According to the updated 2010 practice guidelines of the National Comprehensive Cancer Network (NCCN), the work-up of patients with early breast cancer should not include imaging by positron-emission tomography (PET) or by PET/computed tomography (CT) scanning. This updated guideline has implications for healthcare stakeholders, especially providers and health plans.
In their 2010 annual review, the NCCN Breast Cancer Panel gave a thumbs down for the use of this modality in a number of settings. PET or PET/CT can be helpful in some cases of stage III disease in which standard staging studies are equivocal or suspicious, but it should not be routine in the staging of newly diagnosed stage I, II, or operable stage III breast cancer, the Breast Cancer Panel concluded.
"The implication of our recommendations is that PET/CT is overused in breast cancer," said Robert Carlson, MD, of Stanford Cancer Center, Palo Alto, CA, who chairs the panel. "What is fueling the overuse? I don't really know. It is simple to order, but it is very expensive. So there are financial issues in terms of rewards for physicians who perform them frequently. Our society assumes that any technology with a high price tag has value, but the newest technology is not necessarily the best technology," Dr Carlson said in an interview.
High Rate of False-Positives
The new recommendation is based on studies showing low sensitivity and fairly low specificity in staging of the axillary lymph nodes and poor detection of metastases in patients with apparent early-stage disease. The ultimate result is a high frequency of falsepositive findings, he said.
In a retrospective analysis (presented at ASCO in 2007) from the University of Kansas, 15 of 83 (18%) wo men had suspicious PET/CT scans, but only 2 (13%) of the women were found to have confirmed metastases, and the PET and CT scanning results were often discordant.1
The NCCN Breast Cancer Panel also discourages the use of PET or PET/CT scanning in the work-up of recurrent or metastatic breast cancer. The exception is those clinical situations where other staging studies are equivocal or suspicious.
In contrast, for patients with locally advanced breast cancer, the use of PET or PET/CT scanning has been reported by several studies to detect extra-axial nodal disease in 7% to 25% of cases and distant metastases in 10% to 21% over and above routine studies.2-4 Therefore, the NCCN panel considered PET or PET/CT to be optional in locally advanced disease, but it is a category 2B recommendation based on the low level of evidence and the nonuniformity of practice among the panelists.
Under most circumstances, Dr Carlson concluded, "A positive PET scan in a woman with localized breast cancer is as likely to be a false-positive as a true-positive, and as likely to lead to an incorrect treatment decision as a correct one." PET or PET/CT scanning for most patients, therefore, is not recommended by the NCCN.
- Khan QJ, O'Dea AP, Dusing R, et al. Integrated FDG-PET/CT for initial staging of breast cancer. J Clin Oncol. 2007;25(18 suppl):Abstract 558.
- Fuster D, Duch J, Paredes P, et al. Preoperative staging of large primary breast cancer with [18F]fluorodeoxyglucose positron emission tomography/computed tomography compared with conventional imaging procedures. J Clin Oncol. 2008; 10:4746-4751.
- Bellon JR, Livingston RB, Eubank WB, et al. Evaluation of the internal mammary lymph nodes by FDG-PET in locally advanced breast cancer (LABC). Am J Clin Oncol. 2004;27:407-410.
- Mahner S, Schirrmacher S, Brenner W, et al. Comparison between positron emission tomography using 2-[fluorine-18]fluoro-2-deoxy-D-glucose, conventional imaging and computed tomography for staging of breast cancer. Ann Oncol. 2008; 19:1249-1254.