Timely Diagnosis of Acute Promyelocytic Leukemia

Transcript:Ehab Atallah, MD: Patients with APL usually present with bleeding or sometimes they present with feeling tired and having bone pain. Sometimes, if they’ve had a major CNS bleed, they present with change in mental status.

Elihu Estey, MD: APL is a rare disease. It constitutes about 3% of all people with AML. There are about 30,000 people with AML in the United States a year. So, therefore, there are probably about only a few hundred with APL in the United States each year. But, it’s known that certain people are at particular risk of developing APL among those who develop AML. And the risk factors, each of which is independent of the other, are younger age—generally in their 40s, as opposed to AML, which is generally in the 60s or 70s—Hispanic ethnic origin, and obesity. So, each of those independently predict when someone with AML will have APL. I probably see 10 to 15 a year, but I’ve been doing that for 30 years, so that’s a fair number of APL patients by now.

Ehab Atallah, MD: The differential diagnosis of APL includes many things that can cause low blood counts in many different types of leukemia. The main differential diagnosis is the other types of acute leukemia, which is essentially AML or ALL. When a diagnosis of APL is suspected, the first thing that happens is the pathologist reviews the peripheral blood smear. And just on the peripheral blood smear, sometimes they see certain markers or certain features of the leukemia that would be suggestive of APL. Immediately, we should order a FISH test for the translocation 15;17 to confirm the diagnosis of APL.

Elihu Estey, MD: The major thing in making sure the APL is correctly diagnosed is you have to be aware of the diagnosis. That’s certainly the most important thing. And you should be aware of it when the patient presents with weakness, bleeding, bruises, and things like that. When you see their blood count, it’s generally abnormal, and, in particular, they often have coagulation abnormalities. Once you see someone with this history, in particular with coagulation abnormalities and a very abnormal blood count, then probably the first thing you should do is, even before you actually make the diagnosis, get a bone marrow to make the diagnosis. But, these days, people should probably be started on some kind of therapy even before the diagnosis is firmly established, and the reason for that is that the side effects of the therapy are manageable. So, if you make the wrong diagnosis, worse things have happened than if you give the patient the treatment. But, if you don’t give the patient the treatment fairly promptly, then they generally die, and they most often die of bleeding either in their brain or their lung.

The diagnosis is almost always made by oncologists, hematologists, and oncologists. The main thing that people in the ER or in general practice should be aware of is the existence of the disease and the symptoms, particularly the bleeding that’s part of the diagnosis.

Ehab Atallah, MD: Given that APL has such an excellent prognosis with more than 80% of patients cured, even patients with low-risk disease, a higher percentage of them are cured. Once a diagnosis of APL is suspected, ATRA should be started as soon as possible.

Transcript Edited for Clarity