Tumor Remnants Research Articles

Endoscopic endonasal surgery for non-invasive pituitary neuroendocrinology tumors with incomplete pseudocapsule.

Pituitary neuroendocrinology tumors (PitNETs) with pseudocapsule can be effectively removed by the pseudocapsule-based extracapsular resection technique. In the areas without pseudocapsule, the tumor cells can spread into the adjacent tissues at the cellular level, which brings a great challenge to achieving total tumor resection. Our surgical strategy for PitNETs with an incomplete pseudocapsule is to combine the pseudocapsule-based extracapsular resection technique with the intensive excision technique for the removal of the tumor. Specifically, the pseudocapsule-based extracapsular resection technique is applied in the areas with pseudocapsule, while in the areas without pseudocapsule, the intensive excision technique bounded by adjacent normal structures is adopted. Moreover, a pathological examination was performed to determine the situations of pseudocapsule and tumor cell remnant. All growth hormone-secreting PitNETs achieved biochemical remission after surgery. There was no deterioration of pituitary functions postoperatively, and the preoperative hypopituitarism had improved in all patients postoperatively. In total, two cases suffered a transient diabetes insipidus, and intraoperative cerebrospinal fluid leakage was observed in two cases but no postoperative cerebrospinal fluid leakage in all cases. There was no recurrence during the follow-up. The fragmental pseudocapsule and small tumor remnants were found in the majority of suspicious tissues by histological staining. The effectiveness and safety of the surgical strategy were preliminarily explored for removing PitNETs without incomplete pseudocapsules. In overview, the pseudocapsule-based extracapsular resection technique is applied in areas with pseudocapsule, while the intensive excision bounded by adjacent normal structures is adopted in other areas.

Frequency and Prognostic Relevance of Volumetric MRI Changes in Contrast- and Non-Contrast-Enhancing Tumor Compartments between Surgery and Radiotherapy of IDHwt Glioblastoma

In newly diagnosed IDH-wildtype glioblastoma, the frequency and prognostic relevance of tumor regrowth between resection and the initiation of adjuvant radiochemotherapy are unclear. In this retrospective single-center study we included 64 consecutive cases, for whom magnetic resonance imaging (MRI) was available for both the volumetric assessment of the extent of resection immediately after surgery as well as the volumetric target delineation before the initiation of adjuvant radiochemotherapy (time interval: 15.5 ± 1.9 days). Overall, a median new contrast-enhancement volume was seen in 21/64 individuals (33%, 1.5 ± 1.5 cm3), and new non-contrast lesion volume in 18/64 patients (28%, 5.0 ± 2.3 cm3). A multidisciplinary in-depth review revealed that new contrast-enhancement was either due to (I) the progression of contrast-enhancing tumor remnants in 6/21 patients or (II) distant contrast-enhancing foci or breakdown of the blood-brain barrier in previously non-contrast-enhancing tumor remnants in 5/21 patients, whereas it was unspecific or due to ischemia in 10/21 patients. For non-contrast-enhancing lesions, three of eighteen had progression of non-contrast-enhancing tumor remnants and fifteen of eighteen had unspecific changes or changes due to ischemia. There was no significant association between findings consistent with tumor regrowth and a less favorable outcome (overall survival: 14 vs. 19 months; p = 0.423). These findings support the rationale that analysis of the postsurgical remaining tumor-volume for prognostic stratification should be carried out on immediate postoperative MRI (<72 h), as unspecific changes are common. However, tumor regrowth including distant foci may occur in a subset of IDH-wildtype glioblastoma patients diagnosed per WHO 2021 classification. Thus, MRI imaging prior to radiotherapy should be obtained to adjust radiotherapy planning accordingly.

Gonadotropic pituitary adenomas: Two cases report

The pituitary gonadotropic adenoma is an adenoma developed́ in the gonadotropic cells of the anterior pituitary. It can be secreting releasing in excess in blood and urine; the products of its secretion are gonadostimulines (F.S.H. and L.H.) or non-secreting in this case only histo- cytochemical analysis will be able to allow identification. We report two cases of macroadenoma with LH-FSH immunostaining. Pituitary magnetic resonance imaging revealed a macroadenoma. Transphenoidal surgery was incomplete. Immunohistochemical staining showed that the tumor cells were reactive to LH (70%) and FSH (30%). Control pituitary imaging revealed a residual macroadenoma and deficit replacement was started. Hormonal testing for all patients with pituitary adenoma should be performed even in the absence of symptoms of hypersecretion. The treatment of gonadotropic adenomas is surgical. Complementary radiotherapy is usually indicated in case of postoperative tumor remnants with an effect on the prevention of recurrence. Medical treatment (dopaminergic agonists, somatostatin analogues, GnRH agonists and antagonists) is disappointing.

Surgical Outcomes of Simultaneous Cochlear Implantation and Intracochlear Schwannoma Removal.

Intracochlear schwannoma is very rare, and complete loss of hearing is inevitable after the removal of this tumor. Here, we discuss cochlear implantation (CI) performed simultaneously with the removal of an intracochlear schwannoma. Retrospective single-center study. Tertiary medical institute. Simultaneous CI and intracochlear schwannoma removal were performed in 4 subjects. After subtotal cochleostomy, the tumors were removed meticulously, with preservation of the modiolus. A new slim modiolar electrode (Nucleus CI632) was placed in a manner that hugged the modiolus. The surgical outcomes of functional gain, word recognition score (WRS), sound localization, and hearing in noise and speech intelligibility tests were investigated. Intracochlear schwannomas were removed successfully from the 4 patients, with no remnant tumor. The mean aided hearing threshold 6 months after surgery was 25.0 ± 1.8 dB, and the mean-aided WRS with a 60 dB stimulus was 36.0 ± 18.8% (range 16%-60%). The Categorical Auditory Performance (CAP) score of the 3 single-sided deafness patients under contralateral ear masking was 7. The CAP score of the patient with bilateral sensorineural hearing loss was 6, which improved from a preoperative score of 0. When an intracochlear schwannoma does not completely invade the modiolus, CI with simultaneous tumor removal can be performed successfully, resulting in good hearing performance. A slim modiolar electrode can be placed stably at the modiolus after schwannoma removal.

MXene-modified 3D printed scaffold for photothermal therapy and facilitation of oral mucosal wound reconstruction

The most prevalent oral and maxillofacial cancer is oral squamous cell carcinoma (OSCC). Patient survival is compromised by relapse due to post-operative tumor remnants and significant mucosal defects. Photothermal therapy (PTT) is used to ablate local malignancies, but the capacity of tumor cells to resist it is correlated with the overexpression of heat shock protein 70 (HSP70). In this work, PTT and tissue engineering scaffold were rationally integrated to construct a Ti3C2 MXene, collagen, silk fibroin and quercetin composite scaffold (M-CSQ scaffold), a 3D printed biomaterial that simultaneously kill OSCC cells and promote the regeneration of the mucosal defects. The M-CSQ scaffolds were prepared by cryogenic 3D printing and freeze-drying techniques with sufficient pores that allow an abundant cell migration and provide a proliferation space. Ti3C2 MXene has excellent photothermal conversion ability and stability. Quercetin targeted HSP70 to decrease its expression in OSCC cells, consequently weakening their resistance to high temperature and enhancing the effect of PTT. The M-CSQ scaffold effectively killed OSCC cells in vitro and inhibited tumor growth in vivo. In addition, the M-CSQ scaffold provided adhesion sites for Sprague-Dawley rat (SD rat) buccal mucosal fibroblasts and promoted the repair of buccal mucosal wounds.

Salvage radiosurgery following subtotal resection of vestibular schwannomas: does timing influence tumor control?

The goal of microsurgical resection of vestibular schwannoma (VS) is gross-total resection (GTR) to provide oncological cure. However, a popular strategy is to halt the resection if the surgical team feels the risk of cranial nerve injury is imminent, achieving a maximally safe subtotal resection (STR) instead. The tumor remnant can then be treated with stereotactic radiosurgery (SRS) once the patient has recovered from the immediate postoperative period, or it can be followed with serial imaging and treated with SRS in a delayed fashion if residual tumor growth is seen. In this study, the authors evaluated the efficacy of this multimodality approach, particularly the influence of timing and dose of SRS on radiological tumor control, need for salvage treatment, and cranial nerve function. VS patients treated with initial microsurgery and subsequent radiosurgery were retrospectively included from two tertiary treatment centers and dichotomized depending on whether SRS was given upfront (defined as before 12 months) or later. Radiological tumor control was defined as less than 20% tumor volume expansion and oncological tumor control as an absence of salvage treatment. Facial and cochlear nerve functions were assessed after surgery, at the time of SRS, and at last follow-up. Finally, a systematic literature review was conducted according to PRISMA guidelines. A total of 110 VS patients underwent SRS following microsurgical resection, with a mean preradiosurgical tumor volume of 2.2 cm3 (SD 2.5 cm3) and mean post-SRS follow-up time of 5.8 years (SD 4.1 years). The overall radiological tumor control and oncological tumor control were 77.3% and 90.9%, respectively. Thirty-five patients (31.8%) received upfront SRS, while 75 patients (68.2%) were observed for a minimum of 12 months prior to SRS. The timing of SRS did not influence the radiological tumor control (p = 0.869), the oncological tumor control (p = 0.560), or facial nerve (p = 0.413) or cochlear nerve (p = 0.954) function. An escalated marginal dose (> 12 Gy) was associated with greater tumor shrinkage (p = 0.020) and superior radiological tumor control (p = 0.020), but it did not influence the risk of salvage treatment (p = 0.904) or facial (p = 0.351) or cochlear (p = 0.601) nerve deterioration. Delayed SRS after close observation of residuals following STR is a safe alternative to upfront SRS regarding tumor control and cranial nerve preservation in selected patients.

BORDERLINE TUMORS OF THE OVARY

Borderline tumors of the ovary are lesions that have certain abnormalities, particularly microscopic, common with cancers, nevertheless they are not cancer in the strict sense of the term. The diagnosis of this pathology requires a good expertise in anatomo-pathology because there are several histological variants that can modulate the therapeutic management. They can be located only on one or two ovaries but can also extend to the lymph nodes and/or the peritoneum. These tumors have a very good prognosis overall. The most important prognostic factors are: the stage, the type of peritoneal implants (less good prognosis in case of invasive implants in serous tumors) and the existence of a tumor remnant (in stages II or III). Treatment is primarily surgical. The reference surgery for ovarian tumours (in a patient no longer of childbearing age) is bilateral adnexectomy. However, this surgery must be conservative in a young woman in the case of a stage I or stage II/III tumour but without invasive implants. In case of tumor with peritoneal implants, surgical resection of peritoneal locations is the rule. In macroscopically limited ovarian stages, there is an indication to perform a peritoneal staging (cytology, multiple biopsies and omentectomy) in serous micropapillary forms. Treatment is in the vast majority of cases exclusively surgical (most often conservative - in order to preserve future fertility - in young patients). Indications for chemotherapy are rare. The only indications for chemotherapy are the presence of invasive peritoneal implants and certain forms of lymph node involvement. Follow-up is done on a regular basis, especially in the case of conservative treatment, and is based on a clinical examination, markers and imaging by abdomino-pelvic ultrasound (in patients who have had conservative treatment). Recurrences are not life-threatening since they usually occur in a borderline mode and therefore have a good prognosis. Surveillance beyond 10 years is required (especially after conservative treatment). This surveillance is then based on clinical examination, marker assay and imaging.

Laser fluorescence spectroscopy in surgical treatment of intramedullary tumors: experience of the Burdenko Neurosurgery Center

To analyze efficacy of fluorescence navigation technique and laser fluorescence spectroscopy in surgical treatment of various spinal cord tumors. There were more than 1000 patients with intramedullary spinal cord tumors between 2001 and 2022. Intraoperative fluorescence navigation with laser spectroscopy was used in 47 cases. All patients underwent examination before and after surgery. We analyzed somatic, neurological and functional status (McCormick scale). MRI of the spinal cord and intraoperative fluorescence spectroscopy (OPMI Pentero 900 microscope with a fluorescent module, Carl Zeiss, Germany) were performed. To induce visible fluorescence, we used 5-ALA-Alasens (NIOPIK, Russia). Laser spectroscopy was carried out on a LESA-01-BIOSPEC analyzer (Biospec JSC, Russia). Morphological analysis of intramedullary spinal cord tumors was carried out in the laboratory of neuromorphology of the Burdenko Neurosurgery Center. In our sample, fluorescence navigation and laser fluorescence spectroscopy were used only in surgical treatment of intramedullary tumors. Laser fluorescence spectroscopy was valuable to identify fragments of intramedullary ependymoma and astrocytoma in 86% of cases, visual fluorescence - only in 81% of cases. Advisability of this technique for low-grade astrocytomas is unclear and requires further study. Visual fluorescence combined with laser spectroscopy is a promising method for intraoperative imaging of tumor remnants. This approach can improve safety, quality and results of surgical treatment.

Long and Covalently Conjugated Branched DNA Structures for in Situ Gelation in Vivo

Long and Covalently Conjugated Branched DNA Structures for in Situ Gelation in Vivo

Long-term outcome after management of pilocytic astrocytoma in the posterior fossa in a pediatric population.

To assess the impact of posterior fossa pilocytic astrocytoma (PA) removal in pediatric patients, with special focus on postoperative neurological outcome after repeated surgery for tumor remnants. Our institutional database was screened for patients with PA treated between 2000 and 2019. Patients ≤18 years of age with complete clinical records, preoperative contrast enhanced magnetic resonance imaging (MRI) and postoperative follow-up time of ≥6 months were suitable for study inclusion. Functional outcome was quantified with the modified Ranking Scale (mRS) score and assessed at admission, at discharge and at every follow-up investigation. Predictors of hydrocephalus, cranial nerve deficits and tumor recurrence were evaluated. A total of 57 pediatric patients with a mean age of 7.7±4.8 years were included in the analysis. 27 (47.3%) children suffered from hydrocephalus at diagnosis, out of which 19 (33.3%) required a subsequent VP-Shunt. 22 (39.3%) patients had a partial resection, of which 9 (40.9%) went through second-look surgery. 2 patients with initially radiological confirmation of complete resection, had a tumor recurrence at FU and needed second-look surgery. Among the children requiring second-look surgery, 7 (63.6%) had a complete resection. Favorable outcome (mRS≤2) after initial and second-look surgery was observed in 52 patients (91.2%). Univariate analysis identified tumor location in the floor of the 4th ventricle (p=0.030), and repeated surgery for tumor remnant removal (p=0.043) as predictors for post-operative cranial nerve deficits. Multivariate analysis confirmed this independent association. The incidence of tumor recurrence occurred more often in patients with previous partial resection (p=0.009) as well as in lesions located in the cerebellar peduncles (p=0.043). Partial resection remained an independent predictor after multivariate logistic regression analysis (p=0.045). Incomplete resection of posterior fossa PA is a risk factor for tumor recurrence and repeated surgery to remove tumor remnants increases the risk of new postoperative deficits. Thus, the risk of iatrogenic deterioration due to second look surgery should be implemented in the primary pre- and intraoperative decision-making.

Mediastinal Mass as First Clinical Manifestation of Medullary Thyroid Microcarcinoma in a Patient With Hashimoto’s Thyroiditis

Medullary thyroid cancer is a rare neuroendocrine tumor with aggressive behavior and an uncertain prognosis. Calcitonin is the associated tumor marker; however, neuroendocrine tumors of the lung or intestine can also present high values. We report the case of a 53-year-old patient presenting with dry cough for 3 years. Computed tomography (CT) showed a 58-mm expansive lesion in the right anterior mediastinum and cervical ultrasound informed a 9-mm hypoechoic nodule with a lobulated edge and thick calcifications. Cytology reported Hashimoto’s thyroiditis. He underwent emergent surgery for respiratory failure. The pathological study informed G2 neuroendocrine carcinoma, immunohistochemistry showed: cytokeratin (+), vimentin (+), alpha-actin (-), synaptophysin (+), chromogranin (+), Ki-67: 10%. He progressed with bone metastasis visualized in scintigraphy and mediastinal tumor remnants, adenopathy, and pulmonary nodules on CT scan, prompting chemotherapy. Due to elevated and increasing calcitonin, an ultrasound study with needle washout for calcitonin resulted in 1,724 pg/mL, and cytology of the nodule reported medullary carcinoma. He was finally diagnosed with medullary thyroid microcarcinoma with metastasis to the mediastinum. Coexistence with Hashimoto’s thyroiditis could alter the initial fine-needle aspiration results. We conclude that in the case of calcitonin-secreting neuroendocrine tumors or medullary thyroid cancer, calcitonin fine needle aspirate washout may be helpful in elucidating a diagnosis. Due to its severity, medullary thyroid cancer should always be approached and managed aggressively, even microcarcinomas. J Endocrinol Metab. 2022;12(6):198-201 doi: https://doi.org/10.14740/jem841

S1-Guideline: Microscopically controlled surgery.

Microscopically controlled surgery (MCS) comprises various methods allowing histologically proven complete resection of malignant tumors while at the same time sparing the tumor-free tissue in the immediate vicinity as much as possible. All procedures subsumed under MCS have in common the marking of the excised tissue for topographical orientation, which provides an assignment of remaining tumor remnants. Indications for MCS are malignant skin tumors in problem localizations as well as aggressive subtypes of skin tumors. Established indications for MCS include basal cell carcinoma, cutaneous squamous cell carcinoma, Bowen's disease as well as Bowen's carcinoma, dermatofibrosarcoma protuberans, melanoma in chronically light-damaged skin as well as acral lentiginous melanoma and Merkel cell carcinoma. For other tumors such as extramammary Paget's disease and various cutaneous sarcomas, evidence exists that MCS has demonstrated benefits, such as local recurrence rates. In addition, MCS is indicated when it is foreseeable that a complex closure technique is required and complete resection of the tumor must be assured. Various methods of MCS have been described, including 3D histology, horizontal method and Mohs surgery. A close cooperation of qualified surgeons and (dermato)pathologists as well as laboratory staff is essential for the successful application of MCS.

The role of single fraction Gamma Knife radiosurgery for intraventricular central neurocytomas and the utility of F-18 fluroethyltyrosine: two case reports

BackgroundPrimary treatment of central neurocytomas is surgical resection. Gamma Knife surgery is considered a valuable therapeutic option in case of residual (after subtotal resection) or recurrent central neurocytomas. Here, we focused on the role of F-18 fluroethyltyrosine as a marker to document tumor progression after initial resection, in the context of an atypical central neurocytoma. We also describe MIB-1’s role in evaluating therapeutic decision-making.Case presentationTwo patients with central neurocytomas were treated by Gamma Knife surgery in our center. The first case (31-year-old Caucasian male) had atypical central neurocytoma. Four and a half years after surgical resection, magnetic resonance imaging and F-18 fluroethyltyrosine documented clear progression of residual central neurocytoma, further treated by Gamma Knife surgery (18 Gy at 50%, target volume 1.4 cc, and prescription isodose volume 1.8 cc). The initial post-Gamma Knife surgery clinical course was uneventful, with progressive volumetric reduction of residual tumor up to 4.5 years, when out-of-field recurrence was suspected and confirmed by local F-18 fluroethyltyrosine hyperactivity. Second single-fraction Gamma Knife surgery was performed (18 Gy at 50%, target volume 0.49 cc, prescription isodose volume 0.72 cc). The second (32-year-old Caucasian female) had previous subtotal resection and typical central neurocytoma. Seven years later, she had residual tumor progression. Single-fraction Gamma Knife surgery was performed (16 Gy at 50% isodose line, target volume 1.7 cc, and prescription isodose volume 2.5 cc). Last follow-up showed tumor volume reduction. Follow-up magnetic resonance imaging showed important volumetric reduction of both treated lesions.ConclusionsIn atypical central neurocytomas, F-18 fluroethyltyrosine could be used as postoperative examination to detect small tumor remnants, follow-up evaluation following the Gamma Knife surgery or, in select cases, following surgical resection. The role of MIB-1 is important in therapeutic decision-making, as tumors with MIB-1 exceeding 2% are characterized by more aggressive clinical course. Single-fraction Gamma Knife surgery remains a valuable therapeutic option for postoperative residual atypical central neurocytomas and central neurocytoma recurrences.

Pediatric Low-Grade Glioma Surgery with Sodium Fluorescein: Efficient Localization for Removal and Association with Intraoperative Pathological Sampling.

Low-grade gliomas are among the most common CNS lesions in pediatrics and surgery is often the first-line treatment. Intraoperative tools have been developed to maximize the results of surgery, and in particular dyes such as sodium fluorescein (SF) have been investigated in high-grade adult lesions. The use of SF in pediatric low-grade gliomas is still unclear. We retrospectively reviewed 22 pediatric CNS low-grade gliomas operated on with SF from September 2021 to October 2022. A total of 86% of lesions showed SF uptake, which was helpful intraoperatively (confirmation of initial localization of the tumor, or identification of tumor remnants) in 74% of them. The intraoperative fluorescence seems associated with gadolinium enhancement at the preoperative MRI. Interestingly, the extemporaneous pathological sampling (EPS) was informative in every case showing SF uptake, whereas in cases without SF uptake, the EPS was non-informative, although the tissue was later confirmed as pathological. These findings highlight the interest of SF for perioperative diagnosis of tumor tissue and may suggest in which cases the differentiation of tumor-healthy tissue could be especially blurred, posing difficulties for the pathologist.

QLTI-09. DEFINING GLOBAL BENCHMARK OUTCOMES FOR TRANSSPHENOIDAL SURGERY OF PITUITARY ADENOMAS: A MULTICENTER ANALYSIS OF 2862 CASES

Abstract Benchmarks are important to measure and aid in improve outcomes for surgical procedures. However, best achievable results that have been validated internationally for transsphenoidal surgery are not available. Therefore, we aimed to establish robust, standardized outcome benchmarks for transsphenoidal surgery of pituitary adenomas. A total of 2862 transsphenoidal tumor resections from 12 high-volume centers in 4 continents were analyzed. Patients were risk stratified and the median values of each center’s outcomes were established. The outcome benchmark was defined as the 75th percentile of all median values for a particular outcome as defined by Staiger et al. Out of 2862 patients, 1201 (41.9%) defined the benchmark cohort. The proportion of benchmark cases contributing to the final cohort ranged across centers between 22.1% to 59.7%. Within the benchmark cases, 928 (73.3%) patients underwent microscopic (MTS) and 263 (21.9%) patients endoscopic endonasal resection (EES). The overall postoperative complication rate was 18.9% with an in-hospital mortality between 0.0-0.8%. Benchmark cutoffs were ≤ 3.3% for reoperation rate, ≤ 4.6% for cerebrospinal fluid leak requiring intervention, and ≤ 15.3% for transient diabetes insipidus. At 6 months follow-up, benchmark cutoffs were calculated as follows: readmission rate: ≤ 7.1%, new hypopituitarism ≤ 15.5%, new neurological deficit ≤ 1.2%, tumor remnant ≤ 25.5%. This analysis defines benchmark values for transsphenoidal resection of pituitary adenomas targeting morbidity, mortality, surgical and tumor-related outcomes. The benchmark cutoffs can be used to assess different centers, patients’ populations, and novel surgical techniques.

CTNI-66. THE PREOPERATIVE BRAIN IRRADIATION IN GLIOBLASTOMA (POBIG) STUDY: A NOVEL TREATMENT PARADIGM TO IMPROVE OUTCOMES?

Abstract OBJECTIVE The Preoperative Brain Irradiation in Glioblastoma (POBIG) study evaluates for the first time the safety, feasibility, and impact of single fraction preoperative radiotherapy in newly diagnosed glioblastoma patients. METHODS Operable patients with a radiological diagnosis of glioblastoma, by consensus of a multidisciplinary tumor board including two dedicated neuro-radiologists, are screened for the study. Anatomical and functional MRI sequences are acquired for further tumor characterization and preoperative radiotherapy planning. Radiotherapy is delivered approximately two weeks after the initial screening. Radiation targets the macroscopic and microscopic tumor region at risk of being left behind during surgery and spares at least 2cc tumor volume being debulked to safeguard unperturbed and clinically relevant tissue examination and molecular profiling. The study dose-escalates (from 8Gy to 14Gy) based on the time-to-event Continual Reassessment Methodology. Subsequently, patients undergo surgical debulking followed by postoperative fractionated radiotherapy 60Gy/30fr with concurrent temozolomide. RESULTS The first POBIG study patient underwent preoperative radiotherapy followed by a subtotal resection of a left posterior fronto-opercular tumor and completed the postoperative chemoradiotherapy. Screening, study consent, MRI imaging and analysis, radiotherapy planning and delivery until surgery can be achieved within three weeks from screening while maintaining adequate and personalized patient communication. There were no surgical or radiotherapy delays or complications. During surgery, we successfully sampled unirradiated and irradiated tumor regions. The radiotherapy field covered the whole remnant tumor, and image-guided obtained tumor samples and imaging analysis showed clear evidence of differential radiation-induced changes. CONCLUSION We successfully initiated a new treatment strategy of preoperative radiotherapy for glioblastoma patients. The first patient completed the treatment, and the study is now open for further recruitment. Paired tumor sampling and advanced imaging analysis showed promising results. The POBIG study offers a unique opportunity for a paradigm shift towards personalized treatment regimens, hopefully leading to better outcomes.

CTNI-51. FEASIBILITY AND SAFETY OF NEUROSURGICAL RESECTION AND INTRA-OPERATIVE RADIATION THERAPY USING THE XOFT AXXENT ELECTRONIC BRACHYTHERAPY SYSTEM AND BEVACIZUMAB IN RECURRENT GLIOBLASTOMA

Abstract Glioblastoma (GBM) is the most common and aggressive primary brain tumor. External beam radiation therapy (EBRT) is widely recognized as an effective treatment for primary GBM. EBRT applied after GBM resection is associated with an increase in overall survival. Beyond upfront therapy with radiation and temozolomide chemotherapy, there is no standard therapy that has been proven effective. Re-irradiation with ERBT is minimally effective and with significant comorbidities. Our study uses IORT at the time of re-resection in patients who have recurrent, operable GBM after failure of who received primary EBRT and temozolamide in their first course of treatment. IORT allows the delivery of a large effective radiation dose applied directly to the tumor bed at the time of resection. This affords direct radiation to be delivered to the micro- and macroscopic tumor remnants in the vicinity of the resection cavity immediately following gross resection. In contrast, the more distant, surrounding brain tissue does not receive high radiation exposure. This Phase II study continues to accrue subjects with the primary endpoint of overall survival and several secondary endpoints that includes progression free survival, quality of life, and adverse events/safety. To date, five patients have been treated on this protocol. The technical feasibility and safety of administering intraoperative radiation with the Xoft System has been established in this cohort. Preliminary GLIOX Trial findings demonstrate the safety and feasibility of using the Xoft Axxent® Electronic Brachytherapy System to administer intracranial radiation during resection of recurrent glioblastomas. We will report new and expansive study results to include these early findings.

Tailoring Brachytherapy by Identification of Fibrosis vs. Tumor: Evaluating Acute and Chronic Fibrosis via UTE MRI in Gynecological Cancer

<h3>Purpose/Objective(s)</h3> Radiation injury triggers inflammation, fibroblast migration, and deposition of collagen (acute fibrosis) that later remodels into denser matrices forming scar (chronic fibrosis) at the previous location of tumor. Non-contrast enhanced Short-Inversion-Time (STIR) ultra-short echo time (UTE) MRI has been used to quantify collagen fractions in collagen/aqueous-solution mixtures and to evaluate acute fibrosis. Late-gadolinium enhanced (LGE) IR UTE MRI is a technique that has been used to evaluate chronic scar in the heart. The role of these UTE MR techniques to monitor evolving fibrosis over the course of radiation in cancer has not been studied. We hypothesize that the percentage of fibrosis relative to initial tumor volume increases over the course of external beam radiation prior to brachytherapy in gynecological cancer. <h3>Materials/Methods</h3> <i>Subjects:</i> Cervical and vaginal cancer patients undergoing concurrent chemoradiation were included. MR images were acquired pre- and 1 day post 45 Gy EBRT. <i>Image Acquisition</i>: Imaging was performed on 1.5T MRI using a prototype stack of spirals dual echo (TE_1,2=50, 2690µs) STIR UTE sequence with TI=60, or 80ms. To evaluate acute (diffuse) fibrosis, which has a short-TE, TE₂ images were subtracted from TE₁ images. Chronic fibrosis (necrotic scar) was evaluated using TE₁ of LGE IR UTE, TI=200ms, acquired ≥10 min after contrast injection. <i>Image Analysis:</i> All images were rigidly registered to the treatment planning CT. EBRT CTV contours were propagated onto the MR images. STIR-UTE images were segmented using region-growing. Acute fibrosis (F_A) and chronic fibrosis (F_C) contours were segmented on the non-contrast STIR UTE and on the LGE UTE, respectively. Fibrosis signals were normalized between successive scans based on the femoral heads' cartilage signal. Percentages of the F_A and F_C within the CTV were determined and compared pre- and post-EBRT using a paired t-test. <h3>Results</h3> In five cervical cancer and two vaginal cancer patients, F_A was observed in the irradiated tumor and lymph nodes. The extent of baseline F_A vs. F_C was not significantly different (p=.2) (Table 1). Baseline F_A was significantly lower than post-treatment F_A within the CTV (pre-treatment/post-treatment: 11±11%/34±15%, p=.01). F_C was significantly higher (pre-treatment/post-treatment: 5±2%/18±10%, p=.01). Post-EBRT, there was a significant difference between F_A and F_C within the CTV (p=.01) suggesting a faster increase in acute fibrosis as compared to scar, which requires more time to mature. <h3>Conclusion</h3> We observed an increase in F_A and F_C post-EBRT within the CTV. F_A can serve as an early indicator of F_C. Identifying regions of fibrosis has the potential to guide brachytherapy treatment planning. Future work will focus on precisely prescribing high-doses of brachytherapy to remnant tumor.

Recurrence Rate and Exploration of Clinical Factors after Pituitary Adenoma Surgery: A Systematic Review and Meta-Analysis based on Computer Artificial Intelligence System.

Background The first-line treatment for patients with any type of pituitary adenoma is trans-sphenoidal surgery. Considering the prevalence of the condition globally, the treatment is quite common. The recurrence of pituitary adenoma is a recognized occurrence in the medical field; however, there is limited comprehensive research and analysis of the predictive factors of recurrence rates and the clinical factors impacting relapse rates. Identifying the recurrence rates of pituitary adenomas and the clinical factors associated with them could help increase the remission rate by increasing focus on the specific aspects for early diagnosis and improved treatment. Objective The objective of the current systematic review and meta-analysis is to assess the recurrent rates based on previous studies and to explore the clinical factors after pituitary surgery. Methods A search was performed on PubMed, APA PsycINFO, Scopus, CENTRAL, and Google Scholar databases for English articles published from 1st January 2010 to 1st August 2022. Systematic reviews, meta-analysis, evidence syntheses, editorials, commentaries, preclinical studies, abstracts, theses, and preprints were excluded. Meta XL statistical software was used to conduct a prevalence meta-analysis. Results PubMed, PsycINFO, and Medline databases were searched. All of the articles were written between 2012 and 2022. In the beginning, 612 items were recognized. After removing duplicates and analyzing the remaining articles in terms of inclusion and exclusion criteria, 31 articles remained. Conclusion There is a relationship between recurrence rates and the follow-up period. There were conflicting results about the clinical factors after pituitary adenoma surgery, specifically age and tumor size. Some included studies that there was an association between macroadenomas and high recurrence rates. No study reported that gender was a clinical factor affecting pituitary adenoma surgery outcomes or the recurrence rate. Studies also reported that there was a correlation between the remnant tumor factor and the recurrence rates; adenoma remnants after surgery increased the risk of recurrence rates for patients.

Chondroblastoma of Thoracic Vertebrae: a Case Report and Review of the Literature.

Chondroblastoma is a rare benign cartilaginous bone tumor typically seen at the epiphysis of long axial bones. In this regard, there are rare findings about spinal chondroblastomas. We report a 29-year-old man with T1 vertebral chondroblastoma misdiagnosed with a traumatic fracture following an accident. The patient was admitted to our clinic with a chief complaint of axial back pain and kyphosis following posterior spinal fixation. We report his clinical and imaging data before his past operation and at this admission. Our patient underwent a two-stage operation. In the first stage, posterior spinal reconstruction and kyphosis correction was performed. In the second stage, mass resection was performed anteriorly in the T1 vertebral body as much as possible. The results confirmed the chondroblastoma diagnosis histologically. Our patient remained symptom-free with no growth in tumor remnant during 6months follow-up. Although vertebral chondroblastoma is a sporadic tumor, it should be considered in the differential diagnosis when facing a vertebral infiltrative osteolytic mass, even when mimicking a traumatic fracture after the accident. In addition, histological confirmation is necessary under such conditions. We also reviewed the literature's clinical presentations, imaging findings, and treatments of 34 case reports with vertebral chondroblastoma.