Extramedullary Breast Relapse of Acute Lymphoblastic Leukemia Controlled with a Second Allogeneic/Autologous Hematopoietic Cell Transplant

PET/CT in leukemia: utility and future directions

2-Deoxy-2-[ 18 F]fluoro- d -glucose PET/computed tomography ([ 18 F]FDG PET/CT) has proven to be a sensitive method for the detection and evaluation of hematologic malignancies, especially lymphoma. The increasing incidence and mortality rates of leukemia have raised significant concerns. Through the utilization of whole-body imaging, [ 18 F]FDG PET/CT provides a thorough assessment of the entire bone marrow, complementing the limited insights provided by biopsy samples. In this regard, [ 18 F]FDG PET/CT has the ability to assess diverse types of leukemia The utilization of [ 18 F]FDG PET/CT has been found to be effective in evaluating leukemia spread beyond the bone marrow, tracking disease relapse, identifying Richter's transformation, and assessing the inflammatory activity associated with acute graft versus host disease. However, its role in various clinical scenarios in leukemia remains unacknowledged. Despite their less common use, some novel PET/CT radiotracers are being researched for potential use in specific scenarios in leukemia patients. Therefore, the objectives of this review are to provide a thorough assessment of the current applications of [ 18 F]FDG PET/CT in the staging and monitoring of leukemia patients, as well as the potential for an expanding role of PET/CT in leukemia patients.

Post-transplant leukemia relapse in organs: biology. and behavior in 585 reports

Resistance of extramedullary leukemia growth post-transplant prevents cure. Review of its behavior detailed in 585 published cases should lead to better treatment. Leukemic tumors were found up to 13 years after transplant, most in sites inaccessible to physical exam. In 83%, marrow was not in morphologic relapse; next relapse was most often extramedullary. Induction protocols alone produced few durable responses in acute leukemias and fatal marrow aplasia in 17 %. Overall, 120 patients survived over 2 years, 43 relapse-free up to 18 years, the majority after combined tumor-directed and systemic therapy. Overall median survival was 9 months. This review highlights how results can improve: by defining extent of leukemia involvement with scans before transplant, and emergently when leukemic tumor is found after, ablating tumor directly to abort metastasis, and determining dosing of systemic chemotherapy that protects, without ablating, donor marrow. Monitoring total body remission with body scans should increase transplant cures.

Disease detection methodologies in relapsed B-cell acute lymphoblastic leukemia: Opportunities for improvement

BACKGROUND

Accurate disease detection is integral to risk stratification in B-cell acute lymphoblastic leukemia (ALL). The gold standard used to evaluate response in the United States includes morphologic evaluation and minimal residual disease (MRD) testing of aspirated bone marrow (BM) by flow cytometry (FC). This MRD assessment is usually made on a single aspirate sample that is subject to variability in collection techniques and sampling error. Additionally, central nervous system (CNS) assessments for ALL include evaluations of cytopathology and cell counts, which can miss subclinical involvement.

PROCEDURE

We retrospectively compared BM biopsy, aspirate, and FC samples obtained from children and young adults with relapsed/refractory ALL to identify the frequency and degree of disease discrepancies in this population. We also compared CNS FC and cytopathology techniques.

RESULTS

Sixty of 410 (14.6%) BM samples had discrepant results, 41 (10%) of which were clinically relevant as they resulted in a change in the assignment of marrow status. Discrepant BM results were found in 28 of 89 (31.5%) patients evaluated. Additionally, cerebrospinal fluid (CSF) FC identified disease in 9.7% of cases where cytopathology was negative.

CONCLUSIONS

These results support further investigation of the role of concurrent BM biopsy, with aspirate and FC evaluations, and the addition of FC to CSF evaluations, to fully assess disease status and response, particularly in patients with relapsed/refractory ALL. Prospective studies incorporating more comprehensive analysis to evaluate the impact on clinical outcomes are warranted.

18 FDG-PET/CT: 21st century approach to leukemic tumors in 124 cases

Extramedullary tumors remain an obstacle to curing more acute leukemia patients. Their incidence is unknown because the presence of occult tumors that contribute to relapse is not routinely sought as in other cancers. No standard approach exists for treating tumors at most sites, apparent clinical response is typically followed by further tumors, and achievement of lengthy remission is uncommon. Body scanning with (18) FDG PET/CT now provides a means to identify the extent of occult tumors that enables directed tumor eradication and a way to evaluate tumor response. To evaluate its potential benefits, analysis was undertaken of 124 published cases scanned after apparent tumors were diagnosed. Clinical and radiologic exams underestimated extent of disease in over half of 100 cases. Among 70 cases that reported scans after various treatments, 70% achieved negative scans. Half relapsed subsequently but disease-free survivals up to 6 years were documented. These reported cases add to our knowledge of extramedullary leukemia in showing that further tumors are more likely than marrow relapse, clinical and radiologic evaluation of response is inadequate, intensive chemotherapy alone generally does not prevent progression and is associated with significant mortality, and tumor-directed plus systemic therapies appears the most effective approach, particularly to AML tumors. This analysis suggests this technology could increase our ability to eradicate all foci of leukemia, and identify tumors responsible for refractory, residual, and relapsed disease.