P-147: Central Nervous System Involvement in Multiple Myeloma Cases Reported at Instituto Nacional de Cancerología

Introduction: Central nervous system (CNS) involvement in multiple myeloma represents an unusual presentation of extramedullary disease. Infiltration to the CNS in most cases appear as a sign of progression or relapse, representing less that 1% during the disease course. It is associated to a poor prognosis with a mean survival time of 4 to 7 months.

Methods: A review was carried out from patients diagnosed with multiple myeloma with CNS involvement at the Instituto Nacional Cancerología in Mexico City, between April 2020 and April 2024. All patients had a confirmed diagnosis through imaging studies or cerebrospinal fluid analysis using flow cytometry or cytopathology.

Results: Two hundred and twenty-eight patients were evaluated. We identified 8 patients with central nervous system involvement, 62.5% were women and the mean age of this group was of 52.25 years.

The main clinical manifestations among our patients were amaurosis, headache, neuropathy, paresthesia and neurological deterioration.

Other diagnostic methods used were flow cytometry and cytopathology of cerebrospinal fluid, demonstrating 62.5% (0.04%-80%) with CNS infiltration. On the other hand, imaging modalities included MRI or CT; findings revealed 25% cases of CNS infiltration in MRI and 50% in CT.

The ISS was evaluated; 50% of the cases stage 1, 37.5% ISS 3 and 12.5% with an ISS of 2. One patient presented a relapse involving the central nervous system 6 months after autologous stem cell transplantation.

The first-line therapy used included the combination of thalidomide, bortezomib, and dexamethasone. These medications were administered in half of the patients. Two of the cases were additionally prescribed with bortezomib and thalidomide because of tumor mutational burden. One patient due to functional status and comorbidities required simultaneously intrathecal chemotherapy with dexamethasone, methotrexate and cytarabine.

The overall survival was of 9.68 months (CI±3.41); despite the heterogeneity of regimens used and the implementation of anti-CD-38 therapies in 20% of the patients due to its availability.

Conclusions: We found a 2.6% incidence of central nervous system involvement in patients with multiple myeloma. Progression of the disease occurred in 83% of the patients, consequently an evaluation for subsequent response to the chemotherapy regimens was not possible.

Different types of treatment schemes were prescribed; mainly systemic chemotherapy, followed by intrathecal and in some cases radiotherapy.

The median overall survival meets the range described in other populations from Latin America and the rest of the world.

The limitations of this study are the low number of cases, due to the follow up time in which the study was carried out. This helps us to be aware that greater registration of this pathology is required not only at the national level, but also at the global level to achieve a strategy that improves the survival and quality of life of patients.