Fluorouracil, often abbreviated as 5-FU, is a chemotherapy drug used in the treatment of various cancers. It works by interfering with the growth of rapidly dividing cells, including cancer cells, by disrupting their DNA and RNA synthesis. As an antimetabolite, it mimics natural substances to disrupt cellular processes. Fluorouracil is utilized for several types of cancer, including those affecting the colon, rectum, breast, stomach, and pancreas.
Methods of Administration
Fluorouracil can be administered through several methods, tailored to the cancer type and treatment goals. The most common systemic approach is intravenous (IV) infusion, where the drug is delivered directly into the bloodstream. This can occur through a short tube in the arm (cannula) or a longer-term central line, PICC line, or portacath in the chest. For some patients, a small portable pump attached to a central line allows for continuous infusion, enabling them to receive treatment at home.
Topical application is another method, used for skin conditions like actinic keratoses and superficial basal cell carcinomas. This involves applying fluorouracil as a cream or solution directly to the affected skin area. An oral form, capecitabine, is also available, converting into fluorouracil within the body for systemic treatment. The choice of administration method depends on whether the cancer is localized to the skin or has spread throughout the body.
Treatment Cycles and Duration
Fluorouracil treatment is structured into cycles, involving drug administration followed by rest periods for recovery. The length of these cycles can vary, ranging from weekly to every two, three, or four weeks, depending on the cancer type, its stage, and the patient’s overall health. For instance, regimens for resectable disease might involve daily IV infusion for 21 days within a 21-day cycle, while advanced disease might see infusions for 4 days within a 28-day cycle.
Continuous infusion over an extended period, such as 24 to 46 hours, is also used for some regimens. The total number of cycles and treatment duration are determined by the healthcare team based on the cancer’s response and patient tolerance. For topical applications, treatment for actinic keratoses lasts 2 to 4 weeks, with healing taking 1 to 2 months after stopping the cream. Superficial basal cell carcinomas may require longer topical treatment, ranging from 3 to 6 weeks, and sometimes up to 10 to 12 weeks for healing.
Managing Side Effects
Fluorouracil treatment can lead to side effects, and management strategies are used to support patient comfort and treatment adherence. Gastrointestinal issues such as nausea, vomiting, and diarrhea are common with systemic administration. Anti-sickness medications are often prescribed to control nausea and vomiting; dietary adjustments like small, frequent meals and avoiding fatty foods can also help. For diarrhea, anti-diarrhea medicines may be provided, with advice to maintain hydration by drinking fluids.
Other systemic side effects include temporary hair loss, which often resolves after treatment, and a reduction in white blood cell and platelet counts, increasing the risk of infection and bleeding. Patients should avoid sick individuals and report any signs of infection, fever, or unusual bleeding or bruising immediately. Topical fluorouracil can cause skin irritation, redness, and peeling, which is an expected part of treatment as it destroys damaged skin cells. This inflammatory response can progress to sores and crusts, and while uncomfortable, signifies the drug’s action.
Monitoring and Follow-up
Ongoing monitoring is an important part of fluorouracil treatment to assess its effectiveness and manage complications. Regular blood tests are conducted before and during treatment to check blood cell counts, liver, and kidney function. A blood test for dihydropyrimidine dehydrogenase (DPD) enzyme levels is performed before starting treatment, as a low DPD level can increase the risk of severe side effects, potentially requiring a lower dose or an alternative treatment.
Physical examinations are also performed to assess the patient’s overall health and identify any side effects. Imaging scans may be used periodically to track the cancer’s response to treatment. After active treatment, follow-up appointments monitor for cancer recurrence and address long-term medication effects. This oversight helps ensure good outcomes for patients undergoing fluorouracil therapy.