Correlation between FDG/PET, histology, characteristics, and survival in 332 patients with chronic lymphoid leukemia

Metabolism pathways in chronic lymphocytic leukemia

Alterations in chronic lymphocytic leukemia (CLL) cell metabolism have been studied by several investigators. Unlike normal B lymphocytes or other leukemia cells, CLL cells, like adipocytes, store lipids and utilize free fatty acids (FFA) to produce chemical energy. None of the recently identified mutations in CLL directly affects metabolic pathways, suggesting that genetic alterations do not directly contribute to CLL cells' metabolic reprogramming. Conversely, recent data suggest that activation of STAT3 or downregulation of microRNA-125 levels plays a crucial role in the utilization of FFA to meet the CLL cells' metabolic needs. STAT3, known to be constitutively activated in CLL, increases the levels of lipoprotein lipase (LPL) that mediates lipoprotein uptake and shifts the CLL cells' metabolism towards utilization of FFA. Herein, we review the evidence for altered lipid metabolism, increased mitochondrial activity and formation of reactive oxygen species (ROS) in CLL cells, and discuss the possible therapeutic strategies to inhibit lipid metabolism pathways in patient with CLL.

Lack of clinical impact of 18 F-fluorodeoxyglucose positron emission tomography with simultaneous computed tomography for stage I and II Merkel cell carcinoma with concurrent sentinel lymph node biopsy staging: A single institutional experience from Westmead Hospital, Sydney

BACKGROUND/OBJECTIVE

¹⁸ F-fluorodeoxyglucose (FDG) positron emission tomography with simultaneous computed tomography (PET-CT) FDG PET-CT plays an important clinical role in the staging and management of Merkel cell carcinoma (MCC) although its role in stage I and II disease relative to a sentinel lymph node biopsy (SLNB) is undefined. This study aimed to compare the clinical impact of FDG PET-CT and SLNB on management in stage I and II MCC.

METHODS

This was a retrospective observational study. Between 2000 and 2014, 65 patients with biopsy-proven MCC (all stages) underwent a staging FDG PET-CT as part of their investigations in Westmead Hospital, Sydney. Since 2006, 26 patients have had an SLNB and of these, 16 underwent both an SLNB and FDGPET-CT. All 16 patients had a histological diagnosis consistent with MCC without clinical evidence of regional or distant metastases prior to SLNB and FDG PET-CT (stages IB and IIB). These patients were assessed with respect to MCC staging and the subsequent change of patient management post-SLNB and FDG PET-CT.

RESULTS

The SLNB identified occult lymph node metastases in 10 patients (63%), with FDG PET-CT positive in only one patient (6%). Of the six SLNB-negative patients, none demonstrated additional metastases on the FDG PET-CT.

CONCLUSIONS

In patients with stage I and II MCC, FDG PET-CT is less sensitive than an SLNB in detecting occult metastatic lymph nodes. The routine use of FDG PET-CT in these patients may not be justified.

Ibrutinib and rituximab induced rapid response in refractory Richter syndrome

We report a 53-year-old man diagnosed with Richter syndrome. He was heavily pretreated and was refractory to prior therapy. He received rituximab and ibrutinib, and achieved a significant response after 1 month of therapy. Our case illustrates the importance of investigation of rituximab and ibrutinib in Richter’s syndrome.

Imaging of non-Hodgkin lymphomas: diagnosis and response-adapted strategies

Optimal lymphoma management requires accurate pretreatment staging and reliable assessment of response, both during and after therapy. Positron emission tomography with computerized tomography (PET/CT) combines functional and anatomical imaging and provides the most sensitive and accurate methods for lymphoma imaging. New guidelines for lymphoma imaging and recently revised criteria for lymphoma staging and response assessment recommend PET/CT staging, treatment monitoring, and response evaluation in all FDG-avid lymphomas, while CT remains the method of choice for non-FDG-avid histologies. Since interim PET imaging has high prognostic value in lymphoma, a number of trials investigate PET-based, response-adapted therapy for non-Hodgkin lymphomas (NHL). PET response is the main determinant of response according to the new response criteria, but PET/CT has little or no role in routine surveillance imaging, the value which is itself questionable. This review presents from a clinical point of view the evidence for the use of imaging and primarily PET/CT in NHL before, during, and after therapy. The reader is given an overview of the current PET-based interventional NHL trials and an insight into possible future developments in the field, including new PET tracers.

Richter syndrome: an aggressive transformation

A 71-year-old male patient named M.R. was diagnosed with chronic lymphocytic leukemia (CLL). At the time of diagnosis, M.R. had generalized lymphadenopathy and splenomegaly, which caused him to experience significant abdominal discomfort. M.R. was treated with six cycles of fludarabine, cyclophosphamide, and rituximab (FCR), which is standard first-line chemotherapy, and tolerated this fairly well. His lymphadenopathy quickly resolved and, aside from mild nausea, had no complications from treatment. 
.

Chronic lymphocytic leukemia/small lymphocytic lymphoma, version 1.2015

Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) are different manifestations of the same disease, which are managed in the same way. The advent of novel monoclonal antibodies (ofatumumab and obinutuzumab) led to the development of effective chemoimmunotherapy regimens. The recently approved small molecule kinase inhibitors (ibrutinib and idelalisib) are effective treatment options for CLL in elderly patients with decreased tolerance for aggressive regimens and in patients with poor prognostic features who do not benefit from conventional chemoimmunotherapy regimens. This portion of the NCCN Guidelines for Non-Hodgkin's Lymphomas describes the recent specific to the incorporation of recently approved targeted therapies for the management of patients with newly diagnosed and relapsed or refractory CLL/SLL.

The biology behind PI3K inhibition in chronic lymphocytic leukaemia

Phosphoinositide 3'-kinase (PI3K) is a key component of both chronic active and tonic B-cell receptor-signalling pathways. As such, PI3K inhibitors have emerged as promising therapeutic agents for diverse lymphoid malignancies, particularly chronic lymphocytic leukaemia. Multiple in vitro experiments and clinical trials have shown efficacy of these agents across all prognostic subgroups with a favourable toxicity profile. Moreover, in vitro studies suggest that combinations with monoclonal antibodies and/or other immune strategies could enhance the effect of PI3K inhibition.

FDG/PET in CLL today

In this issue of Blood, Falchi et al present their experience with 2-deoxy-2-[18F] fluoroglucose/positron emission tomography (FDG/PET) in the management of patients with chronic lymphocytic leukemia (CLL) or Richter syndrome (RS) over a 10-year period at a referral center. The results of this study shed light on the potential role of FDG/PET in CLL.