PET in Endocrine Response Neoplasms: Thyroid, Prostate

and Breast Cancer Steven M. Larson, M.D.

Memorial Sloan Kettering Cancer Center

Molecular Imaging and Targeted Radiotherapy: Key Collaborators

@MSKCC Akhurst T; Blasberg R; Ballangrud A; Cheung

NKV; Divgi C; Erdi A; Erdi Y; Finn R, Fong Y, Guillem J; Hamacher K; Heelan R; Humm J.; Hricak H; Jurcic J; Kalaigian J; Kelly WK; Koehne G; Koutcher J; Ling C; Liebel S; Ma D; Macapinlac H; Mehta B; McDevitt M; Nunez R; O’Donoghue J; O’Reilly R; Old L; Pentlow K; Robbins R, Scheinberg D., Scher H; Sgouros G; Sheh H; Slovin S; Tjuvavev Y; Turlakow, A; Welt S; Yeung H; Zanzonico P

Detecting Tumor: Strategy

• We detect the living chemistry of the tumor with biomedical tracers (e.g.FDG, a form of glucose)

• PET imaging is a sensitive diagnostic test that can read these chemical signals that come from a living tumor.

Diagnostic Testing in Thyroid Ca• Blood tests: TSH, T4, TG• Diagnostic Imaging Tests

– Ultrasound– Thyroid Scintigraphy (99mTc, 123I)– MRI– Spiral CT– Whole Body 131I/123I Testing (+/- Thyrogen)– PET* (FDG, Iodine-124 )

*An important complement to other tests

ClinicallyLocalized

Disease

Rising TGno known site

Clinical Metastases:Progressive

ClinicalMetastases:

stable

Nodule Evaluation: No

Cancer Diagnosis

Natural History of Thyroid Ca

CURE

15%

85%

* * *

*PET Improves Care

5%

What Does PET Tell Us about Thyroid Cancer

• Rising Tg

• Known metastases •Stable ?•Progressive/RX•I-131 Rx

Clinical Setting PET Question

• Where is tumor?•Should it be Rx’ed

• How Extensive•Aggressive/Prognosis?•Response to Rx•Will Rx help (124I)

Elevated TG/Negative Dosimetry

• GS, 29 yo female undergoing rTSH dosimetry testing.

• Negative Iodine-131 Whole Body Scans

• TG levels =6 ng/ml @ 72 hr.s after Thyrogen

• PET-FDG scan shows R. Cervical lymph node

• US guided biopsy reveals papillary Ca

• Rx with 200 mCi of I-131

Thyroid Ca

3 March 2000

I-131 Post-RxPET FDG

9 February 2000: Neg. I-131 Dosimetry, post rTSH TG=6 : Where is the tumor?

17 February 2000

360317

Transaxial Coronal Sagittal

Anterior

21 February 2000 US guided FNA R. neck “Positive..Papillary Ca..Thyroid Primary

MB763123

Post RxI-131

FDG-PET Coronal-1 FDG-PET Coronal-2Post Therapy Scan (anterior)

A2 A3

B1 B2 B3

A1

Figure 2

Prognostic Value of FDG-PET Conclusions

• FDG PET scanning can identify a subset of thyroid cancer patients who have more aggressive tumors

• Patients with FDG-avid tumor volumes greater than 125 ml have markedly reduced survival times.

““ // Pairs” Important to Pairs” Important to Targeted Therapies @ Targeted Therapies @

MSKCCMSKCC

TracerTracer • 124I-Iodide • 124I-IUDR• 124I-FAIU• 124I-A33, huM195• 86Y-MX35,huM195

,EC,ECTherapeuticTherapeutic • 131I-Iodide • 125,131I-IUDR• 131,125,123I-FAIU• 125,131I-A33, huM195• 90Y-MX35,huM195

124I-Dosimetry in Metastases

• PK, 53 yo white male with numerous pulmonary nodules discovered on routine CXR, while being W/U for prostate Ca

• 4/28/00 Papillary thyroid Ca, moderately differentiated, locally invasive, 2.0 cm in diameter, with 13/23 lymph nodes

• Refered for Dosimetry 7/2000

THYROID CA 277269

4/25/2000

CXR PA . LT.

THYROID CA 277269

6/20/2000PET-124I7/5/2000

PET-FDG

124I-Iodine in Thyroid Cancer

277269

229 cGy/mCi203 cGy/mCi

125 cGy/mCi

PET in Thyroid Cancer: Reading the Biochemical Signals

• Staging. Extent of Aggressive Ca for optimal treatment planning

• Prognosis: high-risk (FDG positive) and low-risk (FDG negative)

• Dosimetry. Individual lesions with 124I

• Response. Predict susceptibility to treatment and monitor treatment effect

Thyroid Dosimetry

• 124I and 131I give identical results in whole body and blood clearance

• 124I can be used to measure tumor specific dosimetry

• Tumor dose may vary by a factor of 4 or more in the tumor