Pediatric Oncology High Yield One Liners 

How Childhood Cancer Presentation is Unique

The signs and symptoms are unique and variable. The inability to convey precise symptoms is another issue in young children. Irritability can be a sign of pain. The disseminated disease at diagnosis is more in children as compared to adults. Childhood cancers usually originate from the deeper, visceral structures and from the parenchyma of organs. In adults, it's mostly the epithelial lining cancer or superficial cancers that are more common. Pain is the initial symptom in >50% of childhood cancers.

Chemotherapy in Childhood Cancers

Multimodal combination chemotherapy regimens are used. Rapidly proliferating tissues prone to develop side effects like bone marrow, oral and intestinal mucosa., epidermis, liver, and spermatogonia. The most common adverse effect - is bone marrow suppression or myelosuppression.  The other side effects:

• Alopecia
• Renal toxicities due to platinum compounds like cisplatin
• Hemorrhagic cystitis is seen with cyclophosphamide and ifosfamide
• Mucositis
• Neuropathy due to vinca alkaloids.
• Nausea, vomiting, diarrhea

Radiotherapy in Childhood Cancers

To avoid adverse side effects, conformational irradiation is often employed. The radiation volume conforms to the tumor's shape, thereby relatively sparing surrounding normal tissues and allowing precise, high-dose radiation to be delivered only to the tumor. Examples are proton beam therapy and IMRT (intensity-modulated radiation therapy).

Biological Therapy in Childhood Cancers

A rapidly developing field with a significant impact on overall survival. Includes immunotherapy, biological response modifiers, or endogenous molecules that have therapeutic effects in

supraphysiological doses. Examples include:

•  All trans-retinoic acid (ATRA) is the therapy of choice in acute promyelocytic leukemia.
• Imatinib mesylate is the therapy of choice in the Philadelphia chromosome and forms of CML and ALL with the Philadelphia chromosome.
• Rituximab (anti-CD20 monoclonal antibody) is used in CD20+ lymphomas and Hodgkin lymphomas.
• Brentuximab Vedontin (anti-CD30 monoclonal antibody) treats CD30+ lymphomas like the Nodular lymphocyte predominant form of HL. (CD 15–, CD 20–, CD 30+)
• Dinutuximab - FDA-approved for neuroblastoma.
• Radioactive Metaiodobenzylguanidine (MIBG) therapy for neuroblastoma.

Principles of Chemotherapy

• Risk-directed therapy is the standard of treatment in ALL.
• Different study groups used different criteria to define risk.
• As per National Cancer Institute (NCI) and Nelson 21st edition they divide into two groups:
• Standard risk: age 1-10 years and initial TLC is <50000/μL.
• High risk: If the age <1 yr or >10 yr and initial TLC is >50000/μL.
• Anticipation and management of CNS disease are imperative to prevent future relapses.
• The standard therapy requires overall 2-3 years total of chemotherapy

Important One Liners of Childhood Oncology

• RBS, Neuroblastoma, Lymphoma, Langerhans cell histiocytosis, and sometimes Retinoblastoma are malignancies that produce proptosis in children.
• The most radiosensitive tissue is bone marrow.
• The least radiosensitive tissue is neurons or the brain.
• The most radiosensitive blood cells are lymphocytes.
• The least radiosensitive blood cells are platelets.
• The sebaceous gland function does not recover after radiotherapy.
• Bladder and bowel incontinence can occur in patients due to spinal cord compression; they are usually late during the illness. So patients who develop spinal cord compression features early, if managed early, bladder and bowel involvement can be avoided. And so, overall, their incidence is rare compared to the total spinal cord compression seen in these patients.
• The presence of the following portends a favourable outcome in AML:
  • T (8;21)
  • Inv 16
  • T (15;17)- M3 variety
  • AML is associated with Down syndrome.
  • Absent MRD after induction
• The minimal residual disease is prognostic in ALCL and LBL.
• In BL, cell surface markers are -CD10, CD19, CD20, IgM, and Bcl-6, but it never expresses BCL-2.
• In ALCL, there is also evidence that a humoral response to the ALK kinase can be used to predict outcomes. With a superior outcome who mount an antibody titre to ALK.
• Patients with localized disease have a 90-100% survival rate, and those with advanced disease have an 80-95% survival.

Toxicities of Particular Concern

• Leukoencephalopathy is associated with a high dose of methotrexate. 
• Myocardial damage is associated with anthracyclines (Doxorubicin or Daunorubicin) combined with RT or Trastuzumab.
• Pulmonary fibrosis is associated with Bleomycin toxicity.
• Renal dysfunction is associated with platinum agents, Ifosfamide and Nitrosourea.
• Hearing loss is associated with cisplatin-dose-dependent toxicity.

Leukostasis is defined as clinical signs and symptoms associated with:

• Absolute myeloblast count >50,000/mm³ in AML.
• Absolute lymphoblast count >100,000/mm³ in ALL.
• Lymphocyte count >300,000/mm³ in CLL.

Uric Acid Nephropathy

• Precipitation of Uric Acid Crystals is promoted by Acidic Urine.
• Harrison 20th Edition Says: The finding of Uric Acid crystals in the urine is strong evidence for Uric Acid nephropathy. The ratio of Urinary Uric Acid to Urinary Creatinine in patients with Acute Hyperuricemic Nephropathy and<1 in patients with renal failure due to other causes.

Key One-Liners on Brain Tumor 

• Brain tumors are the most common solid malignancy in children.
• Overall, the 2nd most common malignancy after leukemias in the pediatric age group.
• The most common type of brain tumor in children is gliomas > Primitive neuroectodermal tumors (PNET).
• Among gliomas, the most common variety is astrocytoma's (Benign)
  • Gliomas can be benign or malignant, most astrocytoma's are usually benign.
  • The common prototype of PNET is medulloblastoma (Malignant)
  • The most common malignant brain tumor in children: Medulloblastoma.
• The most common histological type of brain tumor in children: Juvenile pilocytic variety of astrocytoma.
• The brain tumor shows CSF metastasis: Medulloblastoma.
• The brain tumor shows extracranial metastasis outside the brain: Medulloblastoma.
• The brain tumor which is associated with hormonal abnormalities: Craniopharyngioma.
• Location-wise, the most common type of brain tumor in children: Infratentorial tumor.
• Glioblastoma multiforme is considered the most common malignant brain tumor in adults.

Key Imaging Points in Brain Tumor

• Medulloblastomas: Heterogeneously or homogeneously, enhancing 4th ventricular mass, often in the midline.
• Pilocytic astrocytoma: Occurs in the posterior fossa and the supratentorial region. With cystic and solid components and less or no vasogenic edema.
• Brainstem Glioma: Diffusely expanded, minimally or partially enhancing mass in 80% of cases, and in 20% have a focal tectal or cervical-medullary lesion in the posterior fossa.
• Ependymomas present are either infratentorial or supratentorial.
  •  Infratentorial ependymoma presents as enhancing 4th  ventricular mass with a predilection for the cerebellopontine region.
  • Supratentorial ependymoma is often present as cystic.
• SEGA shows avid enhancement, always situated close to the lateral ventricle near the Foramen of Monro.
• Glioblastoma: Rare in children, shows heterogeneous enhancement, necrosis, and peritumoral edema.
• Craniopharyngioma: Suprasellar tumor, often large and heterogeneous. shows both cystic and solid areas. It is often calcified and referred to as suprasellar calcification.

Key One-Liners on RETINOBLASTOMA

• Most common intraocular tumor in children.
• The usual age of diagnosis is 1-2 years of age.
• The median age is 2 years, and more than 90% of cases are diagnosed before 5.
• 70% of cases are unilateral, and 30% are bilateral.
• Bilateral cases are multifocal and diagnosed early.
• 60% of cases are sporadic, 40% are familial.
• Bilateral tumors are always familial/Inherited.
• Retinoblastoma is the most common inherited childhood tumor.
• Though Retinoblastoma is highly radiosensitive, the mainstay of therapy is Chemotherapy - Kanski, DeVita. For radiotherapy, external beam radiotherapy (EBRT) should be avoided in heritable retinoblastoma since it can precipitate a second malignancy.
• Brachytherapy is safer but more suited for anteriorly placed tumors.

Key Points about Hemangiomas

• Hemangiomas are benign, proliferative tumors arising from vascular endothelial cells.
• They are the most common benign tumors in infants and young children.
• >50% of hemangiomas occur in the head and neck region, and more than 50% develop during infancy.
• >90% of hemangiomas regress spontaneously by the time the child is 10-15 years of age.

Rule of 10 in Pheochromocytoma

• 10% Extra-adrenal.
• 10% Bilateral in familial cases.
• 10% Childhood.
• 10% Malignant.
• 10% Familial.
• 10% Associated with MEN syndrome.
• 10% not associated with hypertension.
• 10% are found incidentally
• Pheochromocytoma is also known as The Great Masquerader. A high degree of clinical suspicion is needed for diagnosis in a child/adolescent/adult with episodic/severe hypertension not responding to usual therapy.

Important Questions on Childhood Oncology 

Q. What are the risk factors for testicular involvement in ALL?

Ans.

• T cell ALL
• Leucocytosis >20000/mm3
• Mediastinal mass
• Moderate to severe hepatosplenomegaly and lymphadenopathy.
• Thrombocytopenia with platelet <30000/mm3

Q. There is a six-year-old girl having features of raised ICP on imaging, we found that the patient has a midline enhancing mass with features producing 4th ventricular obstruction. What is the likely diagnosis?

Ans. Medulloblastoma

Q. What is the most common primary brain tumor showing metastasis outside the brain?

Ans. Medulloblastoma, Metastatic brain tumors in children are less common than in adults.

Q. Name the syndrome that increases Wilms tumor and neuroblastoma risk.

Ans. Beckwith-Weideman syndrome. It poses a 30-75% risk of Will's tumor and 5-10% neuroblastoma in children.

Q. What are the sites of metastasis of neuroblastoma?

Ans. Site of metastasis: Lymph nodes, bones, bone marrow, and liver. Pulmonary metastasis is rare in neuroblastoma.

Q. Which gene has the strongest association with WT?

Ans. WT1 gene

Codes for a transcription factor

More chances of bilateral WT

More chances of recurrence

Q. A six-month-old child was found to have seven hemangiomas at different locations on the skin. What next needs to be done?

Ans.  If a child has more than one discrete cutaneous hemangioma, always look for underlying visceral hemangiomas. Ultrasonography of the liver and GIT will be recommended for such a child. So, the answer is abdominal ultrasound.

Q. What is the latest IHC marker to distinguish hemangiomas from other similar cutaneous lesions?

Ans.  GLUT-1 is the IHC marker, always present in hemangiomas, and helps to distinguish from other similar lesions.

Q. A 5-year-old child with bright-red, superficial hemangioma on their face has recently developed greyish-white areas in the center. What is the likely possibility?

A. Hemangioma is expanding

B. Hemangioma is regressing

C. Hemangioma is developing thrombi

D. Hemangioma is turning malignant

Ans. Option B - Hemangioma is regressing.

Q. Pediatric Osteosarcoma and Ewing's Sarcoma can be distinguished based upon all of the following except?

A. Presence of systemic features like fever

B. Metastatic pattern

C. Syndromic association

D. Response to radiotherapy

· The answer is their metastatic pattern because both have the same pattern.

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