[Intrathecal chemotherapy for leptomeningeal metastases in patients with breast cancer].

Leptomeningeal metastases are lesions of brain and/or spinal cord sheaths by tumor cells. They occur in 5% of patients with solid tumors, although autopsies reveal these lesions much more often (10-20% of cases). Leptomengeal metastases are an unfavorable prognostic factor. Despite the modern NCCN treatment standards, including intrathecal therapy (ITT), such patients receive only irradiation of the entire brain and/or spinal cord in most cases.

Objective: To evaluate the effectiveness of ITT in patients with leptomeningeal metastases in breast cancer.

Material and methods: Twenty-five patients with breast cancer and leptomeningeal metastases underwent intrathecal administration of methotrexate between 2016 and 2022. Intrathecal chemotherapy was administered through lumbar puncture. We performed an intensive course (intrathecal methotrexate 15 mg 2 times a week for 1 month (8 injections), then intrathecal methotrexate 15 mg 1 time a week (4 injections), and then 15 mg 1 time a month until progression or unacceptable toxicity).

Results: The median duration of ITT was 2.5 months. Complete neurological responses were observed in 3 out of 25 (12%) patients, partial neurological response - in 15 out of 25 (60%) patients, progression of neurological symptoms - in 7 (28%) patients. The number of complete cytological responses was observed in 6 out of 25 (24%) patients. The median overall survival after ITT was 6.7 months.

Conclusion: Effectiveness of ITT is confirmed by higher quality of life (72% of patients), complete cytological responses (24%) and improvement in neuroimaging data. This is an important criterion for severe patients with limited treatment options. First-stage ITT before whole-brain irradiation is preferable, as this approach increases overall survival by 3 months. Undoubtedly, ITT is a treatment option that can be used in routine clinical practice for lesions of brain and spinal cord sheaths.