Assignment 3 Flashcards
what is the most common bone tumor in children?
osteogenic sarcoma
What is the second most common bone tumor in children?
Ewing sarcoma
Is Ewing sarcoma more prevalent in boy or girl children?
Boy children
What is the most common site of Ewing sarcoma?
lower half of the body
25% in the pelvis and 17% in the femur
What is the most frequent presentation of Ewing sarcoma?
pain and swelling
What part of the bone is a more common site of Ewing sarcoma?
diaphysis
What is the classic appearance of Ewing sarcoma on a radiograph?
diaphyseal tumor with involvement of the medullary cavity (known as “onion skin appearance”) and an associated soft tissue mass
How does Ewing sarcoma frequently metastasize?
through the blood stream
About what percentage of Ewing sarcoma patients have mets at the time of diagnosis?
25%
What are the most common metastatic sites of Ewing sarcoma?
bone, bone marrow, and the lungs
In most cases, why would post-operative XRT be recommended after conservative surgery?
to treat positive margins
What is the definition of hyperfractionation?
“Fractional doses smaller than conventional, delivered two or three times daily to achieve an increase in the total dose in the same overall time”
Fractional doses smaller than conventional, delivered two or three times daily to achieve an increase in the total dose in the same overall time
hyperfractionation
Describe the special attention that should be paid to field borders when radiating children?
Strict attention should be paid to field borders when radiating children due to bone growth. When the tumor is near a long bone, the uninvolved epiphysis should be spared to reduce (negative) late growth effects. For flat bones (e.g. vertebrae) the entire bone is included. For ribs with cytologically positive effusion (cancerous cells in fluid), the entire pleural cavity is included.
When radiating extremities, why is a narrow strip of normal tissue spared?
to prevent lymphedema
Are the majority of bone lesions primary or metastatic?
Metastatic
Where does metastatic bone disease most often occur?
Where is it uncommon?
spine, pelvis, femur, and humerus
Radius, ulna, tibia, fibula, hands & feet
What are the most common cancers to metastasize to bone?
lung, breast, and prostate
What is the definition of debulking?
Surgical procedure used to reduce tumor size, reduce tumor burden, and increase the opportunity to obtain a pathologic diagnosis.
List 2 radiopharmaceuticals that are used to treat pain from bone mets.
Sr-89 (Strontium-89) and SM-153 (Samarium-153)
What are the 2 most common locations for primary bone tumors?
the distal femur and proximal tibia
Where are osteosarcomas most commonly found?
distal femur, followed by the proximal tibia and proximal humerus
Where are chondrosarcomas typically found?
Where are they rarely found?
in the pelvis and femur
the distal extremities
Where do MFHs and GCTBs typically arise?
in the metaphysis and epiphysis of long bones, including in the distal femur, proximal tibia, and distal radius
TD 5/5: bone
5200 c/Gy
TD 5/5: bone marrow
2500 c/Gy
TD 5/5: skin
5500 c/Gy
