Secondary acute promyelocytic leukemia following chemotherapy for non-Hodgkin's lymphoma in a child

Advances in Pediatric Acute Promyelocytic Leukemia

Acute promyelocytic leukemia (APL) is a rare disease accounting for only 5%-10% of pediatric acute myeloid leukemia (AML) and fewer than 1000 cases occur annually in the United States across all age groups. Characterized by t (15; 17), with a resultant PML-RARA gene fusion driving leukemia development, advances in therapy have improved outcomes for APL significantly in the past several decades, now making APL the most curable form of AML in both children and adults. Cure rates in APL are now comparable to pediatric B-lymphoid leukemias. The success of APL treatment is due, in part, to the breadth of understanding of the driver PML-RARA mutation as well as collaborative efforts to quickly introduce and maximize the benefit of new therapies. Here, we review the presentation, clinical features, pathogenesis, and treatment advances in pediatric APL.

Therapy-related acute myeloid leukemia in patients with lymphoma: A report of four cases and review of the literature

Due to advances in the treatment of lymphoma, the remission and overall survival rates for this disease have improved in recent years. However, the incidence of therapy-related myelodysplastic syndrome/acute myeloid leukemia (t-MDS/AML) has increased. In order to further the understanding of the mechanisms of t-MDS/AML and reduce its incidence, the present study reports 4 cases of t-AML following treatment for lymphoma. The 4 patients presented aggressive forms of lymphoma in stage III/IV, and 3 were diagnosed with non-Hodgkin's lymphoma. All patients had previously undergone chemotherapy containing alkylating agents and/or topoisomerase II inhibitors. The latency period between the time of primary diagnosis and occurrence of t-AML ranged from 15 to 42 months. At the time of diagnosis of t-AML, 3 of the 4 patients presented pancytopenia, whilst the remaining patient exhibited leukocytosis. The majority of the patients succumbed to their disease within 1 year of t-AML diagnosis, with the exception of the patient in case 3, who survived following allogeneic hematopoietic stem cell transplantation (allo-HSCT). The present cases indicate that an advanced stage of disease at the time of primary diagnosis, prior exposure to radiotherapy, and administration of ≥4 regimens and ≥8 cycles of chemotherapy may be risk factors for the development of t-AML. Based on the present findings and a review of the literature, we propose that allo-HSCT should be recommended for patients at high risk of developing t-AML. In addition, chimeric antigen receptor T-cell immunotherapy may constitute a novel type of immunotherapy for the treatment of cancer, particularly for cases of relapsed and refractory lymphoma or leukemia.

Global characteristics of childhood acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) comprises approximately 5-10% of childhood acute myeloid leukemia (AML) cases in the US. While variation in this percentage among other populations was noted previously, global patterns of childhood APL have not been thoroughly characterized. In this comprehensive review of childhood APL, we examined its geographic pattern and the potential contribution of environmental factors to observed variation. In 142 studies (spanning >60 countries) identified, variation was apparent-de novo APL represented from 2% (Switzerland) to >50% (Nicaragua) of childhood AML in different geographic regions. Because a limited number of previous studies addressed specific environmental exposures that potentially underlie childhood APL development, we gathered 28 childhood cases of therapy-related APL, which exemplified associations between prior exposures to chemotherapeutic drugs/radiation and APL diagnosis. Future population-based studies examining childhood APL patterns and the potential association with specific environmental exposures and other risk factors are needed.

Treatment of paediatric APL: how does the therapeutic approach differ from adults?

Acute promyelocytic leukaemia (APL) in children and adolescents shares many features with APL in adults. There are important distinctions, however, between these age groups in the presentation, complications and treatment outcomes. Paediatric patients are more likely to present with high risk features including elevated WBC count or microgranular variant (M3v). Yet the early death rate is lower in paediatric patients compared to adult patients. Overall outcomes such as CR, OS and EFS appear similar in paediatric and adult patients treated on similar regimens except that very young children may have a higher risk of relapse. While contemporary studies have clearly demonstrated improved survival in adults receiving ATO therapy, currently there is more limited data on the role of ATO in paediatric patients. Here we highlight the similarities and important distinctions between paediatric and adult APL while reviewing available data on treatment of paediatric APL.

Acute promyelocytic leukemia following chemotherapy for EBV-associated hemophagocytic lymphohistiocytosis

We report a case of chemotherapy-related acute promyelocytic leukemia (APL) following therapy with VP-16/etoposide for EBV-associated hemophagocytic lymphohistiocytosis (HLH). A 17-month-old male presented with fever and lymphadenopathy. Bone marrow and liver biopsies showed hemophagocytosis. He responded well to chemotherapy including dexamethasone, VP-16/etoposide, and cyclosporine. One and a half year later, he developed fever and pancytopenia. Clinical work-up revealed APL with t(15;17)(q22;q12);PML-RARα translocation. He underwent chemotherapy for APL and is in remission 8 years after diagnosis. Alternative non-leukemogenic agents to effectively treat HLH would be desirable.

Outcomes of a two-drug chemotherapy regimen for intraocular retinoblastoma

BACKGROUND

Retinoblastoma is the most common intraocular tumor of childhood. Vision salvage rates in advanced cases are less than ideal, and the optimal treatment for intraocular retinoblastoma has not been established. We report the results of an institutional retinoblastoma treatment trial to determine the vision salvage rates and toxicity of a regimen combining carboplatin and etoposide with focal retinal therapy.

PROCEDURE

Twenty-nine patients diagnosed with retinoblastoma in 48 eyes were treated between 1992 and 2004 with at least six cycles of carboplatin and etoposide combined with focal retinal therapy.

RESULTS

The response rate of eyes after six cycles of chemotherapy was 85.4%. Twenty-two eyes were enucleated, but only seven eyes received EBRT. The vision salvage rate without EBRT was 82.6% for eyes with Reese-Ellsworth (R-E) groups I-IV tumors and 20% for eyes with R-E group V tumors. The vision salvage rate without EBRT for eyes with Murphree groups A and B tumors was 77.3% but was only 26.9% for eyes with groups C and D tumors. Acute side effects were minimal.

CONCLUSIONS

The combination of carboplatin and etoposide with focal therapy is a well-tolerated regimen that has acceptable vision salvage rates for R-E groups I-IV and Murphree groups A and B retinoblastoma. This combination avoids the use of EBRT and the toxicity of additional chemotherapy agents. However, patients with R-E group V and Murphree groups C and D retinoblastoma have poorer outcomes and require more intensive therapy.