METHOD: A total of 2937 newly diagnosed patients with stage I and stage II breast cancer in University Malaya Medical Centre between Jan 1993 to Dec 2012 were included in the study. Multinomial logistic regression analysis allowing death to compete with CBC as a study outcome was used; patients with unilateral breast cancer who were alive were taken as reference. A stepwise backward regression analysis including age at diagnosis, ethnicity, family history of breast cancer, TNM stage, hormonal receptor status, HER2 status, chemotherapy, radiotherapy, and hormone therapy was conducted.
RESULTS: Fifty women developed CBC, over a median follow-up of 6 years. The 5- and 10-year cumulative risk of contralateral breast cancer was 1.0% (95% CI 0.6-1.4%) and 2.8% (95% CI 2.0-3.6%), respectively. Young age at diagnosis of first cancer, positive family history, and stage I disease were independent predictors of CBC.
DISCUSSION: The current study suggests that the risk of CBC is very low in a Southeast Asian setting. Any recommendations or practice of CRRM should be reviewed with caution and patients must be counseled appropriately.
CASE REPORT: A 59-year-old man was diagnosed with acute promyelocytic leukaemia. Following this, he underwent all-trans retinoic acid (ATRA) based chemotherapy and achieved remission. Four years later, the disease relapsed and he was given idarubicin, mitoxantrone and ATRA followed by maintenance chemotherapy (ATRA, mercaptopurine and methotrexate). He achieved a second remission for the next 11 years. During a follow-up later, his full blood picture showed leucocytosis, anaemia and leucoerythroblastic picture. Bone marrow examination showed hypercellular marrow with trilineage dysplasia, 3% blasts but no abnormal promyelocyte. Fluorescence in-situ hybridisation (FISH) study of the PML/RARA gene was negative. Karyotyping result revealed complex abnormalities and monosomal karyotype (MK). A diagnosis of therapy-related myelodysplastic syndrome/myeloproliferative neoplasm with unfavourable karyotypes and MK was made. The disease progressed rapidly and transformed into therapy-related acute myeloid leukaemia in less than four months, complicated with severe pneumonia. Despite aggressive treatment with antibiotics and chemotherapy, the patient succumbed to the illness two weeks after the diagnosis.
DISCUSSION AND CONCLUSION: Diagnosis of t-MN should be suspected in patients with a history of receiving cytotoxic agents. Karyotyping analysis is crucial for risk stratification as MK in addition to complex aberrant karyotypes predicts unfavourable outcome. Further studies are required to address the optimal management for patients with t-MN.