Canterbury DHB

Monitoring and Response

FBC and biochemistry

Check FBC, U&E and LFT weekly for the first 4 weeks, and then at least fortnightly until a complete haematological response (CHR) is achieved and confirmed.

Then check FBC and biochemistry profile at least every 3 months.

qRT-PCR BCR-ABL

qRT-PCR for BCR-ABL is best assessed according to the International Scale as the ratio of BCR---ABL1 transcripts to ABL1 transcripts. It is expressed and reported as BCR---ABL1 % on a log scale as a reduction below the standard baseline.

Check qRT-PCR every 3 months for the first 3 years (during highest risk of disease progression). If a major molecular response (MMR) is achieved and confirmed and there are no concerns regarding compliance, consider reducing to 6 monthly. If there is concern about loss of response, repeat PCR as soon as possible.

See London Cancer CML Guidelines⁴ table on page 5.

Refer to patients with undetectable transcripts as having 'molecularly undetectable leukaemia' and specify the number of the control gene transcript copies.

Bone marrow biopsy and cytogenetics

Australasian and European LeukemiaNet guidelines (last updated 2013)⁵ recommend checking BM and cytogenetics (G-banding) at 3 months, 6 months, and then every 6 months or until a complete cytogenetic response (CCR) is achieved.

However, there is increasing validation of peripheral blood BCR-ABL PCR monitoring and experience in its use, along with a wish to spare patients the discomfort of multiple bone marrow biopsies. One practical option is to rely on q-PCR monitoring alone, with a low threshold for checking the patient’s bone marrow if the PCR response is not optimal. Patients whose PCR is ≥10% at 3 months have a significantly lower 8-year probability of overall survival (56.9% vs. 93.3%), and should be monitored more closely.

Check bone marrow, cytogenetic (G-banding) and mutation analysis if there is a loss of response, particularly if there is a need to consider changing therapy.

Topic Code: 533088