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Difficulty: HardPediatric Hematology and Oncology

A crucial component of pediatric hematology and oncology is managing the long-term survivorship of patients exposed to cytotoxic chemotherapy. Match the following chemotherapeutic classes commonly used in pediatric malignancies to their precise mechanism of target-organ toxicity or associated secondary malignancy.

  • Anthracyclines (e.g., Doxorubicin)Generates reactive oxygen species and complexes with topoisomerase II β\beta, causing cumulative, irreversible myocyte necrosis and dilated cardiomyopathy.
  • Platinum compounds (e.g., Cisplatin)Triggers apoptosis of outer hair cells in the basal turn of the cochlea, manifesting as permanent, high-frequency sensorineural hearing loss.
  • Nitrogen mustards (e.g., Cyclophosphamide)Produces the toxic urothelial metabolite acrolein, requiring vigorous hydration and 2-mercaptoethane sulfonate for prevention of hemorrhagic cystitis.
  • Epipodophyllotoxins (e.g., Etoposide)Induces DNA double-strand breaks that increase the risk of secondary acute myeloid leukemia, characteristically featuring 11q23 (KMT2A) translocations.

Answer

Anthracyclines match with reactive oxygen species and topoisomerase II β\beta (cardiomyopathy). Platinum compounds match with apoptosis of outer hair cells (sensorineural hearing loss). Nitrogen mustards match with acrolein production (hemorrhagic cystitis). Epipodophyllotoxins match with DNA double-strand breaks and 11q23 translocations (secondary AML).
Each chemotherapeutic agent causes distinct cellular damage leading to specific late effects. Anthracyclines bind topoisomerase II β\beta and create ROS in myocytes (cardiomyopathy). Cisplatin damages outer hair cells (ototoxicity). Cyclophosphamide yields acrolein (hemorrhagic cystitis). Etoposide causes DNA breaks leading to KMT2A translocations (secondary AML).

Step-by-Step Solution

1
Evaluate the mechanism of toxicity for Anthracyclines (Doxorubicin).
Matched to the generation of reactive oxygen species and interaction with topoisomerase II β\beta.
This is the classic mechanism by which anthracyclines cause cumulative, irreversible dilated cardiomyopathy, a major focus in pediatric cancer survivorship.
2
Evaluate the mechanism of toxicity for Platinum compounds (Cisplatin).
Matched to the apoptosis of outer hair cells in the basal turn of the cochlea.
Cisplatin causes irreversible, bilateral sensorineural hearing loss by damaging the organ of Corti. It also causes nephrotoxicity, but the precise cochlear mechanism is defining.
3
Evaluate the mechanism of toxicity for Nitrogen mustards (Cyclophosphamide).
Matched to the production of the toxic urothelial metabolite acrolein.
Cyclophosphamide causes hemorrhagic cystitis via its metabolite acrolein; this toxicity is specifically prevented by administering mesna, which binds and detoxifies acrolein in the bladder.
4
Evaluate the mechanism of toxicity for Epipodophyllotoxins (Etoposide).
Matched to DNA double-strand breaks increasing the risk of secondary AML with 11q23 translocations.
Etoposide is strongly associated with therapy-related malignancies, classically a secondary acute myeloid leukemia (t-AML) featuring KMT2A (MLL) translocations, usually presenting 1-3 years post-therapy.

Key Concept

Pathophysiologic mechanisms of late effects and toxicities from pediatric chemotherapy
Estimated Time:1m 30s
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Topics

Pediatric Hematology and Oncology

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