I hope you do not need to know about chemotherapy. If you stumble upon this word because you or loved ones need to be treated for cancer or other conditions, there is much more you need to know about chemotherapy than its just not a pleasant treatment. Chemotherapy is a group of medication that targets rapidly dividing cells in our body. Moreover, they interact with some cells leading the cell to its demise.
First watch that video this promotes cancer awareness in young people.
There are several types of alkylating agents agents:
- Mustard gas derivatives: Mechlorethamine, Cyclophosphamide, Chlorambucil, Melphalan, and Ifosfamide.
- Ethylenimines: Thiotepa and Hexamethylmelamine.
- Alkylsulfonates: Busulfan.
- Hydrazines and Triazines: Altretamine, Procarbazine, Dacarbazine and Temozolomide.
- Nitrosureas: Carmustine, Lomustine and Streptozocin. Nitrosureas are unique because, unlike most types of chemo treatments, they can cross the blood-brain barrier. They can be useful in treating brain tumors.
- Metal salts: Carboplatin, Cisplatin, and Oxaliplatin.
Derived made from certain types of plants.
- Vinca alkaloids: Vincristine, Vinblastine and Vinorelbine.
- Taxanes: Paclitaxel and Docetaxel.
- Podophyllotoxins: Etoposide and Tenisopide.
- Camptothecan analogs: Irinotecan and Topotecan.
Made from natural products produced by species of the soil fungus .
- Anthracyclines: Doxorubicin, Daunorubicin, Epirubicin, Mitoxantrone, and Idarubicin.
- Chromomycins: Dactinomycin and Plicamycin.
- Miscellaneous: Mitomycin and Bleomycin.
When the cells incorporate these substances into the cellular metabolism, they are unable to divide.
- Folic acid antagonist: Methotrexate.
- Pyrimidine antagonist: 5-Fluorouracil, Foxuridine, Cytarabine, Capecitabine, and Gemcitabine.
- Purine antagonist: 6-Mercaptopurine and 6-Thioguanine.
- Adenosine deaminase inhibitor: Cladribine, Fludarabine, Nelarabine and Pentostatin.
Interfere with the action of topoisomerase enzymes, necessary for DNA replication.
- Topoisomerase I inhibitors: Ironotecan, topotecan
- Topoisomerase II inhibitors: Amsacrine, etoposide, etoposide phosphate, teniposide
Several useful types of chemotherapy drugs are unique:
- Ribonucleotide reductase inhibitor: Hydroxyurea.
- Adrenocortical steroid inhibitor: Mitotane
- Enzymes: Asparaginase and Pegaspargase.
- Antimicrotubule agent: Estramustine
- Retinoids: Bexarotene, Isotretinoin, Tretinoin
Beyond these, many other types of treatments exist, such as targeted therapy, immunotherapy, and hormone therapy. You can find a more comprehensive list of certain drug or combination used for certain cancers here.
Effect of chemotherapy on ovarian reserve. Egg reserve is determined mainly by the number of small non-growing follicles in the ovary (primordial follicles contain more than 85% of eggs in the ovary). This effect is dependent on
- Type of drug; alkylating agents has more harmful effect than other chemotherapeutics. Some physicians classify the effects on treatment on fertility based on the type of drug used only into high risk e.g cyclophosphamide, intermediate risk e.g cisplatinum, low risk e.g methotrexate and unknown e.g paclitaxel. This classification, however, does not take in consideration other important factors
- Age; generally younger women have more follicles in their ovaries than older women. They are thus more likely to retain some follicles after chemotherapy.
- Combination of drugs; commonly multiple drugs are used simultaneously and add to the damaging effect on primordial follicles.
- Total dose; usually given as in mg per body surface area.
- Frequency of administration
- Density of dose; administering chemotherapy cycle more frequently e.g repeating the cycle of medications every 2 weeks instead of 3 weeks.
- Genetics; certain enzymes are responsible for detox of chemotherapy. Some individuals inherit a weaker or slower form of the enzyme. The drug used is then not eliminated as fast as in individuals carrying the normal form of the enzyme.
- Radiation; exposure of the ovary to radiation further increases the loss of follicles.
Although a lot of information is known about the effects of chemotherapy on the ovaries, it is very difficult to predict the ultimate effects on fertility. Tests for ovarian reserve are helpful but not very accurate. Certainly resumption of menses does not reflect fertility potential after chemotherapy.
- Obtain a list of medication from the oncologist or oncology nurse, before the start of treatment.
- Read about the effect of your specific treatment on future fertility.
- Ask questions about the potential effects of treatment on future fertility. The answer may not be simple. Ask your oncologist, request consultation with a reproductive endocrinologist with expertise in preservation of fertility.
- Tests for ovarian reserve are usually done (FSH, AMH, ultrasound..). These also are useful for comparison when repeated after chemotherapy.
- Consider options for preservation of fertility prior to chemotherapy e.g. embryo freezing
- Keep accurate records of your treatment. Here is a tool to help you.