An 18-year-old man comes to the physician with his parents for a routine health maintenance examination. He noticed a swelling on his back 7 months ago. He has a history of using intravenous heroin but has not used illicit drugs for the past 2 months. There is no personal or family history of serious illness. Vital signs are within normal limits. Examination shows a 2-cm soft, lobulated, mobile swelling on the right side of his upper back. The mass slips away from the fingers when its edges are palpated. Healed track marks are present in the bilateral cubital fossae. The patient is told that the mass on his back is most likely a lipoma, a benign mass consisting of fat tissue that does not require any further treatment. He is aware of the diagnosis and informs you that he wants it removed for cosmetic reasons. Four months ago, he had asked another physician to remove it but the physician refused to perform the procedure since he did not consider it necessary. The patient is counseled regarding the potential benefits and risks of the excision and that there is a chance of recurrence. His parents ask the physician not to perform the excision. However, the patient insists on undergoing the procedure. Which of the following is the most appropriate next step in management?

Refer to the hospital ethics committee

Ask the patient to follow up in 6 months

Refer him to a methadone clinic

After hospitalization for urgent chemotherapy to treat Burkitt’s lymphoma, a 7-year-old boy developed paresthesias of the fingers, toes, and face. Vital signs are taken. When inflating the blood pressure cuff, the patient reports numbness and tingling of the fingers. His blood pressure is 100/65 mm Hg. Respirations are 28/min, pulse is 100/min, and temperature is 36.2℃ (97.2℉). He has excreted 20 mL of urine in the last 6 hours. Laboratory studies show the following: Hemoglobin 15 g/dL Leukocyte count 6000/mm3 with a normal differential serum K+ 6.5 mEq/L Ca+ 6.6 mg/dL Phosphorus 5.4 mg/dL HCO3− 15 mEq/L Uric acid 12 mg/dL Urea nitrogen 54 mg/dL Creatinine 3.4 mg/dL Arterial blood gas analysis on room air: pH 7.30 PCO2 30 mm Hg O2 saturation 95% Which of the following is the most likely cause of this patient’s renal condition?

Precipitation of uric acid in renal tubules/tumor lysis syndrome

Direct tubular toxicity through filtered light chains

Deposition of calcium phosphate in the kidney

Intense renal vasoconstriction and volume depletion

A 55-year-old male with a 60 pack-year smoking history presents to his oncologist for ongoing management of his recently diagnosed small cell lung cancer. His oncologist discusses several options and decides to start the chemotherapeutic medication, etoposide. The patient is warned that one side effect of this drug is myelosuppression so he should be vigilant for development of any infectious symptoms. The beneficial effect of this drug in treating cancer is most likely due to which of the following effects?

Inhibition of supercoil relaxation

Two days after hospitalization for urgent chemotherapy to treat Burkitt’s lymphoma, a 7-year-old boy develops dyspnea and reduced urine output. He also feels a tingling sensation in his fingers and toes. Blood pressure is 100/65 mm Hg, respirations are 28/min, pulse is 100/min, and temperature is 36.2°C (97.2°F). The lungs are clear to auscultation. He has excreted 20 mL of urine in the last 6 hours. Laboratory studies show: Hemoglobin 15 g/dL Leukocyte count 6,000/mm3 with a normal differential serum K+ 6.5 mEq/L Ca+ 7.6 mg/dL Phosphorus 5.4 mg/dL HCO3− 15 mEq/L Uric acid 12 mg/dL Urea nitrogen 44 mg/dL Creatinine 2.4 mg/dL Arterial blood gas analysis on room air: pH 7.30 PCO2 30 mm Hg O2 saturation 95% Which of the following is most likely to have prevented this patient’s condition?

No prevention would have been effective

Pneumococcal polysaccharide vaccine

A 13-year-old male is admitted to the hospital for treatment of acute lymphoblastic leukemia. During his hospital course, he develops a fever of 39.0 degrees Celsius. A CBC demonstrates a leukocyte count of <500 /mm^3. Which of the following is the most appropriate initial management of this patient?

Strict quarantine and hand-washing

Oral ciprofloxacin and amoxicillin/clavulanic acid

Granulocyte colony-stimulating factor (G-CSF)

Pediatric oncology treatment principles

General Principles - Kids Aren't Little Adults

Distinct Biology: Pediatric cancers are typically embryonal (neuroblastoma, Wilms') or hematologic, unlike the epithelial carcinomas common in adults. They grow faster but are more chemosensitive.
Superior Tolerance & Cure: Children tolerate more intensive chemotherapy and radiotherapy. This contributes to higher overall cure rates, often exceeding 80% for many cancers.
Significant Late Effects: Aggressive treatment causes major long-term sequelae: growth/hormonal impairment, neurocognitive deficits, and a high risk of secondary malignancies later in life.
Care Standard: Enrollment in multicenter clinical trials is crucial.

⭐ Most pediatric malignancies arise from embryonal or mesenchymal tissues, contrasting with adult cancers, which are predominantly epithelial (carcinomas).

Pediatric vs. Adult Cancer Mutation Rates

Chemotherapy - Potions Against Proliferation

Principle: Targets rapidly dividing cells (cancerous & normal). Curative intent is common in pediatric cancers.
Dosing: Calculated based on Body Surface Area (BSA) for accuracy.
- Mosteller Formula: $BSA (m^2) = \sqrt{\frac{Height(cm) \times Weight(kg)}{3600}}$
Cell Cycle Specific (CCS) Agents: Act on a specific phase (e.g., Antimetabolites - S phase).
Cell Cycle Non-Specific (CCNS) Agents: Effective at any phase (e.g., Alkylating agents).

Cell Cycle Phases and Chemotherapy Drug Targets

Common Toxicities:
- Myelosuppression (Neutropenia is dose-limiting)
- Nausea & Vomiting
- Mucositis
- Alopecia

⭐ Vinca Alkaloids (Vincristine, Vinblastine): Known for neurotoxicity (peripheral neuropathy). ⚠️ Fatal if administered intrathecally.

Radiation & Surgery - Local Control Crew

Surgery: The primary modality for local control.
- Goals: Biopsy for diagnosis, staging, and complete R0 resection (no microscopic residual tumour).
- Often requires a multidisciplinary approach to preserve organ function and cosmetic outcomes.
Radiation Therapy (RT): Uses ionising radiation to achieve local tumour control.
- Crucial for unresectable tumours, positive margins, or as definitive therapy.
- Principle: ALARA (As Low As Reasonably Achievable) to minimise damage to developing tissues.
- Proton Beam Therapy is preferred to spare normal tissues and reduce long-term toxicity.

⭐ In high-risk Neuroblastoma, achieving good local control with aggressive surgery and radiation to the primary tumour bed is critical for survival, even in the setting of metastatic disease.

Photon vs. Proton Beam Therapy Dose Deposition in Child

Supportive Care - The Safety Net

Febrile Neutropenia (FN): Medical emergency!
- Immediate broad-spectrum antibiotics (e.g., Pip-Taz, Cefepime) after blood cultures.
- Risk stratification guides therapy (inpatient vs. outpatient).

⭐ Exam Favourite: Febrile Neutropenia is defined as a single oral temperature of ≥38.3°C (101°F) or a temperature of ≥38.0°C (100.4°F) sustained for ≥1 hour, in a patient with an Absolute Neutrophil Count (ANC) <500/mm³, or an ANC expected to fall below 500/mm³.

Tumor Lysis Syndrome (TLS):
- Prophylaxis: Aggressive hydration, allopurinol.
- Treatment: Rasburicase for established hyperuricemia.
Chemo-Induced Nausea & Vomiting (CINV):
- Prophylaxis: 5-HT3 antagonists (Ondansetron), NK-1 antagonists (Aprepitant).

Febrile Neutropenia Management in Pediatric Oncology

High‑Yield Points - ⚡ Biggest Takeaways

Combination chemotherapy is the cornerstone of treatment for most pediatric malignancies.

Multi-modal therapy, integrating surgery and radiotherapy with chemotherapy, is the standard of care.

Prophylaxis and management of Tumor Lysis Syndrome (TLS) is critical, especially in high-grade lymphomas and leukemias.

Supportive care, including G-CSF and antiemetics, is vital for managing treatment-related toxicity.

Be vigilant for long-term late effects, such as cardiotoxicity, infertility, and secondary cancers.

Special consideration for sanctuary sites like the CNS and testes is often required.