FDG-avid sclerotic bone metastases in breast cancer patients: a PET/CT case series

Enhancing precision in bone metastasis diagnosis for lobular breast cancer: reassessing the role of 18F-FDG PET/CT

PURPOSE

Detection of osseous metastases by imaging can be challenging in patients with invasive lobular breast cancer (ILC). ILC may demonstrate low metabolic rate due to lower tumor cell density, decreased proliferation rate, diffuse infiltration of surrounding tissue, and low level of GLUT-1 expression. The aim of this study is to assess the diagnostic accuracy of 18F-FDG PET/CT in identifying bone metastases in ILC patients.

MATERIAL AND METHODS

Out of 52 individuals diagnosed with lobular breast cancer and underwent 18F-FDG PET/CT for evaluation of metastases, 21 patients were included in our study population after applying inclusion and exclusion criteria. The radiological and clinical follow-up of at least 6 months served as the reference standard comparator.

RESULTS

Bone metastases were confirmed in six patients. 18F-FDG PET/CT was true positive in two and false negative in four patients. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 18F-FDG PET/CT were 33.33, 93.33, 66.67, 77.78, and 76.19%, respectively (95% confidence interval). The tendency of ILC osseous metastases to be more sclerotic explains the low diagnostic accuracy of 18F-FDG PET/CT in detection of bone metastases, making it a less suited method of evaluation.

CONCLUSION

The results of the present study indicate that 18F-FDG PET/CT has a low diagnostic accuracy in detecting bone metastases in lobular breast cancer and, by inference, new functional modalities can be explored in these patients. The findings contribute valuable insights to optimize the integration of molecular imaging into the diagnostic algorithm for this specific breast cancer subtype.

Evaluation of Treatment Response in Patients with Breast Cancer

Breast cancer (BC) remains one of the leading causes of death among women. The management and outcome in BC are strongly influenced by a multidisciplinary approach, which includes available treatment options and different imaging modalities for accurate response assessment. Among breast imaging modalities, MR imaging is the modality of choice in evaluating response to neoadjuvant therapy, whereas F-18 Fluorodeoxyglucose positron emission tomography, conventional computed tomography (CT), and bone scan play a vital role in assessing response to therapy in metastatic BC. There is an unmet need for a standardized patient-centric approach to use different imaging methods for response assessment.

Bone Metastasis of Breast Cancer: Molecular Mechanisms and Therapeutic Strategies

Bone metastasis is a common complication of many types of advanced cancer, including breast cancer. Bone metastasis may cause severe pain, fractures, and hypercalcemia, rendering clinical management challenging and substantially reducing the quality of life and overall survival (OS) time of breast cancer patients. Studies have revealed that bone metastasis is related to interactions between tumor cells and the bone microenvironment, and involves complex molecular biological mechanisms, including colonization, osteolytic destruction, and an immunosuppressive bone microenvironment. Agents inhibiting bone metastasis (such as bisphosphate and denosumab) alleviate bone destruction and improve the quality of life of breast cancer patients with bone metastasis. However, the prognosis of these patients remains poor, and the specific biological mechanism of bone metastasis is incompletely understood. Additional basic and clinical studies are urgently needed, to further explore the mechanism of bone metastasis and develop new therapeutic drugs. This review presents a summary of the molecular mechanisms and therapeutic strategies of bone metastasis of breast cancer, aiming to improve the quality of life and prognosis of breast cancer patients and provide a reference for future research directions.

Diagnosis of bone metastases in breast cancer: Lesion-based sensitivity of dual-time-point FDG-PET/CT compared to low-dose CT and bone scintigraphy

We compared lesion-based sensitivity of dual-time-point FDG-PET/CT, bone scintigraphy (BS), and low-dose CT (LDCT) for detection of various types of bone metastases in patients with metastatic breast cancer. Prospectively, we included 18 patients with recurrent breast cancer who underwent dual-time-point FDG-PET/CT with LDCT and BS within a median time interval of three days. A total of 488 bone lesions were detected on any of the modalities and were categorized by the LDCT into osteolytic, osteosclerotic, mixed morphologic, and CT-negative lesions. Lesion-based sensitivity was 98.2% (95.4-99.3) and 98.8% (96.8-99.5) for early and delayed FDG-PET/CT, respectively, compared with 79.9% (51.1-93.8) for LDCT, 76.0% (36.3-94.6) for BS, and 98.6% (95.4-99.6) for the combined BS+LDCT. BS detected only 51.2% of osteolytic lesions which was significantly lower than other metastatic types. SUVs were significantly higher for all lesion types on delayed scans than on early scans (P<0.0001). Osteolytic and mixed-type lesions had higher SUVs than osteosclerotic and CT-negative metastases at both time-points. FDG-PET/CT had significantly higher lesion-based sensitivity than LDCT and BS, while a combination of the two yielded sensitivity comparable to that of FDG-PET/CT. Therefore, FDG-PET/CT could be considered as a sensitive one-stop-shop in case of clinical suspicion of bone metastases in breast cancer patients.

Contiguous Multilevel Vertebral Metastasis in Carcinoma Breast Mimicking Spondylodiscitis

A 59-year old female presented with a lump in the right breast for 6 months. She developed progressively increasing backache for 3 months. Magnetic resonance imaging spine was suggestive of hypointense heterogeneous signal intensity in multiple dorsal vertebrae (D3–D8) and suggestive of Pott's spine. Sonomammography suggested a lesion with irregular margin in the retro-areolar region. Fine-needle aspiration cytology was infiltrating duct carcinoma. Fluorodeoxyglucose (FDG) positron-emission tomography–computed tomography revealed mass in the right breast with axillary lymph node. FDG-avid lytic destructive contiguous lesion was noted in mid-dorsal vertebrae. Apart from it, FDG-avid lytic lesion was also noted in the right iliac bone. The patient underwent vertebral lesion biopsy consistent with metastatic breast carcinoma. This case report demonstrates rare contiguous involvement of multiple vertebrae masquerading Pott's spine.

Multiple Myeloma Presenting as Disseminated Osteoblastic Lesions With Intense 18F-FDG Uptake on PET/CT

ABSTRACT

A 42-year-old woman presented with numbness and weakness in the lower limbs. The radiograph, MRI, and 99mTc-MDP bone scintigraphy revealed multiple bone lesions. The lesions were sclerotic on radiograph. Subsequent 18F-FDG PET/CT showed the lesions were disseminated and had intense 18F-FDG uptake. Monoclonal lambda plasmacytoma was confirmed after CT-guided biopsy of the third lumbar vertebral lesion. The laboratory data also showed a monoclonal immunoglobulin G lambda protein in serum and urine immunofixation. The patient was diagnosed as multiple myeloma finally. Multiple myeloma should be in the differential diagnosis scope of multiple osteoblastic lesions with intense 18F-FDG uptake on PET/CT.

The Evolving Role of FDG-PET/CT in the Diagnosis, Staging, and Treatment of Breast Cancer

The applications of 2-deoxy-2-[¹⁸F]fluoro-D-glucose positron emission tomography/X-ray computed tomography (PET/CT) in the management of patients with breast cancer have been extensively studied. According to these studies, PET/CT is not routinely performed for the diagnosis of primary breast cancer, although PET/CT in specific subtypes of breast cancer correlates with histopathologic features of the primary tumor. PET/CT can detect metastases to mediastinal, axial, and internal mammary nodes, but it cannot replace the sentinel node biopsy. In detection of distant metastases, this imaging tool may have a better accuracy in detecting lytic bone metastases compared to bone scintigraphy. Thus, PET/CT is recommended when advanced-stage disease is suspected, and conventional modalities are inconclusive. Also, PET/CT has a high sensitivity and specificity to detect loco-regional recurrence and is recommended in asymptomatic patients with rising tumor markers. Numerous studies support the future role of PET/CT in prediction of response to neoadjuvant chemotherapy (NAC). PET/CT has a higher diagnostic value for prognostic risk stratification in comparison with conventional modalities. With the continuing research on the treatment planning and evaluation of patients with breast cancer, the role of PET/CT can be further extended.

Prognostic utility of FDG PET/CT and bone scintigraphy in breast cancer patients with bone-only metastasis

We performed this retrospective clinical study to examine the prognostic power of bone scintigraphy (BS) and F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in terms of overall survival (OS) of breast cancer with bone-only metastasis.We retrospectively evaluated 100 female invasive ductal breast cancer patients (mean age 48.1 years) with bone-only metastasis. Twenty-five patients had human epidermal growth factor receptor 2 (HER2)-positive tumors, 65 were estrogen receptor (ER) and/or progesterone receptor (PR)-positive, HER2-negative tumors, and 10 were triple negative tumors. The patients were treated properly with various treatments, including chemotherapy, radiotherapy, hormone, and bisphosphonate therapy, based on their clinical status. All patients underwent BS and FDG PET/CT at baseline and 1 year after treatment. The baseline and follow images were visually compared, and the patients were grouped as responders or nonresponders based on their images. OS was compared between the groups.The mean OS after the diagnosis of bone-only metastasis was 57.6 months. Fifty-one patients (51%) died within 5 years after diagnosis of metastasis. No difference in survival was evident between responders and nonresponders based on BS imaging data (P = .090). The response status based on PET imaging data waste only significant independent prognostic factor on multivariate analysis (P = .001). Survival was lower in nonresponders than in responders based on PET imaging (32.7% vs 66.4%; P < .001).Our findings suggest that the response status according to FDG PET imaging can be used to predict OS in breast cancer patients with bone-only metastasis.

Multi-technique imaging of bone metastases: spotlight on PET-CT

There is growing evidence that molecular imaging of bone metastases with positron-emission tomography (PET) can improve diagnosis and treatment response assessment over current conventional standard imaging methods, although cost-effectiveness has not been assessed. In most cancer types, 2-[(18)F]-fluoro-2-deoxy-d-glucose ((18)F-FDG)-PET is an accurate method for detecting bone metastases. For example, in breast cancer, combined (18)F-FDG-PET and computed tomography (CT) is more sensitive at detecting bone metastases than (99m)technetium (Tc)-labelled diphosphonate planar bone scintigraphy (BS) and there is increasing evidence to support the use of serial (18)F-FDG-PET for the assessment of osseous response to treatment. Preliminary data suggest improved diagnostic accuracy of (18)F-FDG-PET-CT in a number of other malignancies including lung, thyroid, head and neck, gastro-oesophageal cancers, and osteosarcoma. As a bone-specific tracer, there is accumulating evidence to support the use of sodium (18)F-fluoride ((18)F-NaF) PET-CT in the diagnosis of skeletal metastases in breast and prostate cancer, although relatively little data are available to support its use for assessment of treatment response. In prostate cancer, (11)C-choline and (18)F-choline PET-CT have better specificities than (18)F-NaF-PET-CT, but equivalent sensitivities in the detection of bone metastases. We review the current literature for staging and response assessment of bone metastases in different cancers.

Molecular and Functional Imaging of Bone Metastases in Breast and Prostate Cancers: An Overview

Our ability to accurately assess the skeleton for metastases in breast and prostate cancers has improved significantly in recent years with hybrid imaging methods. Nevertheless, no consensus has been reached on the best imaging modality for diagnosis and treatment response assessment of skeletal disease. Hybrid SPECT/CT has low false-positive and false-negative rates compared with planar bone scintigraphy (BS) or BS augmented with SPECT in breast and prostate cancers. In breast cancer, 18F-FDG PET is more sensitive and accurate at detecting bone metastases than BS. Currently, little evidence has accrued to support the superiority of 18F-fluoride (18F-NaF) PET in diagnosing osseous metastases or monitoring treatment response in breast cancer when compared with conventional imaging. In prostate cancer, the sensitivities of 18F-NaF PET/CT, 18F-fluorocholine (18F-choline), or 11C-choline PET/CT are equivalent, although 11C-/18F-choline PET/CT scans are more specific. Whole-body MRI, using anatomical sequences complemented by diffusion-weighted MRI, shows early evidence of utility for diagnosis and monitoring therapy response. We review the literature for staging and response assessment in metastatic breast and prostate cancer. While staging accuracy has significantly improved with hybrid imaging, optimal methods for assessing early treatment response have not been determined, and this is an area of active research.

Detection of bone metastases in breast cancer patients in the PET/CT era: Do we still need the bone scan?

AIM

To examine the value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for the detection of bone metastasis in breast cancer patients and assess whether whole body bone scan (BS) with (99m)Tc-methylene diphosphonate provides any additional information.

MATERIAL AND METHODS

Study group comprised 150 patients, mean age 52 years (range 27-85) with breast cancer, suspected of having bone metastases. All patients had undergone both FDG-PET/CT and BS with or without single photon emission tomography/computed tomography (SPECT/CT) within a period of 6 weeks. The final diagnosis of bone metastasis was established by histopathological findings, additional imaging, or clinical follow-up longer than 10 months. Cancer antigen 15-3 (CA15-3) and carcinoembryogenic antigen (CEA) were measured in all patients.

RESULTS

Histologically 83%, 7% and 10% had infiltrating ductal, lobular and mixed carcinoma respectively. Confirmed bone metastases were present in 86 patients (57.3%) and absent in 64 (42.7%). Mean CA15-3 and CEA values in patients with bone metastases were 74.6ng/mL and 60.4U/mL respectively, compared to 21.3ng/mL and 3.2U/mL without metastases (p<0.001). The sensitivity of FDG-PET/CT for the detection of bone metastases was 97.6% compared to 89.5% with SPECT/CT. In 57 patients, FDG-PET/CT correctly identified additional pulmonary, hepatic, nodal and other soft tissue metastases, not detected by BS.

CONCLUSION

Our findings suggest that FDG-PET/CT is superior to BS with or without SPECT/CT.

Fluorodeoxyglucose positron emission tomography/computed tomography imaging of a patient with squamous cell carcinoma of prostate

Primary squamous cell carcinoma is an uncommon tumor of the prostate gland. We report a 77-year-old male patient with urinary frequency and constipation. Fine needle biopsy from prostate was suspicious of squamous cell carcinoma of the prostate. Whole body positron emission tomography/computed tomography scan revealed high fluorodeoxyglucose uptake in prostate gland. Transurethral resection confirmed the diagnosis. In contrast to prostatic adenocarcinoma, high fluorodeoxyglucose accumulation was observed in the primary tumor of the prostate gland.

Role of positron emission tomography/computed tomography in breast cancer

Although positron emission tomography (PET) imaging may not be used in the diagnosis of breast cancer, the use of PET/computed tomography is imperative in all aspects of breast cancer staging, treatment, and follow-up. PET will continue to be relevant in personalized medicine because accurate tumor status will be even more critical during and after the transition from a generic metabolic agent to receptor imaging. Positron emission mammography is an imaging proposition that may have benefits in lower doses, but its use is limited without new radiopharmaceuticals.

[Positron emission tomography-computed tomography in tumors of the locomotor apparatus]

Positron emission tomography/computed tomography (PET/CT) is a hybrid imaging technique that combines the anatomic information from CT with the metabolic information acquired from PET after the administration of specific radiotracers, the most commonly used of which is F18-fluorodeoxyglucose (FDG). In oncology, this technique is based on the increased uptake of FDG by malignant lesions. In the locomotor apparatus, some uptake by bones and soft tissues is physiological or benign and this uptake must be differentiated from uptake by malignancies, whether primary or secondary. The most important limitations are active inflammatory or infectious processes, which are positive on PET images, and malignant lesions that are smaller than 1cm, cystic, necrotic, or low-grade, which are negative on PET images. PET/CT in the locomotor apparatus is especially useful for the detection of metastases from the most common tumors. It is also used for staging and monitoring the response to treatment of some hematological tumors like lymphoma, where it is fundamental to determine whether the bone marrow has been infiltrated, or myeloma. Lastly, although it is not yet an established indication, PET/CT is being increasingly used to study sarcomas, because it can provide additional information that can be useful for the characterization and grading of tumors, for guiding biopsies, for staging and re-staging, and for evaluating the response to neoadjuvant therapy as well as for evaluating new drugs in clinical trials.

Comparison of diagnostic ability between (99m)Tc-MDP bone scan and (18)F-FDG PET/CT for bone metastasis in patients with small cell lung cancer

OBJECTIVE

The aim of this study was to compare the diagnostic ability of (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) with that of (99m)Tc-methylene diphosphonate ((99m)Tc-MDP) bone scan for bone metastasis in staging patients with small cell lung cancer (SCLC).

METHODS

Ninety-five patients with SCLC who underwent both (18)F-FDG PET/CT and (99m)Tc-MDP bone scan for initial staging work-up were retrospectively enrolled. All (18)F-FDG PET/CT and bone scan images were visually assessed. Bone metastasis was confirmed by histopathological results and all available clinical information.

RESULTS

Of 95 patients with SCLC, metastatic bone lesions were found in 30 patients, and 84 metastatic lesions were evaluated on a lesion-basis analysis. The sensitivity of (18)F-FDG PET/CT was 100 % on a per-patient basis and 87 % on a per-lesion basis, and there was no false-positive lesion on PET/CT images. In contrast, the sensitivity of the bone scan was 37 % on a per-patient basis and 29 % on a per-lesion basis. The bone scan showed 11 false-positive lesions. The bone scan detected two metastatic lesions that were not detected by PET/CT, which were outside the region scanned by PET/CT. On follow-up bone scan, 21 lesions that were not detected by the initial bone scan but were detected by PET/CT were newly detected.

CONCLUSIONS

In patients with SCLC, (18)F-FDG PET/CT showed higher detection rate of bone metastasis than (99m)Tc-MDP bone scan. Thus, (18)F-FDG PET/CT can replace bone scan in staging patients with SCLC.