Oncology: Chemotherapy Techniques

Questions and Answers

How does the growth rate of solid tumors typically change as size increases?

It remains constant

It increases indefinitely

It decreases due to lack of nutrients (correct)

It becomes cyclical based on treatment

Which type of chemotherapy is given to maintain remission after other treatments?

Palliative chemotherapy

Adjuvant chemotherapy

Induction chemotherapy

Maintenance chemotherapy (correct)

What is the primary purpose of neoadjuvant chemotherapy?

To enhance recovery after surgery

To shrink tumors before surgical procedures (correct)

To prolong remission after cancer treatment

To attack micrometastases following radiation

What characterizes cell cycle specific chemotherapeutic agents?

They are only effective against replicating cells Signup and view all the answers

What impact does vascularization have on tumor growth?

Poor vascularization can inhibit tumor growth Signup and view all the answers

How are drug dosages for chemotherapy typically determined?

Calculated according to body surface area Signup and view all the answers

What does the log kill phenomenon indicate about the destruction of cancer cells?

A constant percentage of cells is destroyed with each dose Signup and view all the answers

Which cells are generally least sensitive to chemotherapy?

Non-dividing cells in the G0 phase Signup and view all the answers

What is a common effect of chemotherapy on normal cells?

Damage to rapidly dividing cells Signup and view all the answers

Which of the following is an irreversible toxicity associated with certain chemotherapeutic agents?

Cardiotoxicity Signup and view all the answers

What is a potential long-term effect of chemotherapy involving alkylating agents?

Development of treatment-induced neoplasms Signup and view all the answers

How can methotrexate-induced megaloblastic anemia be effectively counteracted?

By administering leucovorin Signup and view all the answers

Which of the following interventions may help minimize chemotherapy-induced bladder toxicity?

Employing intensive diuresis Signup and view all the answers

Why do severe vomiting and stomatitis often occur with chemotherapeutic agents?

They are related to the narrow therapeutic index Signup and view all the answers

What is the primary mechanism of action of alkylating agents in anticancer therapy?

Formation of covalent bonds with DNA Signup and view all the answers

What common condition may arise as a result of bone marrow suppression due to chemotherapy?

Anemia and increased infection risk Signup and view all the answers

What is the primary mechanism through which 5-Fluorouracil affects DNA synthesis?

It competes with deoxyuridine monophosphate for thymidylate synthase. Signup and view all the answers

How does gemcitabine inhibit DNA synthesis?

By being incorporated into DNA strands at cytosine sites. Signup and view all the answers

Which enzyme does gemcitabine diphosphate inhibit to prevent DNA synthesis?

Ribonucleotide reductase. Signup and view all the answers

What type of molecules do doxorubicin and daunorubicin primarily bind to?

Sugar-phosphate backbone of DNA. Signup and view all the answers

What is a consequence of the action of 5-Fluorouracil in cells?

Reduced DNA synthesis due to a lack of thymidine. Signup and view all the answers

Which of the following statements about gemcitabine is false?

Gemcitabine enhances ribonucleotide reductase activity. Signup and view all the answers

What is the primary effect of the binding of doxorubicin and daunorubicin to DNA?

Local uncoiling of DNA. Signup and view all the answers

The action of 5-Fluorouracil significantly reduces which nucleotide's availability, thereby impacting DNA synthesis?

Thymidine. Signup and view all the answers

What is the primary mechanism by which bleomycin causes DNA damage?

Catalyzing the reduction of free radicals Signup and view all the answers

Which of the following best describes the effect of mechlorethamine on DNA?

It alkylates the N7 nitrogen of guanine residues Signup and view all the answers

What are the consequences of the superoxide ions produced by the oxidation of the bleomycin-Fe2+ complex?

They attack phosphodiester bonds in DNA Signup and view all the answers

Which of the following statements about vinca alkaloids is correct?

They are involved in the inhibition of DNA synthesis Signup and view all the answers

What kind of mutations can alkylating agents like mechlorethamine induce?

Miscoding mutations Signup and view all the answers

What role do hormones like flutamide play in prostate cancer treatment?

They are antiandrogens that inhibit androgen effects Signup and view all the answers

What is a common feature of taxanes like paclitaxel in cancer therapy?

They inhibit the mitotic spindle assembly Signup and view all the answers

Why is the formation of a DNA-bleomycin-Fe3+ complex significant?

It results in irreversible chromosomal abnormalities Signup and view all the answers

What is the main action of antimetabolites in the context of DNA synthesis?

They block or subvert one or more metabolic pathways involved in DNA synthesis. Signup and view all the answers

Which enzyme does methotrexate inhibit to affect DNA synthesis?

Dihydrofolate reductase (DHFR) Signup and view all the answers

What is a significant consequence of decreased thymidine production due to methotrexate?

Depressed DNA, RNA, and protein synthesis Signup and view all the answers

What compound does 6-mercaptopurine resemble when it penetrates target cells?

Purine-ring nucleotide Signup and view all the answers

Which of the following groups includes substances that specifically affect microtubule function?

Vinca alkaloids and taxanes Signup and view all the answers

Which amino acids are produced less due to the action of methotrexate?

Methionine and serine Signup and view all the answers

What important steroids are mentioned as hormones affecting cellular processes?

Glucocorticoids, estrogens, and androgens Signup and view all the answers

What is the primary impact of the metabolites inhibited by 6-mercaptopurine on cells?

Inhibition of de novo purine-ring biosynthesis Signup and view all the answers

Study Notes

Adjuvant Chemotherapy

Used post-surgery and radiation to target micrometastases.

Neoadjuvant Chemotherapy

Administered before surgery to shrink tumors.

Maintenance Chemotherapy

Lower doses used to extend remission duration.

Tumor Susceptibility and Growth Cycle

Rapidly dividing cells are more sensitive to chemotherapy than slowly proliferating cells.
Non-dividing cells (G0 phase) tend to survive chemotherapy.
Cell cycle-specific drugs act on replicating cells, while nonspecific drugs can affect both replicating and non-replicating tumor cells.

Tumor Growth Rate

Initial rapid growth in solid tumors slows as size increases, often due to nutrient and oxygen depletion from inadequate blood supply.
Surgical and radiation treatment can reduce tumor burden.

Treatment Regimens and Scheduling

Drug dosages calculated based on body surface area to personalize treatment.

Log Kill Phenomenon

Chemotherapeutic agents follow first-order kinetics, destroying a constant fraction of cancer cells per dose.

Toxicity of Chemotherapy

Chemotherapy affects rapidly dividing normal cells (e.g., bone marrow, GI tract, hair follicles) leading to side effects.
Common adverse effects: vomiting, stomatitis, bone marrow suppression, and alopecia.
Specific toxicities can occur with certain drugs (e.g., cyclophosphamide causes bladder toxicity, doxorubicin causes cardiotoxicity).

Minimizing Adverse Effects

Local tumor perfusion, pre-treatment marrow extraction, and promoting diuresis to mitigate bladder toxicity are potential interventions.
Folinic acid (leucovorin) can counteract methotrexate-induced megaloblastic anemia.

Treatment-Induced Tumors

Antineoplastic agents may lead to new neoplasms years after treatment, especially after alkylating agents.
Treatment-induced neoplasms are usually responsive to subsequent treatment strategies.

Classification of Anticancer Drugs

Alkylating Agents: Form covalent bonds with DNA, impeding replication.
Antimetabolites: Disrupt metabolic pathways involved in DNA synthesis.
Cytotoxic Antibiotics: Prevent mammalian cell division.
Plant Derivatives: Affect microtubule function and mitotic spindle formation.
Hormones: Includes glucocorticoids, estrogens, and androgens.

Antimetabolites

Methotrexate: Inhibits dihydrofolate reductase, decreasing nucleotide synthesis leading to cell death.
6-Mercaptopurine: Functions as a purine antagonist, inhibiting initial steps in purine biosynthesis.
5-Fluorouracil: Competes for thymidylate synthase, reducing thymidine levels and disrupting DNA synthesis.
Gemcitabine: Incorporated into DNA, inhibits ribonucleotide reductase needed for DNA synthesis.

Antibiotics

Doxorubicin and Daunorubicin: Block DNA and RNA synthesis, causing breaks in DNA strands.
Bleomycin: Creates radicals that break DNA strands, leading to chromosomal abnormalities.

Alkylating Agents

Mechlorethamine: Alkylates guanine residues in DNA, causing cross-linking and strand breakage.

Plant Derivatives

Vinca Alkaloids (Vincristine, Vinblastine): Disrupt microtubule function during the mitotic phase.
Taxanes (Paclitaxel): Stabilize microtubules, preventing normal mitotic progression.

Hormones in Cancer Treatment

Flutamide, Nilutamide, Bicalutamide: Antiandrogens used in prostate cancer treatment.

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Description

This quiz covers the different types of chemotherapy, including adjuvant, neoadjuvant, and maintenance chemotherapy. Understand their roles in cancer treatment, particularly following surgery and radiation. Test your knowledge on how these methods impact micrometastases and tumor susceptibility.