Pulmonary Nodules: When to worry, when to ‘chill’
Douglas ArenbergAssociate Professor
Pulmonary & Critical Care
Disclosure• MDCH Grant Funds to improve
tobacco cessation service in the Michigan Medicine Health System
• Past paid service Consultant/Advisory panel member for Nucleix, a company developing lung cancer biomarkers
• I will not be discussing any specific products or medications relevant to either of these financial relationships
Objectives
• Recognize features of the patient and the nodule that predict a likelihood of malignancy
• Understand the indications for (and limitations of) lung nodule biopsy
Let’s start with an exercise
• Each of the next few slides has two nodules found on CT scans
• There are some differences between the nodules
• Select which one you think is more likely to be malignant (A or B), and (in your head) think of one or two words why you chose your answer
Which of these is more likely malignant?
A B
Which of these is more likely malignant?
A B
Which of these is more likely malignant?
• 65 year old man • 32 year old man
A B
Which of these is more likely malignant?
• 65 year old heavy smoker
• 64 year old non-smoker
A B
What features did you use to guess which one was more likely to be cancer?
• Features about the nodule?– Size– Edge characteristics?
• Features about the patient?– Age– Social history
Google “Swensen SPN calculator”
http://www.chestx-ray.com/index.php/calculators/spn-calculatorSwensen et al. Archives of Internal Medicine 1997; 157:849-855.
Approach to the patient with a nodule
Definitely Benign
Definitely Malignant
Younger ageSmall
Smooth bordersFat or calcium
Non-smokerLower lobe
Negative PET
Older age LargeSpiculated bordersHeavy smokerUpper lobeFDG-avid on PET
Low probability IntermediateProbability
Highprobability
What do we do with this “probability”?
Definitely Benign
Definitely Malignant
Low probability Intermediateprobability
Highprobability
Fleischner Zone
PET scan zone“Is this more or less likely to be cancer?
PET scan zone“This is cancer. What stage is it?
PET scan: Correlates anatomic and metabolic data
FDG-PET
~95% sensitivity for malignancy
False negativesGround glassSmall lesions (<8-10 mesions close to the diaphragm
False + (15-20%)ANYTHING inflammatoryDon’t get PET in patients with recent symptoms of infection
63 yo former smoker otherwise healthy with a 3.5 cm RML mass...what would you do next?
A.Biopsy the massB.PET scanC.Refer for surgical
resectionD.MediastinoscopyE.Trick question…take a
history
A case scenario
63 yo former smoker otherwise healthy with a 3.5 cm RML mass...what would you do next?
E. Trick question…take a history
He presented with abrupt onset chest pain, fever, diaphoresis and productive cough
How soon would you repeat the CT?
You’ve determined a pre-test probability of lung cancer
Now what?
Goal: Definitely Benign
Goal: Definitely Malignant
Younger ageSmall
Smooth bordersFat or calcium
Non-smokerLower lobe
Negative PET
Older age LargeSpiculated bordersHeavy smokerUpper lobeFDG-avid on PET
Low probability~5-15% or less
IntermediateProbability
HighProbability >60%
You’ve determined a pre-test probability of lung cancer
Now what?
Goal: Definitely Benign
Goal: Definitely Malignant
Proof of benign:Take it outTime (radiographic observation)
Proof of Malignancy:Any tissue under the
microscope (Biopsy or resection)
Low probability~5-15% or less
IntermediateProbability
HighProbability >60%
WHEN IS BIOPSY INDICATED?
#1. ANY TIME YOU NEED TO PROVE ITS CANCERCorollary: Biopsy cannot prove you don’t have cacer. Absence of evidence is not evidence of absence
When is it appropriate to biopsy a patient with a lung nodule?
• Biopsy is of no use in patients with a high risk of cancer who are good surgical candidates
• For this group, the “biopsy” is a surgical procedure
• Biopsy people who need a diagnosis to facilitate treatment
• Medically or anatomically unresectable
• Make sure biopsy yields an unequivocal stage
• Suspicion of Small cell lung cancer or metastasis
When do we biopsy? What is a biopsy?
Surgical “biopsy”
Don’t let this happen to you…
FEV1 2.40 (73% of predicted), FVC 3.88 (93% of predicted)DLCO 14.5 (72% of predicted)
What is wrong with this picture?…
Serial CT Observation
Diagnostic testing (PET) or biopsy Surgery or invasive staging
Biomarkers with high NPV
Benign imaging features
Safer surgery/Better outcomes?
Higher surgical risk or poorer outcomes
High patient anxiety, safer biopsy techniques, Positive PET
What do we do with this “probability”?Is there a single answer?
When to chill? When there is evidence of benignity**
• Characteristics of benign nodules
– CT is more sensitive for detection of Ca++
– Detection of fat suggests a benign cause
– Important for non-radiologists to recall patterns that are NOT predictive of benign behavior
**How to you pronounce this?
How do you prove a nodule is benign?What tools do we have?
• Calcium or fat • Time
• Cold hard steel
Characteristics of benign nodules: Perifissural nodules
de Hoop B et al. Radiology 2012;265:611-616Pulmonary Perifissural Nodules on CT Scans: Rapid Growth Is Not a Predictor of Malignancy. ©2012 by Radiological Society of North America
Journal of Thoracic Oncology 2013 8, 309-314
Not all GGOs are created equally
How good are we at identifying solid components?
How long should these be followed?
2006 2010
How Long Should Small Lung Lesions of Ground-Glass Opacity be Followed?
108 total non-solid lesions from 61 subjects followed for a median period of 4.2 years
82 of the followed lesions were recorded as “pure GGO”
Of these 82, 18 grew during observation
Journal of Thoracic Oncology 2013 8, 309-314
‘Disarming’ language
• Nodules are common• The VAST majority, even in people
at very high risk for cancer, are benign
• “Lung freckles”• Patient education materials…
http://www.thoracic.org/patients/patient-resources/resources/lung-nodules-online.pdf
Take Home Points
• Nodule and patient features can be used to estimate the probability of malignancy
• This probability can determine the next step(s)• Long term follow up, PET scan, Surgery,
etc., • The PET scan has a very high NPV in the right
scenario• Benign features of nodules should allow
conservative management