Clinical recommendations for treatment of localized angiosarcoma: A consensus paper by the Italian Sarcoma Group.

Angiosarcoma (AS) represents a rare and aggressive vascular sarcoma, posing distinct challenges in clinical management compared to other sarcomas. While the current European Society of Medical Oncology (ESMO) clinical practice guidelines for sarcoma treatment are applicable to AS, its unique aggressiveness and diverse tumor presentations necessitate dedicated and detailed clinical recommendations, which are currently lacking. Notably, considerations regarding surgical extent, radiation therapy (RT), and neoadjuvant/adjuvant chemotherapy vary significantly in localized disease, depending on each different site of onset. Indeed, AS are one of the sarcoma types most sensitive to cytotoxic chemotherapy. Despite this, uncertainties persist regarding optimal management across different clinical presentations, highlighting the need for further investigation through clinical trials. The Italian Sarcoma Group (ISG) organized a consensus meeting on April 1st, 2023, in Castel San Pietro, Italy, bringing together Italian sarcoma experts from several disciplines and patient representatives from "Sofia nel Cuore Onlus" and the ISG patient advocacy working group. The objective was to develop specific clinical recommendations for managing localized AS within the existing framework of sarcoma clinical practice guidelines, accounting for potential practice variations among ISG institutions. The aim was to try to standardize and harmonize clinical practices, or at least highlight the open questions in the local management of the disease, to define the best evidence-based practice for the optimal approach of localized AS and generate the recommendations presented herein.

Prognostic value of mitotic count in leiomyosarcoma: A comprehensive monocentric retrospective study.

BACKGROUND: Leiomyosarcomas (LMSs) include heterogeneous entities with different clinical courses not entirely predicted by known prognostic factors. In particular, the value of mitotic count as independent prognostic factor in LMS has been poorly investigated. METHODS: We retrospectively analyzed all patients with a diagnosis of LMS who accessed to our Institution from June 1999 to May 2022 for which mitotic count was numerically expressed within the pathology report. Univariate and multivariate analyses were conducted to explore the prognostic value of mitotic count along with other clinical and histological variables. RESULTS: We identified 121 eligible patients, with a median follow-up of 91.03 months (range 0.62-275.2 months). Median progression-free survival (mPFS) was 16.7 months, and median overall survival (mOS) was 105.6 months. In univariate analysis, mitotic count showed a significant impact on PFS and OS, with an hazard ratio per mitotic unit of 1.03 (1.01-1.04, p < 0.001) and 1.03 (1.01-1.04, p = 0.007), respectively. Similar results were found for locally advanced and metastatic patients, separately. Other significant prognostic factors for PFS were stage at diagnosis, performance status, tumor size and Ki-67, while differentiation, necrosis, grade, stage at diagnosis, tumor size, performance status and age at diagnosis were identified for OS. In multivariate analysis, the only significant factors were mitotic count and the presence of metastases at diagnosis for PFS, whereas the same two factors plus age at diagnosis were identified for OS. CONCLUSION: Mitotic count represented the most important histological prognostic factor for OS and PFS in localized and metastatic LMS.

Multidisciplinary management of adolescents and young adults (AYA) sarcoma: A successful effort of an adult high-volume cancer center.

INTRODUCTION: The aim of this retrospective study was to investigate the clinicopathological characteristics of AYA sarcomas and their clinical outcomes at a high-volume single center. METHODS: Demographic, clinicopathological data on the diagnosis, treatment and follow-up of all sarcoma patients aged 16-39 years (ys) observed at our Institute between January 2010 and December 2021 were retrospectively collected, including diagnostic (TTD) and treatment delay(TTT), clinical outcomes (OS and PFS), and late-treatment effects. RESULTS: We identified 228 AYA patients, median age 30 years, 29% ≤ 25 years, 57% males, 88% soft tissue sarcomas (STS), and 12% bone sarcomas (BS). Among STSs, 13% were small round cell tumors (SRCT), 52% intermediate-high-grade, 24% low-grade STSs. Among BS, 32% were high-grade. Median TTD and TTT were 120 (0-8255) and 7 days (0-83), respectively. Surgery was performed in 83%, radiotherapy in 29%, and systemic therapy in 27%. Median follow-up was 72.9 months(1.6-145), 5-year and 10-year OS were 78.5% and 62%, respectively. Kaplan-Meyer analysis showed a significantly better 5-year OS and PFS for patients with >92 days of TTD (OS 85.7% vs. 66.7%, p = 0.001, PFS 50.2% vs. 24.9%, p = 0.009). According to age (≤25 years vs. > 25 years), 5-year OS was 69.8% versus 82.2%, respectively (p = 0.047). CONCLUSION: Our analysis confirmed previous data on sarcoma AYA patients followed in a referral center. Unexpectedly, diagnostic delay was not associated with poor OS and PFS. Patients <25 years showed a poorer prognosis due to the higher incidence of SRCT.

Exploring the CXCR4/CXCR7/CXCL12 Axis in Primary Desmoid Tumors.

BACKGROUND: Desmoid tumors have an extremely variable natural history. The uncertainty behind desmoid behavior reflects the complexity, which subtends its development and non-linear advancement. Apart from Wnt- ßcatenin mutation, estrogen receptors, and COX-2 overexpression, little is known about the ability of desmoids to grow and recur while being unable to metastasize. Several tumors have been shown to express the CXCR4/CXCR7/CXCL12 axis, whose functions are essential for tumoral development. AIMS: This study aimed to investigate the expression of the CXCR4/CXCR7/CXCL12 axis in primary desmoid tumors and discuss the potential role of this key-signaling as an antiangiogenic therapeutic strategy. METHODS: In this study, 3 µm-thick consecutive sections from each formalin-fixed and paraffin-embedded tissue block were treated with mouse monoclonal antibodies developed against CD34, CXCR4, CXCR7, and CXCL12. RESULTS: Two distinct vessel populations: CXCR4+ and CXCR4- vessels, have been found. Similarly, chemokine receptor CXCR7 expression in the entire desmoid tumor series positively stained a portion of tumor-associated vessels, identifying two distinct subpopulations of vessels: CXCR7+ and CXCR7- vessels. All 8 neoplastic tissue samples expressed CXCL12. Immunohistochemical positivity was identified in both stromal and endothelial vascular cells. Compared to CXCR4 and CXCR7, the vast majority of tumor-associated vessels were found to express this chemokine. CONCLUSION: It is the first time, as per our knowledge, that CXCR4/CXCR7/CXCL12 axis expression has been identified in a desmoid type-fibromatosis series. CXCL12 expression by neoplastic cells, together with CXCR4 and CXCR7 expression by a subgroup of tumor-associated vessels, was detected in all desmoid tumor tissue samples examined. Since chemokines are known contributors to neovascularization, CXCR4/CXCR7/CXCL12 axis may play a role in angiogenesis in this soft-tissue tumor histotype, thereby supporting its growth.

Glomus Tumor of the Stomach: A Systematic Review and Illustrative Case Report.

INTRODUCTION: Glomus tumor (GT) is a rare mesenchymal neoplasm that can be found anywhere throughout the body, including the stomach. Our goal was to present a case and a systematic review of the literature, reporting clinical, radiological, surgical, and pathological features of the disease. METHODS: We reviewed Pubmed and SCOPUS for all case reports and case series published after 2000. Papers written in languages different from English and letters to the editor were excluded. Screening and data extraction were performed following the PRISMA guidelines. RESULTS: A total of 89 studies were included in the systematic review, consisting of 187 cases of gastric glomus tumor. Mean age was 52 (18-90); most patients were female (61%). The most common clinical presentation was epigastric pain (33.9% of cases). The gastric antrum was the most frequently involved site (75.3%). Mean tumor size was 2.82 cm (0.8-17). Preoperative diagnosis was achieved in 22 cases, mostly by endoscopic ultrasound (EUS)-guided biopsy. Wedge resection was performed in 62% of treated patients. Smooth muscle actin was expressed in all cases with available immunohistochemistry. Malignant GT was reported in 11 cases. DISCUSSION: Epigastric pain and bleeding were the most common symptoms at presentation in patients with diagnosis of glomus tumor. EUS-guided fine needle aspiration can be useful for preoperative diagnosis. Endoscopic elastosonography is a promising tool for the differential diagnosis of gastric submucosal lesions, including glomus tumors. The treatment of choice is wedge resection with adequate free margins. A laparoscopic approach is warranted when technically feasible. Since malignant gastric GTs have been described, long-term follow-up is suggested after surgical excision.

Optimal Predictors of Postoperative Complications After Gastrectomy: Results from the Procalcitonin and C-reactive Protein for the Early Diagnosis of Anastomotic Leakage in Esophagogastric Surgery (PEDALES) Study.

BACKGROUND: The aim of this study was to define whether procalcitonin (PCT) is an earlier and more accurate predictor than C-reactive protein (CRP) for anastomotic leakage (AL) and major infective complications (MICs). METHODS: This was a prospective multicentric observational study conducted in three Italian centers, including all patients undergoing gastrectomy from May 2016 to April 2021. The endpoint was the assessment of the discrimination and accuracy achieved by the PCT and CRP values measured from POD1 to POD7 for predicting the occurrence of AL and MICs. Accuracy was assessed by calculating the area under the receiver operating curve (AUROC) values and Youden's statistics. Two charts were created for risk stratification during the postoperative course. RESULTS: The rate of AL was 4.6%, with a median day of occurrence on POD5 (range 3-26). The overall rate of major infective complications was 19.9%, with a median day of occurrence on POD6 (range 2-30). PCT showed a significant association with AL on POD6 and POD7 and a significant association with MICs on POD2, while CRP values showed a significant association with AL on POD4 and a significant association with MICs on POD1. No difference in the prediction of AL was observed between PCT and CRP, while CRP was found to be a superior predictor of major infective complications on POD5 (p = 0.024) and POD7 (p = 0.035). CONCLUSIONS: PCT was not superior to CRP as an early predictor of AL and major infective complications after gastrectomy. CRP should be used as the reference screening postoperative marker.

Retrospective Analysis of Retroperitoneal-Abdominal-Pelvic Ganglioneuromas: An International Study by the Transatlantic Australasian Retroperitoneal Sarcoma Working Group (TARPSWG).

OBJECTIVE: The Transatlantic Australasian Retroperitoneal Sarcoma Working Group conducted a retrospective study on the disease course and clinical management of ganglioneuromas. BACKGROUND: Ganglioneuromas are rare tumors derived from neural crest cells. Data on these tumors remain limited to case reports and single-institution case series. METHODS: Patients of all ages with pathologically confirmed primary retroperitoneal, intra-abdominal, and pelvic ganglioneuromas between January 1, 2000, and January 1, 2020, were included. We examined demographic, clinicopathologic, and radiologic characteristics, as well as clinical management. RESULTS: Overall, 328 patients from 29 institutions were included. The median age at diagnosis was 37 years with 59.1% of patients being female. Symptomatic presentation comprised 40.9% of cases, and tumors were often located in the extra-adrenal retroperitoneum (67.1%). At baseline, the median maximum tumor diameter was 7.2 cm. One hundred sixteen (35.4%) patients underwent active surveillance, whereas 212 (64.6%) patients underwent resection with 74.5% of operative cases achieving an R0/R1 resection. Serial tumor evaluations showed that malignant transformation to neuroblastoma was rare (0.9%, N=3). Tumors undergoing surveillance had a median follow-up of 1.9 years, with 92.2% of ganglioneuromas stable in size. With a median follow-up of 3.0 years for resected tumors, 84.4% of patients were disease free after resections, whereas recurrences were observed in 4 (1.9%) patients. CONCLUSIONS: Most ganglioneuromas have indolent disease courses and rarely transform to neuroblastoma. Thus, active surveillance may be appropriate for benign and asymptomatic tumors particularly when the risks of surgery outweigh the benefits. For symptomatic or growing tumors, resection may be curative.

The Janus-faced role of TRPM2-S in retroperitoneal liposarcoma via increasing ROS levels.

BACKGROUND: Retroperitoneal liposarcoma (RPLS) is a specific soft tissue sarcoma with a high recurrence rate. The short isoform of transient receptor potential cation channel subfamily M member 2 (TRPM2-S) plays an important role in the regulation of reactive oxygen species (ROS). However, the association between TRPM2-S and RPLS and its underlying mechanisms remains unclear. METHODS: The expression of both TRPM2-S and TRPM2-L in RPLS tissues was verified by kimmunohistochemistry (IHC). The regulation on Ca2+ influx by TRPM2-S was evaluated by Fluo-4 AM staining. The effect of TRPM2-S on cell proliferation and apoptosis was tested by 5-Ethynyl-2'-deoxyuridine (EdU) staining and Flow cytometry respectively. The level of cellular ROS was assessed by the DCFH-DA probe. Different concentrations of H2O2 were used to provide oxidative stress on RPLS cells. The underlying mechanisms were further explored by Western blotting. RESULTS: The IHC assays showed that TRPM2-S, but not TRPM2-L, was prognostic in RPLS. Low TRPM2-S level was associated with poor disease-free survival (DFS). Calcium influx signal intensity was significantly decreased under TRPM2-S overexpression, which resulted in a decrease in the levels of FOXO3a and PTEN. Correspondingly, the levels of pERK, pAKT, pP65, pGSK-3ß, Bcl-2, and ß-catenin were upregulated, and cellular ROS was gently increased under TRPM2-S overexpression. Moreover, TRPM2-S slightly promoted cell proliferation and inhibited apoptosis of RPLS cell lines under normoxia, but largely increased apoptosis rates under oxidative stress. The cleaved caspase3 was significantly upregulated by TRPM2-S overexpression under oxidative stress. N-Acetyl-L-cysteine (NAC), a small molecule antioxidant, could largely rescue RPLS cells from the apoptosis induced by H2O2. CONCLUSION: TRPM2-S exerts Janus-faced effects in RPLS by increasing the ROS levels via inhibition on FOXO3a, which promotes cell proliferation under normoxia but induces apoptosis under oxidative stress. Video abstract.

Blended practical learning in compliance with COVID-19 social distancing.

COVID-19 pandemic has imposed great changes in everyday life. Starting from January 2020, Humanitas University proposed to students digital instruction for continuing medical education, in particular, concerning practical activities. The latter, defined as Professionalizing activities, were transformed into complete online learning. From September 2020, in accordance to the imposed rules of social distancing, we modified the approach to Professionalizing activities. Despite following the new constrains, we came up with a blend online and face-to-face education program. The Kirkpatrick's evaluation model has been followed for validation of the project. Two ad hoc satisfaction questionnaires have been proposed to evaluate the project. Different approaches to blended learning have been described in literature; however, we propose a new method application, which fits to the post-pandemic era, with the purpose of sharing our experience in the field. Advantages and limitations are described. According to students, the overall satisfaction was rated 6.8, while tutors evaluated it with 7.4. The qualitative analysis of data confirms the advantage of the blended learning activities in order to guarantee a continuation of the clinical curriculum. Although it highlighted the necessity for, an increased technical support and an improvement in organization of the meetings. Blended learning is becoming more accepted among academic communities because it combines "the best of both worlds." However, its effectiveness depends on several factors. With our approach, we propose a method, specifically designed to make effective this kind of teaching, which can be considered essential in the pandemic era we are facing.

Prophylactic Ureteral Catheter Placement Appears to Reduce Intraoperative Ureteric Injury During Resection of Primary Retroperitoneal Liposarcoma.

Background: Prophylactic ureteral catheters placement (PUCP) was advocated as an effective strategy for decreasing ureteral morbidities in colorectal surgeries. However, whether it should be routinely used prior to primary retroperitoneal liposarcoma (PRLS) surgeries remains unknown. Methods: It was a retrospective study, conducted at a tertiary sarcoma center. Medical records of patients with PRLS undergoing surgeries from January 2015 through December 2018 were reviewed. Primary endpoint was the rate of ureteral morbidities during and after retroperitoneal liposarcoma resection procedures. Univariate and multivariate analyses determined risk factors associated with ureteral injury (UI) in patients undergoing surgeries. Results: A total of 55 patients of PRLS were included. Fourteen (25.5%) patients underwent PUCP, with 1 UI (7.1%) identified. In 41 patients with no PUCP, 15 (36.6%) exhibited UIs during and post surgeries. There were significant improvements of UIs in group PUCP, compared with patients without PUCP (P < .05). Resection surgeries combined with colectomy and tumor-ureter relationship were 2 risk factors significantly associated to UIs (P < .01). Conclusions: PUCP might be an effective way of preventing UIs in patients with PRLS. It could be suggested especially in patients with ureter encased by tumor or anticipated colectomy during the surgical process.

Quality of life and patient satisfaction in outpatient thyroid surgery.

In the last three decades surgeons have begun to perform outpatient thyroid surgery (OTS). Important outcome measures of a day-hospital procedure are the patient's quality of life (QoL) and satisfaction, but information on these issues in the OTS setting is scanty. The aim of this pilot study was to explore how early discharge after thyroidectomy affects patients' QoL and satisfaction. Postoperative QoL and satisfaction were assessed retrospectively by giving each patient a self-report questionnaire specifically created in our center for OTS and derived from the post-discharge surgical recovery (PSR) scale to assess physical and mental well-being. Twenty-three of 24 patients (96%), 16 women and 7 men with a median age of 48 years (range 16-72), completed the questionnaire, answering 92% of the questions. QoL based on this scale gave a median score of 81.8% (range 62-98.8%). No major or minor complications occurred in the study group. Regarding QoL eight patients (35%) reported feeling "tired all the time" and six patients (26%) reported mild pain, which in two cases resolved spontaneously. Regarding patient satisfaction two-thirds of patients judged OTS positively while the remaining one-third would not recommend it. Our study showed very good uptake by patients of a new questionnaire dedicated to OTS as a possible aid in the identification of areas for improvement of OTS management. However, to be considered a safe procedure with maximum patient compliance and satisfaction, OTS was found to require considerable effort by hospital staff and patients' caregivers compared to inpatient thyroid surgery.

Development of the PERI-Gastric (PEritoneal Recurrence Index) and PERI-Gram (Peritoneal Recurrence Index NomoGRAM) for predicting the risk of metachronous peritoneal carcinomatosis after gastrectomy with curative intent for gastric cancer.

BACKGROUND: A model that quantifies the risk of peritoneal recurrence would be a useful tool for improving decision-making in patients undergoing curative-aim gastrectomy for gastric cancer (GC). METHODS: Five Italian centers participated in this study. Two risk scores were created according to the two most widely used pathologic classifications of GC (the Lauren classification and the presence of signet-ring-cell features). The risk scores (the PERI-Gastric 1 and 2) were based on the results of multivariable logistic regressions and presented as nomograms (the PERI-Gram 1 and 2). Discrimination was assessed with the area under the curve (AUC) of receiver operating curves. Calibration graphs were constructed by plotting the actual versus the predicted rate of peritoneal recurrence. Internal validation was performed with a bootstrap resampling method (1000 iterations). RESULTS: The models were developed based on a population of 645 patients (selected from 1580 patients treated from 1998 to 2018). In the PERI-Gastric 1, significant variables were linitis plastica, stump GC, pT3-4, pN2-3 and the Lauren diffuse histotype, while in the PERI-Gastric 2, significant variables were linitis plastica, stump GC, pT3-4, pN2-3 and the presence of signet-ring cells. The AUC was 0,828 (0.778-0.877) for the PERI-Gastric 1 and 0,805 (0.755-0.855) for the PERI-Gastric 2. After bootstrap resampling, the PERI-Gastric 1 had a mean AUC of 0.775 (0.721-0.830) and a 95%CI estimate for the calibration slope of 0.852-1.505 and the PERI-Gastric 2 a mean AUC of 0.749 (0.693-0.805) and a 95%CI estimate for the slope of 0.777-1.351. The models are available at www.perigastric.org . CONCLUSIONS: We developed the PERI-Gastric and the PERI-Gram as instruments to determine the risk of peritoneal recurrence after curative-aim gastrectomy. These models could direct the administration of prophylactic intraperitoneal treatments.

Measuring the impact of complications after surgery for retroperitoneal sarcoma: Is comprehensive complication index better than Clavien-Dindo Classification?

BACKGROUND: To compare the Clavien-Dindo classification (CDC) and the Comprehensive Complication Index (CCI) in retroperitoneal sarcoma (RPS) surgery in assessing the real burden of post-operative complications on both post-operative length of stay and total costs of hospitalization (PLOS and TCH, respectively). STUDY DESIGN: A series of 417 procedures for both primary and recurrent RPS between January 2000 and December 2017 was analyzed. Complications were classified according to both CDC and CCI. Univariable linear regressions were used to assess predictors associated with PLOS and TCH. Multivariable linear regression models were constructed to identify the factors independently associated with PLOS and TCH. RESULTS: Median PLOS was 10 days (interquartile range [IQR] 7-16); median TCH was 7033.5€ (IQR 1350-305.900). Post-operative complications occurred in 170/417 (40.7%) of the procedures and in 75/417 (17.9%) of the procedures CDCs >3 were identified. Sixty-four (15.34%) patients had more than one complication. Univariable linear regression showed that both PLOS and TCH were significantly associated to both CDC and CCI among other factors. Multivariable linear analyses selected CDC and CCI as independent prognostic factors for both PLOS and TCH. According to the AIC and BIC, models including CCI performed better (5559.53 and 5598.18, respectively, compared with 5561.31 and 5599.95 for CDC models). CONCLUSION: The CCI resulted to perform better than the CDC in describing the overall burden of complications after RPS surgery, both for clinical and economic purposes.

Complement activation promoted by the lectin pathway mediates C3aR-dependent sarcoma progression and immunosuppression.

Complement has emerged as a component of tumor promoting inflammation. We conducted a systematic assessment of the role of complement activation and effector pathways in sarcomas. C3-/-, MBL1/2-/- and C4-/- mice showed reduced susceptibility to 3-methylcholanthrene sarcomagenesis and transplanted sarcomas, whereas C1q and factor B deficiency had marginal effects. Complement 3a receptor (C3aR), but not C5aR1 and C5aR2, deficiency mirrored the phenotype of C3-/- mice. C3 and C3aR deficiency were associated with reduced accumulation and functional skewing of tumor-associated macrophages, increased T cell activation and response to anti-PD-1 therapy. Transcriptional profiling of sarcoma infiltrating macrophages and monocytes revealed the enrichment of MHC II-dependent antigen presentation pathway in C3-deficient cells. In patients, C3aR expression correlated with a macrophage population signature and C3 deficiency-associated signatures predicted better clinical outcome. These results suggest that the lectin pathway and C3a/C3aR axis are key components of complement and macrophage-mediated sarcoma promotion and immunosuppression.

Major vascular resection in retroperitoneal sarcoma surgery.

Major blood vessels may be invaded either by primary sarcomas arising from the vessel wall or by secondary infiltration of a retroperitoneal sarcoma. The involvement of major blood vessels is not considered to be an absolute contraindication for surgical resection. The main issue when evaluating a possible major vascular resection is to balance the possible surgical morbidity with the expected survival benefit. This is strictly related to the tumor's biology and clinical behavior and to the patient's performance status and comorbidities. A multidisciplinary approach in a specialized center is mandatory when approaching a possible oncovascular resection for retroperitoneal sarcoma, given the rarity and the heterogeneity of these tumors.

Morbidity and Outcomes After Distal Pancreatectomy for Primary Retroperitoneal Sarcoma: An Analysis by the Trans-Atlantic Australasian Retroperitoneal Sarcoma Working Group.

BACKGROUND: Multi-visceral resection often is used in the treatment of retroperitoneal sarcoma (RPS). The morbidity after distal pancreatectomy for primary pancreatic cancer is well-documented, but the outcomes after distal pancreatectomy for primary RPS are not. This study aimed to evaluate morbidity and oncologic outcomes after distal pancreatectomy for primary RPS. METHODS: In this study, 26 sarcoma centers that are members of the Trans-Atlantic Australasian Retroperitoneal Sarcoma Working Group (TARPSWG) retrospectively identified consecutive patients who underwent distal pancreatectomy for primary RPS from 2008 to 2017. The outcomes measured were 90-day severe complications (Clavien-Dindo ≥ 3), postoperative pancreatic fistula (POPF) rate, and oncologic outcomes. RESULTS: Between 2008 and 2017, 280 patients underwent distal pancreatectomy for primary RPS. The median tumor size was 25 cm, and the median number of organs resected, including the pancreas, was three. In 96% of the operations, R0/R1 resection was achieved. The 90-day severe complication rate was 40 %. The grades B and C POPF complication rates were respectively 19% and 5% and not associated with worse overall survival. Administration of preoperative radiation and factors to mitigate POPF did not have an impact on the risk for the development of a POPF. The RPS invaded the pancreas in 38% of the patients, and local recurrence was doubled for the patients who had a microscopic, positive pancreas margin (hazard ratio, 2.0; p = 0.042). CONCLUSION: Distal pancreatectomy for primary RPS has acceptable morbidity and oncologic outcomes and is a reasonable approach to facilitate complete tumor resection.