Clinical Outcome of Neoplastic Meningitis Associated with Breast Cancer

Background Neoplastic meningitis (NM) is considered as a terminal event with poor prognosis. Its impact in clinical oncology is growing. Objective To analyze the clinical outcome of patients with carcinoma breast diagnosed with NM. Materials and Methods This study was an observational study in breast cancer patients diagnosed with NM. Patients with typical clinical symptoms and signs with either presence of cerebrospinal fluid (CSF) cytology positive for neoplastic cells or typical radiological features of leptomeningeal involvement in the presence of neurological symptoms or signs were taken as leptomeningeal metastasis (LM) or NM. The estimation of survival was done by Kaplan–Meier method. Results Out of 1,200 patients diagnosed with carcinoma breast during the study period, 15 developed NM. The median age of study population was 51 (range: 44–55) years. Most common presentations were headache (47%), vomiting (47%), diplopia (20%), seizure (20%), and cerebellar signs (7%). Seven (46%) patients were hormone receptor positive, four (30%) were HER2 (Human epidermal growth factor receptor 2) positive and seven (46%) were triple-negative breast cancer. Median time to develop LM from the time of diagnosis of breast cancer was 6 (range: 3–8) months. Nine patients (90%) had features of NM in CSF cytology. Thirteen patients received palliative whole brain radiotherapy (20 Gy in five fractions). Nine out of 12 patients received single-agent Capecitabine as first-line chemotherapy after palliative radiation therapy (RT). Intrathecal methotrexate was given for seven patients. The median overall survival was 3 (range: 0.5–4) months. Conclusion LM is a very aggressive metastatic disease with poor outcome. There is an unmet need for proper guidelines and an overwhelming necessity for a better focus on research for new modalities of disease in this scenario.

Experimental Assessment of Leptomeningeal Metastasis Diagnosis in Medulloblastoma Using Cerebrospinal Fluid Metabolomic Profiles

Diagnosing leptomeningeal metastasis (LM) in medulloblastoma is currently based on positive cerebrospinal fluid (CSF) cytology or magnetic resonance imaging (MRI) finding. However, the relevance of discordant results has not been established. We evaluated the diagnostic potential of CSF metabolomic profiles in the medulloblastoma LM assessment. A total of 83 CSF samples from medulloblastoma patients with documented MRI and CSF cytology results at the time of sampling for LM underwent low-mass ions (LMIs) analysis using liquid chromatography-mass spectrometry. Discriminating LMIs were selected by a summed sensitivity and specificity (>160%) and LMI discriminant equation (LOME) algorithms, evaluated by measuring diagnostic accuracy for verifying LM groups of different MRI/cytology results. Diagnostic accuracy of LM in medulloblastoma was 0.722 for cytology and 0.889 for MRI. Among 6572 LMIs identified in all sample, we identified 27 discriminative LMIs differentiating MRI (+)/cytology (+) from MRI (−)/cytology (−). Using LMI discriminant equation (LOME) analysis, we selected 9 LMIs with a sensitivity of 100% and a specificity of 93.6% for differentiating MRI (+)/cytology (+) from MRI (−)/cytology (−). Another LOME of 20 LMIs significantly differentiated sampling time relative to treatment (p = 0.007) and the presence or absence of LM-related symptoms (p = 0.03) in the MRI (+)/cytology (−) group. CSF metabolomics of medulloblastoma patients revealed significantly different profiles among LM diagnosed with different test results. We suggest that LM patients could be screened by appropriately selected LOME-generated LMIs to support LM diagnosis by either MRI or cytology alone.

BIOM-02. LEPTOMENINGEAL DISEASE SECONDARY TO MELANOMA: UPDATES ON THE VALIDITY OF THE VERIDEX CELLSEARCH SYSTEM

BACKGROUND Leptomeningeal disease (LMD) is devastating with a median survival of 8-10 weeks without treatment. LMD affects approximately 5% to 25% of melanoma patients. Its pathophysiology remains unknown and effective treatments are virtually non-existent. The primary aim of this study was to evaluate the validity of Veridex CellSearch® System (VCS) compared to Gold Standard test (i.e., CSF cytology). MATERIALS AND METHODS A retrospective chart review was performed of subjects with suspected LMD from melanoma enrolled in the MCC 19332/19648 at Moffitt Cancer Center. Patients underwent standard of care with different treatments as deemed appropriate by treating physician. CSF samples were obtained from lumbar punctures, surgeries, and Ommaya reservoir. CSF was evaluated for quantification of CSF circulating tumor cells (CTCs) with the Veridex CellSearch® System (VCS). RESULTS Forty-eight patients were identified with melanoma as primary tumor, ages 29-80. Twenty-seven had LMD (median age 62) with median KPS 70. N=19 (70%) were diagnosed radiographically and n=5 (19%) with CSF cytology; n=14 (54%) had positive cytology on first LP. From 24 patients with LMD who underwent VCS, n=22 (92% patients had positive CSF CTCs. Number of CTCs/mL CSF was significantly higher in patients with LMD versus in patients without LMD (mean SD 227.6 vs. 0.07, p < 0.001). VCS sensitivity and specificity was analyzed. AUC was 0.515, with TPR 0.250 and FPR 0.286. CSF analysis and treatments were described. The median survival of those with LMD was 2.7 months. CONCLUSION These results indicate the potential value of the VCS as an additional tool to the gold standard in the diagnosis of LMD in patients with high suspicion of the disease. Future directions involve doing prospective studies to further validate this method, and to better understand this patient population to enhance diagnostic tools and management of LMD.

NCMP-14. WHOLE BRAIN RADIOTHERAPY COMBINED WITH INTRATHECAL LIPOSOMAL CYTARABINE FOR LEPTOMENINGEAL METASTASIS – A SAFETY ANALYSIS AND VALIDATION OF THE EANO-ESMO CLASSIFICATION

BACKGROUND Although there is no proven standard therapy for leptomeningeal metastases (LM), treatment often includes intrathecal chemotherapy combined with whole brain radiation therapy (WBRT). Little is known on the toxicity of such combination therapies. We performed a retrospective safety analysis for the combination of intrathecal liposomal cytarabine with WBRT in patients with LM and validated the EANO-ESMO classification in this unique cohort. METHODS Treatment toxicities in patients diagnosed with LM between 2004 and 2014 were retrospectively analyzed according to the RTOG (Radiation Therapy Oncology Group) and NCI CTCAE V5.0 (Common Toxicity Criteria Adverse Events) toxicity criteria. Diagnostic criteria and treatment response as assessed by EANO-ESMO classification were correlated with survival by Kaplan Meier analysis and Breslow test. RESULTS 40 patients with LM who were treated with combined WBRT and intrathecal cytarabine, were identified. Ten patients (25%) experienced adverse events ≥ grade 3 according to the RTOG-toxicity criteria, in 22 patients (55%) CTCAE criteria ≥3 grade were detected. Median overall survival (mOS) was 124.0 days [72.9;175.1]. Median time to neurological progression was 52.0 days [41.1; 62.8]. When comparing the diagnostic criteria, patients with a positive CSF cytology (n=26) showed worse prognosis compared to patients with a negative CSF cytology (n=14) (mOS 84 days [44.0;124.0] versus 198.0 days [162.6;233.4] days, p=0.006, respectively). The EANO-ESMO response assessment correlated significantly with survival - “stable” (n=7) mOS 233.0 [76.5;389.5] days, “response” (n=10) mOS 206.0 [193.9;218.9] days, “progression” (n=17) mOS 45.0 [34.4;55.6] days, “suspicion of progression” (n=6) mOS 133.0 [65.8;200.2] days (overall, p< 0.001). CONCLUSIONS In this retrospective analysis, the treatment combination of WBRT and intrathecal liposomal cytarabine shows an acceptable safety profile. The EANO-ESMO classification for diagnosis and treatment response predicts survival

P14.26 Leptomeningeal Disease Secondary to Melanoma: Diagnosis, Treatment, and Outcomes at a Single Institution between 2013 and 2019

BACKGROUND Leptomeningeal disease (LMD) is devastating with a median survival of only 8–10 weeks. LMD affects approximately 5% to 25% of melanoma patients. Its pathophysiology remains unknown and effective treatments are virtually non-existent. The aim was to evaluate demographics, validity of Veridex CellSearch® System (VCS) compared to Gold Standard test (i.e., CSF cytology), risk factors for LMD, and treatment outcomes. MATERIALS AND METHODS A retrospective chart review was performed of subjects with suspected LMD from melanoma enrolled in the MCC 19332/19648 studies between 2013 and 2019 at Moffitt Cancer Center. The patients underwent standard of care with different treatments as deemed appropriate by treating physician. CSF samples were obtained from lumbar punctures, surgeries, and Ommaya reservoir, and sent for analysis. Peripheral blood and CSF were evaluated for detection and quantification of CSF circulating tumor cells (CTCs) with the Veridex CellSearch® System, which is adapted to enumerate CTCs from CSF. RESULTS More than 100 patient charts were reviewed. Only patients with melanoma as primary tumor (N=48) were included in the analysis, with ages 29–80. N=28 (58%) met criteria for LMD (median age 59, M:F ratio of 3:1). Within the LMD group, n=26 patients had cutaneous melanoma as primary tumor; BRAF mutant n=17 (V600E n=14; G469E n=1). At the time of diagnosis, median KPS score was 70, with most prevalent symptoms of headaches, encephalopathy, focal weakness, and nausea/vomiting. N=20 (71%) patients were diagnosed radiographically and n=5 (18%) with CSF cytology; n=14 (52%) had positive cytology on first LP, n=18 (67%) on first two LPs. From 25 patients with LMD who underwent CellSearch® to quantify CTCs, n=22 (88%) patients had positive CSF CTCs; n=18 (72%) on first sample sent for analysis, n=20 (80%) on first two samples. The sensitivity and specificity of the Veridex CellSearch® System compared to the Gold Standard CSF cytology were analyzed. Survival in months plotted against the percentage of CSF-CTCs showed a significant value of p=0.0377. CSF analysis i.e., inflammatory markers, and treatments pre-/post-LMD diagnosis will be described. Most patient were managed with Ommaya reservoir placement, radiation therapy, immunotherapy, BRAF +/- MEK inhibitors, IT thiotepa, or IT topotecan. The median survival of those with LMD was 3.15 months. Two patients outlived their counterparts by 21.1 and 39.0 months after the LMD diagnosis, one of them is still alive but with a very poor functional status. CONCLUSION These results indicate the potential value of the VCS as an additional tool to the gold standard in the diagnosis of LMD in patients with high suspicion of the disease. Future directions involve doing prospective studies to further validate this method, and to better understand this patient population to enhance diagnostic tools and management of LMD.

P14.04 Detection of circulating tumor cells in cerebrospinal fluid for patients with suspected breast cancer leptomeningeal metastases. A prospective study

BACKGROUND Breast cancer (BC) is the most frequent cause of leptomeningeal metastases (LM). LM diagnosis is confirmed by the detection of tumor cells in the cerebrospinal fluid (CSF) using conventional cytology (gold standard). However, even with optimal CSF sample volume and time to the analysis, the sensitivity of this technique is low, demanding repeated samples. Here, we aimed to evaluate the value of circulating tumor cell (CTC) detection in CSF using the CellSearch® system for LM diagnosis. MATERIAL AND METHODS This prospective, monocentric study included adult BC patients with suspected LM (clinical and/or radiological signs). CSF samples from 1–3 lumbar puncture(s) were analyzed: protein level, conventional cytology (60 drops), and CTC detection with the CellSearch® system (60 drops, first lumbar puncture only). Sensitivity (Se) and specificity (Sp) were calculated, using the results of the conventional cytology as the gold-standard. RESULTS Forty-nine eligible patients were included (Jan 2017-Jan 2020): median age 51.8, 95.9% women, 20.4% HER2+ BC, 93.8% previously diagnosed with metastatic BC, 89.8% with clinical symptoms. Among them, 40 were evaluable (CTC detection failure: n=8, eligibility criteria failure: n=1). Median sample volume was 3.0 mL for conventional cytology samples (median time to analysis: 22min) and 3.3 mL for CTC samples. Of the 40 evaluable patients, 18 had a positive cytology (on CSF sample n=°1/n°2: n=16/n=2) and were therefore diagnosed with LM using the gold-standard method. Protein level was elevated in 88.2% of these patients, compared with 45.1% of patients with negative CSF cytology (p=0.005). CTCs were detected in these 18 patients (median 5824 CTCs, range 93-45052). CTCs were also detected in 5/22 patients with a negative cytology (median 2 CTCs, range 1–44). Among them, one patient (44 CTCs) was diagnosed with a cytologically-proven LM 9 months later, while there was no further argument for LM in the other 4 patients’ history (1–3 CTC), who died of the extra-cerebral disease after a median time of 5.2 months (range 0.9–25.9). The detection of at least one CTC in CSF was associated with a Se of 100.0% (IC95% 82.4–100) and a Spe of 77.3% (IC95% 64.3–90.3) for the diagnosis of LM. CONCLUSION CTCs were detected with the CellSearch® system in all patients diagnosed with a cytologically-proven LM, as well as in a few patients without a cytological confirmation of LM. The prognosis of these patients with CSF cytology-/CTCs+ needs to be further investigated in a larger cohort.

LMD-18. Detection and serial monitoring of CSF ctDNA in breast cancer leptomeningeal disease (BCLM)

Background CSF cytology is the gold standard diagnostic test for BCLM, but is hampered by a low sensitivity, often necessitating repeated lumbar puncture to confirm or refute the diagnosis. Furthermore, during the treatment of BCLM, there is no robust quantitative response tool to guide treatment decisions. Material and Methods cfDNA was obtained from CSF and plasma in patients with breast cancer undergoing investigation for BCLM (n = 28) and during subsequent intrathecal treatment (n = 13). Ultra low pass whole genome sequencing (ulpWGS) and estimation of the ctDNA fraction was performed. Results were validated by mutation-specific digital droplet PCR (ddPCR). Results 22/28 cases had confirmed BCLM by positive MRI and/or CSF cytology. The remaining 6/28 had suspected but non-confirmed BCLM, and at median 20 months follow up, these patients were BCLM-free. CSF ctDNA fraction was significantly elevated (median 57.5, IQR 38.3 - 84.9%) in confirmed BCLM compared to 6 non-confirmed BCLM (median 5.0, IQR 0.0 - 6.7%) (p <0.0001). ctDNA fraction was detected in BCLM confirmed cases regardless of negative cytology or MRI. Plasma ctDNA fraction was only detected in extra-cranial disease progression. ctDNA fraction was concordant with mutant allele fraction measured by ddPCR (n = 118 samples). Serial CSF ctDNA fraction during intrathecal treatment showed dynamic changes, while CSF cytology and MRI were often unchanged or equivocal. Early reduction in CSF ctDNA fraction was associated with longer responses to intrathecal therapy. Further, rising ctDNA fraction during intrathecal chemotherapy could be detected up to 6 weeks before relapse in neurological symptoms, cytology or MRI. Conclusion Measuring CSF ctDNA fraction is a sensitive diagnostic test for BCLM and could lead to more timely and accurate diagnosis. During intrathecal chemotherapy, CSF ctDNA also provides a quantitative response biomarker to help guide clinical management in this difficult treatment scenario.

LMD-22. Clinicopathological spectrum of leptomeningeal metastases: A 3 year retrospective study

Objectives Cytological examination of cerebrospinal fluid is a widely used cost effective, simple procedure and a reliable routine diagnostic test. CSF cytology helps in detection of inflammatory diseases of the CNS, diagnosis of subarachnoid haemorrhage and the identification of malignant cells in metastatic or rarely primary CNS malignancies.Leptomeningeal metastases (LM) is estimated to occur in 5% of all patients with cancer. It has a higher propensity to occur in solid tumours compared to haematological malignancies.In view of poor prognosis, early diagnosis may aid in appropriate tumour staging and aggressive therapeutic intervention. Methods All the samples of CSF received in the Department of Laboratory for cytological examination and reported as ‘positive for malignant cells’ during the year January 2018 to December 2020were included in the study. All the cases were routinely evaluated on Neubauer’s chamber, direct smear and a cytospin preparation stained using MGG stain. The clinical records and any further ancillary testing performed were retrospectively analysed. Results 87cases with LM were identified over 3 year duration. Mean age of presentation was 43 years. Metastatic solid malignancies (56%) had a higher incidence of leptomeningeal metastases compared to haematolymphoid malignancies (40%) and CNS medulloblastomas(2%). Most common solid tumour with involvement of CSF was adenocarcinoma lung (51%) followed by breast carcinoma (37%). Of all the cases of adenocarcinoma lung with LM, EGFR mutant NSCLC were 40% while 8% showed ALK gene rearrangement. Amongst the haematological malignancies, acute leukaemia’s constituted 67% of cases while systemic NHLs were 34%. Most of the cases (97%) presented with neurological symptoms during the course of treatment while 3 cases (3%) showed LM at the time of first presentation. Conclusions With appropriate clinicoradiological correlation, CSF cytology remains the gold standard for identification of malignant cells in cases with already known primary tumour (leptomeningeal dissemination of the disease). In this study, clinical features of both solid and haematolymphoid malignancies were evaluated. The group of solid malignancies included adenocarcinomas lung, breast, gastrointestinal tract and renal cell carcinoma. With the availability of EGFR TKIs and ALK inhibitors, overall survival of the patients may be prolonged with therapeutic interventions despite limited CSF and CNS penetration of these drugs.

Necessity for craniospinal irradiation of germinoma with positive cytology without spinal lesion on MR imaging - A controversy

Background Cerebrospinal fluid (CSF) cytology and spinal MR imaging are routinely performed for staging before treatment of intracranial germinoma. However, the interpretation of the results of CSF cytology poses two unresolved clinical questions: 1) Does positive CSF cytology correlate with the presence of spinal lesion before treatment?; and 2) Is craniospinal irradiation (CSI) necessary for patients with positive CSF cytology in the absence of spinal lesion? Methods Multicenter retrospective analyses were performed based on a questionnaire on clinical features, spinal MR imaging finding, results of CSF cytology, treatments, and outcomes which was sent to 86 neurosurgical and 35 pediatrics departments in Japan. Pretreatment frequencies of spinal lesion on MR imaging were compared between the patients with positive and negative cytology. Progression-free survival (PFS) rates were compared between patients with positive CSF cytology without spinal lesion on MR imaging treated with CSI and with whole brain or whole ventricular irradiation (non-CSI). Results A total of 92 germinoma patients from 45 institutes were evaluated by both CSF cytology and spinal MR images, but 26 patients were excluded because of tumor markers, the timing of CSF sampling or incomplete estimation of spinal lesion. Of the remaining 66 germinoma patients, spinal lesions were equally identified in patients with negative CSF cytology and positive cytology (4.9% and 8.0%, respectively). 11 patients treated with non-CSI had excellent PFS comparable to 11 patients treated with CSI. Conclusion CSI is unnecessary for germinoma patients with positive CSF cytology without spinal lesions on MR imaging.

Intrathecal (IT) and intravenous (IV) nivolumab (N) for metastatic melanoma (MM) patients (pts) with leptomeningeal disease (LMD).

9519 Background: MM pts with LMD have a dismal prognosis, with median overall survival (OS) < 3 months, no approved therapies and extremely limited clinical trial options. We previously reported initial safety findings from an open label, single arm, single center phase I/IB trial (NCT03025256), in which IT and IV N were well tolerated, without any CNS-specific or unexpected toxicity. Here we report an update on safety and maximum tolerated dose (MTD) for all patients enrolled, and efficacy for the completed dose cohorts. Methods: MM patients aged >18 with evidence of LMD by MRI and/or CSF cytology, ECOG PS ≤2 were treated with IT and IV N. Dexamethasone ≤4mg/daily and concurrent BRAF/MEK inhibitor(i) treatment was allowed. For cycle 1, IT N was administered via intraventricular reservoir on day (D)1. For subsequent cycles (every 14 days), pts received IT N on D1, followed by IV N 240 mg on D2. IT N doses evaluated were 5, 10, 20 mg and 50 mg. Blood and CSF were collected at multiple time points for translational research. The primary objectives of this first-in-human study were to determine the safety and MTD of IT N given with IV N in MM pts with LMD. Bayesian mTPI methodology was used to define the MTD. Results: To date, 23 pts have been treated: two at 5, three at 10, fourteen at 20 mg and four at 50 mg IT N. Median age at LMD diagnosis was 42 (28-73); 12 pts are male. All pts had radiographic evidence of LMD and neurological symptoms; 14 pts had positive CSF cytology at baseline. 21 pts received prior therapies for their metastatic melanoma: anti-PD1 (n = 19), BRAFi/MEKi (n = 14), chemo (n = 2), IT IL2 (n = 4) other (n = 2). 19 pts had prior XRT, including whole brain RT (n = 7). Two pts were treatment-naïve. The median number of IT N doses was five (1- 66). The combination regimen was well tolerated by all evaluable pts (n=23), with only five pts (22%) experiencing gr 3 AEs, and no reported gr 4 or 5 toxicities. Nausea (30%), diarrhea (26%), and rash (22%) were the most common AEs. Eight pts (23%) experienced AEs after IT N administration, all gr 1. Initial efficacy analysis included only pts (n=19) treated with first three dose levels (5-20mg). Median follow-up for these pts is 4.5 months (mos) (1.1, 31.5 mos) and median OS is 63 % at 3 mos, 42 % at 6 mos and 30% at 12 mos. Conclusions: The trial demonstrates the feasibility and safety of IT administration of modern immunotherapy for MM pts with LMD. No unexpected systemic or neurological toxicity was observed with 20mg IT N. 2 additional patients are required to complete the 50mg IT N cohort. OS rates at 6 and 12 mos are encouraging and support further evaluation of IT administration of immunotherapy agents for pts with MM and LMD. Final presentation will include results of LMD for all dose cohorts, composite response assessment and comparative analysis of longitudinal CSF samples to assess immunologic effects. Clinical trial information: NCT03025256.