Role of FDG PET in the staging of multiple myeloma

Present and future of whole-body MRI in metastatic disease and myeloma: how and why you will do it

Metastatic disease and myeloma present unique diagnostic challenges due to their multifocal nature. Accurate detection and staging are critical for determining appropriate treatment. Bone scintigraphy, skeletal radiographs and CT have long been the mainstay for the assessment of these diseases, but have limitations, including reduced sensitivity and radiation exposure. Whole-body MRI has emerged as a highly sensitive and radiation-free alternative imaging modality. Initially developed for skeletal screening, it has extended tumor screening to all organs, providing morphological and physiological information on tumor tissue. Along with PET/CT, whole-body MRI is now accepted for staging and response assessment in many malignancies. It is the first choice in an ever increasing number of cancers (such as myeloma, lobular breast cancer, advanced prostate cancer, myxoid liposarcoma, bone sarcoma, …). It has also been validated as the method of choice for cancer screening in patients with a predisposition to cancer and for staging cancers observed during pregnancy. The current and future challenges for WB-MRI are its availability facing this number of indications, and its acceptance by patients, radiologists and health authorities. Guidelines have been developed to optimize image acquisition and reading, assessment of lesion response to treatment, and to adapt examination designs to specific cancers. The implementation of 3D acquisition, Dixon method, and deep learning-based image optimization further improve the diagnostic performance of the technique and reduce examination durations. Whole-body MRI screening is feasible in less than 30 min. This article reviews validated indications, recent developments, growing acceptance, and future perspectives of whole-body MRI.

Whole body imaging in musculoskeletal oncology: when, why, and how

The use of whole-body imaging has become increasingly popular in oncology due to the possibility of evaluating total tumor burden with a single imaging study. This is particularly helpful in cases of widespread disease where dedicated regional imaging would make the evaluation more expensive, time consuming, and prone to more risks. Different techniques can be used, including whole-body MRI, whole-body CT, and PET-CT. Common indications include surveillance of cancer predisposing syndromes, evaluation of osseous metastases and clonal plasma cell disorders such as multiple myeloma, and evaluation of soft tissue lesions, including peripheral nerve sheath tumors. This review focuses on advanced whole-body imaging techniques and their main uses in musculoskeletal oncology.

Modern imaging techniques for monitoring patients with multiple myeloma

Bone disease is a serious problem for many patients, often causing pathological bone fractures. A spinal collapse is a condition that affects the quality of life. It is the most frequent feature of multiple myeloma (MM), used in establishing the diagnosis and the need to start treatment. Because of these complications, imaging plays a vital role in the diagnosis and workup of myeloma patients. For many years, conventional radiography has been considered the gold standard for detecting bone lesions. The main reasons are the wide availability, low cost, the relatively low radiation dose and the ability of this imaging method to cover the entire bone system. Because of its incapacity to evaluate the response to therapy, more sophisticated techniques such as whole-body low-dose computed tomography (WBLDCT), whole-body magnetic resonance imaging, and 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) are used. In this review, some of the advantages, indications and applications of the three techniques in managing patients with MM will be discussed. The European Myeloma Network guidelines have recommended WBLDCT as the imaging modality of choice for the initial assessment of MM-related lytic bone lesions. Magnetic resonance imaging is the gold-standard imaging modality for the detection of bone marrow involvement. One of the modern imaging methods and PET/CT can provide valuable prognostic data and is the preferred technique for assessing response to therapy.

Relation of whole-body metabolic tumor volume and total lesion glycolysis on fluorodeoxyglucose PET/computed tomography with clinical and laboratory parameters in newly diagnosed multiple myeloma

OBJECTIVE

This study aims to evaluate the relationships of metabolic fluorodeoxyglucose PET/computed tomography (FDG PET/CT) parameters such as whole-body metabolic tumor volume (WB MTV), WB-total lesion glycolysis (TLG), and bone marrow (BM)-mean standard uptake value (SUVmean) with clinical stage and other prognostic biomarkers in newly diagnosed multiple myeloma (MM) patients.

METHODS

Patients who underwent pretreatment PET/CT with the diagnosis of MM were evaluated retrospectively. The number of focal lesions, WB MTV, WB TLG, and BM SUVmean values were measured on FDG PET/CT images. Clinical stages and prognostic laboratory parameters were recorded the pretreatment period.

RESULTS

WB MTV and WB TLG values were significantly higher in patients with more than three focal lesions on FDG PET/CT scan (all P < 0.001). According to the Revised International Staging System (R-ISS), all WB MTV, WB TLG, and BM SUVmean values are significantly higher in patients with stage 3 disease than in stages 1-2 ( P = 0.027, P = 0.019, P = 0.001, respectively). Serum creatinine level is positively correlated with WB MTV, WB TLG, and BM SUVmean values ( P = 0.020, P = 0.004, P < 0.001, respectively). In addition, the β2 microglobulin level, an essential biochemical prognostic parameter, was positively correlated with the BM SUVmean value ( P = 0.013).

CONCLUSION

The BM SUVmean, WB MTV, and WB TLG values, which reflect FDG avid WB tumor burden, are associated with prognostic biomarkers and R-ISS stage in newly diagnosed MM patients. It contributes to the identification of high-risk patients at the pretreatment staging.

Utility of PET/CT in Assessing Early Treatment Response in Patients With Newly Diagnosed Multiple Myeloma

Multiple Myeloma (MM) is a plasma cell malignancy characterized by diverse clinical presentations. While biochemical assessment of disease activity is commonly utilized to monitor treatment response, findings on magnetic resonance imaging and positron emission tomography/computed tomography (PET/CT), among other imaging modalities, have proven to harbor prognostic value. We sought to corroborate these findings by examining the prognostic significance of Fluorodeoxyglucose (FDG) PET/CT scanning in the setting of newly diagnosed MM. We retrospectively analyzed 195 patients with a PET/CT available both at diagnosis and at 6 months post-treatment to examine the value of PET/CT results as an adjuvant metric to conventional hematologic responses in terms of time to next treatment (TTNT) and overall survival (OS). The median TTNT and OS for the entire cohort were 24.6 (95% CI=20.4-29.1) and 79 (95% CI=63.1-119.1) months, respectively. When comparing PET/CT (-) with PET/CT (+) patients, we found significantly prolonged median TTNT (55.2 vs. 17.8 months, p<0.0001) and OS (unreached vs. 60.8 months, p<0.0001) for the PET/CT (-) group. We then examined the additive value of PET/CT on the hematologic response achieved at 6 months, and we found that PET/CT (-) is associated with significantly increased median TTNT and OS for both the very good partial response (VGPR) group and the less than VGPR group. Importantly, PET/CT retained prognostic significance after adjusting for multiple other predictive variables. We conclude that a PET/CT (-) at 6 months confers a significant prognostic advantage for newly diagnosed MM patients and adds significant value to the hematologic response assessment.

The "Undetermined Significance" of 18F-FDG PET/CT or PET/MRI in Patients with Monoclonal Gammopathy of Undetermined Significance (MGUS)

Monoclonal gammopathy of undetermined significance (MGUS) is a highly prevalent condition with the possible risk of progression to multiple myeloma (MM) or a lymphoproliferative neoplasm in a small percentage of patients. Fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) or positron emission tomography/magnetic resonance imaging (PET/MRI) are imaging methods increasingly used in patients with MM. The aim of this communication is to underline that, taking into account current evidence-based data, compared to MM the role of ¹⁸F-FDG PET/CT or PET/MRI in MGUS is still undetermined and more studies should be performed before suggesting ¹⁸F-FDG PET/CT or PET/MRI for evaluation of MM progression in patients with MGUS.