Nov 14, 2013
What do lung nodules have to do with emergency medicine? Weʼd like to see ourselves as full time resuscitationists and while thatʼs one of our master skills, much of our job involves taking care of non-critical patients and, even more so, having conversations with patients and their families. But arenʼt pulmonary nodules someone elseʼs problem, like the pulmonologist? Yes, and no. The pulmonologist is going to manage things in the long term, but the overwhelming majority of nodules are going to be incidental findings that land in your lap.
You get a phone call from the radiologist on a CT chest, “Thereʼs no PE or sign of dissection, but thereʼs a 5mm non-calcified pulmonary nodule in the right upper lobe” What does that mean? Do you need to pay attention to it? Can you ignore it? What do you tell the patient?
The conversation often goes something like this, “Good news Mr. Jones, we donʼt see a blood clot and, oh by the way, the radiologist saw a small nodule.” For you, someone who is used to getting reports of an incidental pulmonary nodule, itʼs no big deal. For the patient, what they heard is, “You have cancer.” That may sound like hyperbole, but itʼs most patientsʼ first reaction.
Mr. Jones may or may not have cancer and Mr. Jones may or may not ask you questions. We donʼt want to do is to induce fear in the patient by our ignorance but we also donʼt want to dismiss the findings and ignore a possible malignancy.
This comes down to risk and benefit. Risk that this nodule is malignant, the benefit of follow up imaging versus the risk of extra radiation, unnecessary biopsies, surgeries, anxiety, and medical bills. While it’s not well known in emergency medicine, The Fleischner Society is a group in radiology that develops an evidence based consensus guideline on how to follow up pulmonary nodules.
Nodule size and patient risk factors are the principle elements that determine timing and type of follow-up study needed. There are two main pieces of the Fleischner Criteria that are germane to emergency providers:
These guidelines suggest that the likelihood of a small (≤4mm) nodule being cancer in low risk patient is so low that no further follow up is needed. Will some of these nodules turn out to be cancer? Yes, but striving for a zero miss rate in this group is not risk-benefit favorable. The likelihood of the patient having negative sequelae (radiation, unnecessary biopsy, surgery, financial hardship) is greater than the chance of the nodule being cancerous. Itʼs analogous to striving for a 0% MI miss rate. Cost far outweighs benefit.
Not everyone follows the Fleischner guidelines. Some radiologists recommend follow-up imaging, or at least discussion, for every patient with a newly diagnosed nodule. Pulmonary nodules are a complex topic with multiple factors and variables that dictate the best course of action (or no action). These patients need follow up, preferably with a pulmonologist, to discuss risk level and decide what to do next. When weʼre talking about a one millimeter difference dictating a follow up scan versus doing nothing, one of my colleagues who is a chest radiologist, has this to say, “Depending on how much coffee Iʼve had to drink, I can measure the same nodule 20 times and have it be different every time, so trying to make separate recommendations for nodules that are ≤4mm or 4-6mm is silly to me. “
Here are some example scripts for delivering the news of a newly diagnosed nodule...
“Mr Jones, good news, there's no blood clot. The radiologist did mention that he saw a small spot on your lung. The medical term for it is a nodule. It's 5mm, which is about half the width of your little finger or the size of a pea. We see these all the time and 95% turn out to be completely harmless so I don't want you to lose any sleep over this. You will, however need to make sure someone takes a look at this again with a CAT scan to make sure it's not growing. Iʼm going to refer your to our pulmonologist, a lung specialist, who is an expert in lung nodules and will help guide you the rest of the way.”
Maybe Mr. Jones is low risk.... “The chance of this nodule being anything serious is extremely low. The nodule is small, you donʼt smoke and youʼre young. The risk isnʼt zero, but itʼs pretty close. I still think you should follow up to discuss all of the options, but in all likelihood, this will not cause you any problems.”
The overwhelming majority of pulmonary nodules are benign. The bigger they are, the higher the chance of malignancy. There is debate as to whether a very small lung nodule in a low risk patient needs follow up at all. Should an emergency provider make the call that no follow up is needed? I think there is too much uncertainty in sorting out all of the variables that go into risk factor assessment. I refer all patients with newly diagnosed nodules for follow up, risk stratification, and further discussion with their PCP or a pulmonologist.
Patients almost always have questions about the significance of their newly diagnosed pulmonary nodule. What they really want to know is if they have cancer. You canʼt know that looking by at a nodule one time. For a small nodule, itʼs about how it grows (or doesnʼt) on repeat studies. The things that make cancer more likely and follow up more urgent include size >4mm, age over 35, history of smoking, and nodules that are not completely calcified.
In the end, it may be cancer, but chances are, your patient is going to be just fine.
Historically, all patients with non-calcified nodules were recommended to get follow-up chest CTs for 2 years. This was based on the pre helical CT era when most pulmonary nodules were found on chest x-ray. By the time a nodule is seen on CXR, itʼs often big. The old ACCP recommendation for indeterminate solitary nodules was follow up CT at 3-, 6-, 12-, and 24 months. Thatʼs five chest CTs (including the original study), no matter what. When you consider that upwards of 51% of smokers over age 50 have pulmonary nodules, that is a lot of negative CT scans, radiation, unnecessary biopsies, surgeries, anxiety, and money spent. With our ability to diagnose smaller nodules, we needed to change our thinking about what to do with them. Thatʼs what the Fleischner recommendations addressed. Itʼs not one size fits all.
Does it make a difference if the nodule is measured on CT or Chest X-Ray?
These measurements apply only to CT scans. CXR is too inaccurate. The work-up for nodules found on CXR varies depending on the scenario. The first step is to try to get old films to see how long it's been there. If no old films are available, depending on nodule features and clinical story, the patient needs either a CT scan or a short-term follow up CXR (4-6 weeks) to see if it persists. Sometimes it's tough to tell if a nodule is calcified on CXR. If it is obviously calcified, it doesn't need any follow-up.
What does calcification in a nodule suggest? Calcification in a small nodule suggests benign etiology. Mostly. A partially calcified nodule or one with eccentric calcification needs followup. Malignancies, like scar carcinomas (from old granulomas), and mucinous adenocarcinomas can have small calcifications.
How should you think about terms like ground glass, semi-solid, and solid? Does appearance make a difference when it comes to determining nodule behavior?
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