Robot-assisted transcerebellar stereotactic approach to the posterior fossa in pediatric patients: a technical note.

PURPOSE: During the last decade, there has been renewed interest in stereotactic approaches to diffuse intrinsic pontine gliomas (DIPGs) in children, due to the development of new concepts in molecular biology and management, and subsequent need for tissue sampling. Stereotactic frame-based and robot-assisted techniques are associated with reduced target error and have been incorporated into standard practice at our institution. METHODS: Four children (age 2-7 years) underwent a robot-assisted frame-based transcerebellar approach using the Leksell G frame coupled with Renishaw's neuromate® stereotactic robot. The procedures included 3 biopsies (two brainstem tumors and one cerebellar hemispheric lesion) and 1 depth electrode implantation into a low-grade tumor remnant (ganglioglioma) of the middle cerebellar peduncle causing drug-resistant epilepsy in a young girl. Targeting was based on MRI, and in one case, 18F-FET-PET was coregistered to MRI to improve sampling accuracy. The frame was applied 180° rotated compared to standard orientation, and patients were positioned prone during surgery and stereotactic preoperative CT scan. Postoperative CT scan ruled out complications and was coregistered to preoperative MRI to check the target accuracy. RESULTS: No complications occurred, and targeting was accurate in all cases. All tissue samplings provided proper histology; depth electrode EEG exploration was diagnostic and led subsequent resective surgery. CONCLUSIONS: According to our experience, the transcerebellar frame-based robotic stereotactic approach to the cerebellum and the brainstem is feasible, safe, and effective even in young children.

Another Chapter of the Right Versus Left Story: Is Primary Tumor Location a Prognostic Feature in RAS Mutant Metastatic Colorectal Cancer?

BACKGROUND: The prognostic value of primary tumor location (PTL) in patients with metastatic colorectal cancer (mCRC) was reported by recent analyses in RAS wild-type patients. Here, we investigated the prognostic value of PTL in RAS mutated mCRC patients. MATERIALS AND METHODS: PTL was defined as left or right if distal or proximal to the splenic flexure. Primary endpoint was overall survival (OS) according to PTL. Subgroup analyses were conducted according to time to metastases and RAS mutation subtypes. RESULTS: Five hundred sixty-four patients were included. Left- and right-sided cases were 65% and 35%, respectively. No difference in OS was detected according to PTL (hazard ratio [HR] = 0.99, p = .964). No difference in OS was observed in right versus left when looking at synchronous (HR 0.92, p = .557) or metachronous (HR 1.07, p = .807) patients. CONCLUSION: No OS difference was detected in RAS mutated mCRC. Molecular and clinical features able to improve prognosis and treatment strategies in this setting are needed.