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A newly devised, validated prognostic tool – the Burkitt Lymphoma International Prognostic Index – can consistently identify low-risk patients who might benefit from treatment de-escalation, and high-risk patients who are unlikely to be cured with current therapies and may require novel approaches, investigators said.
In a cohort of patients treated at international sites, patients with a low-risk score on the BL-IPI had a 3-year progression-free survival (PFS) rate of 96%, and 3-year overall survival rate (OS) of 99%. In contrast, the 3-year PFS rate for patients in the high-risk category was 63%, and the 3-year OS rate was 64%, reported Adam J Olszewski, MD, from the Lifespan Cancer Institute at Rhode Island Hospital and The Miriam Hospital, both in Providence.
“The Burkitt Lymphoma International Prognostic Index – or the ‘BLI-PI’ [‘blippy’] as it was inevitably called – is a novel prognostic index that is specific to Burkitt lymphoma. It has been validated with sufficient calibration and discrimination in external data sets to allow for simple stratification and comparison of risk distribution in geographically diverse cohorts,” he said in an oral abstract presented virtually during the annual meeting of the American Society of Hematology.
Inconsistent criteria
There is a need for a Burkitt-specific index, he said, because of significant differences in age, stage at presentation, and abnormal lactate dehydrogenase (LDH) levels between patients with Burkitt and those with diffuse large B-cell lymphoma (DLBCL), and because historical definitions of “low-risk” Burkitt lymphoma have been inconsistent, with less than 10% of patients falling into this group, leaving the remainder in a undifferentiated “high-risk” category.
“Burkitt lymphoma is considered highly curable, but current therapy requires administration of dose-intense chemoimmunotherapy for which there are many chemotherapy backbone regimens developed across the world, and used mostly locally. These are often studied in phase 2 studies with limited sample sizes, which makes it difficult to compare populations across trials,” Dr. Olszewski said.
A validated prognostic index can help clinicians and researchers compare cohorts and can be used to help design future trials, he added.
To devise the BL-IPI, the investigators first selected a retrospective cohort of 570 adults with Burkitt lymphoma treated at 30 U.S. centers for whom data on outcomes were available.
They determined the best prognostic cutoffs for age, LDH, hemoglobin and albumin levels, and identified independent risk factors using stepwise selection in Cox regression and lasso regression analysis, a machine learning approach. The variables included age; sex; HIV-positivity status; loss of MYC rearrangement; performance status; stage; nodal involvement; marrow involvement; central nervous system involvement; and LDH, hemoglobin, and albumin levels.
For validation, they pooled data from European, Canadian, Australian, and U.K. studies to identify 457 patients for whom retrospective treatment and outcomes data were available.
The derivation and validation cohorts were similar in most respects, expect for a higher proportion of patients with Eastern Cooperative Oncology Group performance status scores of 2 or higher in the validation cohort (22% vs. 35%), and a higher proportion of patients with CNS involvement in the U.S.-based derivation cohort (19% vs. 10%, respectively).
Therapy also differed markedly between the U.S. and international cohorts, with about 30% each of U.S. patients receiving either the CODOX-M/IVAC (cyclophosphamide, vincristine, doxorubicin, high-dose methotrexate/ifosfamide, etoposide, and high-dose cytarabine) regimen, DA-EPOCH-R (dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab) regimen, or hCVAD/MA (fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone alternating with high-dose methotrexate and cytarabine) regimen, and the remaining 10% receiving other, unspecified therapy.
In contrast, 65% of the patients in the international (validation) cohort received CODOX-M/IVAC, 10% and 9%, respectively, received DA-EPOCH-R and hCVAD/MA, and 16% receiving other regimens.
Rituximab was administered to 91% of U.S. and 95% of international patients.
Higher survival rates outside US
Both PFS and OS were higher in the international versus U.S. cohort. At a median follow-up of 45 months, the PFS rate in the United States was 65%, and the OS rate was 70%.
In the international cohort, after a median follow-up of 52 months, the PFS rate was 75%, and the OS rate was 76%, the investigators found.
Reasons for the differences may be because of differences in treatment regimens, socioeconomic and racial disparities in the United States versus other countries, or to decentralized Burkitt lymphoma therapy in the United States, Dr. Olszewski said.
In univariate analysis, factors significantly predictive of worse PFS included age 40 years or older, ECOG performance status 2 or greater, stage 3 or 4 disease, marrow involvement, CNS involvement, LDH more than three times the upper limit of normal, and hemoglobin <11.5 g/dL (P < .001 for all preceding), as well as albumin <3.5 g/dL (P = .001).
“However, the multivariable analysis was more complicated, because many of these factors were overlapping, and most patients with high LDH also had advanced disease, and this group also encompassed patients who had bone marrow and CNS involvement,” he said.
Using the two types of regression analysis mentioned before, investigators identified ECOG performance status 2 or greater (P = .001), age 40 and older (P = .005), LDH greater than three times the upper limit of normal (P < .001) and CNS involvement (P = .002) as significant predictors for worse outcomes in multivariable analysis, and were included in the final model.
“We initially had five groups according to the number of these factors, but we observed that the survival curves for patients with two, three, or four factors were overlapping, and not significantly different, so ultimately we had three risk groups. In the derivation (U.S.) cohort, patients in the low-risk group, with no risk factors, a 3-year PFS of 92%, compared with 72% for patients with one risk factor (intermediate risk), and 53% for patients with two to four risk factors (high risk).
Respective hazard ratios for worse PFS in the low-, intermediate-, and high-risk groups were 1 (reference), 4.15 (95% confidence interval, 1.99-8.68), and 8.83 (95% CI, 4.32-18.03).
Respective HR for worse OS was 1, 7.06 (95% CI, 2.55-19.53), and 15.12 (95% CI, 5.58-40.99).
There were no significant differences in either PFS or OS when either LDH or stage was added into the model.
The BL-IPI was prognostic for PFS and OS in all subgroups, including HIV-positive or -negative patients, those with MYC rearrangements, stage 1 or 2 versus stage 3 or 4, or those treated with rituximab versus those who were not.
As noted before, 3-year PFS rates in the validation cohort for low, intermediate, high-risk groups were 96%, 82%, and 63% respectively, and 3-year OS rates were 99%, 85%, and 64%.
Why the CNS discrepancy?
In the question and answer session following the presentation, comoderator Christopher J. Melani, MD, from the Lymphoid Malignancies Branch at the National Cancer Institute in Bethesda, Md., said that “it was interesting to see the difference between CNS involvement in both the U.S. and the international cohort,” and asked whether Dr. Olszweski could elaborate on whether baseline CNS involvement was assessed by contrast-enhanced MRI of flow cytometry studies of cerebrospinal fluid.
“Could some of these differences between the U.S. and the international cohort be from the baseline assessment differing between the two?” he asked.
Dr. Olszewski replied that the retrospective nature of the data precluded capturing those data, but added that “I do suspect there may be some differences in the way that central nervous system is staged in different countries. In the United States the use of flow cytometry is more commonly employed, but we don’t know how it is used internationally. We do not know how often this is staged radiographically.”
Asked by others who viewed the presentation whether extranodal disease or peripheral blood involvement were prognostic in the final model, Dr. Olszewski replied that “one has to understand that, when one constructs a prognostic index, there is a balance between trying to input as much information as possible and to create something that is useful, clinically meaningful, and accurate.”
He said that, despite trying different models with different factors, “we couldn’t get the discrimination to be much better than the basic model that we ultimately created, so we favored using a more parsimonious model.”
No study funding source was reported. Dr. Olszewski reported research funding from Spectrum Pharmaceuticals, Genentech, TG Therapeutics, and Adaptive Biotechnologies. Dr. Melani reported having no relevant conflicts of interest.
SOURCE: Olszewski AJ et al. ASH 2020, Abstract 705.
A newly devised, validated prognostic tool – the Burkitt Lymphoma International Prognostic Index – can consistently identify low-risk patients who might benefit from treatment de-escalation, and high-risk patients who are unlikely to be cured with current therapies and may require novel approaches, investigators said.
In a cohort of patients treated at international sites, patients with a low-risk score on the BL-IPI had a 3-year progression-free survival (PFS) rate of 96%, and 3-year overall survival rate (OS) of 99%. In contrast, the 3-year PFS rate for patients in the high-risk category was 63%, and the 3-year OS rate was 64%, reported Adam J Olszewski, MD, from the Lifespan Cancer Institute at Rhode Island Hospital and The Miriam Hospital, both in Providence.
“The Burkitt Lymphoma International Prognostic Index – or the ‘BLI-PI’ [‘blippy’] as it was inevitably called – is a novel prognostic index that is specific to Burkitt lymphoma. It has been validated with sufficient calibration and discrimination in external data sets to allow for simple stratification and comparison of risk distribution in geographically diverse cohorts,” he said in an oral abstract presented virtually during the annual meeting of the American Society of Hematology.
Inconsistent criteria
There is a need for a Burkitt-specific index, he said, because of significant differences in age, stage at presentation, and abnormal lactate dehydrogenase (LDH) levels between patients with Burkitt and those with diffuse large B-cell lymphoma (DLBCL), and because historical definitions of “low-risk” Burkitt lymphoma have been inconsistent, with less than 10% of patients falling into this group, leaving the remainder in a undifferentiated “high-risk” category.
“Burkitt lymphoma is considered highly curable, but current therapy requires administration of dose-intense chemoimmunotherapy for which there are many chemotherapy backbone regimens developed across the world, and used mostly locally. These are often studied in phase 2 studies with limited sample sizes, which makes it difficult to compare populations across trials,” Dr. Olszewski said.
A validated prognostic index can help clinicians and researchers compare cohorts and can be used to help design future trials, he added.
To devise the BL-IPI, the investigators first selected a retrospective cohort of 570 adults with Burkitt lymphoma treated at 30 U.S. centers for whom data on outcomes were available.
They determined the best prognostic cutoffs for age, LDH, hemoglobin and albumin levels, and identified independent risk factors using stepwise selection in Cox regression and lasso regression analysis, a machine learning approach. The variables included age; sex; HIV-positivity status; loss of MYC rearrangement; performance status; stage; nodal involvement; marrow involvement; central nervous system involvement; and LDH, hemoglobin, and albumin levels.
For validation, they pooled data from European, Canadian, Australian, and U.K. studies to identify 457 patients for whom retrospective treatment and outcomes data were available.
The derivation and validation cohorts were similar in most respects, expect for a higher proportion of patients with Eastern Cooperative Oncology Group performance status scores of 2 or higher in the validation cohort (22% vs. 35%), and a higher proportion of patients with CNS involvement in the U.S.-based derivation cohort (19% vs. 10%, respectively).
Therapy also differed markedly between the U.S. and international cohorts, with about 30% each of U.S. patients receiving either the CODOX-M/IVAC (cyclophosphamide, vincristine, doxorubicin, high-dose methotrexate/ifosfamide, etoposide, and high-dose cytarabine) regimen, DA-EPOCH-R (dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab) regimen, or hCVAD/MA (fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone alternating with high-dose methotrexate and cytarabine) regimen, and the remaining 10% receiving other, unspecified therapy.
In contrast, 65% of the patients in the international (validation) cohort received CODOX-M/IVAC, 10% and 9%, respectively, received DA-EPOCH-R and hCVAD/MA, and 16% receiving other regimens.
Rituximab was administered to 91% of U.S. and 95% of international patients.
Higher survival rates outside US
Both PFS and OS were higher in the international versus U.S. cohort. At a median follow-up of 45 months, the PFS rate in the United States was 65%, and the OS rate was 70%.
In the international cohort, after a median follow-up of 52 months, the PFS rate was 75%, and the OS rate was 76%, the investigators found.
Reasons for the differences may be because of differences in treatment regimens, socioeconomic and racial disparities in the United States versus other countries, or to decentralized Burkitt lymphoma therapy in the United States, Dr. Olszewski said.
In univariate analysis, factors significantly predictive of worse PFS included age 40 years or older, ECOG performance status 2 or greater, stage 3 or 4 disease, marrow involvement, CNS involvement, LDH more than three times the upper limit of normal, and hemoglobin <11.5 g/dL (P < .001 for all preceding), as well as albumin <3.5 g/dL (P = .001).
“However, the multivariable analysis was more complicated, because many of these factors were overlapping, and most patients with high LDH also had advanced disease, and this group also encompassed patients who had bone marrow and CNS involvement,” he said.
Using the two types of regression analysis mentioned before, investigators identified ECOG performance status 2 or greater (P = .001), age 40 and older (P = .005), LDH greater than three times the upper limit of normal (P < .001) and CNS involvement (P = .002) as significant predictors for worse outcomes in multivariable analysis, and were included in the final model.
“We initially had five groups according to the number of these factors, but we observed that the survival curves for patients with two, three, or four factors were overlapping, and not significantly different, so ultimately we had three risk groups. In the derivation (U.S.) cohort, patients in the low-risk group, with no risk factors, a 3-year PFS of 92%, compared with 72% for patients with one risk factor (intermediate risk), and 53% for patients with two to four risk factors (high risk).
Respective hazard ratios for worse PFS in the low-, intermediate-, and high-risk groups were 1 (reference), 4.15 (95% confidence interval, 1.99-8.68), and 8.83 (95% CI, 4.32-18.03).
Respective HR for worse OS was 1, 7.06 (95% CI, 2.55-19.53), and 15.12 (95% CI, 5.58-40.99).
There were no significant differences in either PFS or OS when either LDH or stage was added into the model.
The BL-IPI was prognostic for PFS and OS in all subgroups, including HIV-positive or -negative patients, those with MYC rearrangements, stage 1 or 2 versus stage 3 or 4, or those treated with rituximab versus those who were not.
As noted before, 3-year PFS rates in the validation cohort for low, intermediate, high-risk groups were 96%, 82%, and 63% respectively, and 3-year OS rates were 99%, 85%, and 64%.
Why the CNS discrepancy?
In the question and answer session following the presentation, comoderator Christopher J. Melani, MD, from the Lymphoid Malignancies Branch at the National Cancer Institute in Bethesda, Md., said that “it was interesting to see the difference between CNS involvement in both the U.S. and the international cohort,” and asked whether Dr. Olszweski could elaborate on whether baseline CNS involvement was assessed by contrast-enhanced MRI of flow cytometry studies of cerebrospinal fluid.
“Could some of these differences between the U.S. and the international cohort be from the baseline assessment differing between the two?” he asked.
Dr. Olszewski replied that the retrospective nature of the data precluded capturing those data, but added that “I do suspect there may be some differences in the way that central nervous system is staged in different countries. In the United States the use of flow cytometry is more commonly employed, but we don’t know how it is used internationally. We do not know how often this is staged radiographically.”
Asked by others who viewed the presentation whether extranodal disease or peripheral blood involvement were prognostic in the final model, Dr. Olszewski replied that “one has to understand that, when one constructs a prognostic index, there is a balance between trying to input as much information as possible and to create something that is useful, clinically meaningful, and accurate.”
He said that, despite trying different models with different factors, “we couldn’t get the discrimination to be much better than the basic model that we ultimately created, so we favored using a more parsimonious model.”
No study funding source was reported. Dr. Olszewski reported research funding from Spectrum Pharmaceuticals, Genentech, TG Therapeutics, and Adaptive Biotechnologies. Dr. Melani reported having no relevant conflicts of interest.
SOURCE: Olszewski AJ et al. ASH 2020, Abstract 705.
A newly devised, validated prognostic tool – the Burkitt Lymphoma International Prognostic Index – can consistently identify low-risk patients who might benefit from treatment de-escalation, and high-risk patients who are unlikely to be cured with current therapies and may require novel approaches, investigators said.
In a cohort of patients treated at international sites, patients with a low-risk score on the BL-IPI had a 3-year progression-free survival (PFS) rate of 96%, and 3-year overall survival rate (OS) of 99%. In contrast, the 3-year PFS rate for patients in the high-risk category was 63%, and the 3-year OS rate was 64%, reported Adam J Olszewski, MD, from the Lifespan Cancer Institute at Rhode Island Hospital and The Miriam Hospital, both in Providence.
“The Burkitt Lymphoma International Prognostic Index – or the ‘BLI-PI’ [‘blippy’] as it was inevitably called – is a novel prognostic index that is specific to Burkitt lymphoma. It has been validated with sufficient calibration and discrimination in external data sets to allow for simple stratification and comparison of risk distribution in geographically diverse cohorts,” he said in an oral abstract presented virtually during the annual meeting of the American Society of Hematology.
Inconsistent criteria
There is a need for a Burkitt-specific index, he said, because of significant differences in age, stage at presentation, and abnormal lactate dehydrogenase (LDH) levels between patients with Burkitt and those with diffuse large B-cell lymphoma (DLBCL), and because historical definitions of “low-risk” Burkitt lymphoma have been inconsistent, with less than 10% of patients falling into this group, leaving the remainder in a undifferentiated “high-risk” category.
“Burkitt lymphoma is considered highly curable, but current therapy requires administration of dose-intense chemoimmunotherapy for which there are many chemotherapy backbone regimens developed across the world, and used mostly locally. These are often studied in phase 2 studies with limited sample sizes, which makes it difficult to compare populations across trials,” Dr. Olszewski said.
A validated prognostic index can help clinicians and researchers compare cohorts and can be used to help design future trials, he added.
To devise the BL-IPI, the investigators first selected a retrospective cohort of 570 adults with Burkitt lymphoma treated at 30 U.S. centers for whom data on outcomes were available.
They determined the best prognostic cutoffs for age, LDH, hemoglobin and albumin levels, and identified independent risk factors using stepwise selection in Cox regression and lasso regression analysis, a machine learning approach. The variables included age; sex; HIV-positivity status; loss of MYC rearrangement; performance status; stage; nodal involvement; marrow involvement; central nervous system involvement; and LDH, hemoglobin, and albumin levels.
For validation, they pooled data from European, Canadian, Australian, and U.K. studies to identify 457 patients for whom retrospective treatment and outcomes data were available.
The derivation and validation cohorts were similar in most respects, expect for a higher proportion of patients with Eastern Cooperative Oncology Group performance status scores of 2 or higher in the validation cohort (22% vs. 35%), and a higher proportion of patients with CNS involvement in the U.S.-based derivation cohort (19% vs. 10%, respectively).
Therapy also differed markedly between the U.S. and international cohorts, with about 30% each of U.S. patients receiving either the CODOX-M/IVAC (cyclophosphamide, vincristine, doxorubicin, high-dose methotrexate/ifosfamide, etoposide, and high-dose cytarabine) regimen, DA-EPOCH-R (dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab) regimen, or hCVAD/MA (fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone alternating with high-dose methotrexate and cytarabine) regimen, and the remaining 10% receiving other, unspecified therapy.
In contrast, 65% of the patients in the international (validation) cohort received CODOX-M/IVAC, 10% and 9%, respectively, received DA-EPOCH-R and hCVAD/MA, and 16% receiving other regimens.
Rituximab was administered to 91% of U.S. and 95% of international patients.
Higher survival rates outside US
Both PFS and OS were higher in the international versus U.S. cohort. At a median follow-up of 45 months, the PFS rate in the United States was 65%, and the OS rate was 70%.
In the international cohort, after a median follow-up of 52 months, the PFS rate was 75%, and the OS rate was 76%, the investigators found.
Reasons for the differences may be because of differences in treatment regimens, socioeconomic and racial disparities in the United States versus other countries, or to decentralized Burkitt lymphoma therapy in the United States, Dr. Olszewski said.
In univariate analysis, factors significantly predictive of worse PFS included age 40 years or older, ECOG performance status 2 or greater, stage 3 or 4 disease, marrow involvement, CNS involvement, LDH more than three times the upper limit of normal, and hemoglobin <11.5 g/dL (P < .001 for all preceding), as well as albumin <3.5 g/dL (P = .001).
“However, the multivariable analysis was more complicated, because many of these factors were overlapping, and most patients with high LDH also had advanced disease, and this group also encompassed patients who had bone marrow and CNS involvement,” he said.
Using the two types of regression analysis mentioned before, investigators identified ECOG performance status 2 or greater (P = .001), age 40 and older (P = .005), LDH greater than three times the upper limit of normal (P < .001) and CNS involvement (P = .002) as significant predictors for worse outcomes in multivariable analysis, and were included in the final model.
“We initially had five groups according to the number of these factors, but we observed that the survival curves for patients with two, three, or four factors were overlapping, and not significantly different, so ultimately we had three risk groups. In the derivation (U.S.) cohort, patients in the low-risk group, with no risk factors, a 3-year PFS of 92%, compared with 72% for patients with one risk factor (intermediate risk), and 53% for patients with two to four risk factors (high risk).
Respective hazard ratios for worse PFS in the low-, intermediate-, and high-risk groups were 1 (reference), 4.15 (95% confidence interval, 1.99-8.68), and 8.83 (95% CI, 4.32-18.03).
Respective HR for worse OS was 1, 7.06 (95% CI, 2.55-19.53), and 15.12 (95% CI, 5.58-40.99).
There were no significant differences in either PFS or OS when either LDH or stage was added into the model.
The BL-IPI was prognostic for PFS and OS in all subgroups, including HIV-positive or -negative patients, those with MYC rearrangements, stage 1 or 2 versus stage 3 or 4, or those treated with rituximab versus those who were not.
As noted before, 3-year PFS rates in the validation cohort for low, intermediate, high-risk groups were 96%, 82%, and 63% respectively, and 3-year OS rates were 99%, 85%, and 64%.
Why the CNS discrepancy?
In the question and answer session following the presentation, comoderator Christopher J. Melani, MD, from the Lymphoid Malignancies Branch at the National Cancer Institute in Bethesda, Md., said that “it was interesting to see the difference between CNS involvement in both the U.S. and the international cohort,” and asked whether Dr. Olszweski could elaborate on whether baseline CNS involvement was assessed by contrast-enhanced MRI of flow cytometry studies of cerebrospinal fluid.
“Could some of these differences between the U.S. and the international cohort be from the baseline assessment differing between the two?” he asked.
Dr. Olszewski replied that the retrospective nature of the data precluded capturing those data, but added that “I do suspect there may be some differences in the way that central nervous system is staged in different countries. In the United States the use of flow cytometry is more commonly employed, but we don’t know how it is used internationally. We do not know how often this is staged radiographically.”
Asked by others who viewed the presentation whether extranodal disease or peripheral blood involvement were prognostic in the final model, Dr. Olszewski replied that “one has to understand that, when one constructs a prognostic index, there is a balance between trying to input as much information as possible and to create something that is useful, clinically meaningful, and accurate.”
He said that, despite trying different models with different factors, “we couldn’t get the discrimination to be much better than the basic model that we ultimately created, so we favored using a more parsimonious model.”
No study funding source was reported. Dr. Olszewski reported research funding from Spectrum Pharmaceuticals, Genentech, TG Therapeutics, and Adaptive Biotechnologies. Dr. Melani reported having no relevant conflicts of interest.
SOURCE: Olszewski AJ et al. ASH 2020, Abstract 705.
FROM ASH 2020