|
|
|||||||
Malignant Lymphomas |
From Dipartimento di Oncologia ed Ematologia, Università di Modena e Reggio Emilia, Modena (MF, SL, CM, LM, MoB, SP); Dipartimento di Biotecnologie Cellulari ed Ematologia, Università "La Sapienza", II Facoltà di Medicina e Chirurgia, Roma (CG, SB); Cattedra di Anatomia Patologica, Dipartimento di Medicina, Chirurgia e Odontoiatria, Università degli Studi di Milano, A. O. S. Paolo e Fondazione Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena di Milano (UG); Dipartimento Integrato Servizi Diagnostici e di Laboratorio, Università di Modena e Reggio Emilia, Modena (AM); Unità Operativa di Ematologia, A.O. S. Maria Nuova, Reggio Emilia (FM); Divisione di Ematologia, Azienda Ospedaliera "Bianchi-Melacrino-Morelli", Reggio Calabria (CS); Dipartimento di Oncologia ed Ematologia, Ospedale Guglielmo da Saliceto, Piacenza (AL); Medicina Interna, Oncologia Medica, Università di Pavia, IRCCS Policlinico S. Matteo, Pavia (PGG); Unità Malattie Linfoproliferative, Dipartimento di Ematologia, Centro G. Marcora, Ospedale Maggiore, IRCCS, Milano (LB); U. O. Oncologia Medica I, IRCCS, Fondazione Salvatore Maugeri, Pavia (VF); Divisione di Ematologia, Azienda Ospedaliera Papardo, Messina (MaB)
Correspondence: Massimo Federico, MD, Dipartimento di Oncologia ed Ematologia, Centro Oncologico Modenese, Università di Modena e Reggio Emilia, Policlinico, Via del Pozzo 71, 41100 Modena, Italy. E-mail: federico{at}unimore.it
| ABSTRACT |
|---|
|
|
|---|
Design and Methods: The prognostic role of ß2M was evaluated in 236 patients with FL identified from the databases of the Gruppo Italiano per lo Studio dei Linfomi (GISL) and treated with anthracycline-based regimens from 1993 to 2003.
Results: Elevated serum ß2M levels were found in 82 patients (35%). According to multivariate logistic regression analysis, elevated ß2M levels were associated with elevated lactate dehydrogenase (LDH) (p=0.021), age (p=0.029), and number of involved nodal areas (p<0.001). The percentage of elevated ß2M levels increased progressively with increasing FLIPI scores (17%, 38%, and 63% in the low-, intermediate-, and high-risk groups, respectively). Five-year OS was 61% (95% CI, 47–73%) and 89% (95% CI, 82–93%) for patients with elevated vs normal ß2M levels respectively (p<0.001). Cox regression analysis showed that ß2M level had an independent and stable prognostic value (HR=3.0; 95%CI, 1.6–5.7). In a multivariate analysis the impact of ß2M level on survival was independent of FLIPI score, with a HR of 2.94 (95% CI, 1.54–5.62).
Interpretation and Conclusions: Our results demonstrate that in patients treated in the pre-rituximabera, ß2M level was an independent prognostic marker in addition to FLIPI score. We thus suggest that ß2M be routinely assessed and tested in future prognostic studies of FL patients treated with combination chemotherapy and anti-CD20 agents.
Key words: ß2 microglobulin, follicular lymphoma, GISL, prognosis, survival.
Follicular lymphoma (FL) is one of the most frequent and well characterized subtypes of malignant lympophoma in Western countries and accounts for
10–15% of all malignant lymphomas in adults.1 The disease is usually characterized by an indolent clinical course, impressive response to initial therapy, frequent relapses, and response to salvage therapy of shorter duration. Despite continuous efforts to develop effective therapies for FL, population-based studies have shown only modest improvements in long-term survival over the last 30 years.2 As a result, the appropriate initial therapy for FL patients remains a matter of debate. Several treatment options are available, ranging from no initial treatment (i.e., watchful waiting), to high-dose therapy, requiring hematopoietic stem cell support.3 With such a range of options, it is generally agreed that initial treatment should be chosen according to the risk of disease progression in individual patients.
To date, several attempts have been made to better define the prognosis of patients with FL. A predictive model of survival in FL patients was first proposed by the Italian Lymphoma Intergroup (ILI).4 The ILI prognostic index is based on six factors: age, gender, B-symptoms, number of extranodal (EN) sites of disease, erythrocyte sedimentation rate (ESR), and serum lactate dehydrogenase (LDH) levels. More recently, the Follicular Lymphoma Prognostic Factor Project developed the Follicular Lymphoma International Prognostic Index (FLIPI) based on age, Ann Arbor stage, hemoglobin (Hb) level, number of nodal areas involved and LDH levels.5 The ILI and FLIPI indices define three risk categories associated with different survival rates. However, although the indices have demonstrated clinical relevance, they suffer from the limitation of their retrospective nature and share potential biases.6 For instance, though significantly associated with outcome at univariate analysis, it was decided not to include serum ß2 microglobulin (ß2M) in the test sample of the FLIPI because of the very high proportion of patients with missing data.
ß2M is a low molecular weight, single polypeptide chain that is considered the light-chain molecule of the major histocompatibility complex class I antigens. ß2M is found on the membrane surface of almost all nucleated cells. It is particularly plentiful on the surface of white blood cells, and white blood cell membrane turnover is the principal source of serum ß2M.7,8 Increased levels of ß2M have been found to be of prognostic relevance in a wide variety of malignancies, including multiple myeloma,9 chronic lymphocytic leukemia,10 Hodgkins lymphoma,11 and aggressive and indolent lymphomas in general.12,13
Here we present the results of a study on the prognostic value of serum ß2M levels in FL patients who were treated by the Gruppo Italiano per lo Studio dei Linfomi (GISL) in prospective clinical trials for 10 years prior to the advent of anti-CD20 therapy. We analyzed the effects of ß2M levels on survival and evaluated the additional prognostic value of ß2M levels in FLIPI-identified risk groups.
| Design and Methods |
|---|
|
|
|---|
The extent of disease was coded according to the Ann Arbor staging system and assessed by clinical examination, chest and abdomen computed tomography scan, and bone marrow trephine biopsy. Response to treatment was determined 1 month after the end of induction therapy with the examinations necessary to verify the absence of abnormal findings at diagnosis. All evaluations of stage and response to treatment were based on data recorded by GISL investigators. Response criteria for non-Hodgkins lymphoma proposed by the International Workshop were applied.14 Unconfirmed complete response was combined with complete response (CR) for the purpose of the present analysis.
Statistical analysis
Fishers exact test was used to evaluate differences between categorized distributed variables, whereas independent factors related to ß2M levels were assessed by logistic regression analysis. Survival was calculated from the date of diagnosis using the Kaplan-Meier method. The log-rank test was used to compare subgroups in the univariate analysis of survival. Multivariate analysis of factors related to survival was performed using the Coxs proportional hazards regression method considering variables that were statistically significant according to the univariate analysis. The proportional hazards assumption was checked by the Grambsch-Therneau method. p values <0.05 were considered statistically significant. The coefficient stability of the Cox proportional hazards regression, obtained by adjusting ß2M levels by variables with p<0.10 in the univariate analysis, was checked by a bootstrap method.15 All analyses were performed with Stata Statistical Software Release 8.0 (StataCorp, College Station, TX, USA).
| Results |
|---|
|
|
|---|
|
Radiotherapy was always administered as involved field treatment. With induction therapy, 171 patients (72%) achieved a CR, 47 (20%) a partial response, and 18 (8%) patients were classified as non-responders. Fifty patients relapsed after a median interval from diagnosis of 23 months. Salvage treatment for patients with progressive or relapsed disease consisted of chemotherapy with or without radiotherapy (n=53), high dose chemotherapy followed by stem cell transplantation (n=9), radiotherapy alone (n=2), palliative or no treatment (n=10), or unknown treatment (n=11). Rituximab alone or in combination with other therapies was used in 22 patients who received salvage therapy since 1999. Forty-six (20%) patients died at a median interval of 27 months (range 1–88 months) after diagnosis. Thirty-three patients died of disease progression and 13 patients died while off-therapy in CR (3 cases) or in partial response not requiring further therapy (10 cases). After a median follow-up of 46 months (range, 3–140 months) for all cases and 51 months (range, 5–140) for surviving patients, the 5-year survival rate was 80% (95% confidence interval (CI), 73–85%). The mortality rate was 4.5 % per year.
ß2M levels at diagnosis
The frequency of elevated ß2M levels, according to the main clinical and laboratory parameters, is reported in Table 2. According to univariate analysis with Fishers exact test, elevated ß2M levels were associated with Ann Arbor stages III-IV (p=0.003), >1 extranodal sites of disease (p=0.005), >4 involved nodal areas (p<0.001), the presence of B-symptoms (p=0.047), LDH level >UNL (p=0.004), Hb <12 g/dL (p=0.001), and serum albumin level <3.5 g/dL (p=0.011). Elevated ß2M levels were also associated with age when the variable was managed as a continuous variable (p=0.014, Mann-Whitney test). In a multivariate logistic regression analysis, ß2M levels were significantly associated with LDH >UNL (p=0.021), number of involved nodal areas (p<0.001) and age (p=0.029).
|
30 mm/hr, albumin levels <3.5 g/dL, and ß2M levels >UNL had a negative impact on survival (Table 3). Performance status was not included in the univariate analysis because of the low number of patients with a poor performance status. In addition to the above-mentioned parameters, FLIPI was also a strong predictor of outcome with a 5-year survival rate of 90%, 78%, and 59% for patients at low, intermediate, and high risk, respectively (p<0.001).
|
UNL (p<0.001; Figure 1). The hazard ratio (HR) for ß2M in univariate analysis was 4.1 (95% CI, 2.2–7.4). The multivariate Cox regression model also confirmed the prognostic value of ß2M (Table 4a). In particular, the discriminating power of ß2M was only slightly decreased by the inclusion of potentially confounding factors (HR=3.0, 95% CI, 1.6–5.7, p<0.001), confirming its role as an independent prognostic factor. The prognostic role of ß2M levels was also confirmed in an analysis limited to patients with advanced stage disease (data not shown).
|
|
|
| Discussion |
|---|
|
|
|---|
In a more recent study, baseline serum ß2M levels were found to be independent prognostic factors, along with molecular response. Based on this observation, Lopez-Guillermo et al. proposed that FL patients could be stratified into prognostic groups according to baseline ß2M levels and molecular response to induction therapy.17
The prognostic value of ß2M serum levels was assessed in two studies dealing with the risk of histological transformation, with apparently conflicting results. In the study by Bastion et al., ß2M was the only independent prognostic factor.18 In the more recent study by Gine et al. FLIPI and histological subtype, but not ß2M, were found to have independent prognostic roles.19 However, it is notable that Bastion et al. did not analyze FLIPI as a risk factor.
Unfortunately ß2M, although significantly associated with survival at univariate analysis, was not included in the test sample of FLIPI and in the final scoring system because of the very high proportion of patients with missing data (available in 17% of cases).5 Insufficient measurements of ß2M also precluded the inclusion of ß2M levels in other prognostic models, such as ILI and IPI.4,20
We tested the prognostic value of ß2M in a large series of FL patients who were homogeneously treated with upfront anthracycline-containing regimens in the context of controlled clinical trials performed by the GISL. In order to be included in these clinical trials patients were required to have an ambulatory Performance Status and in particular to have normal renal function, thus limiting the chance that medical conditions other than lymphoma could lead to altered ß2M levels. The almost complete compliance with induction therapy (completed in 97% of cases), along with the homogeneity of treatment (all patients were treated with anthracycline-containing regimens), the appropriate observation time (which exceeded 4 years for patients at risk of death), and the limited number of patients lost to follow-up (n=4) allow us to maintain that this series of patients was appropriate for an accurate prognostic evaluation of ß2M levels. That is, for patients with FL elevated ß2M levels have a strong adverse prognostic value, being associated with a poorer outcome in terms of long-term survival. It is also relevant that ß2M retained its prognostic value in a multivariate analysis performed including all the prognostic parameters utilized in the FLIPI, IPI, and ILI indices. Although FLIPI was useful for classifying patients into different risk groups in our study sample, we found that ß2M level had an additional, independent value in discriminating prognosis. Our data suggest that the prognostic effect of ß2M is also retained in the three FLIPI groups, although it seems to be more evident in the low and the intermediate-risk groups. However in the high risk group the lack of a statistically significant difference could have depended on the smaller number of cases falling in this category in our study sample. The association between ß2M levels and survival suggests that soluble ß2M reflects an important biological process that is somehow correlated with tumor mass. In fact, we found that ß2M levels were significantly associated with elevated baseline LDH levels and with the number of nodal areas involved. Similarly, in our study, high ß2M levels were correlated with anemia, which could be considered an effect of bone marrow involvement by lymphoma. The strong independent effect of ß2M on survival suggests that ß2M may not be a simple surrogate of tumor mass but could reflect some still unknown biological characteristics of the tumor or of the microenvironment, with an additive effect on the risk of death. With multivariate logistic analysis, we found an association between elevated ß2M and age when the latter was analyzed as a continuous variable (Table 2); this association could be explained by an effect of the different biology of the elderly patient on ß2M (i.e. reduced creatinine clearance). Although correlated, both age and ß2M level retained independent roles in predicting overall survival, thus suggesting that in the population of patients with FL analyzed in the present study age had only a limited role, if any, on the increase of ß2M.
At present, it is not known whether the prognostic value of ß2M in B-cell lymphomas can be altered by treatment. This is particularly relevant for FL patients, for whom the addition of anti-CD20 monoclonal antibody to chemotherapy has been shown to improve survival compared to chemotherapy alone.21,22 As in the FLIPI, IPI, and ILI studies, none of the patients in our series received rituximab as part of their initial therapy. For this reason, we are cautious about generalizing our results to patients treated with anti-CD20 monoclonal antibody therapies. However, based on the recent study by Buske et al. who demonstrated that in patients treated with CHOP plus rituximab, FLIPI maintained its discriminating power,23 we can expect that the prognostic role of ß2M will also be confirmed. Our study demonstrates that information on ß2M serum levels may contribute, significantly and independently from FLIPI, to the prognostic definition of FL patients treated upfront with anthracycline-containing chemotherapy. The role of serum ß2M levels in the prognosis of FL must be confirmed in future studies investigating FL patients treated with combination chemotherapy plus anti-CD20 agents.
| Appendix |
|---|
|
|
|---|
The following members of the GISL group participated in this study: Divisione di Medicina,Ematologia, Ospedale Costantino Cantu, Abbiategrasso, Milano (G. Girmenia); Divisione di Medicina, Ente Ecclesiastico Ospedale Generale Regionale "Miulli", Acquaviva delle Fonti, Bari (G. Polimeno); Unità Operativa di Medicina, Istituto Oncologico, Bari (G. Colucci, E. Naglieri); Divisione di Ematologia, Presidio Ospedaliero A. Perrino, Brindisi (G. Quarta, G. Quintana); IIa Divisione di Medicina, Az. Istituti Ospedalieri di Cremona, Cremona (S. Morandi); Sezione di Ematologia, Medicina Ia, Ospedale Maggiore di Lodi, Lodi, Milano (L. De Fazio, A. Rovati); Divisione di Medicina II, Ospedale di Melegnano, Milano (G. Benetti, L. Dezza, S. Sari); Dipartimento di Ematologia, Centro Marcora, Ospedale Maggiore, IRCCS, Milano (L. Baldini, M. Goldaniga); Dipartimento di Oncologia ed Ematologia, Università di Modena e Reggio Emilia (M. Federico, S. Luminari; S. Pozzi); Cattedra e Divisione di Ematologia con TMO, Policlinico, Palermo (E. Iannitto); Medicina Interna, Oncologia Medica, Università di Pavia IRCCS Policlinico S. Matteo, Pavia (P .G. Gobbi, C. Broglia); Istituto di Medicina Interna e Sc. Oncologiche, Policlinico Monteluce, Perugia (A.M. Liberati); Dipartimento di Oncologia, Ospedale Santo Spirito, USL di Pescara (M. Lombardo); Medicina Oncologica ed Ematologica, Ospedale Civile, Piacenza (A. Lazzaro, D. Vallisa); Divisione di Medicina IIa, DH Oncoematologico, Ospedale Unico Versilia, USL 12, Lido di Camaiore, Lucca (P. Lambelet); Dipartimento di Oncologia, Divisione di Ematologia, Ospedale S. Chiara, Pisa (M. Petrini, F. Caracciolo); Divisione di Ematologia, Presidio Ospedali Riuniti Bianchi-Melacrino-Morelli, Reggio Calabria (C. Stelitano); Servizio di Ematologia, Azienda Ospedaliera Arcispedale S. Maria Nuova, Reggio Emilia (F. Merli, F. Ilariucci); Divisione di Ematologia, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo (N. Cascavilla, M. DellOlio); Divisione di Medicina, Ospedale Civile, Sassuolo, Modena (G. Partesotti); Clinica Medica, Università dellAquila-Teramo, Osp. Civile di Teramo (L. Ginaldi, M. Ricciotti); Divisione di Ematologia, Ospedale Civile S. Nicola Pellegrino Trani, Bari (A. Riezzo, G. Tarantini); U.O. di Oncologia, Ospedale A. Cardarelli, AUSL 3 di Campobasso (G. Giglio); Dipartimento di Ematologia, Ospedale Santo Spirito, USL di Pescara (F. Angrilli); SOC di Medicina Generale - SOS di Ematologia, A.O. della Valtellina e della Valchiavenna, Ospedale E. Morelli Presidio di Sondalo, Sondrio (A. Pastorini); Dipartimento di Oncologia, Ospedale Civile Santa Maria, Terni (M. Nunzi, M. Brugia); Caserta;U. O. Oncologia Medica I, IRCCS, Fondazione Salvatore Maugeri, Pavia (V. Fregoni); Divisione di Medicina, Ospedale San Sebastiano di Correggio, Reggio Emilia (A. Bagnulo, A. Zoboli); Divisione di Ematologia, Azienda Ospedaliera Papardo, Messina (M. Brugiatelli, D. Mannina); Divisione di Ematologia, Azienda Unità Sanitaria Locale n° 5, P.O. San Vincenzo, Taormina, Messina (M. Russo, G. Mineo); Unità di Oncologia Medica, Azienda Ospedaliera A. Pugliese Ciaccio, Catanzaro (S. Molica, R. Mirabelli); DH di Ematologia, Ospedale di Matera (A. Fragasso); Divisione di Ematologia, Casa di Cura La Maddalena, Palermo (M. Musso, R. Scalone).
| Footnotes |
|---|
MF, CG and SL conceived and designed the study and drafted the article; CM, LM and MoB collected, analyzed and interpreted the data; MF, CG and SL revised the statistical data; MaB critically reviewed the draft; UG, AM, FM, SP, CS, AL, PGG, LB, SB and VF provided clinical information; MF, CG, SL and MaB finally reviewed the concepts and conclusions of the study. All the authors agreed on the final version of the manuscript.
The authors reported no potential conflicts of interest.
Received for publication March 12, 2007. Accepted for publication September 5, 2007.
| References |
|---|
|
|
|---|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | TABLE OF CONTENTS | ARCHIVE | SUBSCRIPTIONS |