor control and incidence of radiation necrosis after reirradiation with stereotactic radiosurgery for brain metastases

OBJECTIVES

To determine the ability of a second course of stereotactic radiosurgery (SRS) to control brain metastases as well as to document the incidence of radiation necrosis (RN) after reirradiation with SRS.

METHODS AND MATERIALS

Between 2001 and 2010, 37 patients with 43 retreated lesions were treated with ≥2courses of SRS to the same brain metastasis. Patient, tumor, and treatment characteristics as well as follow-up data were collected. Magnetic resonance imaging was reviewed to assess tumor response to treatment. Development of RN, as confirmed by pathology or imaging, was recorded. Local control, overall survival, and predictors of RN were analyzed.

RESULTS

The most common histology was melanoma (n=20, 47%) followed by lung (n=9, 21%), and breast (n=8, 19%) cancer. RN was identified in 7/43 (16%) lesions. Using a competing risk model for analysis, with death as the competing risk, the incidence of RN was 11.6% and 16.5% at 6 and 12 months, respectively, and the incidence of local failure was 16.7% and 19.4% at 6 and 12 months, respectively. There was not a statistically significant association between radiation dose, mean tumor size, number of months between SRS courses, use of WBRT, or use of surgery and the development of RN. Median survival after the second course of SRS was 8.3 months, and median survival for those with and without RN was 14.1 and 7.7 months, respectively (p=0.23).

CONCLUSION

Reirradiation with SRS can lead to tumor response in the majority of patients with a low incidence of RN.

Radiosurgery for melanoma brain metastases: the impact of hemorrhage on local control

OBJECTIVE

To investigate the influence of stereotactic radiosurgery on the risk of hemorrhage from brain metastases from malignant melanoma.

METHODS

A cohort of 110 patients treated with stereotactic radiosurgery (SRS) for 358 melanoma brain metastases was identified. The incidence of hemorrhage before and after SRS was determined by review of serial MRI scans. Statistical analysis was performed to determine the influence of SRS on rate of hemorrhage. Overall survival (OS) and local control (LC) were assessed and prognostic factors, including hemorrhage pre- or post-SRS were analyzed.

RESULTS

At presentation 83 of 358 (23.2%) melanoma metastases had hemorrhaged in 44 patients. Following SRS, 73 hemorrhages occurred in 358 treated tumors (20.4%). These rates were not significantly different; p=0.362, HR=0.846 (95% CI 0.591-1.211). The risk of post-SRS hemorrhage in patients was statistically significantly linked to previous hemorrhage. Fourteen of 65 patients (21.5%) who presented without hemorrhage prior to SRS subsequently demonstrated hemorrhage. Twenty-four of 44 patients (54.5%) who presented with hemorrhage went on to demonstrate further hemorrhage following SRS; p=0.005, HR 2.47 (95% CI 1.24-11.3). Mixed effects logistic regression modeling showed no influence of SRS on the risk of hemorrhage of a given lesion (p=0.99).OS at 1 year was better for patients presenting with a single metastasis (41.2%) compared to multiple metastases (20.3%, p=0.009). LC was 60.4% at 1 year following SRS. LC was significantly lower for metastases demonstrating hemorrhage either pre-SRS (51.7% vs 64.9%, p=0.03) or post-SRS (32.7% vs. 67.8%, p<0.001).

CONCLUSIONS

The current data show that SRS does not alter the risk of subsequent hemorrhage of treated metastases. However, hemorrhage may complicate follow-up assessment of response and LC following SRS. Careful assessment of imaging following SRS should include awareness that hemorrhage may mimic treatment failure in these patients.

Self-expanding stent effects on radiation dosimetry in esophageal cancer

It is the purpose of this study to evaluate how self‐expanding stents (SESs) affect esophageal cancer radiation planning target volumes (PTVs) and dose delivered to surrounding organs at risk (OARs). Ten patients were evaluated, for whom a SES was placed before radiation. A computed tomography (CT) scan obtained before stent placement was fused to the post‐stent CT simulation scan. Three methods were used to represent pre‐stent PTVs: 1) image fusion (IF), 2) volume approximation (VA), and 3) diameter approximation (DA). PTVs and OARs were contoured per RTOG 1010 protocol using Eclipse Treatment Planning software. Post‐stent dosimetry for each patient was compared to approximated pre‐stent dosimetry. For each of the three pre‐stent approximations (IF, VA, and DA), the mean lung and liver doses and the estimated percentages of lung volumes receiving 5 Gy, 10 Gy, 20 Gy, and 30 Gy, and heart volumes receiving 40 Gy were significantly lower (p‐values <0.02) than those estimated in the post‐stent treatment plans. The lung V5, lung V10, and heart V40 constraints were achieved more often using our pre‐stent approximations. Esophageal SES placement increases the dose delivered to the lungs, heart, and liver. This may have clinical importance, especially when the dose‐volume constraints are near the recommended thresholds, as was the case for lung V5, lung V10, and heart V40. While stents have established benefits for treating patients with significant dysphagia, physicians considering stent placement and radiation therapy must realize the effects stents can have on the dosimetry.

PACS number: 87.55.dk

Reliability of contour-based volume calculation for radiosurgery

OBJECT

Determining accurate target volume is critical for both prescribing and evaluating stereotactic radiosurgery (SRS) treatments. The aim of this study was to determine the reliability of contour-based volume calculations made by current major SRS platforms.

METHODS

Spheres ranging in diameter from 6.4 to 38.2 mm were scanned and then delineated on imaging studies. Contour data sets were subsequently exported to 6 SRS treatment-planning platforms for volume calculations and comparisons. This procedure was repeated for the case of a patient with 12 metastatic lesions distributed throughout the brain. Both the phantom and patient datasets were exported to a stand-alone workstation for an independent volume-calculation analysis using a series of 10 algorithms that included approaches such as slice stacking, surface meshing, point-cloud filling, and so forth.

RESULTS

Contour data-rendered volumes exhibited large variations across the current SRS platforms investigated for both the phantom (-3.6% to 22%) and patient case (1.0%-10.2%). The majority of the clinical SRS systems and algorithms overestimated the volumes of the spheres, compared with their known physical volumes. An independent algorithm analysis found a similar trend in variability, and large variations were typically associated with small objects whose volumes were < 0.4 cm(3) and with those objects located near the end-slice of the scan limits.

CONCLUSIONS

Significant variations in volume calculation were observed based on data obtained from the SRS systems that were investigated. This observation highlights the need for strict quality assurance and benchmarking efforts when commissioning SRS systems for clinical use and, moreover, when conducting multiinstitutional cross-SRS platform clinical studies.

Stereotactic radiosurgery and radiotherapy for meningiomas: biomarker predictors of patient outcome and response to therapy

Although surgery has traditionally been the primary treatment of meningiomas, stereotactic radiosurgery (SRS) and radiotherapy (SRT) techniques have become a standard part of the treatment approach to intracranial meningiomas. For incompletely resected or inoperable benign meningiomas, SRT and SRS can provide excellent 5-year tumor control rates in 90% to 95% of benign meningioma cases. The current data on prognostic factors in meningioma SRT and SRS treatment outcomes are sparse. Our study aims to define prognostic factors that may help determine meningioma SRT and SRS treatment outcomes. Outcomes of 162 patients with 166 intracranial meningiomas treated with SRT (80 treatments) or SRS (92 treatments) were examined. Patient characteristics and tumor hypoxia-regulated biomarkers were correlated with tumor local control and overall survival. Median follow-up was 52 months, with median tumor volumes and treatment doses of 2.72 cm³/15 Gy and 12.54 cm³/54 Gy for SRS- and SRT-treated patients, respectively. Local control occurred in 68/77 (88.3%) SRT-treated patients and 80/89 (89.9%) SRS-treated patients. Tumor volume was predictive of overall survival for patients treated with SRT. The hypoxia-related biomarkers VEGF, HIF-1, and MIB-1 were useful in predicting outcome after SRT and SRS. SRS and SRT are successful in controlling intracranial meningioma growth. With further study, HIF-1, VEGF, and MIB-1 may be useful as predictive markers for response to SRT and SRS.

Apparatus dependence of normal brain tissue dose in stereotactic radiosurgery for multiple brain metastases

Object

Technical improvements in commercially available radiosurgery platforms have made it practical to treat a large number of intracranial targets. The goal of this study was to investigate whether the dose to normal brain when planning radiosurgery to multiple targets is apparatus dependent.

Methods

The authors selected a single case involving a patient with 12 metastatic lesions widely distributed throughout the brain as visualized on contrast-enhanced CT. Target volumes and critical normal structures were delineated with Leksell Gamma Knife Perfexion software. The imaging studies including the delineated contours were digitally exported into the CyberKnife and Novalis multileaf collimator–based planning systems for treatment planning using identical target dose goals and dose-volume constraints. Subsets of target combinations (3, 6, 9, or 12 targets) were planned separately to investigate the relationship of number of targets and radiosurgery platform to the dose to normal brain.

Results

Despite similar target dose coverage and dose to normal structures, the dose to normal brain was strongly apparatus dependent. A nonlinear increase in dose to normal brain volumes with increasing number of targets was also noted.

Conclusions

The dose delivered to normal brain is strongly dependent on the radiosurgery platform. How general this conclusion is and whether apparatus-dependent differences are related to differences in hardware design or differences in dose-planning algorithms deserve further investigation.