Oncology Support

Key takeaways

• Oncology support medicines fall into four groups: hormone therapies (tamoxifen, anastrozole), targeted kinase inhibitors (imatinib, sorafenib), cytotoxic chemotherapy (cyclophosphamide, capecitabine) and immunomodulators (lenalidomide, thalidomide).
• Imatinib treats chronic myeloid leukemia (CML) and gastrointestinal stromal tumors (GIST) by blocking the specific abnormal enzyme that drives those cancers, unlike older chemotherapy that damages any dividing cell it reaches.
• Thalidomide causes severe birth defects from even a single dose taken during pregnancy. Anyone who could become pregnant or father a child must follow a strict pregnancy prevention program while taking it or lenalidomide.

How oncology support medicines work

These drugs interrupt cancer growth through different routes. Hormone therapies lower estrogen or androgen levels or block the receptors that fuel hormone-sensitive cancers, while cytotoxic chemotherapy damages the DNA of any rapidly dividing cell. Targeted kinase inhibitors block the specific abnormal protein driving one cancer, sparing more healthy tissue than older chemotherapy, and immunomodulators change immune cell behavior while cutting off the blood supply tumors need.

Choosing between tamoxifen, anastrozole, abiraterone, imatinib, capecitabine, cyclophosphamide and thalidomide

• Tamoxifen blocks estrogen receptors in hormone-receptor-positive breast cancer, usually for 5 to 10 years, and raises the risk of blood clots and endometrial cancer.
• Anastrozole, an aromatase inhibitor for postmenopausal hormone-receptor-positive breast cancer, lowers estrogen body-wide and can thin bone, so bone density checks are routine. Letrozole and exemestane work the same way.
• Abiraterone treats metastatic prostate cancer resistant to standard hormone therapy by blocking androgen production, taken with a steroid (prednisone) and regular liver checks.
• Imatinib, the first targeted therapy for CML, also treats GIST by blocking the BCR-ABL enzyme that drives CML growth. Nilotinib and dasatinib are newer drugs in the same family for when imatinib fails.
• Capecitabine converts into fluorouracil in the body and treats colorectal and breast cancer. Hand-foot syndrome (redness, peeling and pain on the palms and soles) is a common side effect.
• Cyclophosphamide damages cancer-cell DNA in lymphoma, leukemia and some solid tumors and can irritate the bladder, so high fluid intake is standard advice. Fluorouracil, hydroxyurea, chlorambucil and melphalan are older cytotoxics that work the same way.
• Lenalidomide and thalidomide treat multiple myeloma by altering immune activity and blocking the blood vessel growth tumors need. Thalidomide is one of medicine's most documented teratogens: taken during pregnancy, it causes severe limb and organ birth defects, so both drugs are dispensed only under a monitored pregnancy prevention program.

Sorafenib treats kidney, liver and thyroid cancer; everolimus treats kidney cancer and also prevents transplant rejection. Bicalutamide and flutamide are anti-androgens that block testosterone's effect in prostate cancer.

Common questions

Do I still need other cancer treatments alongside these tablets?

Most oncology support medicines work alongside surgery, radiotherapy or intravenous chemotherapy, not instead of them. Your oncology team sets the combination for your cancer type and stage.

Why do the dosing schedules vary so much?

Hormone and targeted therapies are taken daily without breaks because they continuously block a pathway, while cytotoxic chemotherapy is dosed in cycles so healthy tissue can recover.

Safety essentials

• Thalidomide and lenalidomide must never be taken during pregnancy; both require pregnancy testing and contraception under a monitored access program.
• Cytotoxic drugs (cyclophosphamide, fluorouracil, chlorambucil, melphalan, hydroxyurea) suppress bone marrow function; regular blood counts catch a low white cell count before it becomes a serious infection.
• Fever, chills, unusual bleeding or bruising, or persistent vomiting during treatment need same-day medical attention.
• Tell your oncology team about every other medicine you take; interactions with this drug class are common.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.