Faculty Bibliography

Background Activation of the mammalian target of rapamycin (mTOR) signaling pathway is thought to be a key driver of tumor growth in Merlin (NF2)-deficient tumors. Everolimus is an oral inhibitor of mTOR complex 1 (mTORC1) with antitumor activity in a variety of cancers. Methods We conducted a single-institution, prospective, 2-stage, open-label phase II study to estimate the response rate to everolimus in neurofibromatosis type 2 (NF2) patients with progressive vestibular schwannoma (VS). Ten eligible patients were enrolled, including 2 pediatric patients. Everolimus was administered at a daily dose of 10 mg (adults) or 5 mg/m(2)/day (children <18 y) orally in continuous 28-day courses, for up to 12 courses. Response was assessed every 3 months with MRI, using 3-dimensional volumetric tumor analysis, and audiograms. Nine patients were evaluable for the primary response, defined as >/=15% decrease in VS volume. Hearing response was evaluable as a secondary endpoint in 8 patients. Results None of the 9 patients with evaluable disease experienced a clinical or MRI response. No objective imaging or hearing responses were observed in stage 1 of the trial, and the study was closed according to predefined stopping rules. Conclusion Everolimus is ineffective for the treatment of progressive VS in NF2 patients. We are currently conducting a pharmacokinetic/pharmacodynamic ("phase 0") study of everolimus in presurgical VS patients to elucidate the biological basis for apparent treatment resistance to mTORC1 inhibition in these tumors.

Endoscopic endonasal surgery has been established as the safest approach to pituitary tumors, yet its role in other common skull base lesions has not been established. To answer this question, we carried out a systematic review of reported series of open and endoscopic endonasal approaches to four major skull base tumors: olfactory groove meningiomas (OGM), tuberculum sellae meningiomas (TSM), craniopharyngiomas (CRA), and clival chordomas (CHO). Data from 162 studies containing 5,701 patients were combined and compared for differences in perioperative mortality, gross total resection (GTR), cerebrospinal fluid (CSF) leak, neurological morbidity, post-operative visual function, post-operative anosmia, post-operative diabetes insipidus (DI), and post-operative obesity/hyperphagia. Weighted average rates for each outcome were calculated using relative study size. Our findings indicate similar rates of GTR and perioperative mortality between open and endoscopic approaches for all tumor types. CSF leak was increased after endoscopic surgery. Visual function symptoms were more likely to improve after endoscopic surgery for TSM, CRA, and CHO. Post-operative DI and obesity/hyperphagia were significantly increased after open resection in CRA. Recurrence rates per 1,000 patient-years of follow-up were higher in endoscopy for OGM, TSM, and CHO. Trends for open and endoscopic surgery suggested modest improvement in all outcomes over time. Our observations suggest that endonasal endoscopy is a safe alternative to craniotomy and may be preferred for certain tumor types. However, endoscopic surgery is associated with higher rates of CSF leak, and possibly increased recurrence rates. Prospective study with long-term follow-up is required to verify these preliminary observations.

9 Background: Traditionally, breast cancer-related lymphedema is considered to be mainly due to the mechanical injury from cancer surgery. Recent research identified that inflammation-infection may be one of the important predictors for lymphedema. This pilot study aimed to explore the associations between lymphatic and pro-inflammatory candidate gene variations and lymphedema. METHODS: A prospective, longitudinal, repeated-measure, and comparative design was used to recruit 178 breast cancer survivors. To ensure the accuracy of lymphedema phenotype, lymphedema was classified into lymphedema of arm and breast. Arm lymphedema must have been validated by infra-red perometer and a bioimpedance device. Breast lymphedema was validated by an observational scale since no objective measure is available. Saliva samples were collected for DNA extraction. Candidate Gene Association Research Method was used to examine the eight genes known for inflammation and lymphatic specific growth factors: cytokines (IL1A, IL6, IL8, IL10, IL13) and PTGS2 (COX2), and lymphatic specific growth factors [VEGF-C and D]. Descriptive statistics, Chi-Squared tests for contingency tables and one-way analysis of variance for continuous variables were used to compare the genotypes for each of these genes in patients with and without lymphedema. Odds ratios of developing lymphedema are estimated. RESULTS: Among 178 survivors, 39 women were confirmed to have arm lymphedema and 43 women had breast lymphedema. Five genes were significantly associated with breast cancer-related lymphedema. Specific single nucleic polymorphisms (SNPs) for lymphatic specific growth factors VEGF-C (rs4604006) and cytokine IL13 (rs1800925) were related to arm lymphedema. Specific SNPs of cytokine IL1A (rs1800587) and PTGS2 (COX2) (rs20417) were associated with breast lymphedema. CONCLUSIONS: Our findings provided preliminary data on genetic susceptibility as a risk factor for breast cancer-related lymphedema. Findings of our study may serve as a preliminary foundation for a priori recognition of genetic risk that may facilitate lymphedema risk prediction prior to surgery and raises the potential for early intervention for a high-risk group.