Pineal gland tumors: experience from the SEER database

Abstract

Pineal gland tumors are rare and account for less than 1% of all primary brain tumor diagnoses. They are more commonly seen in pediatric patients than in adults. We analyzed the available SEER data on pineal gland tumors that were diagnosed during the period 1973-2005. The cohort was subdivided into groups on the basis of tumor histology: germ cell tumors, pineal parenchymal tumors, gliomas, and other pineal tumors. Analyses of incidence, survival, factors influencing survival, and treatment modalities are provided. Among the 633 patients with pineal tumors, male sex was predominant, i.e., sex ratio was 3:1 for the whole group and 11.8:1 for those with germ cell tumors. The 5-year overall survival (OS) for the cohort was 65% +/- 2.1%. Those with germ cell tumors experienced the best survival (OS = 78.9% +/- 2.3%), followed by those with gliomas (OS = 61% +/- 9.3%), and those with pineal parenchymal tumors (OS = 47.2% +/- 4.2%). Non-germ cell tumors, absence of radiotherapy from treatment regimen, and diagnosis before 1993 were the only factors associated with a negative impact on survival. The extent of surgical tumor resection did not affect survival in any histologic subgroup. We conclude that, although pineal tumors are histologically diverse, they share some similarities due to their unique location. An aggressive surgical approach should be considered with caution in this region. Further studies on different pineal tumors subtypes are needed.

Figure 1

(A) Histologic subtypes of pineal tumors in patients. Patients were divided into two groups on the basis of diagnosis era: those diagnosed before 1993 (blue bars) and those diagnosed after 1993 (red bars). (B) The percentages of different pineal tumor histologic subtypes. (C) Kaplan-Meier analysis showing overall survival of the entire cohort. The end point was all-cause mortality. Abbreviations: AT/RT, atypical rhabdoid/teratoid tumor; GCT, germ cell tumor; PPT, pineal parenchymal tumor.

Figure 2

Kaplan-Meier analyses of overall survival of patients in the various pineal tumor subgroups. Abbreviations: AT/RT, atypical rhabdoid/teratoid tumor; GCT, germ cell tumor; PPT, pineal parenchymal tumor. The end point was all-cause mortality.

Figure 3

Kaplan-Meier analyses of survival of patients with pineal germ cell tumors (GCTs; solid line). (A) Survival of patients with GCTs was compared with that of patients from the other histologic subgroups (dashed line). (B) Survival of patients with GCTs who received radiotherapy (solid line) was compared with that of patients with GCTs who did not (dashed line). (C) Survival of patients with GCTs who underwent total surgical excision (sold line) was compared with that of patients who underwent other, less extensive surgical procedures (dashed line). (D) Survival of patients with GCT further subdivided on the basis of GCT subtype: mixed germ cell tumors (solid line), germinomas (dashed line), or nongerminomatous germ cell tumors (dotted line). A log-rank test was used to compare survival curves, and P-values are provided. The end point for all curves was all-cause mortality.

Figure 4

Kaplan-Meier analyses of survival of patients with pineal parenchymal tumors (PPT). (A) Survival of patients with PPT who underwent total surgical excision (sold line) was compared with that of patients who underwent less extensive procedures (dashed line). (B) Survival of patients with PPTs who received radiotherapy (solid line) was compared with that of those who did not receive radiation treatment (dashed line). A log-rank test was used to compare survival curves, and P-values are provided. The end point for all curves was all-cause mortality.