Sigrid Stroobantsdept of Nuclear Medicine

Leuven, Belgium

PET and PET/CT in lung cancer

PET and PET/CT in Lung Ca

• Characterization of a solitaire pulmonary nodule

• Mediastinal staging

• Distant staging

• (Radiotherapy planning)

• (Treatment response assessment)

Solitary Pulmonary Nodules

• FDG-PET useful to distinguish between benign vs malignant nodules– many well documented prospective series– meta-analysis Gould et al; JAMA, 2001

• sensitivity 96% - specificity 78% - accuracy 91%

• Limits– sensitivity: subcentimetric nodules - carcinoids - BAC (GGO)– specificity: inflammatory/granulomatous lesions

• Use of threshold values (e.g. SUV >2.5) not superior

• Clinical use– close FU in PET negative nodules > 1 - 1.5 cm without GGO

Mediastinal staging

• FDG-PET more accurate than CT in mediastinal LN staging– many well documented prospective series– several meta-analyses

Gould et al; Ann Intern Med 2003• Sensitivity 89% (vs. 65%) - Specificity 92% (vs. 80%)

• Limits– spatial resolution (N1 vs N2/N2; adjacent LN in central T)– sensitivity: LNs with minimal tumour load– specificity: inflammatory nodes– accuracy dependent on LN size?

Mediastinal staging

Langen et al, Eur J Cardio Thor Surgery 2006

• Clinical use– high NPV of PET in LN staging omit invasive tests

• BUT “side conditions”– adequate FDG-uptake of primary tumour– caution with central tumours and hilar N1 disease– ? Large nodes on CT

• Always confirm PET+ nodes

Mediastinal staging

• PET improves conventional staging (CS)– detection of lesions missed on CS (5 - 20%)– differentiation of lesions equivocal on CS (7 – 19%)

• caution if lesion < 1 cm !• low sensitivity for brain mets

– change in overall stage in 27 - 62% (up > down)– never alter treatment based on PET+ only

• PET impacts on choice of treatment in 25-41%

Distant Staging

Question?Do you have access to PET or PET/CT1. No

2. Yes, in own hospital

3. Yes, in other hospital

QuestionDo you discuss PET images in a multi discipl. round

1. Yes and radiologist / Nuc Med is present

2. Yes, but no radiologist / Nuc Med is present

3. No, I only rely on the report

Case 1

Case 1

• Male, 55 y, smoker (30 pack y)• Incidental finding of a 1 cm node in LLL• No previous imaging data, normal

bronchoscopy

QuestionWhat would be your next step?

1. Repeat CT scan after 3 months

2. PET

3. Trans thoracic biopsy

4. Surgery (VATS, thoracotomy)

Case 1

Mediastinoscopy + 4LSquamous ca T1N2

Case 1

Case 2

Case 2

• Male, 64 y, painter, smoker (35 pack y, stopped 2y ago)• Persistent cough, dyspnoe, malaise• Chest XR and CT

• Bronchoscopy with aspiration negative• EBUS guided biopsy LLL: squamous cell carcinoma• Brain and abdominal CT negative for M+, normal CEA

Case 2

1. Chemotherapy (stage IV – contralateral lung)

2. Chemoradiation (stage III B – N3)

3. EBUS + FNA

4. Mediastinoscopy

QuestionWhat would be your next step?

Case 2

Case 2

Mediastinoscopy: negative Lobectomy + lymphadenectomie (silicosis)sT2N0

Case 3

Case 3• Male, 61 y, non-smoker• 1991 Cardiac transplant for sarcoidosis R/ Imuran• Co-morbidity Left Hemiparesis 1990 (CVA)

Chronic renal impairmentLung emboli (1994) R/ Marcoumar

• Incidental finding of SPN in RUL during routine annual visit

• Bronchoscopy normal

Case 3

1. Surgery of both lesions in same anesthesia

2. Surgery of limb lesion

3. Surgery of lung lesion

4. Close follow up

QuestionWhat would be your next step?

Case 3

• Surgery of the limb

Pathology = Ancient Schwannoma

• Repeat Chest CT (2 months later)

Case 3

Case 4

Case 4• Female, 69 y, housewife, smoker (45 pack y)• 1990 Larynx ca R/ surgery + radiotherapy• Referred for second opinion

– Chest CT 2 lesions in LUL + mediastinal LN (levels 4R-4L-7)

– Bronchoscopy + aspiration cytology normal– Mediastinoscopy : no tumor– Screening M+ (CT abdomen – CT brain) negative

QuestionWhat would be your next step?

1. PET

2. Trans thoracic biopsy

3. EBUS guided biopsy of lung lesion

4. Surgical exploration and if malignant resection (T4 N0-1M0)

Case 4

• EBUS guided biopsy

Pathology atypical hyperplasia

• PET

Case 4

Case 4

QuestionHow would you interpret this PET scan?

1. All inflammatory disease, no tumor present

2. Malignant lesions in LUL with N3 LN, no metastasis

3. Malignant lesions in LUL with N3 LN and bone M+

Case 4

Case 4

Case 4

• Thoracoscopy for pathology

• T4 Nx M1 • Palliative chemotherapy (Cisplatin-Gemcitabine)• Zometa

undifferentiated large cell ca

Thank You !