SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.
Code 9823/3 is used for CLL, SLL, and CLL/SLL. CLL and SLL are no longer coded separately because it is almost impossible to differentiate between the two diseases. See the hematopoieticPH rules for information on codingprimary site for CLL/SLL. CLL is the most common leukemia of adults in Western countries. The incidence of CLL is very low in Eastern countries and in immigrants from Eastern countries.
CLL is frequently diagnosed by flow cytometry (immunophenotyping), but can also be diagnosed via biopsy (bone marrow).
Flow cytometry is also used for ZAP 70, which is a predictor for aggressive vs indolent disease. If the ZAP 70 is positive, that means the disease is more aggressive and will need closer follow up. If the ZAP 70 is negative, then the disease is on a more indolent course. If the disease is more aggressive, treatment timing will change.
The treatment-free survival time was 30 months for ZAP-70 negative patients and 18 months for ZAP-70 positive patients.