Low Priority: Lymphoma, TBI, Sarcoma, Skin, Pediatrics

What is the hallmark cell of Hodgkin’s Lymphoma

Reed-Sternberg cells

What is the hallmark cell of Hodgkin’s Lymphoma?

20–34 (bi-modal peak, second peak in elderly and tend to do worse)

What are the risk factors for Hodgkin’s?

EBV (Epstein-Barr virus),

immunosuppressive drugs

What are B-symptoms?

Night sweats, fever, weight loss

What are A-symptoms?

Asymptomatic (no symptoms)

What chemo regimen is used for Hodgkin’s?

ABVD (2–3 cycles) for standard risk; BEACOPP for high risk

What RT doses are used for Hodgkin’s?

20–30 Gy (early stage); 30–40 Gy

(bulky disease)

What technique has replaced the mantle field for Hodgkin’s?

ISRT —

Involved Site Radiation Therapy

What is the classic RT technique for Hodgkin’s involving lower abdomen?

Inverted-Y field; paraaortic field

What age group gets NHL and what causes it?

Age 50; caused by lifetime

accumulation of DNA mutations

What chemo is used for NHL?

R-CHOP (primary); RT adjuvant if not

responsive

What are the RT doses for NHL?

Localized: 24–30 Gy; Aggressive: 30–36

Gy

What is the clinical presentation for Hodgkins

Painless mass (around s’clav, cervical, medistinal), enlarged lymph nodes

What is the staging system for lymphoma and what characterizes the stages?

Ann Arbor Staging
1 → Single LN region
2 → 2+ LN on same side of diaphragm
3 → LN on both sides
4 → Extranodal involvement (bone marrow, liver, etc)

What is ALL and who gets it?

Acute Lymphoblastic Leukemia — most

common cancer in children; bone marrow origin, spreads to blood, LN, liver, spleen,

CNS

What chromosome abnormality is associated with ALL?

Philadelphia

chromosome — translocation between chromosomes 9 and 22 (BCR-ABL)

When is RT used in ALL?

Only for CNS or spinal spread

What are the risk factors for AML?

Smoking, prior ionizing radiation

What chemo is used for AML?

Cytarabine + daunorubicin (“7+3” regimen)

What is the RT role in AML?

Palliative or pre-bone marrow transplant

conditioning

What is the risk factor for CLL?

Agent Orange exposure; age 70

What is the genetic hallmark of CML?

BCR-ABL gene fusion → treated

with TKIs (tyrosine kinase inhibitors)

What does CRAB stand for in multiple myeloma?

Calcium

(hypercalcemia), Renal failure, Anemia, Bone lesions

What is the TBI dose and fractionation?

12 Gy / 6 fractions — 2 fractions

per day × 3 days

What is the lung dose limit for TBI?

<7 Gy (achieved with lung blocks)

What is the setup used for TBI?

Extended SSD

What is the purpose of TBI?

Conditioning (myeloablative) before bone

marrow/stem cell transplant — destroys existing marrow and immunosuppresses

What is the tissue of origin for soft tissue sarcomas?

Mesenchymal tissue

Where are soft tissue sarcomas most commonly located?

Extremities

What are the two most common soft tissue sarcoma types?

Liposarcoma

and leiomyosarcoma

What is used for staging of soft tissue sarcomas?

Grade (differentiated vs highly undifferentiated) (not just

TNM)

What are the RT doses for soft tissue sarcoma?

Pre-op: 50 Gy / 25 fx

&gt; - Adjuvant (post-op): 60–66 Gy / 33 fx &gt; - Advanced: 70 Gy / 35 fx

What is the most common primary malignant bone tumour?

Osteosarcoma

What age group gets osteosarcoma?

24 years OR 60+ (associated with

rapid bone growth in young;

What is the treatment for osteosarcoma?

Surgery (amputation or limb-

sparing) + chemo (cisplatin + doxorubicin); RT = SBRT 50–60 Gy / 3–5 fx

Differentiate pre/post op sarcoma RT characteristics

Pre-op = small field + better cell kill, worse healing (RT impairs healing)

Post-op = large field + more fibrosis, better heal

What genetic conditions predispose to skin cancer?

Xeroderma

pigmentosum, albinism

What are the subtypes of BCC and their appearance?

-Nodular/pearly/rodent ulcer
- Superficial/scaly
- Morphea/flat ill-defined

How do BCC and SCC differ in growth rate?

BCC = slow growing; SCC =

fast growing

What does ABCDE stand for in melanoma?

Asymmetry, Border irregularity, Color variation, Diameter >6mm, Evolve

What is the primary treatment for skin cancer? When is RT used?

Surgery = primary; RT = adjuvant

What RT doses are used for skin cancer?

35 Gy/7fx | 45 Gy/10fx | 50

Gy/20fx

What is the role of RT in melanoma?

Mainly palliative (melanoma is

relatively radioresistant)

Electron Beam for Skin — Depth Rule

Energy (MeV) ≈ depth (cm) × 3 OR: depth of treatment ≈ beam energy ÷ 3 (the “1/3 rule”)

What dose of radiation to the thyroid is a risk factor for thyroid cancer?

1 Gy to the thyroid (specifically papillary subtype)

What hormones does the thyroid produce?

T3 and T4

What is Graves disease?

Autoimmune hyperthyroidism — weight loss,

exophthalmos, elevated metabolic rate

What are the four types of thyroid cancer in order of frequency?

Papillary (most common) → Follicular → Medullary → Anaplastic

How is thyroid cancer treated? What is the RT dose?

I-131 (radioactive iodine) for imaging and treatment; EBRT if unresectable: 5000–7000 cGy

What is the primary tumour of the pituitary gland and where is it located?

Benign adenoma in the sella turcica

What are the symptoms of a pituitary adenoma?

Headache + visual field

defects (compression of optic chiasm)

When is RT used for pituitary adenoma?

If not resectable or near visual

structures → SBRT or proton therapy

What is the second most common cancer in children?

Brain tumours

What are the four types of pediatric brain tumours?

Astrocytoma,

ependymoma, medulloblastoma, brainstem glioma

Why is proton therapy preferred for pediatric brain tumours?

Reduced

exit dose → less damage to developing brain tissue and growth structures

What are the CSI doses for medulloblastoma?

- Standard risk: 23.4 Gy
- High risk: 36 Gy
- Posterior fossa boost: 54–55.8 Gy

What is leukocoria and which cancer causes it?

“Cat’s eye reflex” —

caused by retinoblastoma (most common intraocular tumour in children)

How is retinoblastoma treated with RT?

I-125 brachytherapy: 3000–4000

cGy over 1 week; daily general anesthesia

What is the most common extracranial solid tumour in children?

Neuroblastoma (3rd most common cancer overall in children)

What is the median age for neuroblastoma?

<17 months; usually located

in the abdomen

What is the high-risk neuroblastoma treatment sequence?

Induction

chemo → Surgery → Myeloablative chemo → SCT → RT → Immunotherapy

What is Wilms tumour and how is it treated?

Kidney cancer

(nephroblastoma), age 3–4, clear cell type, can be bilateral. Nephrectomy → Stage 1–2:

chemo; Stage 3–4: chemo + RT (1080–2000 cGy)

What is Ewing’s sarcoma treatment?

VDC/IE chemo; surgery preferred 12

weeks after chemo; if no surgery: 45 Gy → boost to 55.8 Gy; whole lung RT = 15 Gy

What staging system is used for pediatric NHL?

St. Jude’s staging

system