Private equity (PE) acquisition of medical practices has been associated with increased prices and use of lucrative treatments. Using Medicare data 2015 to 2021, we compared the prevalence of low-value cancer treatments between PE-owned and non-PE-owned practices. The five low-value treatments were: granulocyte colony stimulating factors (GCSF) for low-risk chemotherapy; denosumab for castration sensitive prostate cancer; nab-paclitaxel for breast or lung cancer; addition of bevacizumab for ovarian cancer; and biologic drugs with biosimilar alternatives. The primary outcome was receipt of a low-value treatment. Comparing patients diagnosed when their oncologist was vs was not practicing at a PE-owned address, adjusted prevalence differences of low-value treatments were: -2.8%-points (-5.5 to -0.2) for GCSF; +3.7%-points (-7.3 to 14.7) for denosumab; -0.7%-points (-3.9 to 1.5) for nab-paclitaxel; -6.5%-points (-12.5 to -0.4) for bevacizumab; and -2.9%-points (-6.0 to 0.2) for biologics. Overall, PE ownership was not associated with increased prevalence of low-value cancer treatments.