Kirtesh R. Patel

Ipilimumab and Stereotactic Radiosurgery Versus Stereotactic Radiosurgery Alone for Newly Diagnosed Melanoma Brain Metastases.

Background: We compared the safety and efficacy of ipilimumab and stereotactic radiosurgery (SRS) to SRS alone for newly diagnosed melanoma brain metastases (MBM). Materials and Methods: We reviewed records of newly diagnosed MBM patients treated with SRS from 2009 to 2013. The primary endpoint of overall survival (OS), and secondary endpoints of local control, distant intracranial failure, and radiation necrosis were compared using Kaplan-Meier method. Univariate and multivariate analysis were performed using the Cox proportional hazards method. Results: Fifty-four consecutive MBM patients were identified, with 20 (37.0%) receiving ipilimumab within 4 months of SRS. Ipilimumab-treated and non-ipilimumab–treated patients had similar baseline characteristics. No difference in symptomatic radiation necrosis or hemorrhage was identified between cohorts. Compared with patients in the nonipilimumab group, 1 year local control (71.4% vs. 92.3%, P=0.40) and intracranial control (12.7% vs. 29.1%, P=0.59) were also statistically similar. The ipilimumab cohort also had no difference in 1-year OS (37.1% vs. 38.5%, P=0.84). Patients administered ipilimumab within 14 days of SRS had higher 1-year (42.9%) and 2-year OS (42.9%) relative to ipilimumab delivered >14 days (33.8%, 16.9%) and SRS alone (38.5%, 25.7%) but these difference were not statistically significant. Univariate analysis and multivariate analysis both confirmed single brain metastasis, controlled primary, and active systemic disease as predictors for OS. Conclusions: Use of ipilimumab within 4 months of SRS seems to be safe, with no increase in radiation necrosis or hemorrhage; however, our retrospective institutional experience with this treatment regimen was not associated with improved outcomes.

Two heads better than one? Ipilimumab immunotherapy and radiation therapy for melanoma brain metastases

Melanoma is an aggressive malignancy with a deplorable penchant for spreading to the brain. While focal therapies such as surgery and stereotactic radiosurgery can help provide local control, the majority of patients still develop intracranial progression. Novel therapeutic combinations to improve outcomes for melanoma brain metastases (MBM) are clearly needed. Ipilimumab, the anticytotoxic T-lymphocyte-associated antigen 4 monoclonal antibody, has been shown to improve survival in patients with metastatic melanoma, but many of these trials either excluded or had very few patients with MBM. This article will review the efficacy and limitations of ipilimumab therapy for MBM, describe the current evidence for combining ipilimumab with radiation therapy, illustrate potential mechanisms for synergy, and discuss emerging clinical trials specifically investigating this combination in MBM.

Disulfiram induces copper-dependent stimulation of reactive oxygen species and activation of the extrinsic apoptotic pathway in melanoma.

Melanoma is the most aggressive and deadly form of skin cancer. The current standard of care produces response rates of less than 20%, underscoring the critical need for identification of new effective, nontoxic therapies. Disulfiram (DSF) was identified using a drug screen as one of the several compounds that preferentially decreased proliferation in multiple melanoma subtypes compared with benign melanocytes. DSF, a member of the dithiocarbamate family, is a copper (Cu) chelator, and Cu has been shown previously to enhance DSF-mediated growth inhibition and apoptosis in cancer cells. Here, we report that in the presence of free Cu, DSF inhibits cellular proliferation and induces apoptosis in a panel of cell lines representing primary and metastatic nodular and superficial spreading melanoma. Both decreased cellular proliferation and increased apoptosis were seen at 50–500 nmol/l DSF concentrations that are achievable through oral dosing of the medication. In the presence of Cu, DSF caused activation of the extrinsic pathway of apoptosis as measured by caspase-8 cleavage. The addition of Z-IETD-FMK, a selective caspase-8 inhibitor, was protective against DSF–Cu-induced apoptosis. Production of reactive oxygen species (ROS) in response to DSF–Cu treatment preceded the induction of apoptosis. Both ROS production and apoptosis were prevented by coincubation of N-acetyl cysteine, a free radical scavenger. Our study shows that DSF might be used to target both nodular and superficial spreading melanoma through ROS production and activation of the extrinsic pathway of apoptosis.

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.

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.

Albendazole sensitizes cancer cells to ionizing radiation

BackgroundBrain metastases afflict approximately half of patients with metastatic melanoma (MM) and small cell lung cancer (SCLC) and represent the direct cause of death in 60 to 70% of those affected. Standard of care remains ineffective in both types of cancer with the challenge of overcoming the blood brain barrier (BBB) exacerbating the clinical problem. Our purpose is to determine and characterize the potential of albendazole (ABZ) as a cytotoxic and radiosensitizing agent against MM and SCLC cells.MethodsHere, ABZs mechanism of action as a DNA damaging and microtubule disrupting agent is assessed through analysis of histone H2AX phosphorylation and cell cyle progression. The cytotoxicity of ABZ alone and in combination with radiation therapy is determined though clonogenic cell survival assays in a panel of MM and SCLC cell lines. We further establish ABZs ability to act synergistically as a radio-sensitizer through combination index calculations and apoptotic measurements of poly (ADP-ribose) polymerase (PARP) cleavage.ResultsABZ induces DNA damage as measured by increased H2AX phosphorylation. ABZ inhibits the growth of MM and SCLC at clinically achievable plasma concentrations. At these concentrations, ABZ arrests MM and SCLC cells in the G2/M phase of the cell cycle after 12 hours of treatment. Exploiting the notion that cells in the G2/M phase are the most sensitive to radiation therapy, we show that treatment of MM and SCLC cells treated with ABZ renders them more sensitive to radiation in a synergistic fashion. Additionally, MM and SCLC cells co-treated with ABZ and radiation exhibit increased apoptosis at 72 hours.ConclusionsOur study suggests that the orally available antihelminthic ABZ acts as a potent radiosensitizer in MM and SCLC cell lines. Further evaluation of ABZ in combination with radiation as a potential treatment for MM and SCLC brain metastases is warranted.

Novel risk stratification score for predicting early distant brain failure and salvage whole-brain radiotherapy after stereotactic radiosurgery for brain metastases.

The purpose of this study was to evaluate predictors of early distant brain failure (DBF) and salvage whole‐brain radiotherapy (WBRT) after treatment with stereotactic radiosurgery (SRS) for brain metastases and create a clinically relevant risk score to stratify patients’ risk for these events.

Can we eliminate neoadjuvant chemoradiotherapy in favor of neoadjuvant multiagent chemotherapy for select stage II/III rectal adenocarcinomas: Analysis of the National Cancer Database

Stage II and III rectal cancers have been effectively treated with neoadjuvant chemoradiotherapy (NCRT) followed by definitive resection. Advancements in surgical technique and systemic therapy have prompted investigation of neoadjuvant multiagent chemotherapy (NMAC) regimens with the elimination of radiation (RT). The objective of the current study was to investigate factors that predict for the use of NCRT versus NMAC and compare outcomes using the National Cancer Data Base (NCDB) for select stage II and III rectal cancers.

BRAF inhibitors and radiotherapy for melanoma brain metastases: potential advantages and disadvantages of combination therapy

Melanoma is an aggressive malignancy that frequently spreads to the brain, resulting in rapid deterioration in both quality and quantity of life. Historically, treatment options for melanoma brain metastases (MBM) have predominantly consisted of surgery and radiotherapy. While these options can help provide local control, the majority of patients still develop intracranial progression. Indeed, novel therapeutic options, including molecularly targeted agents and immunotherapy, have improved outcomes and are now changing the role of radiotherapy. Up to 50% of melanomas contain an activating BRAF mutation, resulting in hyperactive cellular proliferation and survival. Drugs that target BRAF have been introduced for the treatment of metastatic melanoma and offer hope in improving disease outcomes; however, many of these trials either excluded or had a limited amount of patients with MBM. Recent studies have revealed that melanoma cell lines become more radiosensitive following BRAF inhibition, thus providing a potential synergistic mechanism when combining BRAF inhibitor (BRAFi) and radiotherapy. However, neurotoxicity concerns also exist with this combination. This article reviews the efficacy and limitations of BRAFi therapy for MBM, describes current evidence for combining BRAFis with radiation, discusses the rationale and evidence for combination modalities, and highlights emerging clinical trials specifically investigating this combination in MBM.

Outcomes for patients with locally advanced pancreatic adenocarcinoma treated with stereotactic body radiation therapy versus conventionally fractionated radiation.

As systemic therapy has improved for locally advanced pancreatic cancer (LAPC), efforts to improve local control with optimal radiotherapy may be critical. Although conventionally fractionated radiation therapy (CFRT) has more recently shown a limited role in LAPC, stereotactic body radiation therapy (SBRT) is an emerging approach with promising results. With no studies to date comparing SBRT with CFRT for LAPC, this study used the National Cancer Data Base (NCDB) to evaluate these 2 modalities.