Systemic Therapy of Open-label Prophylactic Pravastatin or Pentoxifylline/Tocopherol Prevention of Lymphedema Advancing to Eventual Fibrosis: an Interventional Registry-embedded Bayesian Randomized Trial for Radiation Sequelae (STOP4-LATE-FIBROSE)

Dispositioned to radiotherapy with prescribed dose to unilateral or bilateral neck(s).

Creatinine clearance >30mL/min

Age ≥18 years. Because no dosing or adverse event data are currently available on the use of pentoxifylline/pravastatin in participants <18 years of age, children are excluded from this study

ECOG performance status ≤2 (Karnofsky ≥60%,)