Lecture 4

Question 1

Traditional methods for treating cancer

Answer 1

–Surgery
–Radiation
–Chemotherapy

Question 2

Novel methods for treating cancer

Answer 2

–Photodynamic therapy
–Cryotherapy
–Electrochemotherapy

Question 3

Most important consideration regarding surgical removal of tumors

Answer 3

•Surgery alters vascularity , immune system, and tissue planes
–Allows recurring tumors to be more aggressive
–Makes subsequent surgeries more difficult

Question 4

Limitations of surgical removal of tumors

Answer 4

–Localized tumor, not useful if tumor has or will metastasize (grade and staging important)
–Cosmesis and functionality, removed tissue must be expendable

Question 5

Characteristics of radiation therapy

Answer 5

•Deposition of energy on or near DNA
–Direct and indirect actions
–Breakage of DNA
•Cells die when they try to divide
•Kills a constant proportion of cells
•Damages normal and cancer cells

Question 6

What does direct DNA damage mean?

Answer 6

Chemical bonds broken through direct ionization of DNA molecule

Question 7

What does indirect DNA damage mean?

Answer 7

Bonds broken through the ionization of water, and the formation of damaging reactive radicals. Oxygen require to perpetuate the damage.

Question 8

Limitations of DNA therapy?

Answer 8

–Local disease
–Surrounding normal tissue must tolerate radiation
–Radiation sensitive tumor type (?)
–Anesthesia requirements

Question 9

4 Rs of radiation therapy

Answer 9

–Repair
–Repopulation
–Re-oxygenation
–Redistribution

Question 10

Effect of radiation on tumor and normal tissues effected by:

Answer 10

–Fractionation of total dose helps kill cancer and save normal tissue
–Sensitivity of surrounding tissue/ rapidness of turnover (early and late tissues)
–Tumor size

Question 11

goals of radiation therapy

Answer 11

• Time period allowing reoxygen and
redistribution in tumor, repopulation and
repair in normal cells
• Large total dose (tumor control)
• Small fraction (less late effects)

Question 12

Why are palliative doses of radiation stronger?

Answer 12

Late side effects won’t be seen before the animal passes away

Question 13

acute effects of radiation therapy

Answer 13

–Hair loss
–Moist dermatitis
–Mucositis (conjunctiva, oral cavity, nasal passages)
–Intestine or bladder inflammation
–Nervous tissue inflammation/edema

Question 14

late radiation effects

Answer 14

Normal
–Alopecia
–Hyperpigmentation
–Cataracts
Bad
–Skin fibrosis
–Bone necrosis

Question 15

chemotherapy is more effective against what type of cells

Answer 15

rapidly dividing

Question 16

chemo drug classes

Answer 16

• Alkylating Agents- Chlorambucil, Cyclophosphamide, Lomustine, Melphalan
• Antimetabolites- Cytosine Arabinoside, Methotrexate, Elspar, Azothioprine
• Antitumor Antibiotics- Bleomycin, Anthracyclines (Doxorubicin), Mitoxantrone,
• Spindle Cell Poisons- Vinblastine, Vincristine, Vinorelobine, Taxols
• Platinum drugs- Carboplatin, Cisplatin
• Miscellaneous- Hydroxyurea, Corticosteroids

Question 17

Characteristics of chemo

Answer 17

• Kills a constant proportion of cells
• Rarely cures when gross disease is present but may palliate
• Can only cure tumors with liquid growth and genomic stability

Question 18

limitations of chemo

Answer 18

–Resistance / Multiple drug resistance
–Drug delivery- drug getting to tumor
–Side effects to normal tissues
•Bone marrow
•Hair loss
•Allergic or idiosyncratic reactions
•GI
–Drug specific side effects