Socioeconomics and Survival

Introduction

Accounting for 52% of all primary brain tumors, glioblastoma is the most common and most aggressive. Glioblastomas account for 20% of all intracranial tumors. Disparities in risk factors, incidence, treatment, and follow-up have been shown in the literature for several types of cancer. For patients with glioblastoma, the influence of socioeconomic factors, including gender, race, ethnicity, income level, marital status, and occupation, have been explored in several articles. This issue reviews the literature on socioeconomic status (SES) and glioblastoma.

Proposed risk factors for glioblastoma

Although there are no definable risk factors for glioblastoma, several studies have explored putative risk factors. In one article, 80% of patients with newly diagnosed glioblastoma had detectable cytomegalovirus (CMV) DNA in their peripheral blood, whereas seropositive normal donors and other surgical patients did not show detectable virus. Challenging this finding, another study reported that a series of 5 patients with glioblastoma showed no circulating CMV detected either with reverse transcription polymerase chain reaction or blood culture. Several investigators hypothesized that CMV could be a factor in the genesis of glioblastoma if age at infection is taken into account, because the incidence of both glioblastoma and CMV infection are inversely related to SES. CMV infection in early childhood, which is most common in lower socioeconomic groups, may be protective against glioblastoma, whereas CMV infection in later childhood or adulthood may be a risk factor for glioblastoma. If so, glioblastoma occurrence would resemble paralytic polio, in which low SES, poor hygiene, and early infection are protective. This hypothesis has not been supported in the literature.

Some investigators suggest a relationship between glioblastoma and neurocysticercosis. In a case-control study, 6 of 8 patients with neurocysticercosis and a cerebral glioma had calcified parasitic lesions within and around the tumor. The investigators hypothesized that the intense astrocytic gliosis that surrounds calcified cysticerci, together with the suppression of the cellular immune response induced by cysticerci, may contribute to the development of malignant glial cells in patients with neurocysticercosis. However, the relationship between glioblastoma and neurocysticercosis was not statistically significant.

In terms of behavioral risk factors, a study of cigarette smoking, alcohol intake, and risk of glioma in the National Institutes of Health–AARP (American Association for Retired Persons) Diet and Health Study of 477,095 American men and women found that smoking and alcohol consumption did not increase the risk of glioma.