1. No category

PET SCANS: THE WHO, WHEN AND WHY &
HOW TO GET REIMBURSED
Cecelia E. Schmalbach, MD, FACS
Associate Professor of Surgery
Head & Neck Surgery
Otolaryngology Residency Program Director
No Financial Disclosures
PET SCANS: THE WHO, WHEN AND WHY &
HOW TO GET REIMBURSED
• Background
• Applications
• Evaluation of the Unknown Primary
• Tumor Staging
• “Incidentalomas”
• Thyroid
• Salivary Gland
• Reimbursement
THEORY OF POSITRON EMISSION
TOMOGRAPHY (PET) IMAGING
• Non-invasive diagnostic imaging introduced to
measure metabolic activity within the human body
• 1977:
• Sokoloff et al.
• [14C]deoxyglucose
• cerebral glucose
metabolic rate
PET Theory
• [18fluoro] deoxyglucose
(18FDG)
– Introduced 1979
• Warburg Effect (1930s):
• Cancer cells have aberrantly
high rates of glycolysis
• Tumor hypoxia leads to
anaerobic glycolysis
PET Theory
• Tumor cells lose efficient production
of ATP by Krebs cycle
• 19-fold increase in glucose consumption
per mole ATP
• FDG
• Increased transporter enzyme Glut-1 = rapid uptake
• Phosphorylated and trapped in tumor cells
• Fluorine prevents further metabolism
• 2000: PET received FDA approval for use in H&N cancer
FDG-PET Imaging
• Fast for 4-8 hours prior to scan
• Whole blood glucose checked
• Mod. elevated (200-250 mg/dl) -> 2-4 U insulin
• Marked elevation (> 250mg/dl) -> reschedule
• 10-15 mCi FDG IV
• CT obtained prior to PET emission
• 45 – 60 min delay
FDG-PET Imaging
• PET imaging in 4-5 bed positions
• Axial, coronal, sagittal views
• 5 min per position
• Brain through mid-thigh
• Standardized Uptake Value:
• SUV = Maximum tissue activity of FDG
Injected dose of FDG/ Body Weight
Normal FDG Distribution
• 78 non-H&N cancer
patients
• Multiple factors
• Age
• Smoking
• Location
• > 4 SUV = concern
Nakamoto et al. Radiology. 2005; 234(3):879.
PET Limitations
• PET interpretation requires experience b/c
non-malignant tissue can take up FDG
•
•
•
•
Inflammation/Infection
Asymmetry from surgery
Movement (coughing; talking)
H&N regions with variable FDG uptake:
•
•
•
•
Nasal turbinates
Pterygoid and extraocular muscles
Salivary tissue (Parotid; SMG)
Waldeyer ring/lympoid tissue
• FDG uptake reduced with elevated glucose levels
• Decreased sensitivity with tumors < 10mm
PET IN EVALUATION OF THE
UNKNOWN PRIMARY
(3 – 7% of H&N Patients)
PET in Evaluation of Unknown
Primary
• 26 pts unknown primary H&N
• 8 pts (30.8%) detected by PET
•
•
•
•
3 Palatine tonsils
2 BOT
2 Lung (negative on CXR)
1 Hypopharynx
• 2/8 also detected by panendo and bx
• 6/8 only identified following PET
Miller et al, Arch OTO/HNS. 2005; 131:626.
PET in Evaluation of Unknown Primary
• 26 pts unknown primary H&N
• 1 false positive (tonsil)
• 4 /26 (15.4%) False Negative
• All ≤ 8 mm
• 2 tonsil; 2 BOT
Miller et al, Arch OTO/HNS. 2005; 131:626.
PET in Evaluation of Unknown
Primary
•
•
•
•
Sensitivity = 66%
Specificity = 92.9%
PPV = 88.8%
NPV = 76.5%
CONCLUSION:
A positive PET can help guide the surgeon in
directed biopsies, but a negative PET does
NOT preclude the need for careful
examination (panendo, bx, tonsillectomy)
Miller et al, Arch OTO/HNS. 2005; 131:626.
1. Neck Mass
FNA
SCC; adenoca; anaplastic
2. Chest imaging
3. Contrast CT or MRI (skull base to thoracic inlet)
4. PET/CT *** BEFORE BIOPSY
5. HPV/EBV testing of neck mass
•
Positive status suggests occult primary in BOT or tonsil
•
May help customize radiation to these mucosal targets
www.nccn.org
Case #1: Unknown Primary
• 63 y.o. male
• Right neck mass x 2 mon.
• Tobacco use
– 20 pack/yr history
– Quit 3 years prior
• PMH: Prostate cancer s/p
TURP and XRT
6 cm matted level II LN
Case #1 Unknown Primary
PET: 2 enlarged Rt IIA LNs; Max SUV 16.6
Symmetric activity B BOT at 3.9
No abnormal mucosal uptake
Case #1: TxN3M0 SCC R Neck
• Surgical Management
–
–
–
–
Panendoscopy
Directed biopsies
Negative
B tonsillectomy
Right MRND (6cm mass)
• Chemo/XRT
– Waldyer’s Ring
– Right neck
• Currently NED
Case #2: Unknown Primary
• 43 y.o. male
• Right neck “swelling” x 2 mon.
• Non-smoker; social etoh
• FNA: atypical cells concerning for SCC
2.4x2.7x3.4 cm Heterogeneous Mass Right II
Case #2: Unknown Primary
• PET: no primary identified
• Surgical Management
• Panendoscopy
• Directed biopsies (Right BOT)
• B tonsillectomy
• Right ND
• Final Pathology:
• 0.5 cm non-keratinizing SCC Rt Tonsil
• P-16+
Case #2: T1N2aM0 SCC Rt Tonsil
• Adjuvant chemo/XRT
• Currently NED
PET in Evaluation of Unknown Primary
 PET does not replace careful PE & CT/MRI
 Consider PET prior to panendoscopy/bx
 Positive PET more meaningful than Negative
PET!
STAGING WITH PET
PET in Initial Staging: N-0 NECK
• Brouwer et al, Eur Arch Otorhinolaryngol, 2004
• Sensitivity 2/3 (67%)
• Civantos et al, Head and Neck, 2003
• Sensitivity 3/11 (27%)
• Hyde et al, Oral Oncol, 2003
• Sensitivity 0/4
• Stoeckli et al, Head Neck, 2002
• Sensitivity 2/5 (40%)
PET in Initial Staging: N-0 NECK
KEY POINT:
• PET/CT does not replace standard evaluation for
and treatment of regional disease
• Decision is based on risk of occult nodal
metastasis
• T-stage
• Site
• PNI
• Depth of invasion
PET in Evaluating:
Recurrent/Residual Disease
Meta-analysis of PET/CT to detect recurrent
locoregional disease
• Seven studies, 2007-2010
• 339 patients
• Inclusion
– PET/CT
– Raw data
– Adequate follow-up or confirmatory pathology
PET in Evaluating:
Recurrent/Residual Disease
•Sensitivity was 73% (95% CI: 56% - 85%)
•Specificity was 92% (95% CI: 87% - 95%)
PET in Evaluating:
Recurrent/Residual Disease
•
NO disease in the neck following curative nonoperative treatment
•
•
•
Negative PET/CT fairly accurate
Close observation
Persistent disease in the neck disease
•
•
Variable PET/CT results
Less accuracy
**PET-CT should not be used as the sole
determinant of the need for salvage neck
dissection
PET in In Evaluating:
Recurrent/Residual Disease
Key Points:
1. Sensitivity appears to be good, but not great
• PET/CT will not always be positive when there is
recurrent/residual LR disease
2. Use PET/CT along with other measures
(symptoms, PE, endoscopy, dedicated CT/MRI)
to evaluate for recurrent/residual disease
3. Do NOT get PET less than 3 months after
completion of treatment
PET in Evaluating:
Distant Disease
PET in Evaluating: Distant Disease
• Gourin et al, Laryngoscope, 2009
• N=64, previously treated
• Sensitivity 7/10 (70%); NPV 47/50 (94%)
• Gourin et al, Laryngoscope, 2008
• N= 27, untreated
• Sensitivity 3/3 (100%); NPV 23/23 (100%)
• Teknos et al, Head & Neck, 2001
• N=12, untreated
• Sensitivity 3/3 (100%); NPV 9/9 (100%)
Many other studies, difficult to interpret—don’t know total
number of patients with met dz
PET in Evaluating:
Distant Disease
Key Points:
1. PET-CT may improve detection of distant
metastatic disease in the “high risk” untreated
patient
2. PET-CT may be considered as part of the
evaluation of patients with recurrence prior to
salvage, particularly if salvage surgery carries
high morbidity
PET-CT Accuracy by Indication
Accuracy (%)
100
80
60
40
20
0
unknown
primary
distant
recurrence
Zanation AM et al, Laryngoscope, 2005
PET FOR NON-HNSCC
INDICATIONS & WHAT TO DO
WITH “INCIDENTALOMAS”
PET for THYROID
Blodgett et al, Radiographics 2005
• Diffuse, asymmetric, focal or no FDG uptake
• Reasons for uptake
• Physiologic
• Toxic adenoma
• Goiters
• Thyroiditis
• Malignancies
THYROID “PETomas”
Nishimori H, et al. Can J Surg. 2011;54(2):83
6457 PET Scans
Focal thyroid uptake n=103 (2.2%)
Cytology/histology evaluation n=30
9 (30%) malignant
PET for THYROID
Blodgett et al, Radiographics 2005
Useful in thyroid ca f/u with increasing thyroglobulin
but negative 131I scan
Pts with intense, asymmetric, focal uptake in
lesion ≥ 10mm warrant evaluation and FNA
PET for Salivary Glands
• Unilateral & bilateral uptake can be caused by
benign or malignant disease
• FDG-avid lesions:
• Warthin’s tumor
• Pleomorphic adenoma
• Lymphoma
• Infections/granulomatous processes (sarcoid)
• Parotid malignancies may have little FDG avidity
PET-CT in Salivary Malignancy
(N=55)
•
•
•
•
•
•
Sensitivity = 74.4%
Specificity = 100%
PPV = 100%; NPV = 61.5%
No difference in sensitivity by grade
Useful if positive but not if negative
High accuracy in detecting recurrence and
distant disease
Razfar A et al, Laryngoscope, 2010; 120(4):734.
PET for non-HNSCC Indications
PET for Salivary Glands
KEY POINTS:
1. Benign and malignant parotid tumors cannot be
distinguished by PET alone
2. Lack of FDG uptake does NOT preclude salivary
malignancy
3. Correlate with history (oncologic and surgical),
clinical presentation, and examination
What to Do With “Incidentalomas”
Lymphoid Tissue
• Uptake due to infection, inflammation, or
malignancy
• Generally symmetric in Waldeyer’s ring
• Malignancy can “hide” in symmetric uptake
When searching for an unknown primary with no focal
uptake on PET, perform usual directed biopsies,
including bilateral tonsillectomy
What to Do With “Incidentalomas”
68 yo male with PET/CT for f/u after lymphoma
treatment, referred for uptake in NP.
What to Do With “Incidentalomas”
• Muscle & Brown Fat uptake
• Easier to identify on PET-CT
• Can be due to talking, swallowing, coughing
during uptake phase
Take Home Points:
1. Communicate with radiologist/nuclear medicine
physician
2. Know surgical history, anatomy. Review your scans!
PET for Non-HNSCC Indications
PET REIMBURSEMENT
PET Reimbursement
CMS reimbursement is determined by:
• National Coverage Determination(NCD)
• Local Coverage Determination criteria (LCD) - TX
https://www.cms.gov/medicare-coveragedatabase/overview-and-quick-search.aspx
FDG PET for Head and Neck Cancers (220.6.7)
National Coverage Determination
Medicare coverage is limited to items and
services that are reasonable and necessary
for the diagnosis or treatment of an illness or
injury (and within the scope of a Medicare
benefit category). National coverage
determinations (NCDs) are made through an
evidence-based process, with opportunities
for public participation.
CMS changes ~ June 11, 2013
http://www.cms.gov/medicare-coverage-database/details/nca-decisionmemo.aspx?NCAId=263
1. Ending the requirement for coverage with evidence
development (CED) under §1862(a)(1)(E) of the Social
Security Act. B.
2. CMS has determined that three FDG PET scans are covered
under § 1862(a)(1)(A) when used to guide subsequent
management of anti-tumor treatment strategy after
completion of initial anticancer therapy.
• Coverage of any additional FDG PET scans (> 3) used to guide
subsequent management after completion of initial anti-tumor
therapy will be determined by local Medicare Administrative
Contractors.
PET reimbursement (Nov10, 2009)
PET reimbursement
Timing of scans--Initial
Only one initial scan with PI modifier per
cancer indication
PET reimbursement
Timing of scans– FOLLOW-UP
F/U scans for approved cancer
types covered for up to 3 studies
PET Reimbursement:
FDG PET coverage as of November 10, 2009
Melanoma:
• Non-covered for initial staging of regional lymph nodes
• All other indications for initial treatment strategy are
covered.
Thyroid:
• Covered for subsequent treatment strategy of recurrent
or residual thyroid cancer (follicular cell origin) previously
treated by thyroidectomy and radioiodine ablation and
have a serum thyroglobulin >10ng/ml and have a negative
I-131 whole body scan.
• All other indications for subsequent treatment strategy
are CED.
Use of PET Scans: Are we being smart?
Post Coverage Analysis: Use of PET Scans; Virnig and Durham,
Research Data Assistance Center; 9/20/04;
http://www.cms.gov/DeterminationProcess/Downloads/PCAPetScan.pdf
Use of PET Scans: Are we being smart?
Post Coverage Analysis: Use of PET Scans; Virnig and Durham,
Research Data Assistance Center; 9/20/04;
http://www.cms.gov/DeterminationProcess/Downloads/PCAPetScan.pdf
Use of PET Scans: Are we being smart?
Post Coverage Analysis: Use of PET Scans; Virnig and Durham,
Research Data Assistance Center; 9/20/04;
http://www.cms.gov/DeterminationProcess/Downloads/PCAPetScan.pdf
Questions ?