Roshan S. Prabhu

Current Dosing Paradigm for Stereotactic Radiosurgery Alone After Surgical Resection of Brain Metastases Needs to Be Optimized for Improved Local Control

PURPOSE To describe the use of radiosurgery (RS) alone to the resection cavity after resection of brain metastases as an alternative to adjuvant whole-brain radiotherapy (WBRT). METHODS AND MATERIALS Sixty-two patients with 64 cavities were treated with linear accelerator-based RS alone to the resection cavity after surgical removal of brain metastases between March 2007 and August 2010. Fifty-two patients (81%) had a gross total resection. Median cavity volume was 8.5 cm(3). Forty-four patients (71%) had a single metastasis. Median marginal and maximum doses were 18 Gy and 20.4 Gy, respectively. Sixty-one cavities (95%) had gross tumor volume to planning target volume expansion of ≥1 mm. RESULTS Six-month and 1-year actuarial local recurrence rates were 14% and 22%, respectively, with a median follow-up period of 9.7 months. Six-month and 1-year actuarial distant brain recurrence, total intracranial recurrence, and freedom from WBRT rates were 31% and 51%, 41% and 63%, and 91% and 74%, respectively. The symptomatic cavity radiation necrosis rate was 8%, with 2 patients (3%) undergoing surgery. Of the 11 local failures, 8 were in-field, 1 was marginal, and 2 were both (defined as in-field if ≥90% of recurrence within the prescription isodose and marginal if ≥90% outside of the prescription isodose). CONCLUSIONS The high rate of in-field cavity failure suggests that geographic misses with highly conformal RS are not a major contributor to local recurrence. The current dosing regimen derived from Radiation Therapy Oncology Group protocol 90-05 should be optimized in this patient population before any direct comparison with WBRT.

Effect of the Addition of Chemotherapy to Radiotherapy on Cognitive Function in Patients With Low-Grade Glioma: Secondary Analysis of RTOG 98-02

PURPOSE The addition of PCV (procarbazine, lomustine, and vincristine) chemotherapy to radiotherapy (RT) for patients with WHO grade 2 glioma improves progression-free survival (PFS). The effect of therapy intensification on cognitive function (CF) remains a concern in this population with substantial long-term survival. PATIENTS AND METHODS A total of 251 patients with WHO grade 2 glioma age ≥ 40 years with any extent of resection or age < 40 years with subtotal resection/biopsy were randomly assigned to RT (54 Gy) or RT plus PCV. We observed 111 patients age < 40 years with gross total resection. CF was assessed by Mini-Mental State Examination (MMSE) at baseline and years 1, 2, 3, and 5. RESULTS Overall, few patients experienced significant decline in MMSE score. There were no significant differences in the proportion of patients experiencing MMSE score decline between the randomized study arms at any time point. Both study arms experienced a significant gain in average MMSE score longitudinally over time, with no difference between arms. CONCLUSION The MMSE is a relatively insensitive tool, and subtle changes in CF may have been missed. However, the addition of PCV to RT did not result in significantly higher rates of MMSE score decline than RT alone through 5 years of follow-up. Patients in both randomly assigned arms experienced a statistically significant average MMSE score increase over time, with no difference between arms. The addition of PCV chemotherapy to RT improves PFS without excessive CF detriment over RT alone for patients with low-grade glioma.

Rising Incidence of Mucosal Melanoma of the Head and Neck in the United States

Background. While it is established that the incidence of cutaneous melanoma has risen over time in the United States, the incidence trend for mucosal melanoma of the head and neck (MMHN) is unknown. Methods. We used the Surveillance, Epidemiology, and End Results (SEER) database to determine incidence trends for MMHN from 1987 to 2009 in the United States. We determined annual percent change (APC) by weighted least squares and joinpoint regression analysis. Results. MMHN incidence increased from 1987 to 2009 (APC 2.4%; P < 0.01). Nasal cavity lesions increased in incidence (APC 2.7%; P < 0.01) over this duration, while the incidence of non-nasal cavity lesions remained stable. The highest rate of increase was in white females ages 55 to 84 (APC 5.1%; P = 0.01). Conclusions. The incidence of MMHN in the United States has been rising since 1987. This trend is driven primarily by increased incidence of nasal cavity melanomas.

Phase 2 study of preoperative radiation with concurrent capecitabine, oxaliplatin, and bevacizumab followed by surgery and postoperative 5-fluorouracil, leucovorin, oxaliplatin (FOLFOX), and bevacizumab in patients with locally advanced rectal cancer: ECOG 3204.

Recent studies have demonstrated the feasibility of combining oxaliplatin with 5‐fluorouracil (5‐FU) or capecitibine and radiation therapy. The addition of bevacizumab to chemotherapy improves overall survival for metastatic disease. We initiated a phase 2 trial to evaluate preoperative capecitabine, oxaliplatin, and bevacizumab with radiation therapy followed by surgery and postoperative 5‐FU, leucovorin, oxaliplatin (FOLFOX) and bevacizumab for locally advanced rectal cancer.

Hypofractionated radiosurgery for intact or resected brain metastases: defining the optimal dose and fractionation

BackgroundHypofractionated Radiosurgery (HR) is a therapeutic option for delivering partial brain radiotherapy (RT) to large brain metastases or resection cavities otherwise not amenable to single fraction radiosurgery (SRS). The use, safety and efficacy of HR for brain metastases is not well characterized and the optimal RT dose-fractionation schedule is undefined.MethodsForty-two patients treated with HR in 3-5 fractions for 20 (48%) intact and 22 (52%) resected brain metastases with a median maximum dimension of 3.9 cm (0.8-6.4 cm) between May 2008 and August 2011 were reviewed. Twenty-two patients (52%) had received prior radiation therapy. Local (LC), intracranial progression free survival (PFS) and overall survival (OS) are reported and analyzed for relationship to multiple RT variables through Cox-regression analysis.ResultsThe most common dose-fractionation schedules were 21 Gy in 3 fractions (67%), 24 Gy in 4 fractions (14%) and 30 Gy in 5 fractions (12%). After a median follow-up time of 15 months (range 2-41), local failure occurred in 13 patients (29%) and was a first site of failure in 6 patients (14%). Kaplan-Meier estimates of 1 year LC, intracranial PFS, and OS are: 61% (95% CI 0.53 – 0.70), 55% (95% CI 0.47 – 0.63), and 73% (95% CI 0.65 – 0.79), respectively. Local tumor control was negatively associated with PTV volume (p = 0.007) and was a significant predictor of OS (HR 0.57, 95% CI 0.33 - 0.98, p = 0.04). Symptomatic radiation necrosis occurred in 3 patients (7%).ConclusionsHR is well tolerated in both new and recurrent, previously irradiated intact or resected brain metastases. Local control is negatively associated with PTV volume and a significant predictor of overall survival, suggesting a need for dose escalation when using HR for large intracranial lesions.

Comparing Preoperative With Postoperative Stereotactic Radiosurgery for Resectable Brain Metastases: A Multi-institutional Analysis.

BACKGROUND Stereotactic radiosurgery (SRS) is an increasingly common modality used with surgery for resectable brain metastases (BM). OBJECTIVE To present a multi-institutional retrospective comparison of outcomes and toxicities of preoperative SRS (Pre-SRS) and postoperative SRS (Post-SRS). METHODS We reviewed the records of patients who underwent resection of BM and either Pre-SRS or Post-SRS alone between 2005 and 2013 at 2 institutions. Pre-SRS used a dose-reduction strategy based on tumor size, with planned resection within 48 hours. Cumulative incidence with competing risks was used to determine estimated rates. RESULTS A total of 180 patients underwent surgical resection for 189 BM: 66 (36.7%) underwent Pre-SRS and 114 (63.3%) underwent Post-SRS. Baseline patient characteristics were balanced except for higher rates of performance status 0 (62.1% vs 28.9%, P < .001) and primary breast cancer (27.2% vs 10.5%, P = .010) for Pre-SRS. Pre-SRS had lower median planning target volume margin (0 mm vs 2 mm) and peripheral dose (14.5 Gy vs 18 Gy), but similar gross tumor volume (8.3 mL vs 9.2 mL, P = .85). The median imaging follow-up period was 24.6 months for alive patients. Multivariable analyses revealed no difference between groups for overall survival (P = .1), local recurrence (P = .24), and distant brain recurrence (P = .75). Post-SRS was associated with significantly higher rates of leptomeningeal disease (2 years: 16.6% vs 3.2%, P = .010) and symptomatic radiation necrosis (2 years: 16.4% vs 4.9%, P = .010). CONCLUSION Pre-SRS and Post-SRS for resected BM provide similarly favorable rates of local recurrence, distant brain recurrence, and overall survival, but with significantly lower rates of symptomatic radiation necrosis and leptomeningeal disease in the Pre-SRS cohort. A prospective clinical trial comparing these treatment approaches is warranted. ABBREVIATIONS BM, brain metastasesCI, confidence intervalCTV, clinical target volumeDBR, distant brain recurrenceGTV, gross tumor volumeLC, local controlLMD, leptomeningeal diseaseLR, local recurrenceMVA, multivariable analysisOS, overall survivalPost-SRS, postoperative stereotactic radiosurgeryPre-SRS, preoperative stereotactic radiosurgeryPTV, planning target volumeRN, radiation necrosisSRN, symptomatic radiation necrosisSRS, stereotactic radiosurgeryWBRT, whole-brain radiation therapy.

Lymph node ratio influence on risk of head and neck cancer locoregional recurrence after initial surgical resection: Implications for adjuvant therapy

The purpose of this study was to determine if lymph node ratio is associated with locoregional recurrence for patients with oral cavity or laryngeal cancer treated with initial surgical management.

Metastasis infiltration: an investigation of the postoperative brain-tumor interface.

PURPOSE This study aims to evaluate brain infiltration of metastatic tumor cells past the main tumor resection margin to assess the biological basis for the use of stereotactic radiosurgery treatment of the tumor resection cavity and visualized resection edge or clinical target volume. METHODS AND MATERIALS Resection margin tissue was obtained after gross total resection of a small group of metastatic lesions from a variety of primary sources. The tissue at the border of the tumor and brain tissue was carefully oriented and processed to evaluate the presence of tumor cells within brain tissue and their distance from the resection margin. RESULTS Microscopic assessment of the radially oriented tissue samples showed no tumor cells infiltrating the surrounding brain tissue. Among the positive findings were reactive astrocytosis observed on the brain tissue immediately adjacent to the tumor resection bed margin. CONCLUSIONS The lack of evidence of metastatic tumor cell infiltration into surrounding brain suggests the need to target only a narrow depth of the resection cavity margin to minimize normal tissue injury and prevent treatment size-dependent stereotactic radiosurgery complications.

BRAF inhibitor and stereotactic radiosurgery is associated with an increased risk of radiation necrosis.

We retrospectively compared the outcomes and toxicities of melanoma brain metastases (MBM) patients treated with BRAF inhibitors (BRAFi) and stereotactic radiosurgery (SRS) with SRS alone. We identified 87 patients with 157 MBM treated with SRS alone from 2005 to 2013. Of these, 15 (17.2%) patients with 32 MBM (21.4%) received BRAFi therapy: three (20.0%) before SRS, two (13.3%) concurrent, and 10 (66.7%) after SRS. Overall survival (OS) was compared between cohorts using the product limit method. Intracranial outcomes were compared using cumulative incidence with competing risk for death. Baseline patient characteristics were similar between groups, except for the SRS cohort, which had higher rates of chemotherapy and more recent year of diagnosis. Radiation characteristics, including dose per fraction, total dose, gross tumor volume size, and prescription isodose, were also similar between cohorts. One-year outcomes – OS (64.3 vs. 40.4%, P=0.205), local failure (3.3 vs. 9.6%, P=0.423), and distant intracranial failure (63.9 vs. 65.1%, P=0.450) were not statistically different between the SRS+BRAFi and SRS-alone groups, respectively. The SRS+BRAFi group showed higher rates of radiographic radiation necrosis (RN) (22.2 vs. 11.0% at 1 year, P<0.001) and symptomatic radiation necrosis (SRN) (28.2 vs. 11.1% at 1 year, P<0.001). Multivariable analysis showed that BRAFi predicted an increased risk of both radiographic and SRN. SRS and BRAFi predicted for an increased risk of radiographic and SRN compared with SRS alone. Approaches to mitigate RN for patients receiving SRS and BRAFi should be considered until the clinical trial (http//:www.clinicaltrials.gov: NCT01721603) evaluating this treatment regimen is completed.

Extent of pathologic extracapsular extension and outcomes in patients with nonoropharyngeal head and neck cancer treated with initial surgical resection

Lymph node extracapsular extension (ECE) is a known adverse prognostic factor in head and neck cancer and is an indication for adjuvant chemoradiation (CRT). However, the extent of ECE may provide additional prognostic information in the setting of adjuvant CRT.