What are the likely biopsy findings and optimal management for a 73‑year‑old healthy male with an implantable cardioverter‑defibrillator who has a right lower‑lobe pulmonary nodule that increased from 7.5 mm to 9 mm on contrast computed tomography?

Management of Growing Pulmonary Nodule in a 73-Year-Old Active Male

Your 9 mm right lower lobe nodule that has demonstrated documented growth from 7.5 mm warrants tissue diagnosis via either CT-guided percutaneous biopsy or surgical resection, as growth itself is a high-risk feature that elevates malignancy probability regardless of initial size. 1

Probable Biopsy Results

The documented growth from 7.5 mm to 9.0 mm over the surveillance period significantly increases the likelihood of malignancy, with growing nodules having substantially higher cancer risk than stable nodules of similar size. 2

Malignancy Risk Assessment

• New or growing solid nodules in the 6-8 mm range carry higher cancer risk than baseline stable nodules of the same size, with growth being one of the strongest predictors of malignancy. 2
• Volume doubling time (VDT) <400 days indicates growth consistent with malignancy and requires immediate escalation to tissue diagnosis. 3, 1
• Your age (73 years) and the nodule's growth pattern place you in a higher-risk category that mandates definitive diagnosis rather than continued surveillance. 1

Expected Histologic Findings

• If malignant, the most likely diagnosis is adenocarcinoma, which represents the majority of peripheral lung nodules in this size range. 2
• Cancers associated with growing nodules may have different biologic behavior than those detected at baseline screening, with some studies showing poorer survival outcomes. 2
• Benign diagnoses remain possible and include inflammatory lesions, hamartomas, or infectious granulomas, though growth makes these less likely. 3

Optimal Management Strategy

Immediate Next Steps

Proceed directly to tissue diagnosis without additional imaging surveillance, as documented growth eliminates the option of continued CT monitoring. 3, 1

Biopsy Approach Selection

CT-guided percutaneous needle biopsy is the preferred initial approach for your 9 mm peripheral right lower lobe nodule, offering 90-95% sensitivity and 99% specificity with diagnostic accuracy of approximately 90%. 1, 4

Advantages of Percutaneous Biopsy in Your Case

• The nodule's peripheral location in the right lower lobe makes it technically accessible for transthoracic needle biopsy. 1
• Your implanted cardioverter-defibrillator (ICD) does not contraindicate CT-guided biopsy, though the interventional radiologist should be informed to plan needle trajectory away from the device. 1
• Pneumothorax occurs in 19-25% of cases, with chest tube requirement in 1.8-15%, but your excellent functional status (walking 10 miles daily) suggests good pulmonary reserve to tolerate this complication if it occurs. 1

Alternative: Surgical Diagnosis

Video-assisted thoracoscopic surgery (VATS) wedge resection provides definitive diagnosis approaching 100% accuracy and offers therapeutic benefit if malignancy is confirmed. 1

• VATS should be considered if percutaneous biopsy is nondiagnostic (occurs in 6-20% of cases) or if you prefer a single definitive procedure. 1
• Your excellent functional status makes you an ideal surgical candidate despite your age. 1

Why PET-CT Is Not the Next Step

While PET-CT can be used for risk stratification in nodules ≥8 mm, documented growth has already established high-risk status that mandates tissue diagnosis regardless of PET results. 1, 4

• PET-CT sensitivity for nodules in the 8-10 mm range is suboptimal, with false-negative results possible in well-differentiated adenocarcinomas. 1
• A negative PET scan would not eliminate the need for biopsy given documented growth. 1
• PET-CT may be useful for staging if malignancy is confirmed on biopsy, but should not delay tissue diagnosis. 1

Critical Considerations for Your ICD

Inform both the interventional radiologist (for biopsy) and thoracic surgeon (if surgery is chosen) about your ICD, as electromagnetic interference during procedures requires specific precautions. 1

• The ICD should be interrogated before and after any procedure. 1
• Electrocautery settings may need adjustment during VATS to prevent device interference. 1
• Your cardiologist should be consulted regarding temporary device reprogramming if extensive electrocautery is anticipated. 1

If Biopsy Shows Malignancy

Early-stage lung cancer (which is likely given the small nodule size) has excellent outcomes with surgical resection, with 5-year survival rates exceeding 70-80% for stage IA disease. 1

• Your exceptional functional status (walking 10 miles daily) makes you an excellent candidate for curative-intent surgery despite your age. 1
• Lobectomy via VATS is the standard of care for peripheral lung cancers, offering equivalent oncologic outcomes to open thoracotomy with faster recovery. 1
• Sublobar resection (wedge or segmentectomy) may be considered for nodules ≤2 cm in patients with limited pulmonary reserve, though your excellent functional status favors anatomic lobectomy for optimal oncologic outcomes. 1

If Biopsy Is Nondiagnostic

A nondiagnostic biopsy result does not exclude malignancy and requires either repeat biopsy or surgical resection given the documented growth. 1

• Approximately 6-20% of percutaneous biopsies yield insufficient tissue for diagnosis. 1
• In the setting of documented growth, surgical resection should be strongly considered after a nondiagnostic biopsy rather than returning to surveillance. 1

Common Pitfalls to Avoid

• Do not return to CT surveillance after documenting growth—this delays definitive diagnosis and potentially worsens outcomes if malignancy is present. 3, 1
• Do not assume a negative PET scan excludes malignancy in a growing nodule—tissue diagnosis remains mandatory. 1
• Do not let your age alone influence the decision for aggressive workup—your functional status is the critical determinant, and you are clearly an excellent candidate for any necessary intervention. 1
• Do not delay biopsy to obtain additional imaging—you already have documented growth on two separate CT scans confirming the nodule's progression. 1

Timeline for Action

Schedule tissue diagnosis within 2-4 weeks of the confirmatory CT scan showing growth to 9.0 mm. 1

• Delays in diagnosis for growing nodules may allow disease progression if malignancy is present. 2
• Your excellent health status means there are no medical optimization steps needed before proceeding with biopsy or surgery. 1