Are patients with Hodgkin lymphoma and high-grade non-Hodgkin lymphoma in clinical therapy optimization protocols representative of these groups of patients in Germany?

Testing the "RCT augmentation" methodology: A trial simulation study to guide the broadening of trials eligibility criteria and inform on effectiveness

Background

Exclusion criteria that are treatment effect modifiers (TEM) decrease RCTs results generalisability and the potentials of effectiveness estimation. In "augmented RCTs", a small proportion of otherwise-excluded patients are included to allow for effectiveness estimation. In Hodgkin Lymphoma (HL) RCTs, older age and comorbidity are common exclusion criteria, while also TEM. We simulated HL RCTs augmented with age or comorbidity, and explored in each scenario the impact of augmentation on effectiveness estimation accuracy.

Methods

Simulated data with a population of HL individuals initiating drug A or B was generated. There were drug-age and drug-comorbidity interactions in the simulated data, with a greater magnitude of the former compared to the latter. Multiple augmented RCTs were simulated by randomly selecting patients with increasing proportions of older, or comorbid patients. Treatment effect size was expressed using the between-group Restricted Mean Survival Time (RMST) difference at 3 years. For each augmentation proportion, a model estimating the "real-world" treatment effect (effectiveness) was fitted and the estimation error measured (Root Mean Square Error, RMSE).

Results

In simulated RCTs including none (0%), or the real-world proportion (30%) of older patients, the interquartile range of RMST difference was 0.4-0.5 years and 0.2-0.3 years, respectively, and RMSE were 0.198 years (highest possible error) and 0.056 years (lowest), respectively. Augmenting RCTs with 5% older patients decreased estimation error substantially (RMSE = 0.076 years). Augmentation with comorbid patients proved less useful for effectiveness estimation.

Conclusion

In augmented RCTs aiming to inform the effectiveness of drugs, augmentation should concern in priority those exclusion criteria of suspected important TEM magnitude, so as to minimie the proportion of augmentation necessary for good effectiveness estimations.

Comparison of outcomes between Hodgkin's lymphoma patients treated in and outside clinical trials: A study based on the EORTC-Dutch late effects cohort-linked data

Studies have shown higher survival rates for patients with Hodgkin lymphoma (HL) treated within clinical trials compared to patients treated outside clinical trials. However, endpoints are often limited to overall survival (OS). In this retrospective cohort study, we investigated the effect of trial participation on OS, the incidence of relapse, second cancer, and cardiovascular disease (CVD). The study population consisted of patients with HL, aged between 14 and 51 years at diagnosis, who started their treatment between 1962 and 2002 at three Dutch cancer centres. Patients were either included in the EORTC Lymphoma Group trials (H1-H9) or treated according to standard guidelines at the time. After adjusting for differences in baseline characteristics, trial participation was associated with longer OS (median OS: 29.4 years [95%CI: 27.0-31.6] for treatment inside trials versus 27.4 years [95%CI: 26.0-28.5] for treatment outside trials, p = .046), a lower incidence of relapse (HR = 0.79, 95%CI: 0.63-0.98, p = .036) and a higher incidence of CVD (HR = 1.49, 95%CI: 1.23-1.79, p < .001). The trial effect for CVD was present only for patients treated before 1983. No evidence of differences in the incidence of second cancer was found. Consequently, essential results from clinical trials should be implemented into standard practice without undue delay.

Real‐world data on treatment concepts in classical Hodgkin lymphoma in Sweden 2000–2014, focusing on patients aged >60 years

Treatment for patients > 60 years with classical Hodgkin lymphoma (cHL) is problematic; there is no gold standard, and outcome is poor. Using the Swedish Lymphoma Registry, we analysed all Swedish patients diagnosed with cHL between 2000 and 2014 (N = 2345; median age 42 years; 691 patients were >60 years). The median follow‐up time was 6.7 years. Treatment for elderly patients consisted mainly of ABVD or CHOP, and the younger patients were treated with ABVD or BEACOPP (with no survival difference). In multivariable analysis of patients > 60 years, ABVD correlated with better survival than CHOP (p = 0.027), and ABVD became more common over time among patients aged 61–70 years (p = 0.0206). Coinciding with the implementation of FDG‐PET/CT, the fraction of advanced‐stage disease increased in later calendar periods, also in the older patient group. Survival has improved in cHL patients > 60 years (p = 0.027), for whom ABVD seems superior to CHOP.

Relapse Risk and Loss of Lifetime After Modern Combined Modality Treatment of Young Patients With Hodgkin Lymphoma: A Nordic Lymphoma Epidemiology Group Study

PURPOSE

Estimates of short- and long-term survival for young patients with classic Hodgkin lymphoma (cHL) are of considerable interest. We investigated cHL prognosis in the era of contemporary treatment at different milestones during the follow-up.

PATIENTS AND METHODS

On the basis of a Nordic cohort of 2,582 patients diagnosed at ages 18 to 49 years between 2000 and 2013, 5-year relapse risks and 5-year restricted losses in expectation of lifetime were estimated for all patients and for patients who achieved event-free survival (EFS) for 12 (EFS12), 24 (EFS24), 36 (EFS36) or 60 (EFS60) months. The median follow-up time was 9 years (range, 2.9 to 16.8 years).

RESULTS

The 5-year overall survival was 95% (95% CI, 94% to 96%). The 5-year risk of relapse was 13.4% (95% CI, 12.1% to 14.8%) overall but decreased to 4.2% (95% CI, 3.8% to 4.6%) given that patients reached EFS24. Relapse risk for patients treated with six to eight courses of bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (BEACOPP) was comparable to that of patients treated with six to eight courses of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) despite more adverse risk criteria among patients treated with BEACOPP. Both from diagnosis and if EFS24 was reached, the losses in expectation of lifetime during the following 5 years were small (from diagnosis, 45 days [95% CI, 35 to 54 days] and for patients who reached EFS24, 13 days [95% CI, 7 to 20 days]). In stage-stratified analyses of 5-year restricted loss in expectation of lifetime, patients with stages I to IIA disease had no noteworthy excess risk of death after they reached EFS24, whereas risk remained measurable for patients with stages IIB to IV cHL.

CONCLUSION

Real-world data on young patients with cHL from the Nordic countries show excellent outcomes. The outlook is particularly favorable for patients who reach EFS24, which supports limited relapse-oriented clinical follow-up.

Time to treatment is an independent prognostic factor in aggressive non-Hodgkin lymphomas

In aggressive lymphomas, discrepancies in survival reported from experimental and observational studies may reflect selective non-enrolment of high-risk patients in trials. We examined the association between time from diagnosis to chemotherapy and overall survival in diffuse large B-cell (DLBCL), Burkitt (BL), mantle cell (MCL) and peripheral T-cell lymphoma (PTCL), using National Cancer Data Base records of 130 549 patients treated in 2004-2014. Across the histologies, patients who started chemotherapy within 7 days of diagnosis had more often high International Prognostic Index (IPI) or advanced-stage disease. The discrepancy in 3-year survival between groups treated within 7 or >30 days from diagnosis ranged from 14% in BL to 30% in MCL. After adjusting for the IPI, time to treatment was significantly associated with shorter overall survival. Using the group treated >30 days from diagnosis as reference, patients treated within 7 days had a hazard ratio of 1·38 [95% confidence interval (CI), 1·28-1·48] in DLBCL, 1·42 (95% CI, 1·22-1·66) in BL, 2·23 (95% CI, 1·79-2·78) in MCL and 1·46 (95% CI, 1·18-1·81) in PTCL. Time from diagnosis to treatment may reflect high-risk features uncaptured by standard prognostic assessments. Clinical trials should accommodate patients who need urgent therapy to improve external validity and detect treatment effects in high-risk groups.

Survival benefit of mantle cell lymphoma patients enrolled in clinical trials; a joint study from the LYSA group and French cancer registries

PURPOSE

Mantle cell lymphoma (MCL) is a rare non-Hodgkin's lymphoma entity with a poor prognosis. Therapeutic advances have improved the survival of patients enrolled in clinical trials; however, their impact on patients outside clinical trials remains unclear. In this work, we compared patient outcome inside and outside clinical trials.

METHODS

We identified MCL patients recorded in six French population-based registries between 2008 and 2012 to perform a comparison with patients enrolled in two prospective multicenter MCL clinical trials conducted by the LYSA group during the same period. Variables associated with inclusion in a clinical trial were identified using a logistic regression. Pohar-Perme estimator and Nelson et al. flexible parametric model was used to estimate net survival probabilities and prognosis factors on excess mortality.

RESULTS

A total of 312 registry patients were compared to the 372 patients enrolled in LYSA clinical trials. Patients included in clinical trials were younger (median age 60 vs 74, p < 0.001). Age and Ann Arbor stage IV were independently associated with enrollment [OR = 0.09 (0.06-0.12) and OR = 1.61 (1.11-2.34), respectively]. The 4 year net survival was better in clinical trials [79.9% (75.9-84.7) vs 60.3% (53.6-67.0)]. This result was confirmed in multivariate analysis in patients older than 65 years with a lower excess mortality rate [0.33 (0.17-0.66)].

CONCLUSIONS

MCL included in trials are highly selected patients who are not representative of MCL patients who are encountered in everyday practice. With widened inclusion criteria, clinical trial patients could be more representative of the general population.

Long-term survival in young and middle-aged Hodgkin lymphoma patients in Sweden 1992-2009-trends in cure proportions by clinical characteristics

Trends in Hodgkin lymphoma (HL) survival among patients treated outside of clinical trials provide real-world benchmark estimates of prognosis and help identify patient subgroups for targeted trials. In a Swedish population-based cohort of 1947 HL patients diagnosed in 1992-2009 at ages 18-59 years, we estimated relative survival (RS), cure proportions (CP), and median survival times using flexible parametric cure models. Overall, the CP was 89% (95% CI: 0.87-0.91) and median survival of the uncured was 4.6 years (95% CI: 3.0-6.3). For patients aged 18-50 years diagnosed after the year 2000, CP was high and stable, whereas for patients of 50-59 years, cure was not reached. The survival of relapse-free patients was similar to that of the general population (RS5-year : 0.99; 95% CI: 0.98-0.99, RS15-year : 0.95; 95% CI: 0.92-0.97). The excess mortality of relapsing patients was 19 times (95% CI: 12-31) that of relapse-free patients. Despite modern treatments, patients with adverse prognostic factors (e.g., advanced stage) still had markedly worse outcomes [CP stage: IIIB 0.82 (95% CI: 0.73-0.89); CP stage: IVB 0.72, (95% CI: 0.60-0.81)] and patients with international prognostic score (IPS) ≥3 had 2.7 times higher excess mortality (95% CI: 1.0-7.0, p = 0.04) than patients with IPS <3. High-risk patients selected for 6-8 courses of BEACOPP (bleomycin, etoposide, doxorubicin, cyclofosphamide, vincristine, procarbazine, prednisone)-chemotherapy had a 15-year relative survival of 87%, (95% CI: 0.80-0.92), whereas the corresponding estimate for patients selected for 6-8 courses of ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) was 93% (95% CI: 0.88-0.97). These population-based results indicate limited fatal side-effects in the 15-year perspective with contemporary treatments, while the unmet need of effective relapse treatment remains of concern. BEACOPP-chemotherapy was still not sufficient in high-risk HL patients.

A literature review on the representativeness of randomized controlled trial samples and implications for the external validity of trial results

Randomized controlled trials (RCTs) are conducted under idealized and rigorously controlled conditions that may compromise their external validity. A literature review was conducted of published English language articles that reported the findings of studies assessing external validity by a comparison of the patient sample included in RCTs reporting on pharmaceutical interventions with patients from everyday clinical practice. The review focused on publications in the fields of cardiology, mental health, and oncology. A range of databases were interrogated (MEDLINE; EMBASE; Science Citation Index; Cochrane Methodology Register). Double-abstract review and data extraction were performed as per protocol specifications. Out of 5,456 de-duplicated abstracts, 52 studies met the inclusion criteria (cardiology, n = 20; mental health, n = 17; oncology, n = 15). Studies either performed an analysis of the baseline characteristics (demographic, socioeconomic, and clinical parameters) of RCT-enrolled patients compared with a real-world population, or assessed the proportion of real-world patients who would have been eligible for RCT inclusion following the application of RCT inclusion/exclusion criteria. Many of the included studies concluded that RCT samples are highly selected and have a lower risk profile than real-world populations, with the frequent exclusion of elderly patients and patients with co-morbidities. Calculation of ineligibility rates in individual studies showed that a high proportion of the general disease population was often excluded from trials. The majority of studies (n = 37 [71.2 %]) explicitly concluded that RCT samples were not broadly representative of real-world patients and that this may limit the external validity of the RCT. Authors made a number of recommendations to improve external validity. Findings from this review indicate that there is a need to improve the external validity of RCTs such that physicians treating patients in real-world settings have the appropriate evidence on which to base their clinical decisions. This goal could be achieved by trial design modification to include a more representative patient sample and by supplementing RCT evidence with data generated from observational studies. In general, a thoughtful approach to clinical evidence generation is required in which the trade-offs between internal and external validity are considered in a holistic and balanced manner.

Validation of clinical prognostic indices for diffuse large B-cell lymphoma in the National Cancer Data Base

BACKGROUND

Accurate risk stratification is necessary for epidemiologic and outcomes research in diffuse large B-cell lymphoma (DLBCL). We evaluated performance characteristics of the clinically derived International Prognostic Index (IPI) and revised IPI (R-IPI) with a regression model-based score using the National Cancer Data Base.

METHODS

We studied DLBCL patients diagnosed in 2004-2011, divided into derivation and validation cohorts. The model-based score was calculated from a Cox model incorporating variables routinely recorded by cancer registries. Calibration and discrimination of the indices with regard to overall survival were evaluated in the validation cohort.

RESULTS

The IPI was recorded in 19,511 of 119,942 patients, of whom 79 % received chemotherapy. Both clinical indices provided good survival discrimination (5-year estimate range 33-74 % for the IPI, and 41-87 % for the R-IPI), but explained only 16 % of variation in survival. Survival predictions among chemotherapy-treated patients were similar to estimates from published clinical cohorts. The model-based score had significantly better discrimination characteristics (5-year survival estimate range 22-87 %) and explained 23 % of variation in survival.

CONCLUSIONS

We validated the IPI and R-IPI as recorded by cancer registries to provide robust risk stratification in the general population with DLBCL, but a prognostic model using raw registry data provides superior performance. Explicit recording of prognostic factors is preferable to abstracting coarsened clinical indices for the purpose of population-based epidemiologic research. Considering low variation of survival explained by the standard clinical variables, incorporating molecular markers into registry data is necessary to improve risk stratification.

The effect of specialized cancer treatment centers on treatment efficacy in Hodgkin's lymphoma

BACKGROUND

The presumed benefits of centralization and minimum case numbers often guide health-policy decisions, but these benefits remain inadequately documented, particularly in oncology. In this study, we aim to measure the effect of the type of treatment center and/or the number of patients treated in it on the outcome of patients with Hodgkin's lymphoma.

METHODS

From 1988 to 2002, 8121 patients with newly diagnosed Hodgkin's lymphoma were treated in Germany in multicenter randomized and controlled trials (RCTs) of the German Hodgkin Study Group (GHSG). Center-related effects on progression-free survival (PFS) were assessed univariately with Kaplan-Meier plots and log-rank tests, as well as with a multivariate Cox regression model.

RESULTS

The 500 participating centers in Germany included 52 university hospitals, 304 non-university hospitals, and 144 medical practices specializing in hematology and oncology. No significant differences in PFS were found between patients from centers with high or low case numbers (5-year-PFS: 78.7% and 78.6% for centers with fewer than 50 and more than 50 patients, respectively) or from different types of centers [5-year-PFS: university hospital, 77.7%; non-university hospital, 79.4%; practice, 79.8%]. Even after statistical controls for the effect of other known and unknown prognostic factors and validation in further datasets, no center effects were found.

CONCLUSIONS

The type of center and the minimum number of patients treated in a center have no impact on the treatment outcome of patients with Hodgkin's lymphoma in Germany. In all GHSG centers, regardless of type, the quality standards for successful treatment are apparently met on all levels of patient care.

Challenge of evidence in individualized medicine

Tension between standardization and individualization has always been a characteristic of medical activity. However, whether it is better that interventions should be based on guideline recommendations on the basis of large multicenter trials, or on a genetic biomarker in individualized medicine, can be the subject of debate. With the aid of stratification, evidence-based medicine and individualized medicine could be linked. Networks of large research projects, involving clinical, biomedical, molecular and other expertises are necessary for evidence-based evaluation, standardization, and clinical validation of new methods and algorithms.