PET/CT may offer single staging exam for locally advanced breast cancer

PET/CT depicted almost all lesions shown on conventional imaging in women with locally advanced breast cancer and also showed additional lesions not detected by other exams, according to a study published in the January issue of Journal of Nuclear Medicine.

“This is a step toward the truly personalized medicine that molecular imaging can bring—acquiring an image that provides sufficient information to truly tailor management strategies to the singular needs of each patient,” David Groheux, MD, from the department of nuclear medicine at Saint-Louis Hospital in Paris, said in a press release.

Staging recommendations for locally advanced breast cancer may include multiple exams: bilateral mammography, ultrasound, breast MR, chest or abdominal CT, pelvic CT or MR and bone scanning. The National Comprehensive Cancer Network has commented that PET/CT may be helpful in cases where standard imaging is equivocal or suspicious and in the detection of distant metastases. However, the impact of PET/CT on survival remains unclear.

Groheux and colleagues designed a prospective study to investigate the role of PET/CT in women with locally advanced breast cancer and compare the exam with conventional distant work-up. The researchers wrote, “[If] 18F-FDG PET/CT is helpful it should be a substitute rather than an additional imaging procedure.”  

A total of 117 patients with locally advanced breast cancer were enrolled in the study; 35 women were diagnosed with inflammatory breast cancer and 82 with noninflammatory disease. The women underwent conventional imaging, comprised of bone scanning, chest x-ray or CT, and abdominal ultrasound or CT. PET/CT imaging also was performed on all patients.

FDG uptake was seen on all primary tumors. PET/CT also confirmed N3 nodal involvement in stage IIIC patients and showed unsuspected N3 nodes in 32 additional patients. PET/CT showed distant metastases in 43 patients, and overall PET/CT imaging changed staging for 52 percent of patients, according to Groheux and colleagues.

When the researchers compared PET/CT findings with conventional exams, they found it depicted bone metastases in 30 patients compared with 19 patients via bone scanning. PET/CT and CT showed lung nodules on six patients, while chest x-ray revealed lung nodules on two of the six women. PET/CT showed liver metastases in 10 women; abdominal CT and ultrasound detected nine of these metastases.

The researchers confirmed PET/CT detected all but one distant lesion shown by the combination of conventional imaging, and also found additional unknown metastases in bone, pleura, distant lymph nodes and liver.

Groheux et al acknowledged that PET/CT might miss brain metastases, and suggested dedicated brain imaging for patients at high risk.

In addition to detecting almost all lesions found by conventional imaging and finding additional lesions, PET/CT delivered the advantage of examining the chest, abdomen and bones in a single session, the researchers concluded.

“Based on these findings, 18F-FDG PET/CT may become the single most important distant staging modality in patients with locally advanced breast cancer,” Groheux said in the release.