Management and survival trends for adult patients with malignant gliomas in the setting of multiple primary tumors: a population based analysis.

INTRODUCTION: The impact of multiple primary tumors, in the setting of malignant glioma (MG), has not been heavily explored.

METHODS: We extracted demographics and clinical data from the SEER-18 registry for adult patients with MGs. The cases were separated based on the sequence of MG diagnosis relative to the other primary tumors: Group (A) One primary only or first primary of multiple primaries and Group (B) second primary or subsequent primary tumor. Incidences, frequencies, and glioma-related survivals were analyzed.

RESULTS: Group B constituted 12.8% of new MG. The incidences of group B, relative to those of all new MG, range from 0.14 to 0.18. Compared to group A, group B exhibited an older age. Moreover, group B exhibited a higher proportion of females, Caucasians, smaller tumors, non-operative cases, and those receiving radiation (p < 0.05); the proportion with GTR remained comparable. Multiple groupings (oral cavity, digestive system, respiratory system, skin, breast, genital systems, urinary system, lymphoma) exhibited lower glioma-related observed survival (p < 0.05) compared to Group A. An active diagnosis of "leukemia" appears to confer longer glioma-related survival while a history of "breast" or "digestive system" malignancies portends a shorter glioma-related survival.

CONCLUSION: For newly diagnosed MG, a high proportion does have history of extra-CNS primary tumors. Generally, these patients appear to have worse glioma-related observed survival compare to those with malignant glioma as the only primary or the first of multiple primary tumors. Knowledge regarding epidemiology, clinical factors, and observed survival can help guide clinical management/consultation for this subset of patients.