PET and Its Role in Routine Clinical Care: The Oncologists Perspective

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PET and Its Role in Routine Clinical Care The
Oncologists Perspective

• Anthony F. Shields, M.D., Ph.D.
• Karmanos Cancer Institute
• Wayne State University,
• Detroit, Michigan

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PET Imaging

• PET provides images of tumor and tissue
  metabolism.
  
• PET images complement anatomic images obtained
  with CT and MRI.
  
• Routine imaging with PET uses a radioactive form
  of a sugar analog (FDG- Fluorodeoxyglucose).
  
• FDG uptake is used to measure tumor energy use.

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PET Imaging

• A tumor is just a lump and may represent cancer,
  injury, infection etc.
  
• Increased energy use is seen in most cancers and
  can be detected by PET.
  
• Normal energy use is also seen in the heart and
  brain.
  

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Assessment of Cancer

• What is the role of PET?
• Diagnosis
• Staging
• Response to Therapy
• Documenting Recurrence
• Re-staging

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Assessment of Cancer

• Approved for use in the following cancers
• Lung (Non-small Cell)
• Head and Neck
• Colon
• Esophagus
• Lymphoma
• Melanoma
• Breast
• Thyroid

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Assessment of Cancer

• Approved Pending for use in the following
  cancers
  
• Brain Tumors
• Cervical
• Small Cell Lung
• Testicular
• Pancreas
• Gastrointestinal Stromal
• Prostate
• Multiple Myeloma
• When will it be approved for stomach, biliary,
  small bowel, ampullary, renal, unknown primary,
  adrenal, sarcoma,thymoma, mesothelioma ...

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PET

• Use of PET in Clinical Care
• Will it make added tests unnecessary or direct
  biopsies?
  
• Will a PET scan (positive or negative) change
• your approach to the patient?

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PET Scans Have Limited Use in Some Situations
Normal retention in brain heart bowel kid
neys bladder Infection can show increased FDG
uptake. A physician needs to interpret PET in
the context of all the clinical information
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NORMAL FDG-PET
Heart
NORMAL FDG UPTAKE IN THE HEART, KIDNEYS, BLADDER
Kidney
Bladder
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Assessment of Cancer

• What is the role of PET?
• Diagnosis
• Can PET help us detect cancer?

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Solitary Pulmonary Nodules
Patients often present with nodules in their
lungs on chest X-rays and CT scans.
Recent screening studies has found that 70 of s
mokers have small lung lesions detectable by CT.
PET can be used to help distinguish benign from
cancerous lesions.
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Solitary Pulmonary Nodule
PET is about 90 accurate in determining if a
lesion is malignant.
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Solitary Pulmonary Nodules
Before PET, patients with solitary nodules
routinely had them removed surgically, but only
about 30 were cancerous. With PET, those that
are active are removed immediately.
Inactive lesions are observed without surgery.
They are removed if they grow in size.
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Lung Cancer
MM,pl 23
MM,pl 29
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Lung Cancer
Squamous Cell Lung Cancer
Small Cell Lung Cancer
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PET Scans Can Detect Multiple Cancers
Two primary cancers can look the same as one
metastatic lesion. It is generally better to ha
ve two, localized primary cancers, than one
metastatic cancer.
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No Test is Perfect
Even biopsies can be misread- I always have
pathology read a second time. Oncologists are
used to uncertainty in diagnostic tests- blood
tests, scans, etc. While PET is not perfect, it
adds information that helps us to plan patient
care and determine if additional biopsies are
needed.
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Assessment of Cancer

• What is the role of PET?
• Staging
• Staging It the determination of how far a tumor
  has spread.
  
• Knowing the stage is important in deciding what
  treatment is needed (surgery, radiation,
  chemotherapy).
  

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Accurate Staging FDG PET in Lung Cancer
PET detected -additional lymph nodes in the righ
t chest and neck.
-A lesion in the other lung.
Tumor
Heart
Kidneys
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Lymph Node Staging In Patients with Lung Cancer

PET 14 studies 514 patients CT 29 studies 2,
226 patients PET CT Accuracy 92 75

BA Dwamena, Radiol 213530, 1999
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Dutch Trial of Standard Work-Up without and with
FDG PET in Lung Cancer
Standard Standard Tests Tests PET U
seless Sugery 41 21 At surgery some patient
s did not have cancer, others had cancer that
could not be removed.
Relative Reduction in Unnecessary Surgery 51
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Costs (societal perspective, US)
Standard Standard Tests Tests
PET Tests 1100 2800
Hospitlization 10000 7500 Surgery 130
0 1100 Total/Patient 12400 11400
PET cost 1750
PET can save money in patient care
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PET Limitations
PET It will NEVER beat a pathologist in detect
ing microscopic disease. EXAMPLE Breast cance
r staging of in the armpit is not improved by
PET. On the other hand, studies suggest it may
be useful in the chest nodes.
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Assessment of Cancer

• What is the role of PET?
• Response to Therapy
• After treatment we measure the change in tumor
  size with CT or MR.
  

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Assessment of Cancer Treatment

• Cancer can take weeks to months to change size
  after treatment.
  
• Even when a tumor shrinks, what is left may be
  healthy and grow back.
  
• A tumor that does not shrink may be dead and
  mostly scar tissue.
  

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Assessment of Cancer

• Response to Therapy
• When to image depends on
• Tumor type
• Treatment used
• When you need the answer

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FDG-PET After Radiation and Chemotherpy for Lung
Cancer

Before Treatment Two months after
Treatment

Mac Manus et al.
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Lung Cancer Response to ChemoRTPET and CT

PET Response
CT Response
Complete response (CR) by PET predicted survival,
but CT did not.
MacManus et al.
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Imaging Becomes More Important as the Number of
Therapeutic Choices Increases
Example Therapy for Metastatic Lung Cancer
15 years ago it was debatable that chemotherapy
was effective for lung cancer.
Studies showed that cisplatin based therapy was
cost-effective in improving survival.
We now have a number of therapeutic choices avai
lable for first and second line therapy
(cisplatin, gemcitabine, taxol, taxotere,
navelbine, irinotecan, Iressa).
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Ineffective Chemotherapy Is Very Expensive
Drugs often cost 1000 - 3000/ month.
Chemotherapy can be very hard on patients with i
ncreased morbidity and mortality.

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Pancreas Cancer Therapy

Pre-Therapy After Cycle 1
After Radiation
MRI
PET
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Gastrointestinal Stromal Cancer on Gleevec
Baseline
1 Month
24 Hours
Heart
Kidneys
Bladder
18FDG Avid Tumors in Liver
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Assessment of Cancer

• What is the role of PET?
• Documenting Recurrence
• Re-staging

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Recurrent/ Metastatic Colon Cancer
6 months after surgery, the blood test for CEA
started rising. CT showed fatty liver changes
without evidence of liver metastasis
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Recurrent/ Metastatic Colon Cancer
Patients with limited disease may benefit from
surgery. For example, we can cure patients wi
th a small number of liver tumors.
PET often determines that some lesions seen in t
he liver are not cancer. Other times PET finds
additional lesions, showing us that surgery would
not be helpful.
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Ovarian Cancer
PET FDG
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Ovarian Cancer
CT
PET/CT FUSED
PET FDG
Rising CA125
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When to order PET?
Will a positive scan change therapy?
Will it help direct biopsies?

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PET Imaging in OncologyConclusions

• PET imaging is the most sensitive
• measure of tumor well-being
• It is an effective way to stage, assess
• recurrence and response to therapy
• FDG is a very useful agent in clinical
• oncology and others are being tested
• Imaging is gaining more importance as we as we
  have new therapeutic options