Chemo Basic Principles

Question 1

What are the two big checkpoints in the cell cycle and explain what can happen at each one in tumor growth?

Answer 1

G1 checkpoint we make sure everything is ready to go to S phase and copy and make DNA. This is where activated oncogenes override G1 arrest, just go straight into S phase.
G2 checkpoint is did everything go OK in the S phase and are we ready to divide. This is where inactivated tumor suppressor genes, like TP53, lead to overriding G2 phase.

Question 2

What is the ultimate goal of chemo, and then if we cant have that goal, what is the goal next?

Answer 2

Cure
Control the disease, meaning don’t let it spread and enlarge, and get the patient the best possible quality of life by controlling symptoms.

Question 3

Talk about why we do neoadjuvant chemotherapy?

Answer 3

This is where we have a local cancer and there are local therapies but they are not as effective alone. So the goal here is to shrink the tumor in hopes that those local therapies like resection will work.

Question 4

Explain/define adjuvant therapy?

Answer 4

After surgery, giving chemo for a defined amount of time to prevent relapse and increase overall survival

Question 5

What is the log kill phenomenon?

Answer 5

Chemotherapy induced destruction of tumor cells follows first order kinetics, meaning a specific dose will kill a constant rate of cells.

Question 6

What is the difference between primary and acquired chemo drug resistance?

Answer 6

Primary is already having resistance before any exposure to chemo drugs.
Acquired is now having a resistance, through amplifying or suppressing a gene, after chemo exposure.

Question 7

What does P glycoprotein have to do with chemo drug resistance?

Answer 7

Cells with high expression of PGP can pump the chemo drugs out of the cell, acts as an inherent barrier. Kidney, liver, pancreas, SI, colon BBB and placenta.

Question 8

What is the issue with chemotherapy therapeutic index?

Answer 8

Most chemotherapy drugs have small windows and need high doses to kill cancer cells.

Question 9

What are the 5 main normal cells very susceptible to chemotherapy that present with adverse effects?

Answer 9

Bone marrow precursor cells, so like cytopenias and myelosupression (think infection here)
Intestinal epi cells
Oral mucosa
Hair
Gonadal cells