Effect of PET before liver resection on surgical management for colorectal adenocarcinoma metastases: a randomized clinical trial.

IMPORTANCE: Patients with colorectal cancer with liver metastases undergo hepatic resection with curative intent. Positron emission tomography combined with computed tomography (PET-CT) could help avoid noncurative surgery by identifying patients with occult metastases. OBJECTIVES: To determine the effect of preoperative PET-CT vs no PET-CT (control) on the surgical management of patients with resectable metastases and to investigate the effect of PET-CT on survival and the association between the standardized uptake value (ratio of tissue radioactivity to injected radioactivity adjusted by weight) and survival. DESIGN, SETTING, AND PARTICIPANTS: A randomized trial of patients older than 18 years with colorectal cancer treated by surgery, with resectable metastases based on CT scans of the chest, abdomen, and pelvis within the previous 30 days, and with a clear colonoscopy within the previous 18 months was conducted between 2005 and 2013, involving 21 surgeons at 9 hospitals in Ontario, Canada, with PET-CT scanners at 5 academic institutions. INTERVENTIONS: Patients were randomized using a 2 to 1 ratio to PET-CT or control. MAIN OUTCOMES AND MEASURES: The primary outcome was a change in surgical management defined as canceled hepatic surgery, more extensive hepatic surgery, or additional organ surgery based on the PET-CT. Survival was a secondary outcome. RESULTS: Of the 263 patients who underwent PET-CT, 21 had a change in surgical management (8.0%; 95% CI, 5.0%-11.9%). Specifically, 7 patients (2.7%) did not undergo laparotomy, 4 (1.5%) had more extensive hepatic surgery, 9 (3.4%) had additional organ surgery (8 of whom had hepatic resection), and the abdominal cavity was opened in 1 patient but hepatic surgery was not performed and the cavity was closed. Liver resection was performed in 91% of patients in the PET-CT group and 92% of the control group. After a median follow-up of 36 months, the estimated mortality rate was 11.13 (95% CI, 8.95-13.68) events/1000 person-months for the PET-CT group and 12.71 (95% CI, 9.40-16.80) events/1000 person-months for the control group. Survival did not differ between the 2 groups (hazard ratio, 0.86 [95% CI, 0.60-1.21]; P = .38). The standardized uptake value was associated with survival (hazard ratio, 1.11 [90% CI, 1.07-1.15] per unit increase; P < .001). The C statistic for the model including the standardized uptake value was 0.62 (95% CI, 0.56-0.68) and without it was 0.50 (95% CI, 0.44-0.56). The difference in C statistics is 0.12 (95% CI, 0.04-0.21). The low C statistic suggests that the standard uptake value is not a strong predictor of overall survival. CONCLUSIONS AND RELEVANCE: Among patients with potentially resectable hepatic metastases of colorectal adenocarcinoma, the use of PET-CT compared with CT alone did not result in frequent change in surgical management. These findings raise questions about the value of PET-CT scans in this setting. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00265356.

A prospective evaluation of positron emission tomography scanning, sentinel lymph node biopsy, and standard axillary dissection for axillary staging in patients with early stage breast cancer.

BACKGROUND: Positron emission tomography (PET) is a noninvasive imaging modality that can detect malignant lymph nodes. This study determined the sensitivity, specificity, predictive values, and likelihood ratios of PET scanning compared with standard axillary lymph node dissection (ALND) and sentinel lymph node biopsy (SLNB) in staging the axilla in women with early stage breast cancer. METHODS: Women with clinical stage I or II breast cancer had whole body PET scanning before ALND and SLNB, in a prospective, blinded protocol. ALND were evaluated by standard hematoxylin and eosin (H&E) staining techniques, while sentinel nodes were also examined for micrometastatic disease. RESULTS: A total of 98 patients were recruited. PET compared with ALND demonstrated sensitivity of 0.40 (95% CI, 0.16, 0.68), specificity 0.97 (CI, 0.90, 0.99), positive likelihood ratio 14.4 (CI, 3.21, 64.5), positive predictive value 0.75 (CI, 0.35, 0.97), and false-negative rate of 0.60 (CI, 0.32, 0.84). Test properties were similar for PET compared with sentinel nodes positive by H&E staining. A few false-positive scans (0.028, CI, 0.003, 0.097) were seen. Multiple logistic regression analysis found that PET accuracy was better in patients with high grade and larger tumors. Increased size and number of positive nodes were also associated with a positive PET scan. CONCLUSIONS: The sensitivity of PET compared with ALND and SLNB was low, whereas PET scanning had high specificity and positive predictive values. The study suggests that PET scanning cannot replace histologic staging in early stage breast cancer. The low rate of false-positive findings suggests that PET can identify women who can forego SLNB and require full axillary dissection.