Lung Cancer Misdiagnosed as Pneumonia? Here’s When You Could Have a Claim

A persistent cough. Shortness of breath. A chest X-ray that comes back showing pneumonia. Your doctor sends you home with antibiotics and expects you to feel better in a week or two.

But you don't get better, or you get better and then it comes back in the same spot. Weeks turn into months.

By the time someone orders a CT scan or refers you to a pulmonologist, you learn the truth: it was never just pneumonia. It was lung cancer, and it is now at a later stage than it would have been if someone had looked harder the first time.

If this sounds familiar, you are probably wondering whether it was bad luck or something more. Here's what you need to know

Why Lung Cancer Gets Mistaken for Pneumonia

Lung cancer and pneumonia share many of the same symptoms, and both can leave a shadow on a chest X-ray. The American Cancer Society lists these among the most common lung cancer symptoms:

• A cough that does not go away or gets worse

• Coughing up blood or rust-colored phlegm

• Chest pain that is worse with deep breathing or coughing

• Shortness of breath, wheezing, or hoarseness

• Unexplained weight loss, fatigue, or loss of appetite

• Infections such as bronchitis and pneumonia that don't go away or keep coming back

That last item is the heart of these cases. A tumor growing inside or against an airway can block drainage from part of the lung. Mucus builds up behind the blockage and becomes infected.

Doctors call this post-obstructive pneumonia, and on an X-ray it can look like any other pneumonia. Antibiotics may calm the infection for a while, but the tumor causing it is still there.

A standard chest X-ray also has limits. A tumor can hide behind the heart, the ribs, or the large blood vessels near the center of the chest, and a small nodule may simply be too faint to see. Some patients really do have pneumonia and cancer at the same time, which makes the picture even harder to read.

What Doctors Should Do When Pneumonia Doesn't Behave Like Pneumonia

The 2019 community-acquired pneumonia guideline from the American Thoracic Society and the Infectious Diseases Society of America is the main national standard for treating adults with pneumonia.

It does not call for a repeat chest X-ray for everyone. For adults whose symptoms clear within five to seven days, it suggests not routinely ordering follow-up imaging.

What the guideline does say matters more in a missed cancer case:

• When a patient isn't improving, doctors should look further. A patient who has not stabilized within about five days should be assessed for a resistant infection, a complication, or a different cause altogether.

• Cancer shows up after pneumonia. Studies the guideline reviewed found lung cancer in roughly 1.3 to 4 percent of patients recovering from pneumonia, almost all of them current or former smokers.

• Screening still applies. Many of those patients met criteria for lung cancer screening, and the guideline says screening should be done when clinically indicated.

The ACS screening guideline recommends a yearly low-dose CT for people ages 50 to 80 who smoke or used to smoke and have at least a 20 pack-year history.

In practice, the warning signs that should prompt a CT scan, a pulmonology referral, or a biopsy. The ACS screening guideline recommends a yearly low-dose CT for people ages 50 to 80 who smoke or used to smoke and have at least a 20 pack-year history.

Why Catching Lung Cancer Early Matters So Much

Stage at diagnosis drives lung cancer survival. For non-small cell lung cancer, the most common type, American Cancer Society survival data for people diagnosed from 2015 to 2021 shows these five-year relative survival rates:

• Localized (still in the lung): 67 percent

• Regional (spread to nearby lymph nodes or structures): 40 percent

• Distant (spread to other organs): 12 percent

These are population averages and cannot predict any one person's outcome. But they explain why a delay of a few months can matter so much.

A tumor that might have been removed with surgery at an early stage may later require chemotherapy and radiation, or may no longer be treatable with the goal of a cure.

Can You Sue If Your Lung Cancer Was Misdiagnosed as Pneumonia?

You may be able to. A New York malpractice claim generally requires showing three things:

• The doctor's care departed from accepted medical practice, meaning a reasonably careful physician in the same specialty would have done something different with the same information.

• That departure was a substantial factor in causing harm.

• Real damages resulted, such as a worse prognosis, harsher treatment, lost income, pain and suffering, or in the most serious cases, death.

In a pneumonia misdiagnosis case, the departure is usually not the first antibiotic prescription. It is what happened next: failing to reassess when the patient didn't improve, treating the same pneumonia again and again without imaging, ignoring a radiologist's recommendation for follow-up, or never offering screening to an eligible smoker.

You do not have to prove that earlier treatment would have cured the cancer. In Neyman v. Doshi Diagnostic Imaging Services, a 2017 delayed breast cancer case, the Appellate Division held that detailed expert evidence that a delay diminished the patient's chance of a better outcome was enough to send the claim to a jury.

The court quoted an earlier decision holding that curing cancer "is not the only positive treatment outcome." More time, less suffering, or a real chance at surgery all count.

These cases turn on expert testimony. A pulmonologist, radiologist, or oncologist reviews the original images, the treatment timeline, and the eventual diagnosis to explain how the cancer likely progressed during the delay.

New York also requires a certificate of merit under CPLR 3012-a, in which the attorney certifies that they consulted a physician and concluded there is a reasonable basis for the claim. Our article on a missed pulmonary nodule on a CT scan covers the imaging side of these claims, including how radiologists are supposed to track suspicious findings.

How Long Do You Have to File?

Under CPLR 214-a, the general deadline for a New York malpractice lawsuit is two years and six months from the act or omission.

Missed cancer cases often benefit from a 2018 amendment commonly called Lavern's Law, named for Lavern Wilkinson, a Brooklyn mother whose lung cancer was missed until it was too late to treat.

For a claim based on a negligent failure to diagnose cancer, the two-and-a-half-year period runs from the later of two dates: when you knew or reasonably should have known of the negligent act and the harm it caused, or the date of your last continuous treatment.

The discovery rule has an outer limit of seven years from the negligent act. Continuous treatment means ongoing care for the same condition, and the statute does not count examinations you request only to find out the state of your condition.

If the misdiagnosis happened at a public hospital, such as one run by NYC Health + Hospitals or a county, a formal notice of claim generally must be served within 90 days under General Municipal Law § 50-e.

Because these rules are fact-specific and a missed deadline is permanent, talk to an attorney as soon as you suspect a problem, even if you are not sure you want to pursue a case.

What to Do If You Suspect Your Lung Cancer Was Missed

A few early steps protect your options:

• Request your complete medical records, which you are entitled to under Public Health Law § 18. Include every chest X-ray and CT scan, the radiology reports, antibiotic prescriptions, and notes from each visit.

• Look for repeat pneumonia diagnoses, especially in the same part of the lung, and any report that recommended follow-up imaging.

• Write down a timeline of your symptoms, each visit, and what each doctor told you.

• Get a second opinion from an oncologist or pulmonologist, for your health first and because an independent review can show whether the earlier care fell short.

Talk With a New York Cancer Lawyer

Being told it was just pneumonia when it was lung cancer can mean the difference between catching the disease early and finding it after it has spread.

You can read about lung cancer malpractice claims and our clients' stories. Porter Law Group's New York cancer lawyers work with board-certified medical experts to review these timelines, and you can see our results in delayed cancer diagnosis cases.

Call 833-888-LATE or request a free case evaluation.

Attorney advertising. This article provides general information and is not legal or medical advice. Prior results do not guarantee a similar outcome. Filing deadlines depend on the facts of each case.

Frequently Asked Questions

Can lung cancer be misdiagnosed as pneumonia?

Yes. Lung cancer and pneumonia share symptoms like a persistent cough, chest pain, and shortness of breath, and both can appear as a shadow on a chest X-ray. A tumor blocking an airway can also cause a real infection behind it, called post-obstructive pneumonia, which can hide the cancer underneath.

Should you get a follow-up chest X-ray after pneumonia?

Not always. The 2019 ATS/IDSA pneumonia guideline suggests not routinely repeating imaging when symptoms clear within five to seven days. But pneumonia that does not improve, keeps returning in the same spot, or occurs in a smoker eligible for lung cancer screening calls for a closer look, such as a CT scan or pulmonology referral.

Can I sue if my doctor said I had pneumonia but it was lung cancer?

You may be able to. A claim generally requires showing that the doctor departed from accepted practice, for example by not investigating pneumonia that would not clear, and that the delay was a substantial factor in letting the cancer advance. New York does not require proof that earlier treatment would have cured you.

What are the signs that pneumonia might actually be lung cancer?

Warning signs include pneumonia that does not respond to antibiotics, pneumonia that keeps coming back in the same part of the lung, coughing up blood, unexplained weight loss, and symptoms that last long after treatment. The American Cancer Society lists recurring bronchitis and pneumonia among the common symptoms of lung cancer.

How long do I have to file a lung cancer misdiagnosis claim in New York?

Under Lavern's Law, part of CPLR 214-a, you generally have two years and six months from when you knew or should have known of the mistake and the harm it caused, or from your last continuous treatment. The outer limit is seven years from the missed diagnosis. Public hospitals require a notice of claim within 90 days.