Bone and CT Scans Are Complementary for Diagnoses of Bone Metastases in Breast Cancer When PET Scans Findings Are Equivocal: A Case Report

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1 Bone and CT Scans Are Complementary for Diagnoses of Bone Metastases in Breast Cancer When Scans Findings Are Equivocal: A Case Report Yuk-Wah Tsang 1, Jyh-Gang Leu 2, Yen-Kung Chen 3, Kwan-Hwa Chi 1,4 1 Division of Radiation Therapy and Oncology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan 2 Department of Health Management, Shin Kong Wu Ho-Su Memorial Hospital / School of Medicine, Fu Jen Catholic University, Taipei, Taiwan 3 Division of Nuclear Medicine and center, Shin Kong Wu Ho-Su Memorial Hospital / School of Medicine, Fu Jen Catholic University, Taipei, Taiwan 4 Faculty of Medicine, National Yang Ming University, Taipei, Taiwan Bone is one of the most common metastatic sites of breast cancer. We present a case of breast cancer with bone metastases and the patient was evaluated by FDG-/ CT and a bone scan. The scan had a negative finding, but both bone and CT scans detected bone metastases. In general, FDG- has greater specificity and good sensitivity for detecting bone metastases. However, when FDG- scan findings are equivocal, additional findings from a bone or CT scan can be helpful in diagnosis of bone metastases. Key words: /CT scan, bone scan, breast cancer, bone metastases Ann Nucl Med Sci 2007;20: Received 6/20/2007; revised 7/5/2007; accepted 7/11/2007. For correspondence or reprints contact: Jyh-Gang Leu, M.D., Department of Health Management, Shin Kong Wu Ho-Su Memorial Hospital. 95 Wen Chang Road, Shilin District, Taipei 111, Taiwan. Tel: (886) ext. 6688, Fax: (886) , M004224@ms.skh.org.tw Introduction Bone, lung, liver and the brain are common sites of distant metastases in breast cancer patients. Previously, when patients had suspected signs or symptoms of distant metastases, chest X-ray, liver ultrasound and bone scintigraphy (bone scan) examinations are often the primary tools of investigation. Nowadays, 18 F-flurodeoxyglucose (FDG) positron emission tomography () scan is often readily available in major medical centers, which enables screening or detection of distant metastases by performing a whole body scan. Although and bone scan have comparable sensitivity, scan has higher specificity in detecting bone metastases [1]. We present a case that shows bone scan or CT scan can be complementary to scan in detecting bone metastases in breast cancer patients when scan findings are equivocal. Case Report A 31-year-old lady had a palpable mass over the right upper inner quadrant of her right breast. Excision biopsy revealed infiltrating ductal carcinoma. She was then operated with breast conservative surgery and axillary lymph node dissection. Pathological examination showed intraductal carcinoma and all dissected lymph nodes (total 13) were negative for metastases. All resection margins were free of tumor. Both estrogen and progesterone receptors were strongly positive. Her initial staging was T2N0M0. She received postoperative adjuvant chemotherapy and was regularly followed up in our out-patient clinic. Six years later, she presented persistent mild to moderate cough, for which chest X-ray disclosed no specific finding. A (Figure 1A) and local

2 Tsang YW et al /CT (Figure 1B and 1C) scan were then performed. images (Figure 1A) appeared normal. However, the lung window of the CT images (Figure 1B) showed tiny nodular lesions over the bilateral upper lung. Transbronchial biopsy proved metastatic carcinoma. Two months later, bone scan was done because the patient complained of back soreness. The bone scan showed a faint uptake lesion over the right side of the T10 (Figure 1D). Retrospective review of the original /CT revealed a hyper-dense lesion over the right side of the T10 by adjusting the CT images to the bone window level (Figure 1C). The patient subsequently received salvage chemotherapy and hormone therapy. Eight months later, a second /CT (Figures 2A, 2B and 2C) scan was done. images still appeared almost negative except for very faint uptake over the bilateral lung and faint uptake over the left ilium bone (Figure 2B). CT images in the lung window disclosed enlargement of the previous lung nodules associated with increased multiple small lung nodules (Figure 2C). Bone window of the CT images revealed new lesions over the T12 and left ilium bone (Figure 2A). In the same month, a bone scan was performed. The bone scan (Figure 2D) showed an increase in the number of new lesions with intense uptake in the T12, the posterior portion of the right 6 th, 7 th, 9 th and 10 th ribs and the posterior portion of the left 8th rib. In addition, new lesions in the left ilium, right sacral iliac joint and right acetabulum were noted (not shown). The previous T10 lesion had increased in size and uptake (Figure 2D). The patient s disease was in progression. As the patient failed in first line chemotherapy, a second line chemotherapy was given, but still failed. Brain metastases were recently found and she is now undergoing palliative radiotherapy and hospice care. Figure 1. A 36-year-old female received an operation for her right breast cancer 6 years ago. Coronal view of scan (A) shows no abnormal metabolic lesion in the whole body. However, a CT image from /CT (B) reveals small nodules in the bilateral upper lung (arrow), and (C) hyper-dense lesions in the T10 vertebral body (arrow). Posterior view of bone scan (D) shows a hot spot in the T10 level of spine (arrow). Discussion Breast cancer has the propensity to metastasize to bone, liver, lung and brain. Chest X-ray, liver ultrasound and bone scans are conventional methods of examination in initial staging work-up. With the increased availability of, more institutions perform a scan to evaluate Ann Nucl Med Sci 2007;20: Vol. 20 No. 3 September

3 /CT Bone metastases of breast cancer in and bone scan Figure 2. Patient s /CT and bone scan after chemotherapy and hormone therapy. /CT scan shows mild FDG uptake (B) in bilateral lung lesions and left ilium (arrow), hyper-dense lesions (A) in the T10, T12, left ilium (arrow), and multiple tiny nodules in both lungs (C). Bone scan (D) shows increased new lesions in T12, posterior portion of the right 6 th, 7 th, 9 th and 10 th ribs and posterior portion of the left 8 th rib. An increased size of lesion in T10 is also noted. primary lesion and distant metastases before or after treatment [2-4]. scan has better performance in sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) in detecting tumor recurrence or metastases in comparison to conventional imaging [2]. The effectiveness of or bone scan in detecting bone metastases of breast cancer was addressed in several studies [5-8]. In general, scan is superior to bone scan in detecting osteolytic lesions, but inferior in detecting osteoblastic lesions [5-8]. Patients with osteolytic lesions had a poorer prognosis [5]. For those patients that had both and bone scan, the sensitivity and accuracy could rise to 98% and 97% respectively [6]. Taira et al found that when a /CT scan were performed together, if both the and bone window of the CT findings were concordant, the PPV for bone metastases was high (98%). However, if the scan was positive but the CT scan was negative, the PPV dropped to 61%. If the scan was negative but the bone scan was positive, the PPV diminished to only 17% [9]. Nakamoto et al. found that if bone lesions had moderate to strong uptake and were classified as probable positive and definitely positive, only half of the lesions had morphological change in the CT scan 2007;20:

4 Tsang YW et al [10]. In our case, the first scan had a negative finding, but the bone scan revealed a T10 lesion (Figure 1D). In retrospect review of the CT scan, a lesion over the T10 was also found (Figure 1C). After salvage treatment, the followup scan still had an almost negative finding except for faint uptake over the left ilium bone (Figure 2B). However, the bone scans showed intense uptake of the above lesions and other newly developed lesions (Figure 2D). Reviewing the CT scan, the T12 and left ilium new lesions could be detected but the posterior rib lesions were hardly detected. In conclusion, if both and CT scans are available, we should look at the scan and the bone window of the CT scan together in order to detect any bone lesions. If only scan is available and the findings of the scan are equivocal, a bone scan or a CT scan may be helpful in order to establish a correct diagnosis of bone metastases. References 1. Kao CH, Hsieh JF, Tsai SC, Ho YJ, Yen RF. Comparison and discrepancy of 18 F-2-deoxyglucose positron emission tomography and Tc-99m MDP bone scan to detect bone metastases. Anticancer Res 2000;20: Gallowitsch HJ, Kresnik E, Gasser J, et al. F-18 fluorodeoxyglucose positron-emission tomography in the diagnosis of tumor recurrence and metastases in the follow-up of patients with breast carcinoma: a comparison to conventional imaging. Invest Radiol 2003;38: Moon DH, Maddahi J, Silverman DH, Glaspy JA, Phelps ME, Hoh CK. Accuracy of whole-body fluorine-18 FDG for the detection of recurrent or metastatic breast carcinoma. J Nucl Med 1998;39: Kim TS, Moon WK, Lee DS, et al. Fluorodeoxyglucose positron emission tomography for detection of recurrent or metastatic breast cancer. World J Surg 2001;25: Cook GJ, Houston S, Rubens R, Maisey MN, Fogelman I. Detection of bone metastases in breast cancer by 18 FDG : differing metabolic activity in osteoblastic and osteolytic lesions. J Clin Oncol 1998;16: Abe K, Sasaki M, Kuwabara Y, et al. Comparison of 18 FDG- with 99m Tc-HMDP scintigraphy for the detection of bone metastases in patients with breast cancer. Ann Nucl Med 2005;19: Nakai T, Okuyama C, Kubota T, et al. Pitfalls of FDG- for the diagnosis of osteoblastic bone metastases in patients with breast cancer. Eur J Nucl Med Mol Imaging 2005;32: Yang SN, Liang JA, Lin FJ, Kao CH, Lin CC, Lee CC. Comparing whole body 18 F-2-deoxyglucose positron emission tomography and technetium-99m methylene diphosphonate bone scan to detect bone metastases in patients with breast cancer. J Cancer Res Clin Oncol 2002;128: Taira AV, Herfkens RJ, Gambhir SS, Quon A. Detection of bone metastases: assessment of integrated FDG /CT imaging. Radiology 2007;243: Nakamoto Y, Cohade C, Tatsumi M, Hammoud D, Wahl RL. CT appearance of bone metastases detected with FDG as part of the same /CT examination. Radiology 2005;237: Ann Nucl Med Sci 2007;20: Vol. 20 No. 3 September

5 /CT Bone metastases of breast cancer in and bone scan CT , / / 4 CT CT /CT 2007;20: (02) (02) M004224@ms.skh.org.tw 2007;20: