Rose Natanson underwent a radical mastectomy for breast cancer and was referred for postoperative deep x‑ray therapy using cobalt‑60, then a comparatively new and potent modality. Dr. Kline, a radiologist, supervised the course of cobalt therapy at a hospital facility. Following the treatments, Natanson suffered severe radiation burns and necrosis of tissue in the chest wall, necessitating extensive medical care, including skin grafting and prolonged hospitalization. Natanson sued Dr. Kline (and others) alleging two theories: (1) negligent administration and dosage of radiation, and (2) failure to disclose material risks inherent in cobalt therapy—particularly the risk of severe radiation burns—thereby rendering her consent uninformed. At trial, the evidence on negligent administration was contested, and on the informed‑consent claim Natanson did not present expert testimony establishing what a reasonably prudent radiologist in the same or similar circumstances would have disclosed at the time. The jury returned a verdict for Dr. Kline. On appeal, the Kansas Supreme Court addressed the nature and scope of a physician's duty to disclose and what proof is required to establish a breach.
What is the scope of a physician's legal duty to disclose risks of a proposed medical treatment to obtain a patient's informed consent, and must the plaintiff offer expert testimony to establish the standard and breach of that duty?
A physician has a duty to make a reasonable disclosure to the patient of the nature of the ailment, the nature and probable risks of the proposed treatment, and, where appropriate, feasible alternatives, sufficient to enable the patient to make an intelligent decision. The scope of this duty is measured by the professional standard—what a reasonable medical practitioner in the same or similar circumstances would disclose—not by an absolute or lay standard. Except in the rare case where the need for disclosure is within the common knowledge of laypersons, the plaintiff must present expert medical testimony to establish the standard of disclosure and any deviation from it. Recognized exceptions include emergencies, incapacity, or circumstances in which disclosure would, in the physician's sound medical judgment, pose a serious threat to the patient's well‑being (therapeutic privilege).
The court recognized a physician's duty to make reasonable disclosure of risks but held that the extent of disclosure is governed by the professional standard and generally must be proven by expert testimony. Because the plaintiff failed to offer expert evidence establishing the applicable standard of disclosure and breach, the verdict for the physician was sustained.
The court began by grounding the disclosure duty in principles of bodily autonomy: a competent adult has the right to decide what is done to her body, and meaningful consent requires disclosure of material risks. However, the court declined to impose an inflexible or absolute disclosure rule, emphasizing that medical practice involves complex judgments about patient comprehension, the probabilistic nature of risks, the novelty or hazards of treatments, and the potential for information itself to cause harm or deter beneficial therapy. A purely lay-driven disclosure metric would invite juries to substitute their views for professional judgment without the necessary medical context. Accordingly, the court located the measure of disclosure in the customary practices of reasonably prudent physicians under like circumstances, echoing contemporaneous authorities such as Salgo. This tether to professional norms respects the clinician's expertise while still demanding reasonable transparency. Because those norms are not within ordinary lay knowledge and vary with factors such as the patient's condition, the seriousness and likelihood of risks, the alternatives, and the state of medical science, expert testimony is needed to establish what a reasonable physician would have disclosed and whether the defendant deviated from that standard. The court also acknowledged limited exceptions—emergencies, incapacity, and therapeutic privilege—where full disclosure may be impracticable or counter-therapeutic. Applying these principles, the court concluded that while cobalt therapy carried known hazards, the plaintiff did not supply expert evidence defining the profession's disclosure standard for such therapy or demonstrating a breach by Dr. Kline. Absent such proof, the informed‑consent claim could not go to the jury on a negligence theory. The court therefore let stand the defense verdict, while clarifying the applicable legal framework for future cases.
Natanson is an early and influential articulation of informed consent in negligence, adopting a professional standard for disclosure and requiring expert testimony to prove it. It frames the classic tension between physician‑centered custom and patient‑centered autonomy, paving the way for later doctrinal divergence (e.g., Canterbury's reasonable‑patient standard). It remains a principal case for understanding expert proof in medical malpractice and the scope/limits of the therapeutic privilege.
Natanson v. Kline crystallizes the negligence-based approach to informed consent under a professional disclosure standard. While affirming patients' rights to information necessary for intelligent decision‑making, the court channels the content of that duty through medical custom, generally requiring expert testimony to delineate and prove breach of the duty.