Outcomes in Adult Acute Promyelocytic Leukemia (APL): A Real World Scenario
Authors: Yedla Rajani Priya , Pydi Venkateswar Rao , Palukuri Nageswara Reddy , Ambalathandi Ravichandran , Bala Stalin Chowdary , Konatam Meher Lakshmi , Gundeti Sadashivudu 
Published: October 2019

Abstract
Background:
Acute promyelocytic leukemia (APL) accounts for approximately 10% of acute myeloid leukemia(AML) cases in adults. With the advent of targeted therapy like all- trans retinoic acid (ATRA) and arsenic trioxide, survival rates have improved leading to cure in majority of patients. The present study was designed to analyze the outcomes in newly diagnosed APL.
Aims and objectives:
The primary objective of this study was to analyze overall survival and relapse rate in APL.
Secondary objective was to study the parameters impacting outcomes in APL.
Materials and methods:
All newly diagnosed patients with APL between January 2005 and December 2017 were retrospectively analyzed. Diagnosis of APL was confirmed by demonstration of PML-RARA translocation by polymerase chain reaction or fluorescence in situ hydridization. Risk stratification was done using Sanz risk. Event free survival was defined as the time from diagnosis till relapse, death or lost to follow up. Overall survival was defined as time from diagnosis till death or lost to follow up. Statistical analysis was done using SPSS software, v.25. Overall survival curves were plotted using the Kaplan-Meier method.
INCLUSION CRITERIA:
All cases of APL diagnosed by morphology and confirmed by RT PCR (PML RARα) were included in this study.
EXCLUSION CRITERIA: Age ≤ 18yrs Death within 72 hours of admission / not taken treatment Prior chemotherapy or radiotherapy for the treatment of malignancy.
Results:
Data of 1396 AML patients between 2005 and 2017 was collected, of which 190(13.6%) patients had APL. Of 190 patients, 111 patients who met inclusion and exclusion criteria were analyzed. The median age at presentation was 33 years (range,19-60). The male female ratio was 1.01:1. The median duration of symptoms at presentation was 15 days (range, 3-180). According to Sanz risk grouping, high, intermediate and low risk were seen in 48 (43.1%), 46 (42.4%), 17(14.5%) patients respectively. The baseline characteristics are tabulated in Table 1.
Of 111 patients, 96 (86.5%) patients received induction chemotherapy with ATRA and daunorubicin and 15(13.5%) patients received ATRA and arsenic trioxide. Induction mortality was 23(20.7%). Eighty-eight (79%) patients survived induction chemotherapy, of which 87(98.8%) were in complete molecular remission (CMR) at the end of consolidation. At a median follow up of 30 months, the event free survival rate, overall survival rate and relapse rate were 72%, 74.7% and 9% respectively. The overall survival rate in low-intermediate and high-risk groups were 84.1% and 62.5% respectively. Of eight patients who relapsed, five patients received second line chemotherapy and attained second CMR (100%). On univariate analysis, the strongest predictors for OS were high risk and bcr3 variant(p=0.007, p=<0.001 respectively). On multivariate analysis, only high risk was significant for overall survival (p=0.02).
Conclusion:
Majority of APL patients were high risk at presentation. High risk and bcr3 variant had significant impact on survival outcome in APL. As relapse rates were low and second CMR can be achieved with salvage chemotherapy in majority of patients, improving induction outcomes will further improve survivals in APL.

Disclosures
No relevant conflicts of interest to declare.