Delayed Cancer Diagnosis Claims in Arizona

By Joe Styler, editor (not an attorney). Updated October 17, 2026. Sources checked

Learning that cancer was there months before anyone found it is hard to take in. Under Arizona law, a delayed cancer diagnosis can be medical malpractice, but only if two things can be shown: the care fell below the expected standard, and the delay changed what happened to the patient. This page explains how those questions are looked at, what proof is needed, and when the deadline may start.

The short answer

• A late cancer diagnosis is not automatically malpractice. Arizona law requires proof of a breach of the standard of care and proof that it caused harm (A.R.S. 12-563).
• In cancer cases, the harm question is usually about what an earlier diagnosis would have changed.
• When expert testimony is needed, Arizona requires an expert opinion affidavit early in the case (A.R.S. 12-2603).
• The deadline is generally two years after the claim accrues, which may be earlier than the day you got the diagnosis (A.R.S. 12-542).

How cancer diagnoses get delayed

When families look back at a late diagnosis, the questions they and their lawyers often ask include:

• Was an abnormal scan, biopsy, blood test or screening result ever communicated to the patient and acted on?
• Were reported symptoms, such as a lump, bleeding, pain or weight loss, written off without a test that a careful provider would have ordered?
• Was a referral to a specialist recommended but never made, scheduled or followed up?
• Was an image or slide read in a way another qualified reader would say was clearly wrong?
• Did the patient get mixed messages about whether a follow-up visit was needed?

These questions point to facts. Whether the answers add up to a failure to meet the standard of care is something a qualified expert and a lawyer would have to assess.

The two things Arizona law requires

Arizona’s malpractice statute, A.R.S. 12-563, says both of these are necessary elements of proof:

1. The provider failed to use the care, skill and learning expected of a reasonable, prudent provider in the same profession or class in Arizona, acting in the same or similar circumstances.
2. That failure was a proximate cause of the injury.

In a cancer case, the second element often decides things. The question is generally whether finding the cancer earlier would have made a difference to the patient, for example in the treatment that was possible or how the illness progressed. That is a medical question as much as a legal one, and it depends on the type of cancer and the timeline. Our guide to Arizona medical malpractice law explains both elements, and our page on misdiagnosis and delayed diagnosis claims covers these elements for all kinds of diagnoses.

Why expert opinions come first

Arizona has an early expert step for claims against a health care professional. Under A.R.S. 12-2603, the person bringing the claim must certify whether expert testimony is needed. If it is, a preliminary expert opinion affidavit must be served with the initial disclosures, stating the expert’s qualifications, the facts behind each claim, what the expert considers a violation of the standard of care, and how it caused or contributed to the damages. If a required affidavit is not filed and served, the court shall dismiss the claim without prejudice.

Cancer cases can involve more than one specialty, such as a primary care provider, a radiologist and a pathologist. Under A.R.S. 12-2604, if a defendant is or claims to be a specialist, the expert who testifies about the standard of care generally must practice in the same specialty. That can mean more than one expert. Our page on the expert affidavit requirement explains these rules.

When the two-year clock starts

A.R.S. 12-542 generally requires a malpractice lawsuit to be started within two years after the cause of action accrues. That is not the same as two years from the missed test.

In Walk v. Ring (2002), the Arizona Supreme Court said a medical malpractice claim accrues when a reasonable person would be on notice to investigate whether the injury came from someone’s wrongdoing. A bad result alone is not always enough to start the clock, and when a claim accrued is generally a question for the jury. In a cancer case, the date can be argued, so assume the clock may have started earlier than you hope.

• If the patient has died, the two years for a wrongful death claim run from the date of death (A.R.S. 12-542). See our page on wrongful death after a medical error.
• If any of the care was at a city, county or state facility, a notice of claim is due within 180 days (A.R.S. 12-821.01).
• If the care was at a VA facility, federal rules apply. See our page on VA malpractice claims in Arizona.

Our page on the Arizona statute of limitations sets these clocks out side by side. Sending our form does not stop or pause any deadline.

Not sure when the clock started for your diagnosis? Request a free case review.

Who may be responsible

Arizona’s malpractice chapter applies to licensed health care providers, which the statute defines to include persons, corporations and institutions licensed by the state to provide health care, and their employees and agents working under supervision (A.R.S. 12-561). In a delayed diagnosis, more than one provider or practice can be involved, such as the office that ordered a test and the group that read it.

Arizona generally makes each defendant pay only its own percentage share of fault (A.R.S. 12-2506), with exceptions, including when one party is responsible for its agent or servant. That is one reason a lawyer will want to know every place the patient was seen.

What to gather this week

• a timeline of every visit, test, scan, biopsy and referral connected to the symptoms
• copies of any result letters, portal messages and after-visit summaries
• notes on what you were told at each visit, and by whom
• the date of the cancer diagnosis, and the date you first had reason to think it was late
• a list of every clinic, imaging center, lab and hospital involved

Your medical records will fill in most of the rest. Our page on how to get medical records in Arizona explains how to ask for them, including scans and other images. If you are not sure whether your situation is worth asking about at all, our checklist on whether you may have a malpractice case may help.

Frequently asked questions

Is a delayed cancer diagnosis medical malpractice in Arizona?

It can be, but not automatically. Under A.R.S. 12-563, a claim must prove that the provider failed to use the care, skill and learning expected of a reasonable, prudent provider in the same or similar circumstances, and that this failure was a proximate cause of the injury.

What has to be shown about the delay itself?

The second element of A.R.S. 12-563 requires that the failure was a proximate cause of the injury. In a cancer case, that generally means showing that an earlier diagnosis would have made a difference to the patient. That is usually a medical question as much as a legal one.

When does the deadline start for a delayed cancer diagnosis claim?

A.R.S. 12-542 generally allows two years after the cause of action accrues. In Walk v. Ring (2002), the Arizona Supreme Court said a malpractice claim accrues when a reasonable person would be on notice to investigate whether the injury came from someone’s wrongdoing. Claims against public bodies have shorter deadlines. Sending our form does not stop or pause any deadline.

Do I need an expert for a cancer misdiagnosis claim?

Under A.R.S. 12-2603, the person bringing the claim must certify whether expert testimony is needed. If it is, a preliminary expert opinion affidavit must be served with the initial disclosures, and a required affidavit that is not filed and served leads to dismissal without prejudice.

Can a family bring a claim if the patient has died?

Arizona allows a wrongful death claim when a death is caused by a wrongful act, neglect or default that would have let the person sue had they lived (A.R.S. 12-611). The two-year period runs from the date of death.