The usage of positron emission tomography/ computer-assisted tomography ( PET-CT ) imaging was generally rejected for use in diagnosing breast cancer.

PET-CT imaging usage was rejected for breast cancer diagnosing here at the 15th Annual National Comprehensive Cancer Network (NCCN) Conference on Clinical Practice Guidelines and Quality Cancer Care.

PET-CT combines the ability of PET to image molecular changes and the CT provides the ability to provide anatomical imaging, but the information given to the doctor and patient does not improve outcomes, said Robert Carlson, MD, Stanford University, Stanford, California.

"These imaging techniques are not sensitive or specific enough to give doctors helpful information," Dr. Carlson said on March 11. "It may also give misleading information to doctors."

He cited 1 study in which PET-CT studies in 83 patients returned 15 suspicious findings. Two of those patients were determined to have metastatic disease, meaning 87% of those indications represented false-positive scans. Three of those women had suspicious PET scans and negative CT scans -- all 3 suspicious tests were false-positives. Similarly, 7 women had suspicious CT scans and negative PET scans. All 7 were false-positives.

As far as its use in diagnosis of early-stage breast cancer, Dr. Carlson said a footnote in the 2010 NCCN Breast Cancer Guidelines reads: "The use of PET or PET-CT scanning is not indicated in the staging of clinical stage I, stage II or operable stage III breast cancer."

As far as the use of PET-CT imaging techniques in advanced cancer, Dr. Carlson said the guidelines suggest that the imaging could be ordered as an optional study. However, the breast cancer guidelines committee members said the recommendation was not a consensus decision.

"These imaging studies may be most helpful where standard staging studies are equivocal or suspicious," Dr. Carlson said. "The imaging studies may identify unsuspected regional or distant metastasis."

In another footnote, the new guidelines state: "The use of PET or PET-CT scanning should generally be discouraged for the evaluation of metastatic disease except in those clinical situations where other staging studies are equivocal or suspicious. Even in these situations, biopsy of equivocal or suspicious sites is more likely to provide useful information."

Source: NCCN

Discuss more about PET in the PET user group.