Imaging of Pulmonary Nodules Bradley R. Trotter, MD, DABR, DABNM Department of Radiology [email protected] B R Trotter, MD Scott & White Healthcare

Imaging of Pulmonary Nodules: Overview • Background: From Nodules to Lung Cancer • Review of Imaging Modalities: Tools of the Trade • Review of Imaging Features: “To benign or not to benign, that is the question.” • Likelihood of Malignancy: “… damned lies, and statistics” • Recommendations: Putting it together B R Trotter, MD Scott & White Healthcare

Background: From Nodules to Lung Cancer

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Background: Pulmonary Nodules • “A round opacity, at least moderately well marginated, and no greater than 3 cm in maximum diameter” • “Round” meaning roughly circular or oval shaped but also “spherical” in its 3dimensional nature (not flat or plaque-like) • Completely surrounded by lung parenchyma and not associated with adenopathy, atelectasis, or pneumonia B R Trotter, MD Scott & White Healthcare

Background: Pulmonary Nodules • May be solitary (SPN) or multiple, which affects likelihood of various differential diagnostic considerations • When multiple, imaging features of each nodule identified must be considered , in addition to consideration as a whole • Although our discussion primarily relates to solitary (or clearly dominant) pulmonary nodules, also useful in the setting of multiple B R Trotter, MD Scott & White Healthcare

Background: Pulmonary Nodules • Very common imaging finding, particularly since advent of helical and multidetector CT • Studies report prevalence of one or more nodules from 8% to 69% on CT • Vast majority are benign (95%-98% in most studies)

B R Trotter, MD Scott & White Healthcare

Background: Pulmonary Nodules • Idealistic goals of imaging: – Definitively identify all malignant nodules, and thereby beneficially affect patient outcomes – Definitively identify all benign nodules, and thereby avoid the morbidity and cost of invasive procedures or further imaging that provide no true benefit

• Disappointingly, this remains elusive despite extensive experience and research B R Trotter, MD Scott & White Healthcare

Background: Pulmonary Nodules • Realistic goal of imaging of pulmonary nodules: – Determine which are benign and need no further evaluation – Determine which are suspicious for malignancy and refer for definitive resolution – For nodules that remain indeterminate: • Determine which require biopsy • Determine which require follow-up B R Trotter, MD Scott & White Healthcare

Background: Lung Cancer • Our discussion of pulmonary nodules ultimately falls within the context of lung cancer, which directly influences our management decisions regarding nodules • A few points are worth noting for our discussion …

B R Trotter, MD Scott & White Healthcare

Background: Lung Cancer • It is, overall, an aggressive disease: – “More people in the United States die from lung cancer than from any other type of cancer. This is true for both men and women.” – In the United States in 2008: • 208,493 diagnosed with lung cancer • 158,592 died from lung cancer • Although, incidence and death has more recently been declining following a trend of decreasing smoking B R Trotter, MD Scott & White Healthcare

Background: Lung Cancer • It is a costly disease: – Estimated impact on U. S. economy is over $300 billion annually – Management decisions should include consideration of cost effectiveness that is, as much as possible, based on proven clinical outcomes research

B R Trotter, MD Scott & White Healthcare

Background: Lung Cancer • There are known risk factors: – Smoking: • Accounts for 90% of lung cancers in the U. S. • 15x to 30x more likely to develop or die from lung cancer than nonsmokers • Risk increases with degree and duration (pack years) • Currently estimated 94 million current or former smokers in the U. S. at increased risk

B R Trotter, MD Scott & White Healthcare

Background: Lung Cancer • Other known risk factors include: – Second hand smoke – Asbestos, radon, or uranium exposure – Radiation therapy to the thorax, such as with lymphoma or breast cancer – Family history of lung cancer in 1st degree relative – Age: risk increases with age; rare under age 35 – Chronic lung diseases – Personal history of prior lung cancer B R Trotter, MD Scott & White Healthcare

Background: Lung Cancer • It is a heterogeneous disease: – Non-small cell lung cancer (NSCLC) 80%-85% of lung cancer Squamous cell, Adenocarcinoma, Large-cell, other 5 year survival 50%-70% stage IA to 2% stage IV Can be detected at earlier stages with CT (NLST: 30%75% stage 1A depending on type of NSCLC) • Role of screening with CT to detect at earlier stage? • The primary focus when discussing imaging of pulmonary nodules • • • •

B R Trotter, MD Scott & White Healthcare

Background: Lung Cancer • It is a heterogeneous disease: – SCLC • 15%-20% of lung cancers • 5 year survival 20% limited-stage to 90% sensitivity for nodules 1-3 cm; lower specificity is about 80% B R Trotter, MD Scott & White Healthcare

Review of Imaging Modalities: PET-CT • It’s like Reese’s Peanut Butter Cups • It’s a PET scan with an anatomic contrast agent • It’s a CT scan with a metabolic contrast agent • Either way, combines benefits of both modalities with higher sensitivity and specificity than for either PET or CT alone • Reimbursement? (CMS 15 HU B R Trotter, MD Scott & White Healthcare

Likelihood of Malignancy: “SPN Calculator” • An easily accessible and useable “SPN Calculator” with both the Bayesian analysis and logistic regression models can be found on the web at www.chestx-ray.com/SPN/SPNProb.html • Extremely cool so check it out

B R Trotter, MD Scott & White Healthcare

Recommendations: Putting It Together

B R Trotter, MD Scott & White Healthcare

Recommendations: • Clinical management of an imaging finding • Distill the clinical and imaging variables and formulate a plan of action that is broadly applicable and adheres to the standard of care

B R Trotter, MD Scott & White Healthcare

Recommendations: • First things first: – Comparison with old imaging studies cannot be overemphasized! (Turn on the retrospectoscope) • May obviate need for any further expensive and potentially harmful evaluation. Team effort of clinician, radiologist, and patient. • In general, clearly growing nodules should move to tissue diagnosis if not contraindicated

– If suspected infectious etiology, further diagnostic intervention, therapy, and short-term follow-up imaging best initial management B R Trotter, MD Scott & White Healthcare

Recommendations: • Breaks down into two categories: – Management of small nodules ≤8-10 mm – Management of larger nodules >8-10 mm

B R Trotter, MD Scott & White Healthcare

Small Nodules ≤8-10 mm

B R Trotter, MD Scott & White Healthcare

Recommendations: Small Nodules ≤8-10 mm • Fleischner Society guidelines for management of small nodules have been widely adopted • Apply to: – Incidentally detected nodules on CT – Patients 35 years of age and older

• Do not apply to: – Patient with known or suspected malignancy – Patient with unexplained fever B R Trotter, MD Scott & White Healthcare

Recommendations: Small Nodules ≤8-10 mm

MacMahon H, et al. Guidelines for management of small pulmonary nodules detected on CT scans: a statement from the Fleischner Society. Radiology 2005; 237: 395-400

Recommendations: Small Nodules ≤8-10 mm • A few key rationales for FSG: – Differing follow-up times for low and high risk categories because malignant nodules generally grow faster in smokers – Even in smokers, 8-10 mm • More diagnostic options become feasible with larger nodules: – Advanced imaging with FDG PET or contrast enhanced CT densitometry – Percutaneous needle biopsy or bronchoscopy

• Many management algorithms in the literature—most are very similar • Best integrate clinical and imaging variables B R Trotter, MD Scott & White Healthcare

A management algorithm for patients with SPNs >8 mm and 8-10 mm • “Ask your doctor if this test is right for you…” • Details of application depend on available local resources, expertise, and the wishes of the fully informed patient

B R Trotter, MD Scott & White Healthcare

Thank you for your attention

B R Trotter, MD Scott & White Healthcare

Resources • • • • • • • •

cdc.gov Chestx-ray.com Gould MK, et al. Evaluation of patients with pulmonary nodules: when is it lung cancer?, ACCP evidence-based clinical practice guidelines (2nd ed.). Chest 2007; 132: 108S-130S MacMahon H, et al. Guidelines for management of small pulmonary nodules detected on CT scans: a statement from the Fleischner Society. Radiology 2005; 237: 395-400 NLST Research Team. Reduced lung cancer mortality with low-dose computed tomographic screening. N Engl J Med 2011; 365: 395-409 Winer-Muram HT. The solitary pulmonary nodule. Radiology 2006; 239: 3449 Nicholas E, et al. Evaluation of the solitary pulmonary nodule: A practical approach. Applied Radiology 2010. Vol 40, No 12: 6-15 Swenson SJ, et al. The probability of malignancy in solitary pulmonary nodules: application to small radiologically indeterminate nodules. Arch Intern Med 1997; 157: 849-855 B R Trotter, MD Scott & White Healthcare