Treatment of Leptomeningeal Carcinomatosis

Introduction to Treatment Approaches

The American College of Neurology recommends that treatment of leptomeningeal carcinomatosis should include systemic therapy with central nervous system activity as a fundamental pillar, complemented with focal radiotherapy for symptomatic lesions and intrathecal chemotherapy in selected patients with thin linear deposits and unobstructed cerebrospinal fluid flow 1

The National Comprehensive Cancer Network suggests prioritizing systemic therapy with bioactivity in the central nervous system and blood-cerebrospinal fluid barrier permeability in all patients with leptomeningeal carcinomatosis, for both treating active disease and preventing leptomeningeal reseeding after local therapies 1
For HER2+ breast cancer, consider trastuzumab deruxtecan or combinations with tucatinib 2
For EGFR-mutated lung cancer, use third-generation tyrosine kinase inhibitors such as osimertinib or almonertinib 2
For BRAF-mutated melanoma, consider BRAF/MEK inhibitors with central nervous system penetration 3, 4

The European Society for Medical Oncology states that intrathecal chemotherapy is more effective in patients with thin linear leptomeningeal deposits and unobstructed cerebrospinal fluid flow 1
Traditional agents: methotrexate 15 mg per dose, administered twice a week for 4 weeks, then weekly for 4 weeks, followed by monthly doses 5, 6
Modern agents (Phase I/II studies): intrathecal trastuzumab for HER2+ tumors, intrathecal nivolumab, and intrathecal pemetrexed 1, 2

The American Society for Radiation Oncology recommends considering focal radiotherapy for circumscribed, especially symptomatic lesions 7
Palliative standard dose: 30-36 Gy in 10-12 daily fractions for symptomatic sites 5, 6
Radiation therapy provides faster symptom relief than chemotherapy 8

The American Association of Neurological Surgeons suggests that cerebrospinal fluid diversion devices (ventriculoperitoneal shunts) alleviate symptoms of elevated intracranial pressure in most treated patients and should be offered as a palliative procedure based on patient care objectives and availability of targeted tumor therapy 1

Without specific tumor treatment, median survival is limited to 6-8 weeks, while with directed treatment for leptomeningeal carcinomatosis, it can be prolonged to a few months 3, 4
Important prognostic factors: functional status at diagnosis, primary tumor type, cerebrospinal fluid protein levels, and administration of combined modality treatment 3

Do not administer intrathecal chemotherapy in the presence of cerebrospinal fluid flow obstruction without prior radiotherapy to restore flow 7
Avoid combining craniospinal radiation with intrathecal or systemic chemotherapy (especially methotrexate) due to increased risk of leukoencephalopathy 8
Do not rely solely on negative cerebrospinal fluid cytology - a second lumbar puncture with optimal collection procedures should be performed in patients with high suspicion 1
Do not use the lumbar route for intrathecal chemotherapy when it is feasible to place an Ommaya reservoir, as ventricular administration is associated with better survival 1, 7
Avoid aggressive therapy in patients with a life expectancy of less than 1 month - the approach should be palliative and supportive care 9

The therapeutic approach for adult patients with leptomeningeal metastases from solid tumors depends on performance status, presence of brain parenchymal metastases, and status of extracranial disease, according to the American Society of Clinical Oncology 10 and the European Society for Medical Oncology 11

Intrathecal chemotherapy is most effective in patients with thin linear leptomeningeal deposits, floating tumor cells in CSF, and unobstructed CSF flow, as recommended by the European Society for Medical Oncology 11

Whole-brain radiotherapy (WBRT) with memantine may be recommended for symptomatic leptomeningeal metastases, according to the American Society of Clinical Oncology 10 and the American Society for Radiation Oncology 12
Focal radiotherapy is recommended for circumscribed symptomatic lesions, such as cranial neuropathies, spinal cord compression, or nodular disease, as suggested by the European Society for Medical Oncology 11

For patients with favorable prognosis (KPS >70, controlled extracranial disease), intrathecal therapy plus modification of systemic therapy may be recommended, along with WBRT or focal radiotherapy, as outlined by the European Society for Medical Oncology 11
For patients with poor prognosis (KPS <70 or life expectancy <1 month), best supportive care and palliative measures should be prioritized over disease-directed therapy, according to the American Society of Clinical Oncology 10 and the American Society for Radiation Oncology 12