Dose-dependent efficacy of bevacizumab in recurrent glioblastoma.

BACKGROUND: Bevacizumab (BEV), at a standard dose of 10 mg/kg every 2 weeks is associated with prolonged progression-free survival (PFS) but no improvement in overall survival (OS) in recurrent glioblastoma (rGBM). Few studies have examined the potential dose-dependent efficacy of BEV. In Ontario, reimbursement for the costs of BEV varies, and as a result, our practice began to routinely use lower dose regimens. The main aim of this study was to ensure that there was no harm to patients who received the low dose protocol. METHODS: A single-center retrospective study of patients given BEV for rGBM between 2015 and 2020 was performed. Clinical and treatment data including BEV dose regimen [SD (10 mg/kg every 2 weeks) vs. LD (5 mg/kg every 2-3 weeks or 10 mg/kg every 3 weeks)] received at the time of rGBM diagnosis were captured. Overall survival (OS) and progression-free survival (PFS) on BEV were compared using the Kaplan-Meier product-limit method. Log-rank test was used to compare potential predictive factors. Cox regression model was performed for multivariable analysis of OS and PFS. RESULTS: A total of 96 patients were included with a median follow-up duration of 6.84 months (range 1.12-50.63 months) from the date of the first infusion. The LD group consisted of 55 of the 96 patients. By virtue of funding mechanisms for BEV, the median age in the LD group was significantly higher (62 vs. 54 years p = 0.009). There was no difference in MGMT status between the two groups (p = 0.60). The LD group had prolonged median PFS (5.89 months versus 3.22 months; p = 0.0112) and OS (10.23 months versus 6.28 months; p = 0.0010). Multivariable analysis including the dose of BEV, the extent of resection, gender, and age revealed that standard dose of BEV, subtotal resection, and female sex were associated with worse overall survival. Nine patients in the SD group vs. 18 patients in the LD group reported an adverse event related to BEV. CONCLUSION: For patients with recurrent GBM, we found that a low dose regimen of BEV was associated with prolonged OS and PFS compared to the standard dose regimen. Lower dose schedules may be a better and more cost-effective option for patients with rGBM. Lower costs might provide more equitable access to this very important palliative drug.

Rescue bevacizumab following symptomatic pseudoprogression of a tectal glioma post-radiotherapy: a case report and review of the literature.

PURPOSE: Radiation-induced pseudoprogression is a subacute clinical entity that is distinct from radiation necrosis and mimics tumor progression. Bevacizumab is a well-described treatment option for radiation necrosis, but its role in pseudoprogression is not clearly defined. METHODS: We report a case of radiation-induced pseudoprogression rescued with bevacizumab in a 20-year-old man with a biopsy-proven low-grade astrocytoma of the tectum. A review of the literature was also conducted specific to bevacizumab as a treatment for symptomatic pseudoprogression after radiotherapy for CNS tumors. RESULTS: This patient was treated with definitive intensity modulated stereotactic radiotherapy at a total dose of 54 Gy delivered in 30 daily fractions. Six weeks after radiotherapy the patient developed progressive headache, weakness and a documented deterioration in vision, which was accompanied by worsening of radiographic findings. A diagnosis of pseudoprogression was made and after limited benefit from a trial of dexamethasone, four cycles of bevacizumab were administered which resulted in rapid clinical and radiographic improvement. CONCLUSIONS: Our findings support the potential use of bevacizumab as a rescue agent for symptomatic pseudoprogression.

Evaluation of an Online Education Resource on Radiation Therapy Created for Patients with Postprostatectomy Prostate Cancer and Their Caregivers.

INTRODUCTION: Radiation therapy (RT) after prostatectomy is an important curative treatment option for patients with prostate cancer. It can be delivered immediately after surgery as adjuvant treatment, or after biochemical PSA failure as salvage treatment. There is currently a lack of consensus regarding whether salvage RT in the event of biochemical failure or immediate adjuvant RT is the optimal postprostatectomy RT treatment. Although both types of postprostatectomy RT are generally well tolerated, patients may develop some toxicity that can impact their quality of life and the duration and frequency of treatments can be challenging for patients. It is imperative that patients be provided with evidence-based information so that they are able to make a treatment decision most aligned with their values. METHODS: To help address patients' informational needs, an online education resource was created for patients with prostate cancer considering postoperative RT. Patients and their families were asked to evaluate the effectiveness of this resource using a validated purpose-based information assessment. RESULTS: Nineteen patients were approached and 14 participated, but only five patients returned their evaluations (35%). Sixty percent found the information to be important with regards to each of the six commonly identified purposes in the purpose-based information assessment: organizing, understanding, decision-making, planning, emotional support, and discussing. Only one participant found the information hard to understand and had difficulty finding specific information. DISCUSSION: Patients should be encouraged to actively participate in their treatment decision-making process involving postprostatectomy RT. For patients to make well-informed decisions, patients must be provided with clear and accessible information so that they may understand their disease and the treatment options. CONCLUSION: An online education resource has been developed that most study respondents found clear and helpful for a variety of identified purposes. Overall, this online education resource has the potential to reach a large number of patients and their caregivers who desire specific information and involvement in future treatment decisions.