BackgroundThe authors examined baseline physical functional (PF) impairment among cancer outpatients in the National Cancer Institute Cancer Moonshot study Northwestern University Improving the Management of Symptoms During and Following Cancer Treatment (NU IMPACT). They hypothesized that PF impairment, measured with the Patient Reported Outcome Measurement Information System–Physical Function (PROMIS‐PF) survey, would (1) be common and more prevalent for patients receiving treatment compared with no treatment and (2) differ across tumor types, independent of cancer continuum phase.MethodsAdults who were diagnosed with cancer in NU IMPACT (n = 2273) were sampled, and their PROMIS‐PF scores were compared across tumor types and cancer continuum (curative, noncurative, or no treatment), with scores ≤40 indicating moderate–severe impairment. Multivariable logistic regression models were used to evaluate the relation among patient and cancer factors and PF scores using a 95% confidence interval.ResultsForty percent of the surveyed patients reported moderate–severe PF impairment. Patients with melanoma reported the least impairment, and those with lung cancer were 6.5 times more likely to have moderate–severe impairment (95% confidence interval, 2.393–17.769). The noncurative group was 1.5 times more likely to have moderate–severe impairment (95% confidence interval, 1.045–2.145; mean score, 43; p < .001) than the curative (mean score, 6) and no treatment (mean score, 48) groups. One‐third of those who reported PF impairment also had significant pain and/or fatigue.ConclusionsA sizeable minority experienced PF impairment across tumor types for which pain and/or fatigue co‐occurred, particularly in the noncurative group. The PROMIS‐PF survey effectively identified variations in physical function. Future studies will explore how screening for PF impairment can be used to refer patients for appropriate cancer rehabilitation services.