Hematologist
CION Cancer Clinics
APL: highly treatable, and the most urgent leukaemia | CION Cancer Clinics
Acute promyelocytic leukaemia (APL) is a rare type of acute myeloid leukaemia caused by a faulty joined gene called PML-RARA. It is one of the most treatable leukaemias, but in the first days it can cause serious bleeding. That is why it is treated as an emergency, often before tests confirm it. This page explains what APL is, the signs, and what happens first. At CION Cancer Clinics, every leukaemia, MDS and MPN case is reviewed by our haematologist and discussed at a tumour board before a plan is agreed.
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Medically reviewed by Dr. Basudev PokhrelConsultant Haematologist · last reviewed September 2026, next review due September 2027
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The short answer
What is APL, in plain words?
Acute promyelocytic leukaemia (APL) is a rare, fast-moving type of acute myeloid leukaemia. It is one of the most treatable leukaemias there is, but the first days carry a real risk of serious bleeding, so it is handled as an emergency.
What goes wrong inside the marrow
Your bone marrow is the soft tissue inside your bones where blood is made. In APL, young white cells called promyelocytes stop growing up. They build up in the marrow and crowd out the red cells, working white cells and platelets you need. The cause is a swap of genetic material between two chromosomes, which joins two genes into one faulty gene called PML-RARA.
Why APL is different from other leukaemias
The stuck cells release substances that upset the way blood clots. Clotting factors get used up fast, so bleeding can start in the gut, the lungs or the brain. That is the danger. The good news is that the faulty gene is also the target. Two medicines, ATRA and arsenic trioxide, act on it directly and push the stuck cells to grow up.
Who gets it
APL can happen at any age, but it is more often seen in younger and middle-aged adults than other types of AML. Most people have no clear cause. It is not caught from anyone, and it is not passed down in families.
!
If APL has been mentioned, bleeding cannot wait
Nosebleeds or gum bleeding that will not stop, blood in vomit, urine or stools, new large bruises, a sudden severe headache, confusion, drowsiness or breathlessness. Go to the nearest emergency department now or call 108. Take the blood report and say the doctor suspects APL. Do not wait for a clinic slot the next morning.
Not sure whether this applies to you?
Ask an oncologistHow it usually shows up
What signs lead doctors to suspect APL?
Most people come in with a mix of the signs below. None of them alone means APL. Together with a blood report, they tell the doctor to act quickly.
Bruising and bleeding
Bruises that appear without a knock, tiny red spots on the skin, bleeding gums, long nosebleeds or unusually heavy periods. In APL these often come first and can be worse than the counts suggest.
Tiredness and paleness
When haemoglobin falls, you feel tired, look pale and get breathless on stairs. Some people notice a racing heart or dizziness when they stand up quickly.
Fevers and infections
Few of the white cells can fight germs. Fevers may come without an obvious reason, and infections may last longer than usual.
What the report shows
The pattern that raises the alarm is a low platelet count with abnormal clotting tests.
Often seen together
- Low platelets
- A low or only slightly raised white count
- Abnormal cells on the blood smear
- Low fibrinogen, a clotting protein
The first days
What happens once APL is suspected?
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Admission, not an outpatient visit
APL is managed in hospital from the start. The team needs to watch the clotting tests closely and respond to them quickly.
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ATRA started on suspicion
ATRA is usually started as soon as a doctor suspects APL from the blood smear, before the genetic test comes back. Waiting for proof would leave the bleeding risk untreated.
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Blood products to support clotting
Platelets, plasma or cryoprecipitate may be given to replace what the body has used up. The team decides how much from repeated tests.
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Confirming the diagnosis
A bone marrow test and a genetic test look for the PML-RARA gene or the chromosome swap behind it. This confirms APL and sets the plan.
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The full treatment plan
For most people, ATRA is combined with arsenic trioxide. Some need chemotherapy added, depending on the counts and their general health.
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On your report
What do the words on an APL report mean?
- Promyelocytes
- Young white cells that normally grow up in the marrow. In APL they are stuck at this stage and build up.
- t(15;17)
- The chromosome swap that causes APL. Part of chromosome 15 and part of chromosome 17 change places.
- PML-RARA
- The faulty joined gene created by that swap. Finding it confirms APL.
- Coagulopathy
- A problem with how the blood clots. In APL it causes bleeding and, less often, clots.
- ATRA
- All-trans retinoic acid, a vitamin A based medicine taken by mouth that helps the stuck cells grow up.
- Remission
- No leukaemia can be found with standard tests. It is a milestone in treatment, not the end of it.
Commonly believed
What do families often get wrong about APL?
"Leukaemia is leukaemia. We can take a few days to decide."
APL is the one leukaemia where days matter most. The risk of serious bleeding is highest right at the start, before treatment takes hold. Going to hospital the same day is the single most useful thing a family can do.
"Arsenic is a poison. Why would a doctor give it?"
Arsenic trioxide is a licensed medicine used in a controlled, monitored way. It works on the faulty gene that drives APL. It is nothing like the arsenic in contaminated water, and its side effects are watched with regular tests.
"If treatment starts before the test result, the diagnosis must be a guess."
Early ATRA is a deliberate safety step. The harm of waiting is much greater than the harm of a short course that is stopped if the test does not confirm APL.
"Once the counts are normal, we can stop treatment."
Normal counts mean the treatment is working. The plan still runs its full course, and follow-up tests check that the faulty gene stays out of sight.
Being straight with you
What can this page not tell you about your own case?
This page cannot tell you whether you or your parent has APL. Only a blood smear, a marrow test and a genetic test can do that. It also cannot tell you how things will go for one person.
What shapes the outlook
The outlook in APL is often very good once the early weeks are safely passed. What affects it most is how quickly treatment starts, whether serious bleeding happens early, the white count at diagnosis, age and other health problems. Your haematologist can explain how these apply to you.
What CION does and does not do
CION's haematology team reviews the reports, presents the case to a tumour board and coordinates care with hospitals that can admit and monitor APL around the clock. If you are already admitted elsewhere, stay where you are and keep treatment going. A second opinion can come alongside, never instead of it.
Never stop or change ATRA, arsenic trioxide or any other medicine on your own. The treating team sets every change.Questions we are asked
Common questions about APL
Is APL the same as AML?
APL is a subtype of acute myeloid leukaemia (AML). It behaves differently enough to be treated as its own disease. It has a specific faulty gene, a higher early bleeding risk, and a treatment built around ATRA and arsenic trioxide rather than the chemotherapy used for most other types of AML.
Why is APL called an emergency if it is so treatable?
Both are true. Most of the danger sits in the first days, when the clotting system is badly upset and bleeding can happen in the brain or lungs. Once treatment has settled the clotting problem, the disease usually responds well. Getting safely through that early window is what matters most.
Can APL be diagnosed from a normal blood test?
A complete blood count and a blood smear can raise strong suspicion, especially when platelets are low and clotting tests are abnormal. The diagnosis is confirmed by a bone marrow test and a genetic test for PML-RARA. Treatment usually starts on suspicion, while those confirming results are awaited.
Does APL need chemotherapy?
Many people are treated with ATRA and arsenic trioxide without standard chemotherapy. Some, often those with a high white count at diagnosis, may have chemotherapy added. The plan depends on your counts, age, heart and kidney health, and what is available. Ask your haematologist why a plan was chosen.
Is APL hereditary? Should my children be tested?
No. The gene change in APL happens in the marrow cells during life. It is not inherited from parents and is not passed on to children. Family members do not need testing for it. If relatives have their own symptoms, they should see their own doctor about those.
How long does APL treatment take?
Treatment has an intensive first phase in hospital, followed by further courses and regular follow-up tests. The total length depends on the plan your team chooses and how you respond. Your haematologist will give you a written outline of each phase, so the family can plan work and travel.
What side effects should we watch for at home?
Tell the team straight away about breathlessness, fever, sudden weight gain or swelling, bleeding, fainting or a racing heart. ATRA and arsenic can cause a reaction called differentiation syndrome, and arsenic can affect heart rhythm. These are watched with regular checks, and early reporting makes them easier to manage.
Is APL treatment covered by Aarogyasri or insurance?
Leukaemia treatment is often covered under Aarogyasri, PM-JAY, CGHS, ECHS, EHS and cashless insurance, but package rules and drug coverage change. Check the current rules for your card before you assume a figure. Call the helpline with your card details and we will help you check your cover.
Your Haematologist
Meet CION's haematologist. One specialist for your blood report and your plan.
Dr. Basudev Pokhrel reviews blood counts, transfusion needs and blood disorders, and works with the CION tumour board on blood cancers.
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Where to find us
Our centres in and around Hyderabad
Addressed by landmark, because that is how this city navigates. A haematology consultation can be booked at any of these centres through one helpline, and your team will tell you where each test or treatment takes place.
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Sources
- American Cancer Society — Treating Acute Promyelocytic (M3) Leukemia
- National Cancer Institute — Adult Acute Myeloid Leukemia Treatment (PDQ) - Patient Version
- Cancer Research UK — Acute myeloid leukaemia (AML)
- Leukemia & Lymphoma Society — Acute Myeloid Leukemia (AML)
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Why APL Is Treated Before the Diagnosis Is ConfirmedWhy ATRA starts before the test resultBleeding Risk in APL: What Families Must KnowThe warning signs to act on nowATRA and Arsenic: Chemotherapy-Free Treatment for APLHow the main treatment worksPML-RARA: The Test That Confirms APLThe genetic test on your report
Talk to us
Has APL been mentioned on a report?
Share the reports with us. CION's haematology team will tell you how urgent it is and what to ask the treating team. One helpline serves every CION centre.