Brain tumor headaches: from bedside to bench.

Although most people who have headache pain do not present with an underlying mass lesion, a large number of patients with brain tumors do report headache (as many as 60% in our institution). The problem for clinicians is that the tumor-headache association is not universal, as evidenced by anecdotal reports of patients with large tumors and increased intracranial pressure, but a complete absence of headache pain. In this review, we examine more than 80 years of research on brain tumor headaches, delineating the link between tumor location, laterality, growth rate, and pain. Most importantly, we position our review within the context of current etiological theories and propose new models involving the peripheral and central sensitization of nociresponsive neurons. This review will help clinicians understand why debulking surgery sometimes fails to alleviate neoplastic headache pain in select patients. A brief examination of headaches as a result of surgery and adjuvant chemoradiation therapy is also provided. Headaches can be an early indicator of central nervous system tumors. However, headaches are present in a wide variety of other condition, and are sometimes (surprisingly) absent in patients with primary neoplasms or metastatic tumors. This observation complicates the possibility of linking headaches to brain tumors. Nevertheless, some generalizations concerning brain tumor headaches can be drawn. The following sections review these generalizations, presenting caveats where appropriate. Lingering questions in the field are also addressed and presented together with promising future research avenues.