Citations

Objective: To describe the anesthetic considerations in patients undergoing laser interstitial thermal therapy (LITT) for neurosurgical procedures. Background: LITT for neurosurgical procedures is being increasingly used in a variety of central nervous system diseases. Several studies have demonstrated promising results including a shorter hospital stay. Given the rising trend for the use of LITT, anesthesiologists need to be familiar with the anesthetic considerations to provide care for patients undergoing these types of procedures. Materials and Methods: PubMed was searched in April 2016 using different combinations of the following MeSH terms: “Central nervous System,” “laser therapy,” “Ablation Techniques,” “Anesthesia,” and “Spinal Cord Neoplasms.” A total of 54 relevant manuscripts were included in this review article. Conclusions: LITT is a promising therapeutic approach for multiple central nervous system disorders. Anesthesiologists must be familiar with the anesthetic considerations and the technical aspects of the procedure when providing care for patients undergoing LITT. The literature is scarce on the impact of different anesthesia and analgesia techniques on clinical outcomes. Therefore, studies comparing different anesthetic regimens and the impact on outcomes are needed to make relevant recommendations on the anesthesia care of these patients.

Abstract BACKGROUND Genomic intra- and intertumor heterogeneity is one main reason for relapse and resistance to therapy. There is a shortage of studies characterizing the level of genomic intertumoral heterogeneity of known cancer genes in multiple longitudinal biopsies of individual patients. Additionally, a workflow to deconvulate the intermixture of tumor and stromal components is missing. To overcome these limitations and to decipher the genomic heterogeneity and clonal evolution, we developed a method and applied it on matched (primary-recurrence/metastasis) non-squamous, non-small cell lung cancers (NSCLC). METHODS Multiparameter Ploidy Profiling (MPP) comprises the isolation of nuclei from frozen or formalin and paraffin embedded (FFPE) tissues, followed by multiparamter flow sorting. Sorted populations were subjected to genomic profiling by high resolution array comparative genomic hybridization (aCGH) and massively parallel sequencing (MPS). DAPI allowed to seperate populations by ploidy and anti-TTF1 antibodies was used to control for tumor nuclei. Array-CGH, combined with ploidy, was used to retrieve genome wide copy numbers. The Comprehensive Cancer Panel that covers all-exons of 409 cancer genes was applied on all sorted tumor and stromal populations to detect somatic mutations and their variant allelic frequency (VAF). RESULTS MPP was successfully applied to 44 frozen or FFPE tissue specimens from 19 patients. Array-CGH and MPS of TTF1-negative, normal cells were concordant to germline controls. Sequencing revealed that 50% of mutations are shared between primary tumors and metastases. Except for one patient, mutations with VAF>0.3 are shared between primary and metastasis. The variant allelic frequency was significantly higher in shared mutations than mutations that were private to one tumor. Besides common activating mutations in EGFR and KRAS we found biallelic inactivation in tumor suppressor genes like KEAP1, NF1, STK11 and TP53. Two clonal evolutionary patterns were found: 1) early and 2) late divergence. Matched tumors without any shared mutations were classified as unrelated primary tumors. CONCLUSION The power of MPP is to increase the precision of downstream analysis, due to the sorting of pure populations of tumor cells. It permitted to infer the clonal evolution of tumor populations with unprecedented confidence. The low level of genomic heterogeneity of mutations with VAF>0.3 in this study is in line with recent data from Zhang et al., who showed that the poor precision of low depth sequencing (<277x) contributes to an overestimation of genomic heterogeneity (Zhang et al., Science 2014). Integrational analysis of ploidy, chromosomal aberrations and mutations in 409 cancer genes allowed to draw the evolutionary picture of each patient's disease. MPP appears as a promising tool for identification of genomic vulnerabilities that could be exploited for tailored treatment. Citation Format: Thomas Lorber, Tanja Dietsche, Valeria Perrina, Darius Juskevicius, Arthur Krause, David Mueller, Michael Barrett, Christian Ruiz, Lukas Bubendorf. Clonal evolution and genomic tumor heterogeneity in non-small cell lung cancer deciphered by multiparameter ploidy profiling. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 158.

Abstract Background: Genomic tumor heterogeneity is one reason for recurrence and resistance to cancer therapy. It is still not known what leads to the relapse or the emergence of metastasis in individual patients. To contribute to answer this question, we investigated the evolutionary patterns in squamous cell carcinoma of the lung (SCC) in 10 patients with multiple matched tumors (primary vs recurrence/metastasis). Methods: To identify the genomic profile, frozen tissues from SCC patients were subjected to multiparameter ploidy profiling (MPP). Tumor populations were sorted based on ploidy (DNA-content using DAPI) and p40 was used to control for diploid tumor populations. Subsequent genomic profiling by array comparative genomic hybridization (aCGH) and targeted massive parallel sequencing (Ion Torrent Comprehensive Cancer Panel with an all-exon coverage of 409 cancer genes) was applied. Results: The usage of MPP enabled the determination of the clonal composition of the SCC and define genomic characteristics. Due to flow sorting the tumor populations were effectively isolated and existence of distinct clonal populations was indicated. Aneuploid and diploid tumors were successfully revealed using the additional marker p40. Therefore, the absence of non-malignant cells increased the precision in the genomic analyses Conclusion: The study uncovered the composition of human SCC in the sense of different clonal populations, which harbor private genomic aberrations and mutations confirmed by aCGH and NGS. Even if our data is still preliminary we provide evidence that applying MPP increases the precision of aCGH and sequencing analysis. Genomic analyses of sorted pure tumor population allows to reconstruct the clonal evolution and facilitates the understanding of tumor heterogeneity and their evolutionary pattern, which could have potentially an impact on therapeutic response or metastasis development. Citation Format: Arthur Krause, Thomas Lorber, Valeria Perrina, Tanja Dietsche, Michael Barrett, Christian Ruiz, Lukas Bubendorf. The analysis of the genomic evolution of squamous cell carcinoma of the lung. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 155.