PET/CT changed diagnosis in 21% of breast cancer patients under 40

Patients less than 40 years of age originally diagnosed with one of the first three stages of breast cancer underwent a change in clinical staging as a result of PET/CT scanning, according to a study announced Oct. 1 by the Society of Nuclear Medicine and Molecular Imaging (SNMMI).

General breast-cancer imaging guidelines recommend FDG PET imaging only for patients with stage III breast cancer. However, research conducted at Memorial Sloan Kettering by Christopher C. Riedl, MD, and colleagues revealed that PET/CT imaging in earlier stages of disease can set a more accurate and effective path of treatment, especially for younger patients who may have aggressive forms of cancer. Results of the retrospective analysis were first published Sept. 11 in the Journal of Nuclear Medicine.

The study involved 134 patients diagnosed with stage I-III breast cancer excluding women with prior malignancy or distant metastases. Results of the analysis showed clear up-staging to stage III or IV breast cancer in 28 patients, or 21 percent. Of the 134 patients reviewed, 20 had distant metastases and 15 had extra-axillary regional nodes, or 15 percent and 20 percent, respectively. A total of seven women were found to have both, or 5 percent. Further delineations were made for stages IIA and IIB and IIIA and IIIB. All stage IV up-staging was confirmed with histology.

“Overall F-18 FDG PET/CT revealed stage IV disease in 10 percent of breast cancer patients younger than 40 years with clinical stage I and II breast cancers,” concluded Riedl et al in the published study. “In particular, 17 percent of women younger than 40 years with stage IIB disease were found to have distant metastases. Although current National Comprehensive Cancer Network breast cancer guidelines recommend against systemic staging with F-18 FDG PET/CT in women with stage II disease and recommend that use of the modality be considered optional for the work-up of stage III breast cancer, our data suggest that women younger than 40 years might benefit from PET/CT staging even at stage IIB.”

Researchers still need to conduct a larger prospective study that reduces any potential selection bias to validate these findings, but this preliminary research opens the door to future PET studies that look at factors beyond age to clarify which patient populations benefit most from PET imaging.

“Future NCCN guidelines for initial staging of breast cancer patients may need to consider other factors in addition to clinical stage,” said Gary Ulaner, MD, PhD, assistant professor at Memorial Sloan Kettering in the official SNMMI statement. “This study provides further evidence that molecular imaging and nuclear medicine can help us make better cancer staging and treatment decisions.”