Abstract P3-03-01: Diagnostic performance of PET/CT and bone scintigraphy in breast cancer patients with suspected bone metastasis

Abstract

Abstract Introduction Previous retrospective studies suggest that 18FDG PET/CT (PET/CT) has superior sensitivity and specificity to bone scintigraphy (BS) in detecting breast cancer bone metastases, but the difference in efficacy between these techniques has not been confirmed. Potentially, PET/CT may detect bone metastases more accurately than BS does. To test this hypothesis, this prospective study compared the diagnostic efficacy to detect bone metastases between PET/CT and BS in breast cancer patients. We also compared the response of bone metastases assessed by the PET/CT or BS with the bone metastases. Method This single-institution prospective study included consecutive patients with breast cancer diagnosed by biopsy and suspected bone metastases at the Breast Diseases Unit at Tokai University Hospital, Kanagawa, Japan between September 2011 and March 2014. Inclusion criteria were as follows: bone pain, elevated alkaline phosphatase, elevated tumor marker, and suspected bone metastases on BS. Two nuclear medicine physicians interpreted the PET/CT and BS images. Bone involvement was confirmed by biopsy, especially in the case of oligometastasis. If biopsy proved difficult to perform, conventional imaging and additional directed radiological studies and follow up were helpful. This study was approved by the Institutional Review Board of the Tokai University School of Medicine and is registered with UMIN, number 000006003. All patients provided informed consent. Result Thirty patients were initially enrolled, but two patients were excluded from analysis because they declined further follow-up imaging. The median patient age at diagnosis was 59 years (range, 31–74 years). Among the 28 patients, bone pain was observed in 6 patients, elevated alkaline phosphatase in 4, elevated tumor marker in 17, and suspected bone metastases were detected on BS in 7 patients. Among 10 patients were diagnosed bone metastases, PET/ CT detected 10 of 10 bone metastases, however BS detected 7 of 10 bone metastases. PET/CT and BS were not highly concordant in detecting osseous metastases; among 19/28 paired studies (68%), 2 (10%) were positive for metastasis, and 17 (90%) were negative. Nine occurrences (32%) were discordant; of these, 2 of 9 were PET/CT positive and BS negative; 5 of 9 were PET/CT positive and BS equivocal; one case was PET/CT negative and BS equivocal; and one was PET/CT equivocal and BS negative. Conclusion This study supports the use of PET/CT for detecting suspected osseous metastases. A large prospective study is needed to determine whether PET/CT could replace bone scintigraphy in detecting suspected bone metastases. Citation Format: Naoki Niikura, Jun Hashimoto, Toshiki Kazama, Jun Koizumi, Rin Ogiya, Mayako Terao, Risa Oshitanai, Toru Morioka, Banri Tuda, Takuho Okamura, Yuki Saito, Yutaka Imai, Yutaka Tokuda. Diagnostic performance of PET/CT and bone scintigraphy in breast cancer patients with suspected bone metastasis [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-03-01.