Smith v. Kannarkatt: Pennsylvania Supreme Court Sends Lymphoma Misdiagnosis Case to a Third Jury

In Smith v. Kannarkatt, decided October 29, 2026, the Pennsylvania Supreme Court held that a family suing an oncologist over treatment aimed at the wrong cancer presented enough expert evidence to reach a jury, because Pennsylvania law requires only proof that the doctor's conduct increased the risk of the harm that occurred, not proof that correct care would have saved the patient. The ruling affirms a Superior Court order vacating a compulsory nonsuit, which means the case returns to York County for a third trial and the rule of Hamil v. Bashline survives a direct challenge backed by the American Medical Association.

The decision is not a finding of malpractice and awards nothing. What it settles is procedural but consequential for every Pennsylvania delayed-diagnosis and wrong-treatment claim: a trial judge may not take a case from the jury simply because the plaintiff's expert cannot say, to a reasonable degree of medical certainty, that the patient would have lived with proper care.

What the Pennsylvania Supreme Court decided in Smith v. Kannarkatt

The court framed the appeal narrowly. In the majority's words, the task in "this discretionary appeal" was to "determine whether the Superior Court correctly applied this so-called 'increased risk of harm' standard of causation in this case." Justice P. Kevin Brobson, writing for the majority, answered yes.

Three propositions emerge from the opinion as reported:

• The standard is the Hamil standard, unchanged. A plaintiff makes out a prima facie case where expert medical testimony establishes, to a reasonable degree of medical certainty, that the defendant's conduct increased the risk of the harm the patient actually suffered. Once that showing is made, whether the conduct was a substantial factor in causing the harm is for the jury.
• The record met it. The estate's evidence, including testimony that the oncologist failed to follow up on findings inconsistent with breast cancer while the real disease, a lymphoma, progressed during chemotherapy, was sufficient to support a jury finding that her conduct increased the risk of progression and premature death.
• The defense read the record selectively. The majority characterized the oncologist's arguments as resting largely on "a selective review of the record," a signal that sufficiency challenges in this posture will be measured against the evidence viewed in the plaintiff's favor.

The disposition is an affirmance. The Superior Court had vacated the nonsuit and remanded for a new trial; that order now stands.

The underlying claim: breast cancer treatment for a lymphoma

The estate's theory is easy to state. Tanya Smith was diagnosed, on a pathology read, with metastatic breast cancer. Her treating oncologist, Dr. Annie Kannarkatt of Cancer Care Associates of York, Inc., began a regimen of chemotherapy and radiation directed at breast cancer. A later biopsy showed that Smith actually had ALK-positive large B-cell lymphoma, a rare and aggressive blood cancer. According to the opinions, radiological studies after the original pathological diagnosis never confirmed breast cancer at all.

The claim against Dr. Kannarkatt is not that she made the original pathology error. The Pennsylvania Medical Society's description of the case is that another physician produced the misdiagnosis and the estate alleges the oncologist, faced with inconsistent findings, should have questioned it. The estate's position is that she instead continued treatment that could not work against lymphoma while the lymphoma advanced. Smith died; her husband, Marvin Smith, sued as administrator and has since died himself, so the caption now reads "Marvin Smith (Deceased), Individually and as Administrator of the Estate of Tanya Smith, Deceased."

The causation problem was built into the facts. The Superior Court's memorandum records that the plaintiffs' expert could not say with certainty that earlier, correct treatment would have changed the outcome, and that ALK-positive large B-cell lymphoma is so rare that roughly 150 cases had been reported. That is exactly the gap the increased risk of harm doctrine exists to fill.

Timeline: from a 2018 complaint to a third trial

Date	Court	Event
2018	York County Court of Common Pleas	Action docketed, No. 2018-SU-002317, against Dr. Kannarkatt and Cancer Care Associates of York
October 2021	York County C.P.	First jury trial ends in a mistrial after the jury hangs
April 25, 2022	York County C.P.	Second jury trial begins; after plaintiffs rest, the court grants defendants' motion for compulsory nonsuit for insufficient causation evidence; post-trial motion to remove the nonsuit denied
March 11, 2024	Superior Court (No. 1084 MDA 2022)	Non-precedential memorandum by Judge Lazarus (with Judge Bowes and President Judge Emeritus Stevens) vacates and remands for a new trial
2024	Supreme Court (No. 300 MAL 2024)	Allowance of appeal granted on whether the Superior Court properly applied the Hamil standard
August 2025	Supreme Court	AMA and Pennsylvania Medical Society amicus brief urges reversal
March 11, 2026	Supreme Court (No. 17 MAP 2025)	Oral argument; justices signal skepticism of the oncologist's bid to avoid a third trial
October 29, 2026	Supreme Court	Majority opinion by Justice Brobson affirms; Justice Mundy concurs; Chief Justice Todd concurs and dissents

What is the increased risk of harm standard in Pennsylvania?

The increased risk of harm standard is a relaxed causation rule for professional negligence cases in which a defendant failed to protect a patient from a harm that was already threatening her. It comes from Hamil v. Bashline, 481 Pa. 256, 392 A.2d 1280 (1978), in which the Pennsylvania Supreme Court adopted Section 323(a) of the Restatement (Second) of Torts. Under Section 323(a), a person who undertakes to render services to another is liable for harm resulting from a failure to exercise reasonable care if that failure increased the risk of the harm.

Hamil's practical consequence is a two-step allocation between expert and jury:

1. The expert's job: testify, to a reasonable degree of medical certainty, that the defendant's negligence increased the risk of the harm that actually occurred.
2. The jury's job: decide whether, in light of that increased risk, the negligence was a substantial factor in bringing about the harm.

The plaintiff still carries the burden of proof by a preponderance of the evidence. What changes is the degree of certainty demanded of the expert on the counterfactual question of what proper care would have achieved. In Hamil itself, the plaintiff's expert put the decedent's chance of survival with prompt treatment at 75 percent, while the defense expert said death was imminent regardless. The court held that conflict was for the jury.

The Supreme Court reaffirmed the approach in Mitzelfelt v. Kamrin (1990), holding that an expert need not state with absolute certainty that the negligence caused the harm if the testimony establishes an increased risk. Smith v. Kannarkatt is a significant modern restatement of the rule, and it arrived over organized opposition from the medical profession.

Court	How it treated the expert evidence	Result
York County C.P. (2022)	Expert could not say correct treatment would have changed the outcome; causation insufficient	Compulsory nonsuit
Superior Court (2024)	Testimony met Hamil's reduced standard of certainty on increased risk; substantial factor is a jury question	Nonsuit vacated, new trial
Supreme Court (2026)	Superior Court properly applied Hamil; defense relied on a selective reading of the record	Affirmed

Does the plaintiff's expert have to say the patient would have survived?

No. Under Smith v. Kannarkatt and Hamil, a plaintiff's expert in Pennsylvania does not have to testify that the patient would have survived, or even probably survived, with proper care; it is enough to testify with reasonable medical certainty that the negligence increased the risk of the harm that occurred. That is the point the trial court missed, according to both appellate courts.

Nor is there a magic-words requirement. The opinion, consistent with the Superior Court's 2014 decision in Klein v. Aronchick, recognizes that an expert need not use the phrase "increased the risk of harm" so long as the substance of the testimony supports that conclusion. Courts read the testimony as a whole rather than parsing it for a formula.

What the expert cannot do is speculate. The doctrine lowers the certainty threshold on the counterfactual; it does not dispense with a reasoned medical link between the negligent act and an elevated risk of the specific harm alleged. Defense counsel will still be able to argue to the jury that the elevated risk was too small to make the negligence a substantial factor.

Why is the Kannarkatt case going to a third trial?

The case goes to a third trial because the second trial never reached a verdict: the York County judge granted a compulsory nonsuit after the plaintiffs rested, and the Supreme Court has now agreed with the Superior Court that the nonsuit was wrong. The first trial, in October 2021, ended in a hung-jury mistrial.

At argument on March 11, 2026, counsel for the oncologist argued she should not have to face a third trial. The justices appeared unpersuaded, suggesting that disputed facts about the patient's care made the case suitable for a jury, and the October 29 opinion bears that out. The new trial will be a full trial on liability, causation and damages; nothing in the appellate rulings decides whether Dr. Kannarkatt breached the standard of care or what the claim is worth.

Who dissented, and who weighed in as amici?

The Supreme Court's opinion postings list two separate writings alongside the majority: a concurring opinion by Justice Sallie Mundy and a concurring and dissenting opinion by Chief Justice Debra Todd. The indexed record does not disclose the precise scope of the partial dissent, and practitioners should read it in full before relying on it.

The amicus line-up shows how much was riding on the case:

• American Medical Association and Pennsylvania Medical Society. Their joint brief urged reversal, warning that the Superior Court's approach would impose "a lowered standard to establish liability" and create a "cloud of liability over the medical profession." The brief argued that letting the jury infer causation rather than weigh the proofs would significantly expand plaintiffs' ability to prevail.
• Hospital and Healthsystem Association of Pennsylvania. The statewide hospital trade group also filed an amicus brief, giving institutional providers a voice alongside physicians.
• Pennsylvania Association for Justice. The state trial lawyers' association filed in support of the estate.

The opinion recounts the critique that the standard lowers plaintiffs' burden of proof while shifting significant costs to medical professional defendants. The affirmance nonetheless leaves Hamil fully in place.

How Smith v. Kannarkatt fits with the UPenn Hagans appeal

The ruling arrives while a second increased risk of harm question sits before the same court. On July 29, 2026, the Pennsylvania Supreme Court granted allocatur in Hagans v. Hospital of the University of Pennsylvania, No. 30 EAP 2026, the appeal from the roughly $207 million birth-injury judgment against HUP. One of the two questions is whether a verdict slip may combine "factual cause" with "increased risk of harm" in a single question, an issue on which Superior Court panels have split; Lewis v. Reading Hospital treated the combined formulation as reversible error, while the Hagans panel found any error harmless.

Kannarkatt and Hagans address different stages of a case. Kannarkatt is about sufficiency: what evidence gets an increased-risk claim to the jury. Hagans is about instruction: how the jury is told to apply the standard once it gets there. A reaffirmed Hamil standard in Kannarkatt makes it less likely the court will use Hagans to retreat from increased-risk causation as a doctrine, though it leaves fully open how trial courts must structure the charge and the verdict form. Superior Court decisions such as the unpublished Matthews v. Hospital of the University of Pennsylvania (February 26, 2026), which addressed when the relaxed charge is warranted, will need to be read alongside both rulings.

What it means for defendants, plaintiffs' counsel and insurers

For medical malpractice defendants and their counsel. A compulsory nonsuit or directed verdict on causation is now harder to obtain in any case pleaded under Section 323(a). Defense strategy shifts from arguing that the plaintiff's expert lacked certainty about survival to attacking whether the expert reliably tied the negligence to an increased risk of the specific harm, and to persuading the jury that the increase was too small to be a substantial factor. Motions that rely on isolated deposition answers will be measured against the whole record, given the majority's criticism of a "selective review."

For plaintiffs' personal injury firms. The decision confirms that rare-disease, delayed-diagnosis and wrong-treatment claims remain viable in Pennsylvania even when no expert can quantify survival odds. Expert reports should still state the increased-risk opinion expressly, even though magic words are not required, because the cleanest path past a nonsuit motion is testimony that tracks Hamil's two steps.

For medical professional liability insurers and hospital systems. Reserve and settlement models for Pennsylvania delayed-diagnosis claims should assume that more such cases will reach juries. Combined with the pending Hagans appeal and the state's 2023 venue rule change, which restored plaintiffs' ability to file malpractice cases in Philadelphia and other counties outside the county where care was provided, the decision keeps Pennsylvania among the more challenging jurisdictions for malpractice defense.

For trial judges. The ruling is a reminder that sufficiency is assessed with the evidence and its reasonable inferences viewed in the plaintiff's favor, and that the substantial-factor question in an increased-risk case belongs to the jury once the expert threshold is met.

FAQ

What did the Pennsylvania Supreme Court decide in Smith v. Kannarkatt?

It held on October 29, 2026 that the estate's expert testimony was sufficient under the increased risk of harm standard to send its claim against oncologist Dr. Annie Kannarkatt to a jury, affirming the Superior Court's order vacating a compulsory nonsuit and remanding for a new trial.

Did the court find the oncologist liable?

No. The decision resolves only whether the evidence was sufficient to reach a jury. Liability, causation and any damages will be decided at the new trial in the York County Court of Common Pleas.

What is the increased risk of harm standard?

It is Pennsylvania's relaxed causation rule from Hamil v. Bashline (1978) and Restatement (Second) of Torts Section 323(a): the plaintiff's expert must show with reasonable medical certainty that the defendant's negligence increased the risk of the harm that occurred, and the jury then decides whether that negligence was a substantial factor.

Does an expert have to use the words "increased risk of harm"?

No. Pennsylvania courts, including the Superior Court in Klein v. Aronchick and the Supreme Court in Smith v. Kannarkatt, look at the substance of the testimony rather than requiring a set phrase.

Who dissented in Smith v. Kannarkatt?

Chief Justice Debra Todd filed a concurring and dissenting opinion, and Justice Sallie Mundy filed a concurring opinion. Justice P. Kevin Brobson wrote for the majority.

Does the ruling affect the UPenn Hagans appeal?

Not directly. Hagans asks how juries should be instructed on increased risk of harm and whether it may be combined with factual cause on a verdict slip; Kannarkatt addresses what evidence is needed to reach the jury. The reaffirmation of Hamil in Kannarkatt, however, frames the doctrine the court will apply when it decides Hagans.