Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada.
Department of Oncology, Western University, London, Ontario, Canada.
Neuro Oncol. 2022 Oct 3;24(10):1738-1748. doi: 10.1093/neuonc/noac072.
Malignant gliomas are treated with temozolomide chemoradiotherapy. Because pneumocystis pneumonia (PCP) can occur in patients receiving temozolomide, the product monograph recommends PCP prophylaxis during temozolomide chemoradiotherapy. Not all neuro-oncologists follow these recommendations, though.
We performed a population-based retrospective cohort study of glioma patients undergoing temozolomide chemoradiotherapy 2005 to 2019 in Ontario, Canada. A propensity score model was used to predict the use of PCP prophylaxis. We compared the risk of PCP within 90 days of starting radiotherapy with versus without PCP prophylaxis using inverse probability of treatment weighting (IPTW). We also examined overall survival, hospitalizations, and myelosuppression.
There were 3,225 patients included in the cohort (648 received antibiotics and 2,434 did not). Only 18 patients developed PCP within 90 days of therapy. The IPTW-adjusted absolute risk reduction in PCP with antibiotics was 0.0035 (95% CI, -0.0013 to 0.0083), number needed to treat: 288. Neither overall survival nor hospitalization count differed between the groups. The number needed to harm by causing grade 3/4 neutropenia was 39.
In regions (like Ontario) where PCP is rare, routine PCP prophylaxis with trimethoprim-sulfamethoxazole should not be offered, since the harms may outweigh the benefits.
恶性神经胶质瘤采用替莫唑胺放化疗进行治疗。由于接受替莫唑胺治疗的患者可能会发生肺囊虫肺炎（PCP），因此产品说明书建议在替莫唑胺放化疗期间进行 PCP 预防。然而，并非所有神经肿瘤学家都遵循这些建议。
我们在加拿大安大略省进行了一项基于人群的回顾性队列研究，研究对象为 2005 年至 2019 年期间接受替莫唑胺放化疗的神经胶质瘤患者。采用倾向评分模型预测 PCP 预防的使用情况。我们使用逆概率治疗加权（Inverse Probability of Treatment Weighting，IPTW）比较了使用与不使用 PCP 预防措施的患者在开始放疗后 90 天内发生 PCP 的风险。我们还检查了总生存率、住院情况和骨髓抑制。
该队列共纳入 3225 例患者（648 例接受抗生素治疗，2434 例未接受抗生素治疗）。仅 18 例患者在治疗后 90 天内发生 PCP。抗生素治疗后 PCP 的 IPTW 调整后的绝对风险降低为 0.0035（95%置信区间，-0.0013 至 0.0083），需要治疗的人数：288。两组的总生存率和住院人数均无差异。导致 3/4 级中性粒细胞减少的危害需要治疗的人数为 39。
在 PCP 罕见的地区（如安大略省），不应该常规使用复方磺胺甲噁唑进行 PCP 预防，因为其危害可能超过益处。
