18-fluorodeoxyglucose positron emission tomography in the early diagnostic workup of differentiated thyroid cancer patients with a negative post-therapeutic iodine scan and detectable thyroglobulin.

BACKGROUND: Surgery and high-dose radioactive iodine ((131)I) treatment are the cornerstones in the treatment of differentiated thyroid cancer. Patients without (131)I uptake on the post-therapeutic whole body scan (WBS), but with detectable thyroglobulin (Tg) during thyroxine withdrawal (Tg-off), are evaluated with an 18-fluorodeoxyglucose positron emission tomography ((18)F-FDG-PET) for tumor localization within three months. The yield of (18)F-FDG-PET imaging and clinical usefulness of a Tg-off cutoff value to predict a positive scan were assessed. METHODS: From 2002 to 2011, 52 patients with a negative WBS and concurrent detectable Tg-off were evaluated. Thirty-five PET scans were performed during initial treatment, 17 after recurrent disease. Thirty-two patients were on substitution therapy, 17 were evaluated with endogenous thyrotropin elevation, and 3 after recombinant human thyrotropin stimulation. To determine the Tg-off cutoff value, a receiver operating characteristic curve was used. RESULTS: Nine (17%) (18)F-FDG-PET scans were true positive, 3 (6%) false positive, 36 (69%) true negative, and 4 (8%) false negative (sensitivity 69%, specificity 92%). In 13%, a true-positive scan resulted in a change in the clinical management. The area under the receiver operating characteristic curve is 0.82 [CI 0.64-0.99] (p<0.01), and the Tg-off cutoff value is 38.00 ng/mL (sensitivity 67%, specificity 95%). Ninety percent of (18)F-FDG-PET true-positive patients had a Tg-off >2.00 ng/mL. CONCLUSIONS: An (18)F-FDG-PET within three months after a negative WBS with detectable Tg-off showed additional tumor localization in 17% of the patients, leading to a change in clinical management in 13%. A clinically useful Tg-off cutoff value was not found, but 90% of positive (18)F-FDG-PET scans occurred in patients with a Tg-off >2.00 ng/mL.

The value of surveillance mammography of the contralateral breast in patients with a history of breast cancer.

PURPOSE: To determine the contribution of surveillance mammography to the early detection of metachronous contralateral breast cancer (MCBC) and to assess its impact on the survival of breast cancer patients with relation to compliance. METHOD: Breast cancer patients (5589) were identified using files from the regional cancer registry of the Comprehensive Cancer Centre North Netherlands (CCCN Groningen, The Netherlands). The programme sensitivity and the impact on prognosis of follow-up mammography with relation to compliance were evaluated in 114 patients who developed MCBC during hospital follow-up. RESULTS: The cumulative MCBC incidence rate at year 10 was 3.4% (95% CI: 2.8-4.0%). The programme sensitivity of surveillance mammography was 59.6% (95% CI: 50.6-68.7). In patients who complied with annual mammography, sensitivity was increased to 70.8% (95% CI: 61.7-80.0). Patients with MCBCs detected by routine mammography have better survival rates than patients with MCBCs detected by other means (HR: 3.18; 95% CI: 1.59-6.34). Though there was a trend towards improved survival in patients being compliant with regular clinical follow-up (HR: 1.69; 95% CI: 0.72-3.96), this was not the case for patients being compliant with annual mammography (HR:1.02; 95% CI:0.50-2.09). CONCLUSION: Mammography is a valuable tool for the early detection of MCBC during hospital follow-up of breast cancer patients and is probably beneficial to survival. The utilisation of follow-up surveillance in breast cancer patients and its potential impact on survival deserve further investigation.