A change in diagnosis resulted from PET/CT imaging of patients who were younger than 40 years with an initial diagnosis of stage I-III breast cancer, according to a retrospective analysis. Although guidelines recommend FDG-PET/CT imaging only for women with stage III breast cancer, this study found these scans also help physicians more accurately stage the disease in women whose breast cancer was initially diagnosed as an earlier stage.

Assessing if and how far breast cancer has spread throughout the body is what doctor’s refer to as staging. Most cases of breast cancer are diagnosed at earlier stages, meaning stage 1 or 2 of a possible 4 stages, as explained by first author Christopher Riedl, MD, of Memorial Sloan Kettering Cancer Center in New York, New York. Current National Comprehensive Cancer Network (NCCN) guidelines consider systemic FDG-PET/CT staging only for stage III breast cancer patients.

However, more recently, experts have debated whether factors other than stage should be considered when making treatment decisions. One such factor is patient age, as younger patients with breast cancer often have more aggressive tumors.

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In this study, reported in The Journal of Nuclear Medicine (2014; doi:10.2967/jnumed.114.143297), a team of researchers from Memorial Sloan Kettering evaluated for the first time the impact of FDG PET/CT staging specifically in a young patient cohort. The study suggests that patients with breast cancer who are younger than 40 years may benefit from systemic staging with FDG PET/CT at earlier stages than NCCN guidelines suggest.

“Proper staging right after the breast cancer has first been diagnosed will help doctors make the right treatment decisions. And figuring out which breast cancer patients will benefit most from this ‘advanced staging’ with FDG PET/CT helps us to improve patient care while avoiding unnecessary tests,” stated Riedl. “Our data suggest that women younger than 40 [years] may benefit from PET/CT staging at earlier stages than doctors previously believed.”

The study included 134 patients with initial diagnoses of stage I to IIIC breast cancer; those with signs of distant metastases or with prior malignancy were excluded. PET/CT findings lead to upstaging to stage III or IV in 28 patients (21%). Unsuspected extra-axillary regional nodes were found in 11% and distant metastases in 15%, with 5% demonstrating both.

PET/CT revealed stage IV disease in 5% of patients who disease was initially staged as clinical stage I, 5% initially staged as stage IIA, 17% initially staged as stage IIB, 31% initially staged as stage IIIA, 50% initially staged as stage IIIB, and 50% (1 of 2) whose disease was initially staged as stage IIIC. All 20 patients upstaged to stage IV were histologically confirmed. Four synchronous thyroid malignancies and one rectal malignancy were identified.

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