The efficacy and safety of low-dose temozolomide maintenance therapy in elderly patients with glioblastoma: a retrospective cohort study.

Abstract

Radiotherapy combined with temozolomide chemotherapy (STUPP regimen) is the standard treatment regimen for newly diagnosed glioblastoma (GBM). It is considered feasible to prolong the treatment cycle of temozolomide (TMZ), however, the efficacy and safety of prolonging the treatment cycle of TMZ are still lacking in elderly patients with glioblastoma. This study observed the efficacy and safety of low dose TMZ maintenance therapy in elderly patients with glioblastoma after receiving standard STUPP regimen. The clinical data were retrospectively analyzed in 34 patients with glioblastoma aged ≥65 years from April 2017 to April 2021 in Ningbo First Hospital. The patients received conventional radiotherapy (59.4 Gy/28 F/5.5 weeks) and TMZ (75 mg/m2·d) concurrent chemotherapy, followed by sequential TMZ (150-200 mg/m2·d, d1-5, q28d) adjuvant treatment for 6 cycles, and patients with no disease progress or intolerable side effects received low dose TMZ (100 mg/m2·d, d1-5, q28d) maintenance treatment. The patient's progression free survival time (PFS), total survival time (OS) and adverse reactions were observed by telephone, outpatient reexamination and other follow-up methods. Kaplan-Meier method was used to calculate and draw the survival curve for survival analysis. Twenty-four of 34 patients were finally included in the analysis, including 13 males and 11 females (65-74 years old), with a median of 14 cycles (8-38 cycles) of adjuvant TMZ chemotherapy. The median PFS was 11.0 months [95% confidence interval (CI): 8.67-13.33 months] and the median OS was 17.4 months (95% CI: 12.49-22.31 months). The main adverse reactions were digestive tract reactions and hematological toxicity. Three cases of grade III granulocytopenia occurred during the adjuvant treatment, while no grade III or above related adverse reactions occurred during the follow-up TMZ reduction maintenance treatment: leukopenia (5/24), anemia (2/24), decreased blood platelets (2/24), asthenia (5/24), nausea (4/24), and abnormal liver function (3/24). In general, for elderly patients with good Karnofsky Performance Scale (KPS) scores, further reducing TMZ to maintain chemotherapy after the standard STUPP regimen may improve the PFS and OS to a certain extent, with tolerable adverse reactions and reduced cost. However, prospective randomized grouping study is still needed to determine whether clinical benefits will be achieved.