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Background Natural killer/T-cell lymphoma (NKTCL) is an aggressive lymphoma with poor prognosis mainly seen in Asian and South American countries, most patients have nasal involvement. Non-nasal NKTCL have a dismal prognosis. However, data about this very specific population is mostly known in Asians but little known in Latin American (LATAM) population. Our aim is to describe the clinical characteristics and survival of newly diagnosed NKTCL patients in Peru Methods: This is a retrospective study, including all patients with a pathological diagnosis of NKTCL patients >13 years at the Instituto Nacional de Enfermedades Neoplasicas (INEN) and Oncosalud between 2002 and 2019. The estimate of the survival curves was performed by the Kaplan-Meier method, and the difference was computed by the log-rank test. Results: 60 patients were included for the analysis. The median age was 37 years (range 15-83). 62% were male, 51% had B-symptoms, 56% had stage III/IV disease, 54% had elevated serum LDH, 29% had nodal involvement. The most frequent non-nasal sites were oropharynx, soft tissue, cutaneous, gastrointestinal and orbit with 24%, 17%, 12%, 7% and 5%, respectively. 79% patients received systemic chemotherapy, 7% received radiotherapy alone and 14% did not received chemotherapy because poor performance status. Of patients who received chemotherapy only 20% received a L-asparaginase-based chemotherapy. The median follow-up time was 8 months (1-103). The median overall survival (OS) was 14 months (interquartile range [IQR] 4-29), 1y OS was 51% (95% CI 33-67), 3y OS 21% (95% CI 7-40), 5y OS 14% (95% CI 3-34), figure 1. The median overall survival according to LDH level was 10 months regardless of the levels (p=0.84), figure 2. The median OS for female and male were 8 and 10 months, respectively p=0.59) Conclusions: Peruvian patients with non-nasal NKTCL are younger, with presence of B-symptoms, advance stage and elevated LDH levels compared to those reported in nasal NKTCL. The most frequent non nasal NKTCL is located on the oropharynx. OS of non-nasal NKTCL is extremely poor. Elevated LDH and sex are not prognostic factors for OS. A larger cohort and follow-up are needed to evaluate prognostic factors in this population. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Background Follicular lymphoma (FL) is the second most common non-Hodgkin lymphoma subtype seen in Caucasian countries. Recent data were published on FL from Latin America (LATAM), presenting information of 12 countries. However, this information is widely variable because of the diversity of the Latin population (Caucasian and mestizo individuals). Our aim was to evaluate the clinical features, treatment patterns outcomes of non-Caucasian patients with FL from a single cancer center. Our second aim was to validate FLIPI1, FLIPI2, PRIMA and POD-24 score in our cohort. Methods: This is a retrospective study, including all patients with a pathological diagnosis of FL at the National Institute of Neoplastic Diseases in Lima, Peru from 2010 to 2019. All cases were reviewed by specialized pathologists. Baseline clinical and pathological data were collected. Responses were assessed based on the Lugano criteria. Overall survival (OS) was estimated using the Kaplan-Meier method. Differences were compared with the log-rank test. Results From 2010 to 2019 4480 patients with B-cell lymphoma were diagnosed, 449 patients (10%) had grade 1 to 3A FL, 302 patients had the five variables for FLIPI, 242 for FLIPI2, 257 for the 2 variables for PRIMA prognostic index and 209 received systemic treatment and had enough information to evaluate POD24. The median age for the entire cohort was 59 years old (range 24-92), 49% of patients were ≥60 years, 46% were male, 22% had extranodal involvement, 34% had bulky disease (≥6 cm in diameter), 68% had stage III/IV disease, 32% had hemoglobin 4. Low, intermediate and high FLIPI were seen in 39%, 27% and 34% of patients, respectively. Low, intermediate and high-risk FLIPI2 was seen in 23%, 54% and 23% of patients, respectively. Low, intermediate, and high PRIMA was seen in 53%, 12% and 35%, respectively. 209 patients received systemic treatment, 60% received CHOP ± rituximab (R), 13% CVP ± R, 15% CHOP, 11% CVP. Response data were available in 158 patients with complete response in 35%, partial response in 57% and no response in 8%, for an overall response rate of 92%. 19% of patient had disease progression within 24 months of first treatment initiation (POD24). For the entire cohort, the median follow-up time was 2.6 years (Interquartile range [IQR] 0.08-13.6), the median OS was not reached (IQR 4.2-not reached). 5y was OS 72% (95% CI 65-77). 5y OS for low, intermediate and high FLIPI were 90% (95% CI 81-94.5), 65% (95% CI 47.3-78.2) and 60.1% (95% CI 46.6-72.4), respectively (p Conclusion: FL has a lower incidence in non-Caucasian patients in Peru compared to those reported for Western countries or other LATAM Caucasian population. FL patients showed higher rates of high FLIPI and FLIPI2 than previously reported in the literature. Chemoimmunotherapy is the standard approach to FL patients, which is associated with high rates of overall response, but low rate of complete response. The OS rates are shorter than those reported in the previously LATAM cohort. Our study validates the prognostic value of FLIPI1, FLIPI2, PRIMA and POD24. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Differences in the Distribution of non-Hodgkin Lymphoma in public versus private institution in a Latin American country: A cohort of 5,807 cases. Background: Non-Hodgkin lymphoma (NHL) is the most frequent hematological malignancy. B-cell (BCL) and T-cell (TCL) NHL subtypes differs in high income and low-and middle-income countries. In Peru, the healthcare system (HCS) is divided mainly into public and private institutions. We previously demonstrated that there is a difference in the distribution of NHL between the HCS. We aimed to describe the subtypes of NHL seen according to healthcare facilities in a large cohort. Methods: We reviewed medical records at National Cancer Institute and Oncosalud, both the leading public and private cancer centers in Peru, respectively. All patients diagnosed with NHL from 2010-2019 according to the 2016 WHO classification were included. Baseline characteristics were compared between public and private institutions using Student's t test and Chi-square as appropriate. Results: A total of 5,807 NHL were included from both institutions. The median age was 60 years (range 15-103), 50.6% were male. Most patients NHL cases were encountered at the public institution (92.4%, n = 5,368); 82.9% (n = 4,815) were BCL and 17.1% (n = 992) TCL. Differences of BCL and TCL frequencies were seen among institutions. More BCL cases were seen at the private institution (86.1%, n = 378 versus 82.7%, n = 4,437, respectively) whereas TCL were common in the public institution (17.3%, n = 931 versus 13.9%, n = 61, respectively) (p < 0.065). The most frequent BCL was DLBCL with 68.6% (n = 3045) and 54.2% (n = 205) seen in public and private institutions, respectively (p < 0.001). The second most frequent BCL was follicular lymphoma (FL) with 11.2% (n = 495) and 20.9% (n = 79) seen in the public and private institutions, respectively (p < 0.001). Chronic lymphocytic lymphoma (CLL) and Burkitt lymphoma (BL) were most frequent in private institution (CLL 6.3%, n = 24 vs. 3.5%, n = 154, p = 0.004; BL 3.4%, n = 13 vs. 1.4%, n = 60, p = 0.001). The most frequent TCL was peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS) (24.5%, n = 228) for the public institution and mycosis fungoides (MF) (42.6%, n = 26) for the private institution. The second most frequent TCL was natural killer/TCL (NKTCL) (23.5%, n = 219) for the public institution, and PTCL, NOS (21.3%, n = 13) for the private institution. There was significant difference in the number of NKTCL and MF cases seen during the study period among institutions (NKTCL public 23.5%, n = 219 vs. private 4.9%, n = 3, p = 0.001; MF public 9.1%, n = 90 vs. private 42.6%, n = 26, p Conclusions: The distribution of NHL subtypes differs according to the type of healthcare system in Peru. Our large cohort confirms that DLBCL and NKTCL are more frequent in patients treated at the public cancer center than in private center. On the contrary FL, CLL, BL and MF are more frequent in private cancer center. The difference in the distribution of BCL and TCL was not statistically significant. Disclosures No relevant conflicts of interest to declare.

Background Follicular lymphoma (FL) is the second most common non-Hodgkin lymphoma subtype, being nodal involvement its main characteristic. However, data about Extranodal (EN) involvement is not reported in Latin American patients. Our aim was to evaluate the clinical features, treatment patterns outcomes of Peruvian patients with ENFL from two cancer centers and validate FLIPI1, FLIPI2, PRIMA and POD-24 prognostic index in our cohort. Methods: This is a retrospective study, including all patients with a pathological diagnosis of FL grade 1 to 3A treated at the National Institute of Neoplastic Diseases and Oncosalud, both in Lima, Peru from 2010 to 2019. All cases were reviewed by specialized pathologists. Baseline clinical and pathological data were collected. Responses were assessed based on the Lugano criteria. Overall survival (OS) was estimated using the Kaplan-Meier method. Differences were compared with the log-rank test. Results A total of 86 patients were evaluated. The median age was 61 years (30-91), 43% were male, 20% had bulky disease (≥6 cm in diameter), 51% had stage III/IV disease, 31% had hemoglobin 4. The most frequent EN sites were gastrointestinal, bone marrow, cutaneous and breast with 22%, 21% and 9%, and 6%% respectively. Low, intermediate and high-risk FLIPI1 was seen in 56%, 23% and 21% of patients, respectively. Low, intermediate and high-risk FLIPI2 was seen in 28%, 58% and 14% of patients, respectively. Low, intermediate, and high PRIMA was seen in 57%, 10% and 33%, respectively. 55 patients (64%) received any treatment, 47% received CHOP ± rituximab (R), 16% CVP ± R, 22% radiotherapy alone, 9% CHOP, 15% other treatments. Response data were available in 44 patients with complete response in 45%, partial response in 43% and no response in 12%, for an overall response rate of 88%. From patients who received CHOP/CVP ± R, 13% patients had disease progression within 24 months of first treatment initiation (POD24). For the entire cohort (N=88) the median follow-up time was 2.1 years (interquartile range [IQR] 0.08-11.3), median overall survival was 8.25 years (IQR 4.4-not reached [NR]). 5y OS was71.7% (95% CI 55.3-82.9), figure 1. For the FLIPI group 5y OS for low, intermediate and high FLIPI were 86.9% (95% CI 64.7-95.6), 60.1% (95% CI 24.4-83.2) and 75.7% (95% CI 30.4-93.7), respectively (p=0.07; Figure 2). For the FLIPI2 group (N=58) 5y OS for low, intermediate and high FLIPI2 were 79.5% (95% CI 39.3-94.5), 77% (95% CI 55.3-89.2) and 86% (95% CI 33.4-97.8), respectively (p=0.86). For the PRIMA group (N=38) 5y OS for low, intermediate and high PRIMA was 86% (95%55.6-96.6), 100% (95% CI 100), and 80% (95% CI 42-95), respectively (p=0.80). Patients who had and did not have POD24 had median OS of NR (IQR 0.6-NR) and NR (IQR 2.69-NR), respectively. 5y OS for patients who had and did not have POD24 was 71.2 % (95% CI 48-85) and 75% (12.7-96), respectively (p Conclusion: Peruvian patients with ENFL showed a higher rate of female patients. Gastrointestinal involvement was the most common primary site. The OS rates is similar to our nodal involvement cohort. Chemoimmunotherapy is the standard approach to FL patients, which is associated with high rates of overall response. In our study FLIPI, FLIPI2, PRIMA and POD24 were not predictors for OS, but larger cohorts and longer follow-up are needed to find more accurate predictors of survival in these patients. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Introduction: T-cell lymphomas are a relatively rare and heterogeneous group of lymphoid neoplasms. Its incidence relies on viral infections incidence as Human T-cell lymphotropic virus type I-II (HTLV-I/II) and Ebstein Bar virus (EBV). Specifically, these viruses have a significantly higher incidence in Latin-American populations. Our objective was to calculate the incidence and survival of T-cell lymphomas in the largest Peruvian population based on a national registry. Methods: We conducted a multicenter, retrospective registry study of non-Hodgkin T cell lymphoma. The data was extracted from Instituto Nacional de Enfermedades Neoplasicas and Oncosalud-AUNA, Lima-Peru, from January 2010 to December 2019, a total of 948 patients who were diagnosed as mature T cell non-Hodgkin lymphoma based on the World Health Organization Classification 2008 were enrolled. T-lymphoblastic lymphoma/leukemia was excluded. Overall survival was calculated based on death dates from the Peruvian national identification registry (RENIEC). Results: The median age was 51 years (range, 1-94), and male and female patients were 512 (54%) and 436 (46%). Among the 948 patients enrolled, Peripheral T-cell lymphoma was the common neoplasm accounting for 23% (n=221), and Extra-Nodal NK T-lymphoma (22%, n=213), Adult T-cell lymphoma (22%, n=205), Anaplasic Large cell lymphoma (14%, n=131), Cutaneous T-cell lymphoma (14%, n=129) (Figure 1a). At the time of diagnosis, extranodal disease was found in 68.6% (650) of patients. By July 2021, only 15.3% of cases were in remission and 37% (350) were alive. Median global overall survival of T-cell lymphomas was 1 year (0.8-1.1), Cutaneous T-cell lymphoma had the highest survival and Adult T-cell lymphoma had the lowest survival (Table 1 and Figure 1b). Conclusion: This initial report shows a relatively high frequency of mature T-cell lymphomas in Latin-America real-world setting, and confirms that T-cell lymphomas patients had a dismal outcome. The clinical outcome for patients with T-cell lymphomas subtypes is poor with standard therapies, and novel agents and new modalities are needed to improve survival. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Background:Acute Myeloid leukemia (AML) and High-risk Myelodysplastic Syndrome (MDS) are two aggressive myeloid neoplasms characterized by dismal outcomes in patients not suitable for intensive treatment. During the last decades, hypomethylating agents (HMA) represented a valuable treatment option for AML and MDS, particularly in older or unfit patients. However, the limited efficacy and high-costs concerns in developing countries limited its general use. Azacytidine is the most representative and available HMA in limited-sources facilities. We aimed to explore the efficacy of azacytidine as frontline treatment in terms of event-free (EFS) and overall survival (OS) for newly diagnosed patients with AML non-candidates to intensive chemotherapy and MDS in Peru. Methods: We reviewed medical records of patients diagnosed and managed for AML at three private cancer institutions in Lima-Peru (Oncosalud, Clinica Delgado and Clinica Angloamericana) between 2010 and 2019. Cytogenetics and molecular markers were not retrospectively available during data obtention. Clinical characteristics, laboratory data and outcomes were evaluated for patients with AML and MDS who received at least 1 cycle of AZA as frontline treatment. AZA was given at accumulated dose of 75mg/m2/daily for 7 days every 4 weeks, however further dose reductions were allowed by physician criteria. Best responses were assessed according to Leukemia.net consensus, but summarize as complete remission (CR), partial response (PR) and stable disease (SD). Survival curves (event-free and overall survival) were estimated using the Kaplan-Meier method and compared with the Log-rank test. Results:A total of 76 patients were included and had sufficient data for analysis. Fifty-two cases had AML and 24 MDS. Clinical characteristics, Laboratory data, Treatment and Outcomes were summarized in Table 1. Median ages for AML was 74 and 69 for MDS, 37% and 54% had less than 70 years in AML and MDS, respectively. Female/male ratio was 1:1 for AML and 1:3 for MDS. One-third of AML cases and 48% of MDS had an ECOG performance status ≤1. Twenty-five (48%) of AML patients had Secondary AML to MDS, and 25% had prior cancer treatment. Median number of cycles of AZA was 5 for both groups. A high composite CR rates were seen for AML (39%) and MDS (25%), PR were 10% and 8% for AML and MDS, respectively. The majority of MDS cases reached stable disease (62%), and 35% in AML. Three patients underwent to allo-transplant (2 AML and 1 MDS). Relapsed rates were more frequent in AML cases (AML 63% vs. 30%), however, deaths were similar in both groups. At a median follow-up of 4-years, the EFS was 3% for AML and 20% for MDS, and OS was 16% and 30% for AML and MDS patients, respectively. Conclusions: Azacytidine represents an effective and accessible therapy for AML non-candidates to intensive chemotherapy and MDS in limited-sources settings. Access to novel effective therapies must be warranted for these highly aggressive myeloid neoplasms in developing countries. Disclosures No relevant conflicts of interest to declare.

Background: Acute myeloid leukemia (AML) is a highly heterogeneous disease with new cases commonly diagnosed in the elderly population. Despite advances in AML therapy, disease outcomes remain poor. Between 2010 and 2016, the reported 5-year overall survival in the U.S. was 28.7% (Source: NCI SEER 13 statistics). National based registries are vital to monitor the incidence, outcome and survivorship of AML patients. Therefore, we aim to explore the incidence and outcome of AML patients managed at the National Cancer Institute in Peru over the past decade. Methods: We conducted a retrospective analysis of all newly diagnosed AML patients seen at the National Cancer Institute (INEN) in Lima-Peru between January 2008 to December 2018. The INEN is the major governmental leukemia center providing care for about 60% of newly diagnosed AML patients in Peru. Patient eligibility screening was performed using the Flow Cytometry Core Lab Registry. We excluded patients with acute promyelocytic leukemia. Demographic and clinical characteristics were obtained from medical records. Place of birth and death records were confirmed using the Peruvian National Registry of Identification and Civil Status (RENIEC). Survival analysis was performed using Kaplan Meier and Log-rank tests. The cumulative 11-year AML incidence rate was calculated and plotted using a choropleth map of Peru. Results: A total of 1,499 newly diagnosed AML cases were identified and had sufficient data for analysis. Median age at diagnosis was 44 years (range: 0-92) with a female:male ratio of 0.9:1. Clinical characteristics and outcome are presented in Table 1. Twenty-two percent (n=324) of patients were older than 65 years-old at the time of diagnosis. Most patients (n=926, 62%) came from the coastal region of Peru, followed by the mountains (30%) and the rainforest (8%). The cumulative 11-year incidence rate according to geographical location is shown in Figure 1. Overall, the Peruvian hospital-based cumulative incidence rate was 4.79 AML cases per 100,000 habitants, with the highest incidence rate observed in Piura (a coastal city in Northern Peru) with 38 AML cases per 100,000 habitants. At a median follow up of 68 months, the global 5-year overall survival (OS) rate of AML cases seen in Peru was 16%. Worse survival rates were found in patients aged 66 years and older (5-year OS 3%, median survival time [MST] 2 months, p Conclusions: This is the first study describing the incidence and outcome of AML patients in Peru. In this large contemporary cohort, we found a cumulative 11-year incidence rate of 4.79 AML cases per 100,000 habitants, with an alarming high incidence of AML cases observed in the city of Piura which needs further epidemiological evaluation. Despite improvements in supportive care in the contemporary era, our inpatient mortality for adult patients with AML remains high particularly among older patients. Further analyses are warranted to examine predictors of AML-related deaths in Peru and to develop strategies that improve patient outcomes. Disclosures No relevant conflicts of interest to declare.

Background: Diffuse large B-cell lymphoma (DLBCL) is the most common variant of non-Hodgkin lymphoma (NHL) accounting for approximately 30% of the NHL cases worldwide. Previous reports have associated certain viral infections with the development of DLBCL such as HIV and EBV, both infections related with an aggressive clinical course and worse outcome. The human T-lymphotropic virus type 1 (HTLV-1) is a retrovirus regarded as the pathogenic agent for adult T-cell lymphoma/leukemia. HTLV-1 is endemic in Japan, the Caribbean basin, South America, and parts of Africa. In Peru, up to 3% of the healthy adult population carries HTLV-1. As data on the impact of HTLV-1 infection in DLBCL outcomes is scarce, we aim to describe the clinical features and outcomes of HTLV-1-positive patients with a pathological diagnosis of DLBCL. Methods: We retrospectively reviewed medical records of patients diagnosed and managed for DLBCL at the National Institute of Neoplastic Diseases in Lima-Peru between 2007 and 2019. Patients were evaluated for HTLV-1 infection at the time of diagnosis. Positive HTLV-1 cases were matched to negative HTLV-1 controls based on age, sex, and cancer staging. Treatment responses were assessed according to the Lugano criteria. Overall survival (OS) and event-free survival (EFS) curves were estimated using the Kaplan-Meier method and compared with the Log-rank test to determine the impact of HTLV-1 infection. Multivariate Cox regression models were reported with adjusted Hazar Ratios (aHR) with a 95% confidence interval (95% CI). Results: A total of 192 patients with DLBCL were identified and had sufficient data for analysis. Seventy (37%) cases were positive for HTLV-1 infection and 122 (63%) were not. Table 1 summarizes the clinical features and outcomes of DLBCL patients according to HTLV-1 status. Overall, the majority of patients were ≥65 years (59%), had ECOG performance status ≤2 (95%) and were stage III-IV (51%) at diagnosis. One third (n=64) of patients had extranodal involvement with 71 affected sites of which bone marrow involvement was frequently found in HTLV-1-negative DLBCL cases (55% vs. 7%, p Conclusion: To the best of our knowledge, this is the largest case series describing the clinical characteristics and outcome of HTLV-1-positive DLBCL patients. A study from Japan on early stage localized (head and neck) B-cell-NHL (n=198, HTLV-1 seropositive n=21 and with DLBCL n=12) treated with radiotherapy and/or multi-agent chemotherapy found poorer prognosis on HTLV-1 carriers compared to non-carriers (5-year OS: HTLV-1-positive n=21, 49% vs. HTLV-1-negative n=177, 78%, p=0.007; Hiroaki et al BJH 2003). In this study, we included DLBCL patients with both early and advanced stage disease along with localized and extranodal involvement. We found that HTLV-1 infection had no significant impact on 5-year OS and EFS rates when using conventional therapy for DLBCL. Moreover, we did not find differences in relapsed and mortality rates. Further investigation is needed to confirm the potential impact of HTLV-1 infection in DLBCL outcome. Disclosures No relevant conflicts of interest to declare.

Background:Brentuximab Vedotin (BV) is an active drug in patients with relapsed / refractory (R/R) Hodgkin Lymphoma (HL). Autologous stem cell transplantation (ASCT) remains standard of care for these patients and achieving a clinical response pre-ASCT predicts favorable outcomes. Pre-ASCT salvage chemotherapy combinations with BV have been explored in this setting. Objective:To evaluate the efficacy and safety of the combination of BV and chemotherapy in heavily pretreated R/R HL patients eligible for ASCT. Methods:We reviewed the clinical characteristics, treatment, response, safety, and survival of 21 heavily pretreated R/R HL patients in 2 Peruvian institutions between June 2018 and February 2020. Survival curves were estimated using the Kaplan-Meier method. Results:A total of 21 patients (15 (71%) refractory and 6 (29%) relapsed) were included. The median age was 31 years (range, 19-55), 13 (62%) patients were female. The median of previous treatment lines was 3 (range, 1-4). Patients received BV plus chemotherapy (CT) on day 1: Dexamethasone, Cytarabine and Cisplatin (DHAP) (43%), Gemcitabine-based CT (33%), Ifosfamide, Carboplatin and Etoposide (ICE) (14%), and other CT (ESHAP, Bendamustine) (10%). After a median of 3 cycles of combination therapy (range, 2-7), the objective response rate was 81 %, with 8 (38%) patients achieving CR. 10 (48%) patients had successful peripheral blood stem cell (PBSC) collection. 7 (33%) patients underwent ASCT, the remaining responding patients had a delay in either collection or ASCT due to COVID-19 pandemic. The most significant adverse events were thrombocytopenia (69%) (G3-4: 53%), neutropenia (47%) (G3-4: 28%), infections (37%), febrile neutropenia (33%) and G1-2 peripheral neuropathy (16%). The Progression Free-Survival (PFS) at 1 year was 86% in ASCT patients. Conclusion:The combination of Brentuximab and chemotherapy is active as a bridge for ASCT in heavily pretreated R/R HL patients. The CR rates were lower than previously reported and it could be related with the number of previous lines of treatment received; there was also a higher incidence of febrile neutropenia in our cohort. We could hypothesize that the combination of Brentuximab and chemotherapy provides greater benefit if it is administered earlier in patients with R/R HL. Disclosures No relevant conflicts of interest to declare.

Background: The human T-cell lymphotropic virus type 1 (HTLV-1) is an oncogenic retrovirus that affects CD4+ T-cell lymphocytes and is the cause for adult T-cell leukemia/lymphoma (ATLL), an aggressive peripheral T-cell neoplasm. Hodgkin-like ATLL subtype is a unique entity usually indistinguishable from Hodgkin lymphoma (HL) in the setting of HTLV-1 infection. HTLV-1 proviral integration and TCR Cb1 gene rearrangement testing are often necessary to differentiate both entities. However, less is known on HTLV-1 carriers diagnosed with HL (HTLV-1+ HL). We aim to compare survival outcomes between HTLV-1+ HL and matched controls treated at the National Cancer Institute in Peru. Methods: We reviewed medical records of patients diagnosed and managed for HL at the National Cancer Institute (Instituto Nacional de Enfermedades Neoplasicas, INEN) in Lima-Peru between 2002 and 2019. All patients should have had serologic evaluation for HTLV-1 infection at the time of diagnosis and should have had no suspicion (or confirmation) of a T-cell neoplasm during pathological examination. To investigate the impact of HTLV-1 infection on survival, we matched HTLV-1+ HL cases to HTLV-1-negative HL patients (controls) based on age, sex, cancer staging, and comorbidities. Treatment responses were assessed according to the Lugano criteria. Survival curves (event-free and overall survival) were estimated using the Kaplan-Meier method and compared with the Log-rank test. Multivariate Cox regression analysis was fitted and reported as Hazard Ratios (HR) with a 95% confidence interval (95% CI). Results: A total of 68 HL patients were identified and had sufficient data for analysis. Twenty cases had HTLV-1+ HL and 48 HTLV-1-negative HL. Table 1 summarizes the clinical features and outcomes of HL patients. In all patients the median age at diagnosis was 55 years with a female/male ratio of 1:1. Histological subtypes of HL were not statistically different among both groups with mixed cellularity as the most common subtype (HTLV-1+ HL 50% vs. HTLV-1-negative HL 38%), followed by nodular sclerosis (HTLV-1+ HL 15% vs. 31%), lymphocyte-rich (HTLV-1+ HL 15% vs. 15%), and nodular lymphocyte-predominant (HTLV-1+ HL 5% vs. 4%). ECOG performance status ≤2, advanced-stage disease (III-IV), presence of B symptoms, and presence of extranodal disease at the time of diagnosis were not different in both groups. Co-infections were presented in 5 (7.4%) HL patients (1 strongyloidiasis and 3 tuberculosis in the HTLV-1+ HL group, and 1 tuberculosis in the HTLV-1 negative HL group). All HTLV-1-negative HL patients were treated with first-line ABVD regimen compared to 18 (90%) HTLV-1+ HL patients; the remaining HTLV-1+ HL patients received involved-field radiation (n=1) and best supportive care (n=1). HTLV-1+ HL patients had inferior response rates (complete and partial response) compared to the matched control group (CR: 60% vs. 71%, and PR: 15% vs. 27%, respectively, p=0.015). At a median follow-up of 5-years, the overall survival was 55% in HTLV-1+ HL versus 67% in the matched control group (aHR: 1.39, 95%CI [0.6-3.4], p=0.47) (Figure 1). In the multivariate analysis, HTLV-1 infection was not a significant prognostic factor for worse event-free or overall survival. Relapsed rates were not different between both groups (HTLV-1+ HL 25% vs. 20.8%), however, more deaths were seen in the HTLV-1+ HL group (60% vs. 35%) but this was not statistically significant. Conclusion: To the best of our knowledge, this is the first case series describing the characteristics and outcome of HTLV-1 carriers diagnosed with HL. We found lower response rates to conventional treatment in HTLV-1+ HL patients compared to HTLV-1 negative individuals. However, long-term outcomes and relapsed rates were not different among groups. Further investigation is needed to confirm the potential impact of HTLV-1 infection in HL outcome. Disclosures No relevant conflicts of interest to declare.

Background:Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and fatal myeloid malignancy characterized by clonal proliferation of immature plasmacytoid dendritic cells. BDCN has been frequently described in men and age above 60 years, and usually involves the skin and bone marrow. Immunophenotyping is based on CD123+, CD4+ and CD56+ expression and is necessary rule out other myeloid malignancies. Objective: We aimed to describe the clinical characteristics and immunophenotype of BPDCN cases diagnosed at two tertiary Peruvian cancer institutions between 2018-2019. Methods: We retrospectively reviewed medical records of patients diagnosed of BPDCN at two tertiary Peruvian cancer centers (Instituto Nacional de Enfermedades Neoplasicas and Oncosalud-AUNA, Lima-Peru) between 2008 and 2019. Clinical characteristics, treatments, outcomes and immunophenotype by pathology or flow cytometry review, were collected. Patients were classified according to their maturation stage using CD34 and CD117 expression into three subgroups: Immature-Intermediate blastic (IIB-BPDCN; partial expression of CD117 and absence or minimal expression of CD34), mature (M-BPDCN; absence of CD34 and CD117) and unknown(U-BPDCN). Overall survival (OS) and event-free survival (EFS) curves were estimated using the Kaplan-Meier method and compared with the Log-rank test to determine the impact of immunophenotype. Results: Thirty-eight cases were included during the study period. The median age at diagnosis was 38 years (7-82), only six (16%) were older than 65 years, and a notorious female predominance (F/M ratio: 1.7:1) was observed. Twenty-four cases had CD34/117 expression available and were classified according to the maturation stage in IIB-BPDCN (13) and M-BPDCN(11), additionally 14 cases had unknown stage (U-BPDCN). Table 1 summarizes clinical characteristics, treatment and outcomes according to their immunophenotype. Bone marrow infiltration was more frequent in immature phenotypes (92% IIB-BPDCN vs 73% M-BPDCN, p=0.001), as well as skin infiltration was more common in mature phenotype (72% vs 31%, p=0.008). CNS infiltration at diagnosis was 15% and 55% in IIB-BPDCN and M-BPDCN, respectively. Sixteen patients received treatment based on ALL-like protocols, 8 AML-like, 5 CHOP-like and 9 patients only palliative care. At 5 years median follow-up, median EFS and OS was 12 and 16 months, respectively. IIB-BPDCN had the lowest survival (4 months EFS and 6 months OS). Conclusions: We describe a Peruvian cohort of BPDCN patients with younger age at diagnosis and female predominance than reported previously by other series, however further studies in Latino population are required to confirm these results. Immature phenotypes based on CD34 and CD117 expression were associated with high rate of bone marrow infiltration and fatal outcomes. New successful target therapies must be warranted for this rare and fatal condition. Disclosures No relevant conflicts of interest to declare.

Background Acute myeloid leukemia and myelodysplastic syndrome (AML/MDS) represents a broad and complex group of diseases characterized by involvement of the myeloid lineage on hematopoiesis with remarkable variability on clinical presentation, genes mutations, karyotype and molecular abnormalities. Precise characterization on AML/MDS biology is important and the identification of the pathogenic mutated genes is relevant for risk stratification and therapy strategy, mainly for those patients in which targeted therapies is a must. Among pathogenic mutated genes in AML/MDS; TP53 is associated with lower response and high mortality rates. The cumulated number of mutated genes is associated with bad clinical outcomes as well. Aims To explore the frequency and impact of mutated genes on clinical outcomes in a cohort of Peruvian patients diagnosed with AML/MDS studied at diagnosis. Methods In this report we showed 31 consecutive AML/MDS cases treated at three medical centers in Lima (Clínica Delgado, Clínica Anglo Americana and INEN) from January 2016 until July 2020. Information available at diagnosis was: clinical, karyotype, molecular PCR panel, Illumina TruSight Myeloid Sequencing (TSM) panel which include 53 genes involved on oncogenesis, therapy regimen, response to treatment and overall survival (OS). Results A total of 31 cases were studied. F/M ratio 0.55 (11/20), median age 62 years (range 16-87), number of cases by disease were AML=23 and MDS=8. Among the 26 available karyotypes, the abnormal vs diploid karyotype ratio was 0.18 (4/22). Ad hoc PCR panel were positive in just 5 cases among 30 studies available, for FLT3-ITD(n=2), CBFB-MYH11(n=1), NPM1(n=1) and AML-ETO (n=1). In the TSM analysis, median number of pathogenic mutated genes was 3 (range 0-15). Most common (≥18%) pathogenic mutated genes wereBCOR (n=11; 35,5%), CUX1 (n=7; 22,6%) , DNMT3 (n=7; 22,6%), RAD21(n=6; 19,4%), and STAG2 (n=6; 19,4%)with different rates compare with other series (figure 1). Response rate were as follow: 58,1% complete (18/31), 9,7% partial (3/31), 19,3% non-response (6/31) and 12,9% non-evaluable (4/31). The estimated median OS was 36,67 months for the entire cohort, the 1 and 3-years OS rates were 69,9% and 62,2% respectively. For AML and MDS cases median OS was not reached, 1-year OS rates were 68,6% and 72,9% respectively, 3-years OS rates were 54,9% and 72,9% respectively (Log Rank 0,071 p=0,79). MutatedTP53was detected in 5 cases (MDS=3 and AML=2) with no therapy response in 4 and all of them had already dead; median OS for mutatedTP53cases was 3,53±0,43 months; 1-year OS rates for non-mutated vs mutatedTP53cases were 80,2% and 20% respectively, 3-year OS rates for cases with non-mutated vs mutatedTP53were 70,2% and 20% respectively (Log Rank 14,6 p Conclusion NGS for LMA/MDS is an important tool for diagnosis, assessment and risk stratification in our serie of cases. Only 5 over 53 genes were detected in ≥ 18% of casesBCOR, CUX1, DNMT3, RAD, and STAG. TP53 was related with a high therapy failure response and short OS. Number of pathogenic mutated genes ≥3 or ≥4 by TSM showed tendencies for shorter OS. A composite analysis for patients with 4 mutated genes with or without mutated-TP53showed significant shorter OS. Further studies with mature data and more cases are warrant to propose genetics characterization and risk stratification by NGS in Peruvian AML/MDS cases. Disclosures No relevant conflicts of interest to declare.

Background:Plasmablastic lymphoma (PBL) is an aggressive lymphoma associated mainly to HIV infection, although cases in immunocompetent patients are described as well. Objective:To describe the clinicopathologic features and determine the overall survival of lymphoma patients according human immunodeficiency virus (HIV) status in Peruvian patients. Methods:We reviewed the pathology databases of 2 cancer centers and a general hospital from Peru. Forty cases were documented between 2005 and 2020. Categorical variables were compared using Fisher's exact test. Survival curves were estimated using the Kaplan-Meier method and compared using the log-rank test. Statistical analysis was based on SPSS Program version 23. All cases were reviewed by two pathologists. Results:32 patients (80%) were HIV-positive. The median age for the whole cohort was 40 years (range, 22-86). The median age for HIV-positive and HIV-negative PBL patients were 37 years (range 22-67 years) and 57 years (range 27-86 years), respectively. The proportion of patients ≥60 years was lower in HIV-positive than in HIV-negative patients (8% and 37%, respectively; p= 0.046). 80% of patients in the whole cohort were female, and 84% and 62% in the HIV-positive and HIV-negative group, respectively. Extra-oral primary sites were the most frequent primary sites in both groups (66% and 88%, respectively). There were no statistically significant differences in Ann Arbor stage, Ki-67 expression, LDH levels, IPI scores, albumin levels, and neutrophil/lymphocyte ratio between HIV-positive and HIV-negative patients. All cases showed large lymphoid cells, of plasmablastic morphology with expression of at least one plasma cell marker (CD138, CD38, MUM1), CD45 positivity, variable expression of EMA, CD79 and CD30 and absence of expression of CD20, CD3, CD68 and LMP1; the proliferative index Ki67 varied between 60 and 90%. A small proportion of patients (18%) did not receive chemotherapy because of poor performance status or a personal decision. DA-EPOCH regimen was used in 52% and 25% of HIV+ and HIV- patients, respectively and CHOP/CHOEP regimen in 48 % and 75%, respectively. The overall response rate was 68% and 57% in HIV+ and HIV- patients with complete response (CR) in 32% and 14%, respectively. In the HIV-positive group, 66% of patients were antiretroviral therapy (ART)-naïve. The median progression-free survival (PFS) was 38 months and 7 months for HIV+ and HIV- patients, and the 1-year PFS was 74% and 0%, respectively. The median overall survival (OS) was 43 months (range 0.2-86.5) in HIV-positive patients and 10 months (range 0.5-19.0 months) in HIV-negative patients and the 1-year OS were 59% y 38%, respectively (p=0.27). Conclusions: PBL is a rare lymphoma, specially, if not related to HIV infection. In this study, 60 years or older was the only variable that showed significant difference. In our cohort, HIV-positive patients had better prognosis than HIV-negative PBL patients. Disclosures No relevant conflicts of interest to declare.

Frequency of IKZF1 Deletions in a Peruvian Population with B-cell Acute Lymphoblastic Leukemia Background: B-cell Acute Lymphoblastic Leukemia (B-ALL) is an aggressive disease with worse outcomes in older patients, and latino ethnicity. Additionally, Latino populations are at higher risk of developing B-ALL.IKZF1is an essential lymphoid transcription factor with deletions (ΔIKZF1)implicated in treatment failure and relapses. We aimed to evaluate the frequency ofIKZF1deletions in a cohort of Peruvian patients with newly diagnosed B-ALL. Methods: We collected diagnostic bone marrow samples from 41 consecutive patients with B-ALL diagnosed between 2015-2019 at Instituto Nacional de Enfermedades Neoplasicas (INEN; Lima, Peru). Bone marrow samples were cryopreserved prior to induction treatment. DNA was extracted using High Pure PCR Template Preparation Kit (Roche) at INEN. Samples with adequate DNA were screened forΔIKZF1by multiplex endpoint PCR covering four main deletions - dominant negative Δ4-7 or the loss of function Δ2-7, Δ4-8, and Δ2-8 IKZF1 deletions at UCL Cancer Insitute (London, UK) using the primers described by Caye et. al. We analyzed outcomes byIKZF1status. Results: Forty-one cases were enrolled during the study period. Clinical characteristics are presented in Table 1. Median age was 20 years[1-63]. Fifteen∆IKZF1cases (37%) were detected (67%BCR-ABL1 negand 33%BCR-ABL1pos).Cases withΔIKZF1were older than those with wild-typeIKZF1(median age 31 vs 13 years, p=0.002). Median presenting white blood count (WBC) was 48 x109/L [R:2-218], with a higher WBC inΔIKZF1compared to wild-type (87 vs 24 x109/L, p=0.001). The most frequent deletion was ∆4-7 (sevenBCR-ABL1 negand threeBCR-ABL1 pos) additional deletions are described in table 2. All patients received intensive 'pediatric-based' treatment, 21 with BFM-2009 and 19 with the CALGB 10403 protocol. CR rates after induction were 67% and 92% for∆IKZF1and wild-type cases, respectively. Eleven (73%) of patients with∆IKZF1subjects (73%) were MRD positive by flow cytometry after induction compared to 11 (44%) among wild-type. At a median follow-up of 2 years EFS was 38% in the∆IKZF1group and 58% in the wild type group, correspond OS was 38% and 58%, respectively. Conclusion: A high frequency of IKZF1 deletions was found in a Peruvian population with B-ALL and was associated with older age and higher presenting white blood counts. Prospective studies with larger Latino population are warranted to confirm this finding. Disclosures No relevant conflicts of interest to declare.

Introduction: The introduction of imatinib mesylate as first-line treatment has led to great improvements in the prognosis of patients with chronic myeloid leukemia (CML). The most used prognostic scores are Sokal, EUTOS and Hasford. Also, the time from diagnosis to imatinib and cytogenetic response influence the prognosis of patients with CML. However, there is no information about CML patients in chronic phase treated with imatinib in developing countries. Objectives: The aim of this study was to determine the prognostic factors in Peruvian patients with CML in chronic phase treated with imatinib (Glivec). Methods: Retrospective cohort of peruvian patients with chronic phase CML that received Imatinib (Glivec-Novartis) through the Glivec International Patient Assistance Program (GIPAP) in a national cancer center. The patients were classified according to prognostic scores of Sokal, EUTOS and Hasford at the beginning of imatinib therapy. The overall survival (OS) was calculated from the date of initiation of imatinib until the date of death or last contact. Event-free survival (EFS) was calculated from the date of start of treatment to date of occurrence of death from any cause during treatment, progression to accelerated phase or blast crisis CML or loss of major cytogenetic response. Transformation-free survival (TFS) was calculated from the date of start of treatment to date of occurrence of accelerated progression to blastic phase. Survival curves were estimated by Kaplan-Meier and comparison was done by log-rank test. Multivariate analysis for OS was performed with the Cox proportional hazard regression model. Results: 99 patients met the eligibility criteria and had a median observation time of 71.3 months. The average time from diagnosis to start imatinib was 11.4 months (CI 7.58-15.31). 14% of the patients had an age>55 years. The complete cytogenetic response at 12+3 months was 36%; the partial response was 16.67% and the lower response was 13.89%. According to the criteria of Sokal, EUTOS and Hasford, 59.58%, 49.49% and 27.27% were classified as higher risk, respectively. The 5-yrs-OS was 66.67% (CI 0.04-0.18%); 5-yrs-EFS, 68.63% (CI 0.13-0.38%) and 5-yrs-TFS, 60.82% (CI 0.21-0.41%). The patients with an age>55 years had significantly lower OS compared with the younger patients (p=0.039). The patients with a time higher than 12 months from diagnosis to imatinib had significantly lower OS than the patients that started it earlier (p=0.0076). The OS was significantly different according to the risk groups of Sokal score (p=0.0221). Also, significant difference was found in the EFS according to cytogenetic response (p=0.042). In the multivariate analysis, the factors that influence OS were high risk according toSokal score (HR=9.42 CI1.09-81.29) and a time greater than 12 months from diagnosis Imatinib (HC=3.53 CI1.12-11.18). Conclusion: In this Peruvian population, the majority of patients are at high risk groups of Sokal, EUTOS and Hasford scores. High risk according to Sokal score and a time higher than 12 months from diagnosis to imatinib were the main prognostic factors. Disclosures No relevant conflicts of interest to declare.