Early post transplant (F-18) 2-fluoro-2-deoxyglucose positron emission tomography does not predict outcome for patients undergoing auto-SCT in non-Hodgkin and Hodgkin lymphoma

Analysis of Positive Results of 18F-FDG PET/CT Imaging after Hematopoietic Stem Cell Transplantation in Lymphoma

PURPOSE

The purpose of this study was to differentiate between false-positive and true-positive positron emission tomography (PET) results after hematopoietic stem cell transplantation (SCT) for lymphoma involvement by analyzing several clinical variables and specific imaging features.

PATIENTS AND METHODS

Patients with lymphoma who received SCT and underwent post-transplantation ¹⁸F-FDG PET/CT scans between January 2013 and April 2021 at our institution were included. Associations between PET positivity and related clinical information were assessed using t-tests and χ² tests. The significance of variables differentiating benign lesions from malignant FDG-avid lesions was evaluated by logistic regression analysis. Survival probabilities were derived from Kaplan-Meier curves and compared using the log-rank test.

RESULTS

A total of 185 patients (235 post-transplantation PET/CT scans) were enrolled in our present study. Compared with those with true-positive PET results, patients with false-positive PET results exhibited a better prognosis. For the autologous SCT group, false-positive cases were more commonly seen when FDG-avid foci appeared outside the sites of the original disease (p = 0.004), and the integrated CT imaging showed negative results (p = 0.000). In multivariate logistic regression analysis, integrated CT results were the only significant factor. For the allogeneic SCT group, false-positive cases were significantly more commonly seen when DS = 4 (p = 0.046), FDG-avid foci appeared outside the sites of the original disease (p = 0.022), and the integrated CT imaging showed negative results (p = 0.001). In a multivariate logistic regression analysis, whether FDG-avid foci were in the sites of the original disease and integrated CT results were both significant factors.

CONCLUSION

False-positive FDG uptake in post-transplantation PET was not uncommon. Several variables could provide an important reference to differentiate false-positive from true-positive post-SCT PET results for lymphoma involvement.

TRIAL REGISTRATION NUMBER

ChiCTR2300067355.

Prognostic Value of 2-Deoxy-2-[18F]fluoro-D-glucose Positron Emission Tomography/Computed Tomography after Autologous Hematopoietic Stem Cell Transplantation in Lymphoma Using Deauville Scores

Purpose

In the present study, we mainly aimed to evaluate the prognostic value of 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]F-FDG) positron emission tomography (PET)/computed tomography (CT) after autologous stem cell transplantation (ASCT) in lymphoma. Procedures. A total of 76 lymphoma patients who benefited from [¹⁸F]F-FDG PET-CT (within 3 months and 3–6 months) after ASCT in our institution between April 2010 and December 2019 were enrolled in this retrospective study. These abovementioned patients were divided into two groups based on the Deauville criteria. The Kaplan–Meier method was used in survival analysis, and the log-rank method was adopted in comparison. Prognostic factor analysis was performed by the Cox regression model.

Results

Positive post-ASCT [¹⁸F]F-FDG PET-CT was associated with lower progression-free survival (PFS) and overall survival (OS) (p = 0.001 and p = 0.022, respectively). Univariate analysis showed the post-ASCT PET-CT result was the only independent factor associated with PFS (p = 0.002). Both the number of previous treatments and post-ASCT PET-CT result had a different impact on OS (p = 0.040 and p = 0.028, respectively). Multivariate analysis showed the post-ASCT PET-CT result was the only independent factor associated with OS (p = 0.028). The results showed no significant change from the abovementioned results when DS < 3 was defined as the negative result. For patients who had a PET-CT scan within 3–6 months after ASCT, the negative PET-CT group had a better prognosis including PFS and OS (p = 0.009 and p = 0.025, respectively). However, among the patients receiving PET-CT within 3 months, the result was not statistically significant (p = 0.064 and p = 0.445, respectively).

Conclusion

Collectively, we found that the post-ASCT [¹⁸F]F-FDG PET-CT was a strong indicator for PFS and OS, and a time window of 3–6 months was appropriate for post-ASCT [¹⁸F]F-FDG PET-CT. Trial registration number: ChiCTR2100042745.

International Pediatric Non-Hodgkin Lymphoma Response Criteria

PURPOSE

Response criteria are well established for adult patients with non-Hodgkin lymphoma (NHL). A revised set of response criteria in adults with NHL was recently published. However, NHL in children and adolescents involves different histologies, primary sites of disease, patterns of metastatic spread, approaches to therapy, and responses to treatment compared with adult NHL. However, there are no standardized response criteria specific to pediatric NHL. Therefore, we developed international standardized methods for assessing response to therapy in children and adolescents with NHL.

METHODS

An international multidisciplinary group of pediatric oncologists, pathologists, biologists, and radiologists convened during and after the Third and Fourth International Childhood, Adolescent and Young Adult NHL Symposia to review existing response and outcome data, develop methods for response evaluation that reflect incorporation of more sensitive technologies currently in use, and incorporate primary and metastatic sites of disease for the evaluation of therapeutic response in children and adolescents with NHL.

RESULTS

Using the current adult NHL response criteria as a starting point, international pediatric NHL response criteria were developed incorporating both contemporary diagnostic imaging and pathology techniques, including novel molecular and flow cytometric technologies used for the determination of minimal residual disease.

CONCLUSION

Use of the international pediatric NHL response criteria in children and adolescents receiving therapy for NHL incorporates data obtained from new and more sensitive technologies that are now being widely used for disease evaluation, providing a standardized means for reporting treatment response.

Managing Hodgkin lymphoma relapsing after autologous hematopoietic cell transplantation: a not-so-good cancer after all!

Hodgkin lymphoma (HL) relapsing after an autologous hematopoietic cell transplant (HCT) poses a therapeutic challenge. In this setting, salvage chemotherapy (for example, gemcitabine-based, ifosfamide-containing and others) or immunotherapy (for example, brentuximab vedotin) is essential as a bridging-cytoreduction strategy to an allogeneic HCT. Myeloablative allogeneic hematopoietic cell transplantation in relapsed HL is associated with high rates of non-relapse mortality. In carefully selected patients with chemosensitive disease, allografting following lower-intensity conditioning regimens can provide durable disease control rates of about 25-35%. Promising early results with haploidentical and umbilical cord transplantation are noteworthy and are expanding this procedure to patients for whom HLA-matched related or unrelated donors are not available. Unfortunately, a significant number of HL patients relapsing after an autologous HCT are not candidates for allografting because of the presence of resistant disease, donor unavailability or comorbidities. Brentuximab vedotin is approved for HL relapsing after a prior autograft. Rituximab and bendamustine are also active in this setting, albeit with short durations of remission. Histone deacetylase inhibitors (for example, panobinostat, mocetinostat), mTOR inhibitors (for example, everolimus) and immunomodulatory agents (lenalidomide) have shown activity in phase II trials, but currently are not approved for this indication. Second autologous HCT are rarely performed but this approach should not be considered standard practice at this time. The need for effective agents for post autograft failures of HL largely remains unmet. Continuous efforts to ensure early referral of such patients for allogeneic HCT or investigational therapies are the key to improving outcomes of this not-so-good lymphoma.

When should FDG-PET be used in the modern management of lymphoma?

Positron Emission Tomography (PET) is a functional imaging technique that, combined with computerized tomography (PET-CT), is increasingly used in lymphoma. Most subtypes accumulate fluorodeoxyglucose (FDG) and the increased sensitivity of PET-CT, especially for extranodal disease, compared to CT, makes PET-CT an attractive staging tool. The availability of a staging PET-CT scan also improves the accuracy of subsequent response assessment. 'Interim' PET-CT can be used to assess early response and end-of-treatment PET-CT assesses remission. Clinical trials are currently seeking to establish whether the predictive value of PET-CT can be successfully used to guide individual treatment to reduce toxicity and/or to improve outcomes. Standardized methods for performing and reporting PET have been developed in the context of trials. The role of PET in transplantation selection is currently evolving, as it appears to be more accurate and prognostic than CT. The role of FDG PET-CT throughout the management course in patients with lymphoma is explored in this review, with areas discussed that may limit the use of PET-CT imaging which clinicians should be familiar with to inform practice.

PET scan integration in lymphoma management

SUMMARY Despite a marked improvement in lymphoma treatment outcome, current prognostic models, relying on a pretreatment set of static clinical variables, appear unable to support a risk-adapted therapeutic strategy. On the other hand, functional imaging with 18F-fluoro-2-deoxy-D-glucose (FDG)-PET proved to be a reliable tool to dynamically assess tumor FDG uptake changes during and after treatment. In this article we aim to review the prognostic value of FDG-PET in all the stages of Hodgkin’s and non-Hodgkin’s lymphoma management, without the intent to address the diagnostic value of PET or to replace available consensus guidelines. In particular we focused on two critical issues: the cost–effectiveness of PET in the overall strategy of lymphoma diagnosis and treatment; and ongoing clinical trials adopting an interim PET-based strategy to modulate treatment intensity based on PET results. Finally, new trends in multimodality imaging, as well as in new radiopharmaceutical tracers, are briefly reviewed.

Hodgkin's lymphoma in adults: diagnosis, treatment and follow-up

BACKGROUND

With an incidence of 2 to 3 cases per 100 000 persons per year, Hodkgin's lymphoma (HL) is rare, but nonetheless one of the most common cancers in young adults. Improved treatment has made HL curable even in advanced stages, but controversy still surrounds a number of issues in patient care. Current research focuses on the avoidance of long-term adverse effects and secondary malignancies.

METHODS

We selectively searched MEDLINE, CENTRAL, and the Guideline International Network for publications about HL. Two experts independently screened the retrieved publications for pertinence and extracted data from potentially relevant meta-analyses, randomized controlled trials (RCTs), and cohort studies into evidence tables.

RESULTS

32 key questions were answered with 160 recommendations on the basis of evidence from 43 RCTs, 21 meta-analyses, and 119 cohort studies. Patients in an early stage of HL should be treated with two cycles of ABVD followed by involved-field radiotherapy (IF-RT) at a dose of 20 Gy (5-year overall survival [OS]: 94%). Patients in an intermediate (early unfavorable) stage should be treated with two cycles of BEACOPP escalated followed by two cycles of ABVD and 30 Gy IF-RT (5-year OS: 97.2%). Patients in an advanced stage should be treated with six cycles of BEACOPP escalated, and the decision whether this should be followed by consolidating radiotherapy (30 Gy) should be based on the findings of positron-emission tomography (radiate in case of PET-positive residual tumor; 5-year OS: 95.3%). Depending on the treatment regimen, there may be adverse effects including infection, leukopenia, anemia, thrombocytopenia, secondary neoplasia, and fertility disorders.

CONCLUSION

Most questions in the treatment of HL can now be answered on the basis of sufficient evidence from the literature. This holds in particular for the potential benefit to be gained from PET, follow-up care, and lifestyle recommendations for patients.

Burkitt lymphoma: staging and response evaluation

The refinements in both the staging and response evaluation of children with Burkitt lymphoma (BL) have contributed to the improvements in treatment outcome observed over the past 40 years. Ziegler and Magrath designed a staging system in the 1970s for children with BL in equatorial Africa. Currently, the most widely used staging system around the world is that described by Murphy in 1980, which was developed for children with non-Hodgkin lymphoma (NHL) of any histology. There are opportunities for refinement in this system, particularly with respect to certain extra-nodal sites, such as skin and bone. The findings obtained at diagnosis with novel technologies (functional imaging [e.g., positron emission tomography [PET]] and minimal residual disease [MRD] technology), which are more sensitive with respect to disease detection than historic modalities, also need to be considered. Technological advances have also had impact on the assessment of response evaluation. Standard x-rays were routinely used in the 1960s; nuclear imaging became widely used in the 1970s; computerized axial tomography was incorporated in the 1980s; PET imaging was incorporated and, in many cases, has replaced gallium/bone scans since 2000; and MRD technology has been explored in some of the most recent clinical trials. There is clearly a need for more clinical data on the use of PET and MRD technology in the determination of response evaluation of children with BL as well as other histological subtypes of NHL. An international working group is currently addressing the refinement of both disease staging and response evaluation in children with NHL.