Long-term survival and loss in expectancy of life in a population-based cohort of 7114 patients with diffuse large B-cell lymphoma

Genetic and transcriptomic analyses of diffuse large B-cell lymphoma patients with poor outcomes within two years of diagnosis

Despite the improvements in clinical outcomes for DLBCL, a significant proportion of patients still face challenges with refractory/relapsed (R/R) disease after receiving first-line R-CHOP treatment. To further elucidate the underlying mechanism of R/R disease and to develop methods for identifying patients at risk of early disease progression, we integrated clinical, genetic and transcriptomic data derived from 2805 R-CHOP-treated patients from seven independent cohorts. Among these, 887 patients exhibited R/R disease within two years (poor outcome), and 1918 patients remained in remission at two years (good outcome). Our analysis identified four preferentially mutated genes (TP53, MYD88, SPEN, MYC) in the untreated (diagnostic) tumor samples from patients with poor outcomes. Furthermore, transcriptomic analysis revealed a distinct gene expression pattern linked to poor outcomes, affecting pathways involved in cell adhesion/migration, T-cell activation/regulation, PI3K, and NF-κB signaling. Moreover, we developed and validated a 24-gene expression score as an independent prognostic predictor for treatment outcomes. This score also demonstrated efficacy in further stratifying high-risk patients when integrated with existing genetic or cell-of-origin subtypes, including the unclassified cases in these models. Finally, based on these findings, we developed an online analysis tool ( https://lymphprog.serve.scilifelab.se/app/lymphprog ) that can be used for prognostic prediction for DLBCL patients.

Increase in the Life Expectancy of Patients with Cancer in the United States

BACKGROUND

Cancer is becoming more of a chronic disease due to improvements in treatment and early detection for multiple cancer sites. To gain insight on increased life expectancy due to these improvements, we quantified trends in the loss in expectation of life (LEL) due to a cancer diagnosis for six cancer sites from 1975 through 2018.

METHODS

We focused on patients diagnosed with female breast cancer, chronic myeloid leukemia (CML), colon and rectum cancer, diffuse large B-cell lymphoma (DLBCL), lung cancer, or melanoma between 1975 and 2018 from nine Surveillance, Epidemiology, and End Results cancer registries. Life expectancies for patients with cancer ages 50+ were modeled using flexible parametric survival models. LEL was calculated as the difference between general population life expectancy and life expectancy for patients with cancer.

RESULTS

Over 2 million patients were diagnosed with one of the six cancers between 1975 and 2018. Large increases in life expectancy were observed between 1990 and 2010 for female breast, DLBCL, and CML. Patients with colon and rectum cancer and melanoma had more gradual improvements in life expectancy. Lung cancer LEL only began decreasing after 2005. Increases in life expectancy corresponded with decreases in LEL for patients with cancer.

CONCLUSIONS

The reported gains in life expectancy largely correspond to progress in the screening, management, and treatment of these six cancers since 1975.

IMPACT

LEL provides an important public health perspective on how improvements in treatment and early detection and their impacts on survival translate into changes in cancer patients' life expectancy.

Smedby K, Eloranta S. Patient trajectories after diagnosis of diffuse large B-cell lymphoma-a multistate modelling approach to estimate the chance of lasting remission

BACKGROUND

Achieving lasting remission for at least 2 years is a good indicator for favourable prognosis long term after Diffuse large B-cell lymphoma (DLBCL). The aim of this study was to provide real-world probabilities, useful in risk communication and clinical decision-making, of the chance for lasting remissions by clinical characteristics.

METHODS

DLBCL patients in remission after primary treatment recorded in the Swedish Lymphoma register 2007-2014 (n = 2941) were followed for relapse and death using multistate models to study patient trajectories. Flexible parametric models were used to estimate transition rates.

RESULTS

At 2 years, 80.7% (95% CI: 79.0-82.2) of the patients were predicted to remain in remission and 13.2% (95% CI: 11.9-14.6) to have relapsed. The relapse risk peaked at 7 months, and the annual decline of patients in remission stabilised after 2 years. The majority of patients in the second remission transitioned into a new relapse. The probability of a lasting remission was reduced by 20.4% units for patients with IPI 4-5 compared to patients with IPI 0-1, and time in remission was shortened by 3.5 months.

CONCLUSION

The long-term prognosis was overall favourable with 80% achieving durable first remissions. However, prognosis varied by clinical subgroups and relapsing patients seldom achieved durable second remissions.

Assessing lead time bias due to mammography screening on estimates of loss in life expectancy

BACKGROUND

An increasingly popular measure for summarising cancer prognosis is the loss in life expectancy (LLE), i.e. the reduction in life expectancy following a cancer diagnosis. The proportion of life lost (PLL) can also be derived, improving comparability across age groups as LLE is highly age-dependent. LLE and PLL are often used to assess the impact of cancer over the remaining lifespan and across groups (e.g. socioeconomic groups). However, in the presence of screening, it is unclear whether part of the differences across population groups could be attributed to lead time bias. Lead time is the extra time added due to early diagnosis, that is, the time from tumour detection through screening to the time that cancer would have been diagnosed symptomatically. It leads to artificially inflated survival estimates even when there are no real survival improvements.

METHODS

In this paper, we used a simulation-based approach to assess the impact of lead time due to mammography screening on the estimation of LLE and PLL in breast cancer patients. A natural history model developed in a Swedish setting was used to simulate the growth of breast cancer tumours and age at symptomatic detection. Then, a screening programme similar to current guidelines in Sweden was imposed, with individuals aged 40-74 invited to participate every second year; different scenarios were considered for screening sensitivity and attendance. To isolate the lead time bias of screening, we assumed that screening does not affect the actual time of death. Finally, estimates of LLE and PLL were obtained in the absence and presence of screening, and their difference was used to derive the lead time bias.

RESULTS

The largest absolute bias for LLE was 0.61 years for a high screening sensitivity scenario and assuming perfect screening attendance. The absolute bias was reduced to 0.46 years when the perfect attendance assumption was relaxed to allow for imperfect attendance across screening visits. Bias was also present for the PLL estimates.

CONCLUSIONS

The results of the analysis suggested that lead time bias influences LLE and PLL metrics, thus requiring special consideration when interpreting comparisons across calendar time or population groups.

Myocardial infarction in diffuse large B-cell lymphoma patients - a population-based matched cohort study

BACKGROUND

The outcome for diffuse large B-cell lymphoma (DLBCL) patients has improved with the immunochemotherapy combination R-CHOP. An increased rate of heart failure is well documented following this treatment, whereas incidence and outcome of other cardiac complications, for example myocardial infarction, are less well known.

METHOD

We identified 3548 curatively treated DLBCL patients in Sweden diagnosed between 2007 and 2014, and 35474 matched lymphoma-free general population comparators. The incidence, characteristics and outcome of acute myocardial infarctions (AMIs) were assessed using population-based registers up to 11 years after diagnosis. The rate of AMI was estimated using flexible parametric models.

RESULTS

Overall, a 33% excess rate of AMI was observed among DLBCL patients compared with the general population (HR: 1.33, 95% CI: 1.14-1.55). The excess rate was highest during the first year after diagnosis and diminished after 2 years. High age, male sex and comorbidity were the strongest risk factors for AMI. Older patients (>70 years) with mild comorbidities (i.e. hypertension or diabetes) had a 61% higher AMI rate than comparators (HR: 1.61, 95% CI: 1.10-2.35), whereas the corresponding excess rate was 28% for patients with severe comorbidities (HR: 1.28, 95% CI: 1.01-1.64). Among younger patients (≤70), a short-term excess rate of AMI was limited to those with severe comorbidities. There was no difference in AMI characteristics, pharmacological treatment or 30-day survival among patients and comparators.

CONCLUSION

DLBCL patients have an increased risk of AMI, especially during the first 2 years, which calls for improved cardiac monitoring guided by age and comorbidities. Importantly, DLBCL was not associated with differential AMI management or survival.

Age is the most important predictor of survival in diffuse large B-cell lymphoma patients achieving event-free survival at 24 months: a Swedish population-based study

Routine follow‐up for diffuse large B‐cell lymphoma have been shortened to 2 years when event‐free survival at 24 months (EFS24) emerged as a new milestone. In the present study, we aimed to determine whether the achievement of this milestone affected overall survival (OS). We compared OS to that of an age‐ and sex‐matched population, analysed other factors governing OS, and reviewed the causes of death. Data were collected from the Swedish Cancer Registry and from individual patient’s records. We included 1169 adult patients from five counties between the years 2001 and 2014. The median (range) age was 64·6 (18–91) years, 56·6% were men and the median follow‐up was 82·3 months. For early stages, the achievement of EFS12 did not improve OS. More than two‐thirds of the patients (n = 837, 71·6%) achieved EFS24, of which 190 (22·7%) died during follow‐up. Lymphoma (20%), cardiovascular disease (22·4%) and malignancies (16%) contributed to causes of death. Patients aged <60 years had an OS that matched the standard population. In multivariate analysis, only age >60 years significantly affected OS after EFS24 compared with the standard population. We concluded that follow‐up beyond EFS24 should be considered for patients aged >60 years.

Cancer cure for 32 cancer types: results from the EUROCARE-5 study

BACKGROUND

Few studies have estimated the probability of being cured for cancer patients. This study aims to estimate population-based indicators of cancer cure in Europe by type, sex, age and period.

METHODS

7.2 million cancer patients (42 population-based cancer registries in 17 European countries) diagnosed at ages 15-74 years in 1990-2007 with follow-up to 2008 were selected from the EUROCARE-5 dataset. Mixture-cure models were used to estimate: (i) life expectancy of fatal cases (LEF); (ii) cure fraction (CF) as proportion of patients with same death rates as the general population; (iii) time to cure (TTC) as time to reach 5-year conditional relative survival (CRS) >95%.

RESULTS

LEF ranged from 10 years for chronic lymphocytic leukaemia patients to <6 months for those with liver, pancreas, brain, gallbladder and lung cancers. It was 7.7 years for patients with prostate cancer at age 65-74 years and >5 years for women with breast cancer. The CF was 94% for testis, 87% for thyroid cancer in women and 70% in men, 86% for skin melanoma in women and 76% in men, 66% for breast, 63% for prostate and <10% for liver, lung and pancreatic cancers. TTC was <5 years for testis and thyroid cancer patients diagnosed below age 55 years, and <10 years for stomach, colorectal, corpus uteri and melanoma patients of all ages. For breast and prostate cancers, a small excess (CRS < 95%) remained for at least 15 years.

CONCLUSIONS

Estimates from this analysis should help to reduce unneeded medicalization and costs. They represent an opportunity to improve patients' quality of life.

Detecting deviations from the efficacy and safety results of single-arm trials using real-world data: The case of a CAR-T cell therapy in B-cell lymphoma

PURPOSE

Personalized therapies are leading to an increasing number of marketing authorizations based on single-arm trials, which increases the demand for better post-authorization monitoring strategies. The aim of the present study was to estimate the power over time as data accrue in population-based registries for detecting deviations from the expected efficacy/safety of chimeric antigen receptor T cell (CAR-T) therapy approved for relapsed/refractory large B-cell lymphoma (RR-LBCL).

METHODS

The number of real-world RR-LBCL patients was projected over time in a general population of 5, 15, and 25 million citizens using lymphoma registry data. For each scenario, we computed the power over time for detecting significant deviations in efficacy (1-year overall survival [1yOS]) when comparing to historical controls (SCHOLAR-1 study; 1yOS, 28%) and RR-LBCL patients treated with CAR-T cell therapy in a single-arm trial (ZUMA-1; 1yOS, 59%) as well as deviations in selected adverse events (grade ≥3 aphasia) from the ZUMA-1 trial. We assumed a 10% absolute deviation in 1yOS (efficacy) and a relative increase of 50% in grade ≥3 aphasia (safety).

RESULTS

Assuming a general population of 5, 15, and 25 million, the accrual time needed to achieve 80% power for detecting a significant increase over the 1yOS reported in SCHOLAR-1 was 9, 4, and 3 years, respectively, while 80% power for detecting a significant decrease in 1yOS compared to ZUMA-1 required 10.5, 4.5, and 3 years of data accrual, respectively. However, corresponding estimates for aphasia were >20, 8, and 5 years, respectively.

CONCLUSIONS

Projections of the statistical power for detecting important deviations in efficacy/safety from that reported in pivotal clinical trials(s) provide critical information about the expected performance of post-authorization monitoring programs.

Cancer survival statistics for patients and healthcare professionals - a tutorial of real-world data analysis

Monitoring survival of cancer patients using data collected by population-based cancer registries is an important component of cancer control. In this setting, patient survival is often summarized using net survival, that is survival from cancer if there were no other possible causes of death. Although net survival is the gold standard for comparing survival between groups or over time, it is less relevant for understanding the anticipated real-world prognosis of patients. In this review, we explain statistical concepts targeted towards patients, clinicians and healthcare professionals that summarize cancer patient survival under the assumption that other causes of death exist. Specifically, we explain the appropriate use, interpretation and assumptions behind statistical methods for competing risks, loss in life expectancy due to cancer and conditional survival. These concepts are relevant when producing statistics for risk communication between physicians and patients, planning for use of healthcare resources, or other applications when consideration of both cancer outcomes and the competing risks of death is required. To reinforce the concepts, we use Swedish population-based data of patients diagnosed with cancer of the breast, prostate, colon and chronic myeloid leukaemia. We conclude that when choosing between summary measures of survival it is critical to characterize the purpose of the study and to determine the nature of the hypothesis under investigation. The choice of terminology and style of reporting should be carefully adapted to the target audience and may range from summaries for specialist readers of scientific publications to interactive online tools aimed towards lay persons.

Primary Diffuse Large B-Cell Lymphoma of the Female Urethra: A Case Report and Review of the Literature

Primary urethral non-Hodgkin's lymphoma (NHL) is uncommon. This case study reports the case of a 52-year-old woman with a light red mass at the urethral orifice. Her clinical manifestations included frequent urination, urgency, dysuria, and occasionally blood in urine. The tumor was surgically removed, and the pathological and immunohistochemistry examination confirmed the presence of a diffuse large B-cell lymphoma (DLBCL). Examination using positron emission tomography/computed tomography (PET/CT) revealed multiple hypermetabolic lymph nodes next to the external iliac vessels and bilateral inguinal regions, and focal hypermetabolic lesions in the vulvar nodules (consistent with the changes caused by lymphoma infiltration). Eight cycles of chemotherapy with rituximab, cyclophosphamide, doxorubicin, vincristine, and dexamethasone (R-CHOP) were prescribed after surgery. Re-examination using PET/CT showed lack of hypermetabolic tumor recurrence signs, and the presence of multiple slightly large lymph nodes in the lateral iliac vessels and inguinal regions, but without significant lymph node metabolism increases. To date, only fifteen cases of primary diffuse large B-cell lymphoma of the urethra (including this one) have been reported in the literature. Therefore, we reviewed the etiology, clinical manifestations, diagnosis, differential diagnosis, treatment, and prognosis of DLBCL based on the existing literature to help characterize this rare disease.

Clinical characteristics and outcomes among 2347 patients aged ≥85 years with major lymphoma subtypes: a Nordic Lymphoma Group study

There is a lack of data regarding treatment and prognosis for the growing group of oldest old patients with lymphoma. Therefore, we studied 2347 patients aged ≥85 years from the Danish and Swedish lymphoma registers 2000–2016 (Denmark) and 2007–2013 (Sweden). Outcome was assessed using relative survival (RS). The 2‐year RS overall for patients with aggressive lymphomas was 38% [95% confidence interval (CI) 35–42%], of whom 845 (66%) patients received active treatment (chemotherapy, radiotherapy, immunotherapy, other). For aggressive lymphomas, not receiving active treatment was associated with an inferior 2‐year RS of 12% (95% CI 9–17%) compared to 49% (95% CI 45–53%) for patients who received active treatment (excess mortality rate ratio 2·84, 95% CI 2·3–3·5; P < 0·0001). For patients with indolent lymphoma, the 2‐year RS was 77% (95% CI 72–82%). Here, 383 (46%) patients received active treatment at diagnosis, but did not have better 2‐year RS (75%, 95% CI 67–81%) compared to those who did not receive active treatment (83%, 95% CI 74–89%). We conclude that outcomes for the oldest old patients with lymphoma are encouraging for several subtypes and that active treatment is associated with improved outcome amongst the oldest old patients with aggressive lymphomas, indicating that age itself should not be a contraindication to treatment.

Transcriptome profiling reveals an integrated mRNA-lncRNA signature with predictive value for long-term survival in diffuse large B-cell lymphoma

For patients with diffuse large B-cell lymphoma (DLBCL), survival at 24 months is a milestone for long-term survival. The purpose of this study was to develop a multigene risk score (MGRS) to refine the International Prognostic Index (IPI) model to identify patients with DLBCL at high risk of death within 24 months. Using a robust statistical strategy, we built a MGRS incorporating nine mRNAs and two lncRNAs. Stratification and multivariable Cox regression analysis confirmed the MGRS as an independent risk factor. A nomogram based on IPI+MGRS model was constructed and its calibration plot showed close agreement between predicted 2-year survival rate and observed rate. The 2-year AUC was bigger with the IPI+MGRS model (ΔAUC=0.162; 95%CI 0.1295–0.1903) than with the IPI model, and the IPI+MGRS model more accurately predicted the prognostic risk of DLBCL. The 2-year survival decision curve revealed the IPI+MGRS model was more useful clinically than the IPI model. Functional enrichment analysis showed that the MGRS correlated with cell cycle, DNA replication and repair. The results were validated using an independent external dataset. In conclusion, we successfully developed an integrated mRNA–lncRNA signature to refine the IPI model for predicting long-term survival of patients with DLBCL.

Increased Risk of Hip Fracture in Patients with Lymphoma, a Swedish Population Study of 37,236 Lymphoma Patients

Increased bone loss has been noted in lymphoma patients; however, the incidence of hip fracture is not known. The aim of our study was to explore the risk for hip fracture in patients with lymphoma compared with the entire Swedish population. The risk of hip fracture was determined in a retrospective population cohort study of adult Swedish lymphoma patients (n = 37,236), diagnosed 1995-2015 and compared with the entire Swedish population during the same period. The incidence of hip fracture in lymphoma patients was higher in women than in men, increased by age, and decreased by calendar year as also demonstrated in the total population. 2.2% of the men and 4.7% of women with lymphoma sustained a hip fracture. For the total group of females, the hazard ratio (HR) was 1.19 (95% CI 1.11-1.28) and for men, the hazard ratio was 1.06 (95% CI 0.97-1.17) compared with the Swedish population. The HR for hip fracture (2016) was 2.80 (95% CI 1.20-6.53), 2.04 (95% CI 1.30-3.20), 1.56 (95% CI 1.21-2.01), 1.08 (95% CI 0.89-1.30), and 1.07 (95% CI 0.92-1.25) in females aged 40, 50, 60, 70, and 80 years, respectively. Corresponding figures for men were not significant in 2016. Unmarried men with lymphoma had a two times higher risk for hip fracture (HR 2.02 95% CI 1.63-2.50) compared with married men. Patients with lymphoma had an increased risk of hip fracture, especially younger women and unmarried men. The incidence of hip fracture is decreased by calendar year in the lymphoma patients and the entire Swedish population.

A real-world study of first-line therapy in 280 consecutive Swedish patients ≥80 years with newly diagnosed diffuse large B-cell lymphoma: very elderly (≥85 years) do well on curative intended therapy

This real-world study investigated outcome of first-line treatment in elderly patients with diffuse large B-cell lymphoma (DLBCL). All (n = 292) new DLBCL patients ≥80 years diagnosed in the Stockholm region from 2000-2015 were included. Median age was 85 years, most had good performance status and low comorbidity score. CHOP (cyclophosphamide/doxorubicin/vincristine/prednisone) was used in 60/230 patients, R-CHOP in 170/230. Only 12% of patients aged 80-84 years and 6% of ≥85 years received full-dose chemotherapy. Infections (≥ grade III) occurred in 49% and 37% in the two age groups, respectively. Addition of rituximab resulted in a similar and significant improvement in both age subsets regarding complete remission, progression-free (PFS) and overall survival (OS). Rituximab, performance status and stage, but not age, were significantly associated with PFS and OS by multivariate analysis. Strictly consecutive patients ≥85 years from a well-defined geographical region responded to and tolerated R-CHOP equally well as patients aged 80-84 years.

Survival of very elderly patients with diffuse large B-cell lymphoma according to treatment intensity in the immunochemotherapy era: a Swedish Lymphoma Register study

Diffuse large B-cell lymphoma (DLBCL) incidence rises with increasing age. Rituximab-anthracycline-based regimens offer a potential cure but also risks of adverse events, especially in the elderly. Using Swedish registers, we conducted a nationwide, population-based study of DLBCL in the very elderly. We obtained information on clinical characteristics, residence, comorbidity, therapy and survival for the 1194 patients aged ≥80 years diagnosed in Sweden 2007-2014. To address selection bias, we also investigated treatment differences between Sweden's Healthcare Regions and whether there were survival differences between the Regions. The 2-year overall and relative survivals were better in patients aged ≥80 years given treatment with curative intent (54%; 64%) than low-intensity (26%; 33%), or palliative treatment (6%; 7%). The fraction of patients treated with curative intent varied between the Healthcare Regions (45-76%). Survival was significantly inferior in Regions with few patients treated with curative intent (multivariable hazard ratio 1.3, 95% confidence interval 1.1-1.6). When treatment intensity and Regions competed, Regions were no longer independent, suggesting that Regional survival differences are due to therapeutic differences. Furthermore, we found that the age-adjusted International Prognostic Index was independently associated with survival. We conclude that patients aged ≥80 years with DLBCL appear to benefit from rituximab-anthracycline-based treatment given with curative intent.

Trends in the prevalence, incidence and survival of non-Hodgkin lymphoma subtypes during the 21st century - a Swedish lymphoma register study

Non-Hodgkin lymphoma (NHL) prognosis has improved in recent years, yet the number of patients living with the diagnosis, i.e. the prevalence, has seldom been reported. The prevalence provides a measure of the burden of disease, useful for healthcare planning and to optimise resource allocation. We provide a systematic presentation of temporal trends in absolute numbers of prevalent patients by NHL subtypes, linking them to trends in incidence, survival and mortality. Patients diagnosed 2000-2016 were identified in the national Swedish lymphoma register. Incidence and mortality rates, relative survival and prevalence were estimated for NHL overall and for major clinical and morphological subtypes. Poisson regression was used to test for temporal trends. Increasing incidence and improved survival have led to a 47% increase in the five-year prevalence of NHL overall in 2016 compared to 2004. An increasing prevalence was observed for all investigated subtypes during the study period, but most notably for diffuse large B cell lymphomas among aggressive subtypes (66%), and marginal zone lymphomas among indolent subtypes (135%). This dramatic increase in NHL prevalence underscores the need to develop and evaluate alternative follow-up schemes to use resources efficiently and still ensure optimal care of lymphoma survivors.

Characteristics, management and outcome of DLBCL patients, presenting with simultaneous systemic and CNS disease at diagnosis: A retrospective multicenter study

The incidence of systemic diffuse large B cell lymphoma (DLBCL) concurrently involving the central nervous system (CNS) at diagnosis, is very low and data regarding the clinical course of these patients are scarce. We investigated characteristics, efficacy of treatment regimens including consolidative autologous stem cell transplantation and outcome of patients presenting with concomitant systemic and CNS DLBCL. The records of 44 patients, diagnosed between 2004 and 2017, who fulfilled the inclusion criteria, were retrospectively reviewed. CNS involvement was diagnosed as solely parenchymal in 41%, solely leptomeningeal in 43%, and paranchymal with leptomeningeal in 11% of the patients. Induction regimens were anthracycline-based combined with high-dose methotrexate (HD-MTX) in 80% (n = 35) of patients, anthracycline-based combined with intrathecal MTX in 3, cytarabine-based (without antracyclines) in 2, HD-MTX in 1 and palliative in three. Five of 41 patients treated with chemotherapy died of treatment-related toxicity, all due to infections. Nineteen patients had consolidative autologous transplantation. Overall response rate following induction was 80% (complete responses 66% and partial responses 15%). All relapses (n = 11) occurred within less than 2 years. Within a median follow-up of 26.8 months, 3-years projected overall survival (OS) and progression free survival rates for the entire cohort were 56% ± 8.3 and 42% ± 8.9, respectively. In multivariate analysis, RCHOP-HD MTX-based induction [HR = 0.228, (0.054-0.964)], administration of 3.5 g/m² MTX [HR = 0.735 (0.620-0.871)], and attaining CR following induction [HR = 0.185, (0.051-0.667)] predicted longer OS. RCHOP-HD MTX can provide prolonged remissions in DLBCL patients presenting with concomitant systemic and CNS involvement whereas role of autograft remains uncertain.

EZH2/Bcl-2 Coexpression Predicts Worse Survival in Diffuse Large B-cell Lymphomas and Demonstrates Poor Efficacy to Rituximab in Localized Lesions

Enhancer of zeste homolog 2 (EZH2) and Bcl-2 gene rearrangement or protein upregulation played pivotal roles in the carcinogenesis of various malignancies including lymphomas. However, EZH2/Bcl-2 expression pattern and its clinicopathologic/prognostic significance in diffuse large B-cell lymphoma (DLBCL) remain unclear. To identify the association among EZH2, Bcl-2, clinicopathologic parametres in DLBCL, 2 DLBCL patient sets (test cohort, n=85; validation cohort n=51) and DLBCL cell lines were studied by tumor tissue microarray (TMA), immunohistochemistry and western blot. The optimal cut-off of EZH2 was determined by X-tile program from test cohort, as was verified in validation cohort. The prognostic significance was determined via Kaplan-Meier survival estimates and log-rank tests. Consequently, EZH2 and Bcl-2 expression were both enhanced and positively correlated with each other (𝑃=0.001) in both DLBCL patients and cell lines. EZH2/Bcl-2 coexpression was associated with poor overall survival (OS) and progression-free survival (PFS) in all DLBCL patients (all P<0.05). Univariate analyses revealed that EZH2/Bcl-2 coexpression correlated to worse objective response rate (ORR), shorter OS and PFS in DLBCL patients treated with RCHOP while multivariate analysis indicated that only elevated LDH level (P=0.001) and presence of B symtom (P=0.008) rather than EZH2/Bcl-2 coexpression were associated with worse OS. No survival benefit from rituximab regimen had been demonstrated in the early-staged DLBCL patients with EZH2/Bcl-2 coexpression. While in the subgroup of III-IV stage, RCHOP regimen showed obvious better OS and PFS than CHOP (P=0.039 and 0.005). In conclusion, EZH2/Bcl-2 coexpression defines unrecognized subgroup of DLBCL patients with distinct epigenetic phenotype and worse outcome.