Question: Dr. Chiragbhai, thank you for explaining in last part about Myeloproliferative Neoplasms, including their common features, and specific molecular diagnostic tests. Can you tell us more about these diseases, each one specifically?
Ans: We will discuss the common ones specifically. Let me remind you again that even though now they are classified as Neoplasms (cancers), many of them run a benign course in most patients. It is important to recognize that many of these patients have near normal life span, if they are taken care of well. At the same time, if not well controlled, the complications are serious and organ or life threatening. One such serious complication which is largely preventable is Thrombosis in a patient with polycythemia or essential thrombocytosis. Many of these are in critical sites leading to liver failure, intestinal gangrene, stroke, amputation etc. However, if blood counts are maintained in advisable limits, thrombosis is very uncommon. To put it in numbers, a patient with polycythemia vera has a median survival of less than 2 years if untreated, but more than 10 years if treated.
Let us start with polycythemia vera. This is a disease associated with primarily high Hb/Hct/RBC count. However many patients do have associated increase in wbc and platelet count. Patients present with either incidental high Hb or with following symptoms. Symptoms may be nonspecific like headache , weakness, dizziness, gout related pain, pruritus especially after a hot water bath etc. Erythromelalgia i.e. pain in fingers and toes or tingling OR transient visual disturbances are other symptoms. Erythromelalgia is typically relieved by aspirin. Abdominal pain, peptic ulcer are also common. On examination, there may be facial plethora (darker skin and tongue due to high Hb), splenomegaly, hepatomegaly.
Bone marrow is hypercellular. JAK 2 V617F mutation is present in more than 90% cases. RBC mass is no longer available at most places in world, and is rarely done. Some patients may present with normal cbc or only mild high Hb, due to splenomegaly which may mask the disease. Any patient with thrombosis at odd sites such as portal or mesenteric vein or hepatic vein, should be tested for JAK 2 mutation to uncover such masked polycythemia patients. This is very important to ensure they are treated and recurrent event prevented.
Serum erythropoietin at low or normal levels is another test which is indicative of polycythemia in a patient with high Hb, along with bone marrow findings. Testing for Epo level also helps to rule out uncommon but important secondary causes of high Hb, such as some tumors, hypoxia.
Que: What is the treatment and prognosis of these patients?
Ans: As noted earlier, treated patients have a very good prognosis. Some patients may still develop critical site thrombosis such as heart, stroke, GI – all of which are frequently life threatening. Other serious complications are conversion to acute leukemia or bone marrow fibrosis.
Best treatment for PV is PHLEBOTOMY. This is the simplest, safest and still considered the best therapy. Goal is to keep Hct below 45. Initially more frequent phlebotomy is required, but later generally every 2-3 months is sufficient. Iron rich diet is to be avoided. Low dose Aspirin is given to all patients, however benefit is small and somewhat controversial. Higher dose aspirin should be avoided as there is risk of increased bleeding in these patients. Hydroxyurea is used for high risk patients defined as age >60 or those with a history of thrombosis. Anagrelide is required in some patients if hydroxyurea is not tolerated or not effective. Pruritus responds to fluoxetine or paroxetine. If uric acid is high or gout, give allopurinol.
Optimal platelet count is not known. Patients with thrombosis are treated with hydroxyurea to keep platelet count near normal.
Dr. Chirag A. Shah; M.D. Oncology/Hematology (USA), 079 26754001. Diplomate American Board of Oncology and Hematology. Ahmedabad. firstname.lastname@example.org Shyam Hem-Onc Clinic. 402 Galaxy, Near Shivranjani, Opp Jhansi ki Rani BRTS, Ahmedabad. www.shyamhemoncclinic.com