Breast Cancer - Moose and Doc

A breast cancer explanations website

 

By Dr. Halls

Positron Emission Tomography and Breast Cancer staging

PET scans are sometimes used in breast cancer diagnosis and follow-up. Positron Emission Tomography has a very high sensitivity rate, and may be useful in differentiating breast cancer from other benign lesions, especially for lesions 7 mm or greater. On the whole PET imaging is not used for initial screening purposes, and has relatively small role with respect to primary breast cancer. It is often used as a complement to conventional imaging in improving the characterization of breast lesions and may show multifocal involvement.

I just want to let you know that I have created a newer version of this page with more up-to-date information on PET scans. However, even though this page is getting a little bit old, doesn’t mean you still can’t use it. It still has great information.

pet-scan

Positron Emission Tomography (PET) most commonly uses radiopharmaceutical 18F-fluorodeoxyglucose (labelled with “F18 in the FDG molecule) which is injected intra-venous. The F18 emits positrons in such a way, that a 3 dimensional image can be created. With a dedicated PET camera, it is possible to view the distribution of FDG and to identify tumors. The FDG molecule is a form of non-metabolized glucose that is absorbed by cells proportionally to glucose metabolism.

Malignant cells typically have and increased glycolytic rate, therefore making it possible to differentiate cancer cells from benign tissue. New PET tracers, such as radio-labeled thymidine, are being developed that will monitor tumor growth with greater specificity, detailing elements such as early tumor response and recurrence after irradiation.

Below is a PET scan reconstructed in 3-D, which reveals a lesion on the left breast, multiple liver metastasis, a sacra bone metastasis, axillary and supra-clavicular adenopathies, and other tumors behind the bladder.

petscanwoman

PET scanning perhaps the only non-invasive imaging procedure that can detect tumors in the breast, lymph nodes, liver, lung, and bone and bone marrow with reasonable accuracy and high sensitivity. It may be a valuable tool in staging and management breast cancer, but in spite of its high sensitivity, it is often difficult to differentiate the different elements of the scan.

PET imaging does not detect microscopic metastatic disease, and cannot reliably determine the number of involved lymph nodes. Commonly found false-positive results with PET scans are caused by infectious or inflammatory lesions, which may include mastitis, hemorrhagic inflammation after biopsy or surgery, low-grade malignancy (tubular, lobular), and non invasive carcinoma (in situ).

So, while FDG-PET may be more sensitive perhaps than conventional imaging in the detection of metastatic or recurrent breast cancer, the overall impact of the increased sensitivity of PET scans used for staging in terms of patient care and overall outcome has really not been demonstrated.

For further reading, I suggest you visit this page to know more information about breast cancer screening using PET scans.

References

  1. Senekowitsch.-Schmidtke, R.; Ruth, F. Bernatz, S. ," Radiolabeled thymidine : A sensitive tracer for early tumor response and recurrence after irradiation". The Journal of nuclear medicine (1999) ,vol. 40, no10, pp. 1702-1705.
  2. Rostom AY, Powe J, Kandil A, Ezzat A, Bakheet S, el-Khwsky F, el-Hussainy G, Sorbris R, Sjoklint O. Positron emission tomography in breast cancer: a clinicopathological correlation of results. Br J Radiol. (Nov. 1999) 72(863):1064-8.
  3. Quon A, Gambhir SS. FDG-PET and beyond: molecular breast cancer imaging. J Clin Oncol. (Mar. 2005) 10;23(8):1664-73.
  4. Doshi NK, Shao Y, Silverman RW, et al: Design and evaluation of an LSO PET detector for breast cancer imaging. Med Phys (2000) 27:1535-1543.
  5. Smith IC, Ogston K, Whitford P, et al: Staging of the axilla in breast cancer: Accurate in vivo assessment using positron emission tomography with 2-(fluorine-18)-fluoro-2-D-glucose. Ann Surg (1998) 228:220-227.
  6. Ohta M, Tokuda Y, Suzuki Y, et al: Whole body PET for the evaluation of bony metastases in patients with breast cancer: Comparison with Tc-99m-MDP bone scintigraphy. Nucl Med Commun (2001) 22:875-879.
  7. Mankoff DA, Peterson LM, Stekhova S, et al: Uptake of [F-18]-Fluoroestradiol (FES) predicts response of recurrent or metastatic breast cancer to hormonal therapy. J Nucl Med (2003) 44:126.
  8. Lovrics P, Chen V, Coates G, et al: A prospective comparison of positron emission tomography scanning, sentinel lymph node biopsy and axillary dissection in staging patients with early stage breast cancer. Breast Cancer Res Treat (2002)76:S129.
  9. Guller U, Nitzsche E, Moch H, et al: Is positron emission tomography an accuate non-invasive alternative to sentinel lymph node biopsy in breast cancer patients? J Natl Cancer Inst(2003) 95:1040-1043.
  10. Hodgson, NC., Gulenchyn, KY. Is There a Role for Positron Emission Tomography in Breast Cancer Staging? Journal of Clinical Oncology, (Feb. 2008)Vol 26, No 5 pp. 712-720

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About Steven Halls

Dr Halls has 25 years experience as a radiologist. He worked for 13 years at Cross Cancer Institute in Edmonton, a world-class cancer treatment facility. He has had high-volume experience with cancer, interventional procedures, clinical trials and his own phase 1 and 2 research in MRI and breast cancer staging.