PET/CT Improves the Definition of Complete Response and Allows to Detect Otherwise Unidentifiable Skeletal Progression in Multiple Myeloma

Abstract

Purpose: To evaluate the role of 18F-FDG PET/CT in 282 symptomatic multiple myeloma patients treated up-front between 2002 and 2012.Experimental Design: All patients were studied by PET/CT at baseline, during posttreatment follow-up, and at the time of relapse. Their median duration of follow-up was 67 months.Results: Forty-two percent of the patients at diagnosis had >3 focal lesions, and in 50% SUV max was >4.2; extramedullary disease was present in 5%. On multivariate analysis, ISS stage 3, SUV max >4.2, and failure to achieve best complete response (CR) were the leading factors independently associated with shorter progression-free survival (PFS) and overall survival (OS). These 3 variables were used to construct a prognostic scoring system based on the number of risk factors. After treatment, PET/ CT negativity (PET-neg) was observed in 70% of patients, whereas conventionally defined CR was achieved in 53%. Attainment of PET-neg favorably influenced PFS and OS. PET-neg was an independent predictor of prolonged PFS and OS for patients with conventionally defined CR. Sixty-three percent of patients experienced relapse or progression; in 12%, skeletal progression was exclusively detected by systematic PET/CT performed during follow-up. A multivariate analysis revealed that persistence of SUV max >4.2 following first-line treatment was independently associated with exclusive PET/CT progression.Conclusions: PET/CT combined with ISS stage and achievement or not of CR on first-line therapy sorted patients into different prognostic groups. PET/CT led to a more careful evaluation of CR. Finally, in patients with persistent high glucose metabolism after first-line treatment, PET/CT can be recommended during follow-up, to screen for otherwise unidentifiable progression.

Baseline bone involvement in multiple myeloma - a prospective comparison of conventional X-ray, low-dose computed tomography, and 18flourodeoxyglucose positron emission tomography in previously untreated patients

“…In a recently published study, Zamagni et al reported that 15% of newly diagnosed, symptomatic MM patients with a positive PET-scan had a negative CT-scan. 12 The frequency of PET-positive patients in our study is lower than that reported by others. 13 The reason for this is not clear but may be due to difference in methodology, the definitions of osteolysis and PET-positivity, the MM population studied, and/or small sample size.…”

Whole body magnetic resonance imaging in newly diagnosed multiple myeloma: early changes in lesional signal fat fraction predict disease response

“…Longer follow‐up of our patient cohort is needed in order to explore an association of MRI response parameters with survival, as has been reported for PET‐CT negativity (Zamagni et al , 2011, 2015). Our results also need confirmation in a larger cohort of patients treated prospectively, ideally in a uniform manner.…”

“…Furthermore, advanced imaging techniques have also been described to have clinical utility in prognostication. For instance, the number of FLs and metabolic response on PET‐CT following treatment were found to have independent prognostic value in newly diagnosed patients (Zamagni et al , 2011, 2015; Moreau et al , 2014). …”

Should minimal residual disease negativity not be the end point of myeloma therapy?

“…Several groups have attempted to improve the current MRD approach by including imaging techniques, specifically PET-CT and/or MRI. 20 These initiatives have demonstrated that PET-CT-positive lesions frequently occur in MRDnegative patients and that PET-CT negativity is associated with better PFS. Consequently, PET-CT-positive lesions need to be punctured to confirm (treatment-refractory) MM.…”