Second primary cancers in long-term survivors of glioblastoma

Overall survival (OS) in glioblastoma (GBM) is poor at an average of 14 to 18 months, and long-term survivors (LTS) of GBM are rare. LTS of GBM, defined as surviving >5 years postdiagnosis, represent only 2% to 10% of all GBM patients. LTS of cancer are at high risk of developing second primary neoplasms. This study looks at occurrences of second primary neoplasms in LTS of GBM.

Records from adult patients newly diagnosed with GBM between January 1, 1998 and February 8, 2010, were retrospectively reviewed to identify LTS, defined as patients who survived ≥5 years. We focused on the identification of a new diagnosis of cancer occurring at least 2 years after the initial GBM diagnosis.

We identified 155 LTS of GBM, with a median OS of 11.0 years (95% CI: 9.0 to 13.1 years) and a median follow-up of 9.6 years (95% CI: 8.7 to 10.7 years). In this cohort of patients, 13 (8.4%) LTS of GBM developed 17 secondary cancers. Eight could potentially be attributed to previous radiation and chemotherapy (skin cancer in radiation field [n = 4], leukemia [n = 2], low-grade glioma [n = 1], and sarcoma of the scalp [n = 1]). The other 9 cases included melanoma (n = 2), prostate cancer (n = 2), bladder cancer (n = 1), endometrioid adenocarcinoma (n = 1), basal cell carcinoma (n = 1), and renal cell carcinoma (n = 1).

Although second primary cancers are rare in GBM LTS, providers should continue close monitoring with appropriate oncologic care. Moreover, this highlights the need for survivorship care of patients with GBM.