Question: Dr. Chiragbhai, thank you for explaining in last part about Non Hodgkin’s Lymphoma etiology, broad categories and diagnosis. We learnt a very important lesson that FNAC should not be done when suspecting lymphoma. An excisional node biopsy should be done. Does this mean that biopsy is sufficient to differentiate so many subtypes of NHL?
Answer: Good question. Biopsy i.e. basic histopathology reading under the microscope, is sufficient in some cases but not all. Increasingly, IHC (immunohistochemistry) is done to confirm diagnosis and subtype of NHL. IHC is important for following reasons:
- Confirmation of diagnosis – low grade lymphomas can be misleading on histology alone. Often needs support of IHC and other special tests.
- Subtype determination – such as B cell or T cell. Also, to determine further subtyping, which is often important for prognosis and sometimes for deciding which therapy to use, such as ALK testing.
- Treatment determination – for example, only CD 20 positive lymphomas respond to a targeted therapy called Rituximab. Also determination of exact subtype may change therapy decisions, for example a lymphoblastic lymphoma is treated like ALL-acute lymphoblastic leukemia.
Other special tests, such as molecular genetics are also useful and sometimes mandatory for diagnosis. Cyclin D1 determination helps diagnosis of Mantle cell lymphoma, C-Myc for Burkitt and others.
Que: What is the next step after Diagnosis?
Ans: Staging and Prognostication. This requires imaging studies such as PET-CT scan or CT scan/USG, bone marrow biopsy in most cases, and special tests as noted earlier. Based on subtype and site of disease, there are some variations in these tests. HIV should be done in all cases, as HIV induced immune suppression is a risk factor for specific types of lymphomas, and they need to be managed differently. Hepatitis B test is required before Rituximab. Hepatitis C is important in some rare subtypes.
One of the most important parameter in judging prognosis is not based on special tests, but on basic clinical information. This is known as IPI-International Prognostic Index. IPI is not applicable for low grade lymphomas. It includes age, stage, LDH, performance status (or fitness of the patient in simper terms – there are good ways to objectively measure this by simple questions asked during our routine patient interview), number of extranodal sites (such as lung, liver..). IPI correlates well with prognosis, such as those with score 0 have a 80% cure rate whereas score 3 have a 30% cure rate.
For low grade lymphomas, there is a different tool known as FLIPI.
PET–CT response after 2-4 cycles of chemotherapy is one of the best prognostic markers. Those with complete response have a markedly better survival-about 80%, compared with those who do not-about 20%.
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