The participants are being treated with Tumor Treating Fields (TTFields) for malignant glioma, and this type of treatment may cause skin-related side effects. This study will test whether using clindamycin and triamcinolone topical lotions can prevent skin-related side effects of TTFields.

Inclusion Criteria:

• Age ≥18 years
• Diagnosis of newly diagnosed or recurrent GBM with plan to initiate treatment with TTFields with or without systemic therapy, confirmed by the enrolling institution
• Able to self-administer topical interventions or has available another person who can apply the topical agents
• Treatment with TTF should be initiated within 7 days of planned initiation on this trial.

Exclusion Criteria:

• Known history of allergy to any ingredient of the study agents
• Preexisting scalp disorders such as psoriasis or dermatitis that, in the opinion of the investigator, will affect the grading of skin adverse events, confirmed by enrolling institution.
• Use of concurrent topical therapy to the scalp for another dermatologic condition
• Active, uncontrolled infection requiring systemic or oral antibiotic therapy within 14 days of enrollment
• Use of greater than 4 mg dexamethasone a day within 14 days of enrollment
• Malignant glioma
• Pregnant Women

Memorial Sloan Kettering Cancer Center supports the international committee of medical journal editors (ICMJE) and the ethical obligation of responsible sharing of data from clinical trials. The protocol summary, a statistical summary, and informed consent form will be made available on clinicaltrials.gov when required as a condition of Federal awards, other agreements supporting the research and/or as otherwise required. Requests for deidentified individual participant data can be made beginning 12 months after publication and for up to 36 months post publication. Deidentified individual participant data reported in the manuscript will be shared under the terms of a Data Use Agreement and may only be used for approved proposals. Requests may be made to: crdatashare@mskcc.org.