Cancer treatment Flashcards
Nature of how cytotoxic drugs/chemo is given?
Given at intervals (cycles of treatment) to allow recovery of normal tissue
Chemo is the only systemic treatment for cancer (surgery and radio are local)
Chemotherapy should be prescribed and given only under expert guidance by people trained in its use
Types of chemotherapy include:
Single-agent: rarely curative as genetically resistant cells are selected out
Combination chemo: combination of drugs with different MoAs + different side-effect profiles reduces the likihood of resistance and toxicity
Adjuvant: after other initial treatment to reduce risk fo relapse, eg following surgical removal or, eg breast, bowel cancer
Neoadjuvant: used to shrink tumours prior to surgical or radiological treatment, may allow later treatment to be more conservative
Palliative: no curative aim, offers symptom relief, may prolong survival
Explain criteria of cytotoxics for combination chemotherapy:
The drugs used should have:
- cytotoxic activity for that tumour, preferentially able to induce remission
- different mechanisms of action, ideally additive or synergistic effects
- non-overlapping toxicity to maximize benefit of full therapeutic doses
- different mechanisms of resistance
Classes of cytotoxic drugs:
Alkylating agents: anti- proliferative drugs that bind via alkyl groups to DNA leading to apoptotic cell death
Angiogenesis inhibitors: eg bevacizumab, afilbercept, sunitinib
Antimetabolites: interfere with cell metabolism including DNA and protein synthesis
Antioestrogens: aromatoase inhibitors (eg letrozole, anastrozole), oestrogen receptor antagonists (eg tamoxifen, raloxifene) used in breast cancer treatment
Antitumour antibiotics: interrupt DNA function, eg dactinomycin, doxorubicin, mitomycin, bleomycin
Monoclonal antibodies: antibodies to a specific tumour antigen can slow tumour growth by enhancing host immunity, or be conjugated with chemotherapy/radioactive isotopes to allow targeted treatment.
Topoisomerase inhibitors: interrupt regulation of DNA winding, eg etoposide
Vinca alkaloids and taxanes: ‘spindle poisons’ which target mechanisms of cell division, eg vincirstine, vinblastine, docetaxel
Side effects of cytotoxics
Due to cytotoxic effects on non-cancer cells
greatest effect seen on dividing cells, ie gut, hair, bone marrow, gametes
- Vomiting: prophylaxis given with most cytotoxic regimens
- Alopecia: may profoundly impact quality of life
- Neutropenia: neutropenic sepsis is life threatening
Surgery: Prevention
Risk-reducing surgery e.g thyroidectomy in men, colectomy in FAP
Surgery: screening
Endoscopy, colposcopy
Surgery: diagnosis + staging
Fine needle aspiration, core needle biopsy, vacuum-assisted biopsy, excisional/incisional biopsy, sentinel lymph node biopsy, endoscopy, diagnostic/staging laparoscopy, laparoscopic ultrasound
Surgery: Treatment
Resection of solid tumour (may be combined with chemo/radiotherapy)
Surgery: Reconstruction
Eg following treatment for breast, head and neck cancers
Surgery: palliation
bypass, stoma, stenting, pathological fractures
Chemotherapy and radiation effects of fertility: (physiology)
may:
- damage spermatogonia causing spermatogenesis or male sterility
- hasten oocyte depletion leading to premature ovarian failure
If cancer treatment carrier a risk of infertility, fertility preservation techniques should be discussed prior to treatment being given:
Men: semen cryopreservation should be offered before treatment due to the risk of genetic damage in sperm after initiation of chemotherapy. Intracytoplasmic sperm injection means that even a small amount of banked sperm can be used successfully in the future.
Women: Cryopreservation of:
1. embryos
2. oocytes: if ethical objections to embryo preservation or no partner
3. ovarian tissue: no ovarian stimulation required, experimental technique
Beau’s lines?
Horizontal depressions in the nail plate that run parallel to the moon-shaped portion of the nail bed
Result from a sudden interruption of nail keratin synthesis and may be due to local infection/trauma, systemic illness, or from medication
each line in this photo coincided with a round of chemotherapy for breast cancer
