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In spite of increasing attention on targeted therapeutics in the treatment of glioblastoma multiforme, radiation therapy remains the most clinically effective treatment modality. However, radiotherapy only offers palliation, with hypoxia representing a major mechanism of tumor resistance. Traditional strategies to overcome the therapeutic barrier to irradiation imposed by tumor tissue hypoxia consist of improving tumor oxygenation and administering agents that increase the tumor cell sensitivity to irradiation (radiosensitizers). There is also increasing evidence that tumor tissue is composed of diverse populations of cells with heterogeneous sensitivities to irradiation. The radioresistant tumor-initiating CD133-positive glioblastoma cancer stem cells are preferentially expanded in hypoxic conditions. Therefore, identifying therapies that can specifically target the glioblastoma cancer stem cells will lead to more durable responses to radiation therapy.

Background: Most safety and efficacy trials of the SARS-CoV-2 vaccines excluded patients with cancer, yet these patients are more likely than healthy individuals to contract SARS-CoV-2 and more likely to become seriously ill after infection. Our objective was to record short-term adverse reactions to the COVID-19 vaccine in patients with cancer, to compare the magnitude and duration of these reactions with those of patients without cancer, and to determine whether adverse reactions are related to active cancer therapy. Patients and Methods: A prospective, single-institution observational study was performed at an NCI-designated Comprehensive Cancer Center. All study participants received 2 doses of the Pfizer BNT162b2 vaccine separated by approximately 3 weeks. A report of adverse reactions to dose 1 of the vaccine was completed upon return to the clinic for dose 2. Participants completed an identical survey either online or by telephone 2 weeks after the second vaccine dose. Results: The cohort of 1,753 patients included 67.5% who had a history of cancer and 12.0% who were receiving active cancer treatment. Local pain at the injection site was the most frequently reported symptom for all respondents and did not distinguish patients with cancer from those without cancer after either dose 1 (39.3% vs 43.9%; P=.07) or dose 2 (42.5% vs 40.3%; P=.45). Among patients with cancer, those receiving active treatment were less likely to report pain at the injection site after dose 1 compared with those not receiving active treatment (30.0% vs 41.4%; P=.002). The onset and duration of adverse events was otherwise unrelated to active cancer treatment. Conclusions: When patients with cancer were compared with those without cancer, few differences in reported adverse events were noted. Active cancer treatment had little impact on adverse event profiles.

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