Isotretinoin maintenance therapy for glioblastoma: a retrospective review

The current standard treatment of glioblastoma includes maximal safe surgical resection, radiation, and temozolomide. Although isotretinoin has been used for maintenance therapy to delay tumor recurrence, this approach has not been proven to be effective. The objectives of the study are to compare the overall survival, progression-free survival and tolerability of isotretinoin maintenance therapy in patients who received isotretinoin maintenance therapy to patients who did not receive this treatment.

This study is a retrospective review of adult patients with glioblastoma treated at MD Anderson Cancer Center from 2004 to 2009. Patients who underwent surgical resection, radiation with concurrent temozolomide, and adjuvant treatment with temozolomide were included in the control group, and compared to similarly treated patients who received isotretinoin maintenance following adjuvant temozolomide.

Eighteen patients who received isotretinoin maintenance therapy and 70 control patients were included in the analysis. Progression-free survival was 25.3 months with maintenance therapy versus 8.3 months for those not receiving maintenance (p = 0.04). There was no difference in the 2-year or 3-year overall survival estimates (p = 0.11). The common toxicities of isotretinoin included dermatologic-, metabolic-, and psychiatric-related adverse effects.

Isotretinoin maintenance therapy was associated with increased progression-free survival, but did not increase the overall survival in this retrospective review. The potential benefit of maintenance therapy should be weighed against toxicities and negative impact on quality of life in this patient population.