It was found that 75% of patients stabilize or improve over several months as opposed to 25% of patients who do not respond and have progressive disease. But despite initial improvement, most patients survive only a few months. Breast cancer and small cell lung cancer are the two solid tumors that respond best to treatment Some patients do better than others, particularly those whose primary cancer is hematologic, bone marrow and lymph nodes. Factors that lower survival
Much of prognosis can be determined from the damage due to primary cancer. Negative hormone receptor status, poor performance status, more than 3 chemotherapy regimes, and high Cyfra 21-1 level at diagnosis, all indicates lower survival period of patients with NM. Cyfra 21-1 is a fragment of the cytokeratin 19 and may reflect the tumor burden within the CSF. Epidemiology
In the United States, 1–8% of cancer patients are diagnosed with leptomeningeal disease, with approximately 110,000 cases per year. The exact incidence of leptomeningeal disease is difficult to determine, since gross examination at autopsy may overlook signs of leptomeningeal disease, and microscopic pathological inspection may be normal if the seeding is multifocal or if an unaffected area of the central nervous system (CNS) is examined. Current research
New treatments and clinical trial for breast cancer patients and non-small cell lung cancer patients with leptomeningeal disease are currently being explored.People with leptomeningeal metastasis are generally excluded from clinical trials, thereby limiting the systematic assessment of novel therapies in this subgroup of patients with poor prognosis.
The metastatic tumor cells grow either attached to the pia mater covering the brain and spinal cord or floating unattached to the subarachnoid space. Tumors of diverse origins and hematologic cancers may spread to this space.Some patients can develop a leptomeningeal tumor while receiving chemotherapy for their primary tumor. Pathology
There are three anatomic patterns by which the tumor can spread in the subarachnoid space. More than one pattern may coexist in the same patient.First, there may be plaque-like deposits of cells in the leptomeninges with invasion of Virchow-Robin spaces and, usually, the shedding of tumor cells into the cerebrospinal fluid.Second, there may only be a thin coating of meninges, in some cases with only a single cell layer, but also with shedding of tumor cells into the cerebrospinal fluid. Third, there may be a pattern of nodular deposits of tumor on cranial and spinal nerve roots, frequently without tumor cells being shed into the cerebrospinal fluid.The first and third patterns are common in solid tumors whereas the second occurs most frequently with leukemia and lymphoma. Spinal cord
Neoplastic meningitis (NM) shows diffuse infiltration of tumor cells into the subarachnoid space which may be associated with increased intracranial pressure, signs of meningeal irritation, and damage to the cranial and spinal nerve roots. Pathological feature include:
Circular necrosis of the white matter in the periphery of the spinal cord was also noted which probably resulted from circulatory disturbance secondary to tumor infiltration.