Report from SNM: PET/CT restaging alters management for one-third of breast cancer cases

FDG-PET/CT is gaining attention for its role in staging and restaging breast cancer. A trial from the Technical University of Munich, presented Sunday at the 2008 Society of Nuclear Medicine meeting in New Orleans, found that PET/CT detected local or distant recurrence in 67% of breast cancer patients and changed the management plan in 33% of the cases. "We believe PET/CT has prognostic potential for restaging breast cancer," said presenter Dr. Michael Souvatzoglou of the nuclear medicine department.The prospective two-center study included 118 patients with suspected breast cancer recurrence on the basis of elevated tumor markers; abnormal MRI, CT, mammography, or ultrasound studies; or clinical signs. PET/CT results were correlated with patient management and outcomes.

PET/CT returned positive findings in 79 cases (67%). Local recurrence was identified in 12%, while metastases were diagnosed in 55%. Metastatic sites included:

• lymph nodes (36%)
• bone (32%)
• liver (14%)
• lungs (10%)
• adrenal glands (3%)
• pleura (2%)

Coregistered CT changed the anatomic location of the FDG-PET-detected lesions in 24 patients (20%), within either the same or a different organ or tissue.

Follow-up data on 87 patients showed that a change in therapeutic management was made based on PET/CT findings for 29 patients (33%). Changes included initiation of chemotherapy in 14, initiation of radiotherapy in 12, and initiation of chemoradiotherapy in three (3%).Survival was significantly correlated with PET/CT findings. Median survival was 3.4 years for patients with a positive PET/CT test but has not yet been reached in the PET/CT-negative group. The hazard ratio for PET/CT positivity was almost 3.4 (

p

= .0026 by log rank test), Souvatzoglou said. Senior investigator Dr. Andreus K. Buck, also from the nuclear medicine department of Technical University, emphasized that PET/CT renders information on the entire body and thus finds metastases missed by MRI and other imaging modalities. "With PET/CT we have a whole-body technique. We are able to see the uncommon metastases, such as cutaneous lesions," he said. "It also offers much better specificity. We can see the lesions clearly on CT and with the PET component we can determine if they are malignant." For more information from the Diagnostic Imaging archives:

Whole-body cancer staging requires frequent follow-up in some patients

PET affects treatment in over a third of cancer cases

PET/CT finds footing in breast, cervical, and ovarian carcinoma