Defining Primary Vs Secondary AML: Correlation between Pathology and NGS/FISH

Introduction: The treatment of acute myelogenous leukemia (AML) is often determined by factors that include an antecedent dysplasia. At presentation it is often unknown whether a patient has had dysplastic bone marrow features or not. We opted to look back at our leukemia patients to determine the frequency of antecedent dysplasia and to determine if next generation sequencing (NGS) or Florescent in situ hybridization (FISH) findings correlate with the pathologic review.

Methods: We chart reviewed 43 charts from a period of 9/21/2021 to current from Orlando Health records. We focused on 29 charts that we could gather complete information from. We reviewed initial bone marrow biopsies and NGS/ FISH findings. We determined if a patient had a known history of myelodysplasia from previous records. If there was no known history of myelodysplastic syndrome (MDS) but dysplasia was seen on the bone marrow biopsy, we looked at NGS/FISH. While there can be overlap with AML, findings that suggest MDS are as follows:

NGS: TET2, NRAS, U2AF1, RUNX1, TP53, SF3B1

FISH: 5q-, -5 (5p15, 5q31, 5q33), 7q-, -7 (Cen 7, 7q22, 7q31), Trisomy 8 (Cen 8), MLL (11q23), 20q- (20q12, 20qter)

We then examined what treatments were used based on these findings.

Results:

Overall:

11/29 patients had dysplasia mentioned in their initial pathology report. 4/11 had a known preexistent dysplasia. Of the 7 who didn't have known dysplasia, 6/7 had an NGS or FISH suggesting MDS.

Age:

Of the patient who had dysplastic findings as well as NGS/FISH to support those findings, the patients had an average age of 57. The one patient without MDS/FISH findings has an age of 69. The average age of all patients with dysplastic findings on their bone marrow was 60. Of the patients who did not have any dysplastic findings on the bone marrow, the average age was 58.

Treatment:

Vyexos (liposomal daunorubicin and cytarabine), a therapy generally used for secondary leukemias was only used in two patients. Age and performance status was cited as a reason to use alternative therapy. Although one patient did receive 7+3 (idarubicin and cytarabine) instead of Vyxeos. One patient also had severe COVID pneumonia at diagnosis as the reason for not getting induction with Vyexos and instead getting venetoclax/azacitidine. Four patients were either treated with hypomethylating agent of either azacitidine or decitabine, again this was normally chosen due to performance status, age, or active COVID pneumonia as above.

Conclusion: These results show that pathology findings of underlying dysplastic changes seem to correlate with NGS or FISH findings. Of the 7 patients with these bone marrow changes but no known MDS, 6 of them had NGS or FISH to support an underlying disease. Factors such as age did not help to predict antecedent MDS. Based on this information it may be appropriate to start with induction therapies such as Vyxeos when dysplastic changes are seen on the bone marrow while FISH and NGS are still pending, if their performance status and age allow to do so. Further larger retrospective studies to compare underlying dysplastic findings versus FISH/NGS findings should be done to further support this concept.

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