Cancer therapy complications and supportive care: SAQ

This boy presents three overlapping toxicities of the anticancer therapy that the supportive care is built to manage. The cyclophosphamide at a dose above one gram per square metre is a high emetogenic agent, and the ondansetron alone is underpowered for the risk, which explains the breakthrough vomiting. The extensive oral ulceration that stops the eating and the drinking is the severe mucositis of the WHO grade 3 or 4, and the single temperature of 38.7 degrees with the absolute neutrophil count of 120 is the febrile neutropenia that needs the antibiotic within the hour. Each toxicity has a specific, guideline-anchored response. [1][9]

Question 1 (10 marks)

Outline the antiemetic management and the mucositis management for this boy, justifying each step with the relevant guideline evidence. [1]

A full-mark answer addresses the emetogenic risk stratification, the three-drug antiemetic combination, the mucositis grading, and the evidence-based preventive and therapeutic interventions. [1]

Antiemetic management (5 marks). The cyclophosphamide above one gram per square metre is a high emetogenic agent, and the Dupuis guideline of the Pediatric Oncology Group of Ontario sets the standard that the high emetogenic regimen receives the three-drug combination of a 5-HT3 antagonist plus dexamethasone plus the NK1 antagonist aprepitant. The ondansetron alone, given at 0.15 mg per kg per dose to a maximum of 8 mg per dose, is the backbone but is insufficient for the high risk, so the dexamethasone and the aprepitant are added. The aprepitant is continued through the days two and three for the delayed nausea, because the NK1 antagonist has a sustained effect on the substance P pathway. The breakthrough vomiting on the day one predicts the refractory nausea through the cycle, and the matched prophylaxis is started before the next dose. [1]

Mucositis management (5 marks). The extensive ulceration that stops the eating and the drinking is the severe mucositis of the WHO grade 3 or 4, with the grade 3 the liquid diet only and the grade 4 the oral intake impossible. The analgesia is escalated to the opioid by the continuous infusion or the patient-controlled analgesia, because the uncontrolled pain drives the dehydration and the sympathetic response. The nasogastric or the intravenous nutrition is started early because the oral intake is impossible. The prevention for the next cycle rests on the MASCC and ISOO evidence: the oral cryotherapy with the ice chips is suggested for the short-half-life mucotoxic chemotherapy, the low-level laser photobiomodulation is recommended for the stem-cell transplant recipients, and the palifermin at 60 microg per kg per day is given before and after the high-dose conditioning. The mouth is swabbed and the blood cultured for the secondary Candida or herpes, because the broken barrier is the entry route for the oral bacteria when the child is neutropenic. [4]

Question 2 (10 marks)

Explain the immediate response to the fever and the neutropenia, and appraise the evidence for the dexrazoxane cardioprotection that protects the boy across the anthracycline exposure. [9]

A full-mark answer reproduces the febrile neutropenia pathway and appraises the dexrazoxane guideline and the Chow study. [9]

The febrile neutropenia response (5 marks). The single temperature of 38.7 degrees with the absolute neutrophil count of 120 meets the definition of the febrile neutropenia, because the threshold is the single oral temperature at or above 38.3 degrees with the count under 500. The response is the blood cultures taken from each lumen of the central line plus a peripheral sample when feasible, followed by the empiric antipseudomonal beta-lactam such as cefepime, piperacillin with tazobactam, or meropenem given within one hour. The well appearance is deceptive, because the suppressed neutrophil blunts the local signs, and the delay kills the neutropenic child. The vancomycin is added for the suspected line infection or the haemodynamic instability. The reassessment at the 48 to 72 hours determines the low-risk child who can be stepped down to the oral ciprofloxacin with the amoxicillin and the clavulanate. [9]

The dexrazoxane cardioprotection (5 marks). The boy will receive the anthracyclines across the induction and the maintenance, and the dexrazoxane is the primary cardioprotection. The 2022 harmonisation guideline of de Baat and the International Late Effects of Childhood Cancer Guideline Harmonization Group recommends the dexrazoxane for the child who is expected to receive the anthracycline, given at a ten-to-one ratio with the doxorubicin dose, so that 300 mg per square metre of the dexrazoxane accompanies 30 mg per square metre of the doxorubicin. The dexrazoxane chelates the iron and interrupts the free-radical cascade that scars the cardiomyocyte. The Chow study of the childhood cancer survivors, published in the Journal of Clinical Oncology in 2023, confirmed that the dexrazoxane preserves the long-term heart function without compromising the cancer control, addressing the past concern that the drug reduced the efficacy or raised the secondary malignancy. The surveillance is the second pillar, with the baseline echocardiogram before the first anthracycline and the serial echocardiogram and the troponin through the treatment and into the survivorship. [6][9]