The role of FDG-PET in defining prognosis of Hodgkin lymphoma for early-stage disease

Harnessing multi-source data for individualized care in Hodgkin Lymphoma

Hodgkin lymphoma is a rare, but highly curative form of cancer, primarily afflicting adolescents and young adults. Despite multiple seminal trials over the past twenty years, there is no single consensus-based treatment approach beyond use of multi-agency chemotherapy with curative intent. The use of radiation continues to be debated in early-stage disease, as part of combined modality treatment, as well as in salvage, as an important form of consolidation. While short-term disease outcomes have varied little across these different approaches across both early and advanced stage disease, the potential risk of severe, longer-term risk has varied considerably. Over the past decade novel therapeutics have been employed in the retrieval setting in preparation to and as consolidation after autologous stem cell transplant. More recently, these novel therapeutics have moved to the frontline setting, initially compared to standard-of-care treatment and later in a direct head-to-head comparison combined with multi-agent chemotherapy. In 2018, we established the HoLISTIC Consortium, bringing together disease and methods experts to develop clinical decision models based on individual patient data to guide providers, patients, and caregivers in decision-making. In this review, we detail the steps we followed to create the master database of individual patient data from patients treated over the past 20 years, using principles of data science. We then describe different methodological approaches we are taking to clinical decision making, beginning with clinical prediction tools at the time of diagnosis, to multi-state models, incorporating treatments and their response. Finally, we describe how simulation modeling can be used to estimate risks of late effects, based on cumulative exposure from frontline and salvage treatment. The resultant database and tools employed are dynamic with the expectation that they will be updated as better and more complete information becomes available.

Interim PET-results for prognosis in adults with Hodgkin lymphoma: a systematic review and meta-analysis of prognostic factor studies

BACKGROUND

Hodgkin lymphoma (HL) is one of the most common haematological malignancies in young adults and, with cure rates of 90%, has become curable for the majority of individuals. Positron emission tomography (PET) is an imaging tool used to monitor a tumour's metabolic activity, stage and progression. Interim PET during chemotherapy has been posited as a prognostic factor in individuals with HL to distinguish between those with a poor prognosis and those with a better prognosis. This distinction is important to inform decision-making on the clinical pathway of individuals with HL.

OBJECTIVES

To determine whether in previously untreated adults with HL receiving first-line therapy, interim PET scan results can distinguish between those with a poor prognosis and those with a better prognosis, and thereby predict survival outcomes in each group.

SEARCH METHODS

We searched MEDLINE, Embase, CENTRAL and conference proceedings up until April 2019. We also searched one trial registry (ClinicalTrials.gov).

SELECTION CRITERIA

We included retrospective and prospective studies evaluating interim PET scans in a minimum of 10 individuals with HL (all stages) undergoing first-line therapy. Interim PET was defined as conducted during therapy (after one, two, three or four treatment cycles). The minimum follow-up period was at least 12 months. We excluded studies if the trial design allowed treatment modification based on the interim PET scan results.

DATA COLLECTION AND ANALYSIS

We developed a data extraction form according to the Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies (CHARMS). Two teams of two review authors independently screened the studies, extracted data on overall survival (OS), progression-free survival (PFS) and PET-associated adverse events (AEs), assessed risk of bias (per outcome) according to the Quality in Prognosis Studies (QUIPS) tool, and assessed the certainty of the evidence (GRADE). We contacted investigators to obtain missing information and data.

MAIN RESULTS

Our literature search yielded 11,277 results. In total, we included 23 studies (99 references) with 7335 newly-diagnosed individuals with classic HL (all stages). Participants in 16 studies underwent (interim) PET combined with computed tomography (PET-CT), compared to PET only in the remaining seven studies. The standard chemotherapy regimen included ABVD (16) studies, compared to BEACOPP or other regimens (seven studies). Most studies (N = 21) conducted interim PET scans after two cycles (PET2) of chemotherapy, although PET1, PET3 and PET4 were also reported in some studies. In the meta-analyses, we used PET2 data if available as we wanted to ensure homogeneity between studies. In most studies interim PET scan results were evaluated according to the Deauville 5-point scale (N = 12). Eight studies were not included in meta-analyses due to missing information and/or data; results were reported narratively. For the remaining studies, we pooled the unadjusted hazard ratio (HR). The timing of the outcome measurement was after two or three years (the median follow-up time ranged from 22 to 65 months) in the pooled studies. Eight studies explored the independent prognostic ability of interim PET by adjusting for other established prognostic factors (e.g. disease stage, B symptoms). We did not pool the results because the multivariable analyses adjusted for a different set of factors in each study. Overall survival Twelve (out of 23) studies reported OS. Six of these were assessed as low risk of bias in all of the first four domains of QUIPS (study participation, study attrition, prognostic factor measurement and outcome measurement). The other six studies were assessed as unclear, moderate or high risk of bias in at least one of these four domains. Four studies were assessed as low risk, and eight studies as high risk of bias for the domain other prognostic factors (covariates). Nine studies were assessed as low risk, and three studies as high risk of bias for the domain 'statistical analysis and reporting'. We pooled nine studies with 1802 participants. Participants with HL who have a negative interim PET scan result probably have a large advantage in OS compared to those with a positive interim PET scan result (unadjusted HR 5.09, 95% confidence interval (CI) 2.64 to 9.81, I² = 44%, moderate-certainty evidence). In absolute values, this means that 900 out of 1000 participants with a negative interim PET scan result will probably survive longer than three years compared to 585 (95% CI 356 to 757) out of 1000 participants with a positive result. Adjusted results from two studies also indicate an independent prognostic value of interim PET scan results (moderate-certainty evidence). Progression-free survival Twenty-one studies reported PFS. Eleven out of 21 were assessed as low risk of bias in the first four domains. The remaining were assessed as unclear, moderate or high risk of bias in at least one of the four domains. Eleven studies were assessed as low risk, and ten studies as high risk of bias for the domain other prognostic factors (covariates). Eight studies were assessed as high risk, thirteen as low risk of bias for statistical analysis and reporting. We pooled 14 studies with 2079 participants. Participants who have a negative interim PET scan result may have an advantage in PFS compared to those with a positive interim PET scan result, but the evidence is very uncertain (unadjusted HR 4.90, 95% CI 3.47 to 6.90, I² = 45%, very low-certainty evidence). This means that 850 out of 1000 participants with a negative interim PET scan result may be progression-free longer than three years compared to 451 (95% CI 326 to 569) out of 1000 participants with a positive result. Adjusted results (not pooled) from eight studies also indicate that there may be an independent prognostic value of interim PET scan results (low-certainty evidence). PET-associated adverse events No study measured PET-associated AEs.

AUTHORS' CONCLUSIONS

This review provides moderate-certainty evidence that interim PET scan results predict OS, and very low-certainty evidence that interim PET scan results predict progression-free survival in treated individuals with HL. This evidence is primarily based on unadjusted data. More studies are needed to test the adjusted prognostic ability of interim PET against established prognostic factors.

Interim PET-results for prognosis in adults with Hodgkin lymphoma: a systematic review and meta-analysis of prognostic factor studies

BACKGROUND

Hodgkin lymphoma (HL) is one of the most common haematological malignancies in young adults and, with cure rates of 90%, has become curable for the majority of individuals. Positron emission tomography (PET) is an imaging tool used to monitor a tumour's metabolic activity, stage and progression. Interim PET during chemotherapy has been posited as a prognostic factor in individuals with HL to distinguish between those with a poor prognosis and those with a better prognosis. This distinction is important to inform decision-making on the clinical pathway of individuals with HL.

OBJECTIVES

To determine whether in previously untreated adults with HL receiving first-line therapy, interim PET scan results can distinguish between those with a poor prognosis and those with a better prognosis, and thereby predict survival outcomes in each group.

SEARCH METHODS

We searched MEDLINE, Embase, CENTRAL and conference proceedings up until April 2019. We also searched one trial registry (ClinicalTrials.gov).

SELECTION CRITERIA

We included retrospective and prospective studies evaluating interim PET scans in a minimum of 10 individuals with HL (all stages) undergoing first-line therapy. Interim PET was defined as conducted during therapy (after one, two, three or four treatment cycles). The minimum follow-up period was at least 12 months. We excluded studies if the trial design allowed treatment modification based on the interim PET scan results.

DATA COLLECTION AND ANALYSIS

We developed a data extraction form according to the Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies (CHARMS). Two teams of two review authors independently screened the studies, extracted data on overall survival (OS), progression-free survival (PFS) and PET-associated adverse events (AEs), assessed risk of bias (per outcome) according to the Quality in Prognosis Studies (QUIPS) tool, and assessed the certainty of the evidence (GRADE). We contacted investigators to obtain missing information and data.

MAIN RESULTS

Our literature search yielded 11,277 results. In total, we included 23 studies (99 references) with 7335 newly-diagnosed individuals with classic HL (all stages).Participants in 16 studies underwent (interim) PET combined with computed tomography (PET-CT), compared to PET only in the remaining seven studies. The standard chemotherapy regimen included ABVD (16) studies, compared to BEACOPP or other regimens (seven studies). Most studies (N = 21) conducted interim PET scans after two cycles (PET2) of chemotherapy, although PET1, PET3 and PET4 were also reported in some studies. In the meta-analyses, we used PET2 data if available as we wanted to ensure homogeneity between studies. In most studies interim PET scan results were evaluated according to the Deauville 5-point scale (N = 12).Eight studies were not included in meta-analyses due to missing information and/or data; results were reported narratively. For the remaining studies, we pooled the unadjusted hazard ratio (HR). The timing of the outcome measurement was after two or three years (the median follow-up time ranged from 22 to 65 months) in the pooled studies.Eight studies explored the independent prognostic ability of interim PET by adjusting for other established prognostic factors (e.g. disease stage, B symptoms). We did not pool the results because the multivariable analyses adjusted for a different set of factors in each study.Overall survivalTwelve (out of 23) studies reported OS. Six of these were assessed as low risk of bias in all of the first four domains of QUIPS (study participation, study attrition, prognostic factor measurement and outcome measurement). The other six studies were assessed as unclear, moderate or high risk of bias in at least one of these four domains. Nine studies were assessed as high risk, and three studies as moderate risk of bias for the domain study confounding. Eight studies were assessed as low risk, and four studies as high risk of bias for the domain statistical analysis and reporting.We pooled nine studies with 1802 participants. Participants with HL who have a negative interim PET scan result probably have a large advantage in OS compared to those with a positive interim PET scan result (unadjusted HR 5.09, 95% confidence interval (CI) 2.64 to 9.81, I² = 44%, moderate-certainty evidence). In absolute values, this means that 900 out of 1000 participants with a negative interim PET scan result will probably survive longer than three years compared to 585 (95% CI 356 to 757) out of 1000 participants with a positive result.Adjusted results from two studies also indicate an independent prognostic value of interim PET scan results (moderate-certainty evidence).Progression-free survival Twenty-one studies reported PFS. Eleven out of 21 were assessed as low risk of bias in the first four domains. The remaining were assessed as unclear, moderate or high risk of bias in at least one of the four domains. Eleven studies were assessed as high risk, nine studies as moderate risk and one study as low risk of bias for study confounding. Eight studies were assessed as high risk, three as moderate risk and nine as low risk of bias for statistical analysis and reporting.We pooled 14 studies with 2079 participants. Participants who have a negative interim PET scan result may have an advantage in PFS compared to those with a positive interim PET scan result, but the evidence is very uncertain (unadjusted HR 4.90, 95% CI 3.47 to 6.90, I² = 45%, very low-certainty evidence). This means that 850 out of 1000 participants with a negative interim PET scan result may be progression-free longer than three years compared to 451 (95% CI 326 to 569) out of 1000 participants with a positive result.Adjusted results (not pooled) from eight studies also indicate that there may be an independent prognostic value of interim PET scan results (low-certainty evidence).PET-associated adverse eventsNo study measured PET-associated AEs.

AUTHORS' CONCLUSIONS

This review provides moderate-certainty evidence that interim PET scan results predict OS, and very low-certainty evidence that interim PET scan results predict progression-free survival in treated individuals with HL. This evidence is primarily based on unadjusted data. More studies are needed to test the adjusted prognostic ability of interim PET against established prognostic factors.

Early-stage Hodgkin lymphoma in the modern era: simulation modelling to delineate long-term patient outcomes

We developed a novel simulation model integrating multiple data sets to project long-term outcomes with contemporary therapy for early-stage Hodgkin lymphoma (ESHL), namely combined modality therapy (CMT) versus chemotherapy alone (CA) via ¹⁸ F-fluorodeoxyglucose positron emission tomography response-adaption. The model incorporated 3-year progression-free survival (PFS), probability of cure with/without relapse, frequency of severe late effects (LEs), and 35-year probability of LEs. Furthermore, we generated estimates for quality-adjusted life years (QALYs) and unadjusted survival (life years, LY) and used model projections to compare outcomes for CMTversusCA for two index patients. Patient 1: a 25-year-old male with favourable ESHL (stage IA); Patient 2: a 25-year-old female with unfavourable ESHL (stage IIB). Sensitivity analyses assessed the impact of alternative assumptions for LE probabilities. For Patient 1, CMT was superior to CA (CMT incremental gain = 0·11 QALYs, 0·21 LYs). For Patient 2, CA was superior to CMT (CA incremental gain = 0·37 QALYs, 0·92 LYs). For Patient 1, the advantage of CMT changed minimally when the proportion of severe LEs was reduced from 20% to 5% (0·15 QALYs, 0·43 LYs), whereas increasing the severity proportion for Patient 2's LEs from 20% to 80% enhanced the advantage of CA (1·1 QALYs, 6·5 LYs). Collectively, this detailed simulation model quantified the long-term impact that varied host factors and alternative contemporary treatments have in ESHL.

Oncologists’ Perspectives on Consolidation Radiation Treatment after Chemotherapy for Lymphomas: A Survey Study by the Lymphoma Working Committee of the Turkish Oncology Group (TOG)

In this study, we aimed to determine the perspectives of medical and radiation oncologists regarding consolidation radiotherapy in patients with a complete response after chemotherapy for Hodgkin’s and non-Hodgkin’s lymphomas. The survey was designed to identify demographic and occupational features of medical and radiation oncologists and their views on application of consolidation radiotherapy in their clinical practices, as based on a five-point Likert scale (never, rarely, sometimes, often, and always). The study covered 263, out of 935, physicians working in the oncology field as either medical or radiation oncologists; the rate of return on the invitations to participate was 28%. The majority of the participants were male radiation oncologists, with a duration of between 5 and 10 years of work as a university hospital official, and the mean age was 38 ± 14 (years). Although the most commonly followed international guidelines were NCCN, among the physicians, the majority of the respondents suggested that the guidelines were unclear regarding recommendations for consolidative radiotherapy. The administered dose for consolidative radiotherapy in lymphoma patients was indicated as 40 Gy by 49% of all the physicians and the most common cause of hesitancy concerning consolidative radiation treatment was the risk of secondary malignancies as a long-term adverse effect (54%). In conclusion, we suggest that medical oncologists could be most active in the treatment of lymphoma through a continuous training program about lymphomas and current national guidelines.

Frontline Therapy for Classical Hodgkin Lymphoma by Stage and Prognostic Factors

Hodgkin lymphoma is a highly curable malignancy in early and advanced stages. Most patients are diagnosed in their teens or twenties and are expected to live decades beyond their treatment. Therefore, the toxicity of treatment must be balanced with the goal of cure. Thus, treatment has been refined through prognostic models and positron emission tomography-computed tomography (PET-CT)-directed therapy. Stratification by prognostic models defines groups of patients with favorable characteristics who may be treated with less intensive therapy upfront, including fewer cycles of chemotherapy, lower doses of radiation, or omission of radiation altogether. Alternatively, high-risk patients may be assigned to a more aggressive initial approach. The modern use of interim PET-CT allows further tailoring of treatment by response.

Current developments in the treatment of early-stage classical Hodgkin lymphoma

PURPOSE OF REVIEW

After presenting the current treatment recommendations for early-stage Hodgkin lymphoma, we give an overview on recently published clinical trials in this setting. Furthermore, the potential influence of current trials on the treatment of early-stage Hodgkin lymphoma and integration of newly emerging drugs into treatment protocols will be discussed.

RECENT FINDINGS

Trials attempting treatment de-escalation and omission of radiotherapy on the basis of early interim PET-scans have been disappointing so far, but results of some large trials employing this strategy are still awaited. In contrast, a more defensive strategy of starting treatment with less aggressive doxorubicine, bleomycin, vinblastine, dacarbazine (ABVD) chemotherapy and intensifying treatment in early interim PET-positive patients has shown encouraging results. New drugs such as brentuximab vedotin and immune checkpoint inhibitors have shown promising results in relapsed and refractory Hodgkin lymphoma. Clinical trials of brentuximab vedotin in early-stage Hodgkin lymphoma have been initiated. Additionally, biomarker-based treatment de-escalation might be a possible route for future improvements.

SUMMARY

The challenge for future clinical research in early-stage Hodgkin lymphoma is to continue to cure the majority of patients with first-line treatment while reducing long-term toxicity. New strategies to achieve that goal are currently being developed and will further refine treatment of early-stage Hodgkin lymphoma.

How to Approach a Patient With Limited Stage Hodgkin Lymphoma Who Remains PET Positive at the End of Chemotherapy: Radiation Therapy?

The use of 18-F fluorodeoxyglucose (FDG) positron emission tomography (PET) with computed tomography has emerged as a crucial tool for response-adapted therapy in Hodgkin lymphoma (HL). Although more studies have focused on the predictive value of an interim or early PET obtained after 2 cycles of chemotherapy, there are indications that the end of therapy PET might even be more predictive of outcome. The optimal treatment of patients with limited stage HL who are PET-positive after chemotherapy is unknown. Here we review the prognostic significance of end of treatment PET in early stage HL, the role of consolidative radiotherapy in patients who have FDG-PET avidity at the end of chemotherapy, and discuss the place of salvage chemotherapy and autologous transplantation in these patients.

Interim PET Scans in Diffuse Large B-Cell Lymphoma: Is It Ready for Prime Time?

Prognostication of patients with diffuse large B-cell lymphoma (DLBCL) has improved in the past decade with a variety of clinical, morphologic, molecular, and radiographic methods. Comparable to data on the value of interim positron emission tomography (I-PET) in Hodgkin lymphoma, several retrospective and prospective studies are attempting to assess the value of I-PET scanning in DLBCL patients. In this review, we briefly describe and analyze the various prognostic methods in DLBCL with specific focus on the value of I-PET scanning in this disease. This is a timely analysis, as tailoring therapies based on prognosis at diagnosis are becoming of increased investigational interest.

Interim FDG-PET/CT in Hodgkin lymphoma: the prognostic role of the ratio between target lesion and liver SUVmax (rPET)

OBJECTIVE

To evaluate the prognostic role of the ratio between target lesion and liver SUVmax (rPET) in patients with Hodgkin lymphoma (HL) undergoing interim FDG-PET/CT and to compare rPET with the 5-point Deauville Score (5p-DS).

METHODS

Sixty-eight patients with HL undergoing interim FDG-PET/CT after first courses of chemotherapy were evaluated. The receiver operating characteristic (ROC) approach was applied to identify the optimal cutpoint of rPET with respect to progression free survival (PFS). The prognostic significance of rPET was compared with 5p-DS (scores 4 and 5 considered as positive). Positive predictive value (PPV) and negative predictive value (NPV) were calculated using the presence of an adverse event as the gold standard.

RESULTS

The ROC analysis for rPET as a predictor of progression showed an optimal rPET cutpoint of 1.14. Both 5p-DS and rPET were strong outcome predictors (p < 0.001). Patients with negative 5p-DS and patients with rPET <1.14 had a similar two-year PFS (86 and 87 %, respectively). Patients with a positive 5p-DS had a 2-year PFS of 27 %, while patients with rPET >1.14 had a 2-year PFS of 15 %. 5p-DS and rPET cutoff of 1.14 showed a PPV of 58 versus 70 %, and a NPV of 85 versus 86 %, respectively.

CONCLUSIONS

rPET could be considered an accurate prognostic factor in patients with HL undergoing interim FDG-PET/CT. Larger prospective studies are needed to confirm these data.

Hodgkin Lymphoma: the Changing Role of Radiation Therapy in Early-Stage Disease—the Role of Functional Imaging

Early-stage classical Hodgkin lymphoma (CHL) is a highly curable malignancy. Historically, extended-field radiotherapy (EFRT) alone showed excellent cure rates, but the risk of radiotherapy (RT)-associated toxicities led to combined modality therapy (CMT) replacing RT alone. RT has subsequently evolved further with significant reductions of dose and field size, and is currently restricted to involved sites only (ISRT). Contemporary CMT yields cure rates in excess of 85%, and most studies do not have adequate follow-up required to evaluate the risk reduction in late effects. In an effort to avoid RT altogether, response-adapted treatment approaches utilizing results of interim [(18)F]fluorodeoxyglucose (FDG) positron emission tomography with fused computed tomography (PET/CT) imaging have been studied. Results from two studies in favorable-risk (UK RAPID and EORTC H10F) and one in unfavorable-risk patients (EORTC H10U) suggest that omission of RT in patients with a negative interim PET/CT response (Deauville score ≤2) yields slightly inferior progression-free survival (PFS) compared to conventional CMT, but with no difference in overall survival (OS) albeit with short-term follow-up. In order to extrapolate results to daily practice, it is critical to understand the selection of patients entered on trials since definitions of favorable and unfavorable disease vary between study groups. Currently, CMT continues to be the standard of care for the vast majority of patients with early-stage CHL and RT is an integral part of therapy in patients with bulky disease. However, for selected patients with favorable characteristics, emerging data suggest that a chemotherapy-alone approach is reasonable.

Application value of diffusion weighted whole body imaging with background body signal suppression in monitoring the response to treatment of bone marrow involvement in lymphoma

PURPOSE

To investigate the application value of diffusion weighted whole body imaging with background body signal suppression (DWIBS) in monitoring the response to treatment of bone marrow involvement in lymphoma.

MATERIALS AND METHODS

Twenty-one lymphoma patients with bone marrow involvement underwent 1.5 Tesla DWIBS before chemotherapy and after the second chemotherapy session (median interval, 8 weeks; range 7-11 weeks). Apparent diffusion coefficient (ADC) values of bone marrow lesions were measured before and after treatment. The difference in ADC values before and after treatment in responders and nonresponders was analyzed.

RESULTS

Seventy-three cases of bone marrow lesions were diagnosed in 21 lymphoma patients before the treatment. After the second chemotherapy session, 18 patients (57 lesions) and 3 patients (9 lesions) were categorized into the responder and nonresponder group, respectively. The mean pretreatment ADC value of all lesions was 0.90 ± 0.39 × 10^-3 mm² /s, of which the mean ADC values of the responder group and nonresponder group were 0.92 ± 0.40 × 10^-3 mm² /s and 0.79 ± 0.29 × 10^-3 mm² /s, respectively (between-group difference: t = -0.94; P = 0.351). The posttreatment ADC value of the responder group significantly increased (66.39% ± 83.11%; P < 0.001) while the posttreatment ADC value of the nonresponder group slightly increased (5.32% ± 17.31%). The difference in the rate of change of ADC values in the responder and nonresponder groups before and after the treatment was significant (P < 0.05).

CONCLUSION

DWIBS in combination with the measurement of ADC values enabled a good short-term response evaluation for bone marrow involvement in lymphoma. However, the pretreatment ADC value indicated no significant predictive value for responses to the treatment. J. Magn. Reson. Imaging 2016;44:1522-1529.

The evolving role of response-adapted PET imaging in Hodgkin lymphoma

(18)F-fluorodeoxyglucose positron emission tomography with (FDG-PET) has a well-established role in the pre- and post-treatment staging of Hodgkin lymphoma (HL), however its use as a predictive therapeutic tool via responded-adapted therapy continues to evolve. There have been a multitude of retrospective and noncontrolled clinical studies showing that early (or interim) FDG-PET is highly prognostic in HL, particularly in the advanced-stage setting. Response-adapted treatment approaches in HL are attempting to diminish toxicity for low-risk patients by minimizing therapy, and conversely, intensify treatment for high-risk patients. Results from phase III noninferiority studies in early-stage HL with negative interim FDG-PET that randomized patients to chemotherapy alone versus combined modality therapy showed a continued small improvement in progression-free survival for patients who did not receive radiation. Preliminary reports of data escalating therapy for positive interim FDG-PET in early-stage HL and for de-escalation of therapy [i.e. bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine and prednisone (BEACOPP)] for negative interim FDG-PET in advanced stage HL (i.e. deletion of bleomycin) have demonstrated improved outcomes. Maturation of these studies and continued follow up of all response-adapted studies are needed. Altogether, the treatment of HL remains an individualized clinical management choice for physicians and patients. Continued refinement and optimization of FDG-PET is needed, including within the context of targeted therapeutic agents. In addition, a number of new and novel techniques of functional imaging, including metabolic tumor volume and tumor proliferation, are being explored in order to enhance staging, characterization, prognostication and ultimately patient outcome.

Management of Adolescent Low-Risk Classical Hodgkin Lymphoma: Which Chemotherapy Backbone Gives the Best Chance of Omitting Radiotherapy Safely

Even though more than 90% of adolescents with low-risk classical Hodgkin lymphoma (LRcHL) will be cured with first-line therapy, many will suffer serious late toxic effects from radiotherapy (RT). The goals for care have shifted toward minimizing late toxic effects without compromising the outstanding cure rates by adapting a risk and response-based therapy. Recent published and ongoing randomized clinical trials, using functional imaging, may allow for better identification of those patients for whom RT may be safely omitted while maintaining excellent cure rates. To evaluate the best chemotherapy regimens with a reasonable toxicity profile and that are expected to have a high chance of omitting RT based on a response-directed therapy while maintaining high cure rates, a mini review was conducted of the recent clinical trials in pediatric and adult LRcHL. The UK RAPID trial chemotherapy backbone (3 × ABVD) followed by a response-based positron emission tomography scan offers up to a 75% chance of safely omitting RT without compromising the cure rate, which remained well above 90%.

Primary intratesticular rhabdomyosarcoma: A case report and literature review

Rhabdomyosarcoma (RMS) that primarily occurs in the testes is particularly rare, with only retrospective studies and sporadic cases reported in the literature. The present study describes the case of a large, primary intratesticular RMS (ITRMS) that was treated with a radical inguinal orchiectomy (RIO) and a regimen of chemotherapy. The study also presents a review of the literature regarding primary ITRMSs, aiming to elucidate the clinical characteristics and optimal treatment of the disease. A 14-year-old male presented with a 1-year history of a slow-growing, painless, left scrotal mass. Magnetic resonance imaging identified a mass in the left scrotum with mixed signal intensity; no abnormal signals were identified in the right testicle and retroperitoneal lymph node. An X-ray of the chest demonstrated no evidence of metastasis. Subsequent to this, a left RIO was performed. Histopathological and immunohistochemical examination confirmed the final diagnosis of embryonal ITRMS. At 21 days post-surgery, an ¹⁸F-fluorodeoxyglucose-positron emission tomography-computed tomography (FDG-PET-CT) scan identified widespread metastatic lesions in the lungs, local lymph nodes and bones, presenting as increased glucose metabolism nodules. Subsequently, the patient received six sequential cycles of adjunct chemotherapy. The patient is alive with disease in October 2015. The case described is noteworthy as it is an example of ITRMS, in which the patient received successful treatment. However, multidisciplinary treatment may further improve the outcome of the disease.

Computed Tomography Observer Agreement in Staging Malignant Lymphoma

OBJECTIVE

To determine pretreatment computed tomography observer agreement in patients with newly diagnosed lymphoma.

METHODS

Forty-nine computed tomography scans were reviewed by 3 experienced radiologists, with each scan assessed twice by 1 observer. Predefined nodal and extranodal regions were assessed, and Ann Arbor stages were assigned. K-statistics were defined as poor (κ < 0.2), fair (κ > 0.2 to κ ≤ 0.4), moderate (κ > 0.4 to κ ≤ 0.6), substantial (κ > 0.6 to κ ≤ 0.8), and almost perfect (κ > 0.8 to κ ≤ 1).

RESULTS

Nodal interobserver agreement varied from 0.09 for infraclavicular involvement to 0.95 for para-iliac involvement; intraobserver agreement was substantial to almost perfect, except for infraclavicular nodes. Extranodal interobserver agreement varied from 0.56 to 0.88; intraobserver agreement was substantial to almost perfect. Ann Arbor stage interobserver agreement varied from 0.57 to 0.69; intraobserver agreement was substantial.

CONCLUSION

Computed tomography observer agreement in staging malignant lymphoma appears to be suboptimal.