5-FU or FLUOROURACIL (Adrucil®)has been used since the 1950′s to treat cancer and still remains the backbone of colorectal cancer chemotherapy. Today, 5-FU is almost always given with leucovorin (folinic acid) which makes the 5-FU more effective. 5-FU can also be combined with other chemotherapy drugs.
When 5-FU is used (alone or in combination with other drugs)
- Stage II or III rectal cancer: 5-FU is given simultaneously with radiation treatments as a continuous infusion, either before surgery to shrink a rectal tumor or after surgery to help prevent recurrence at the site.
- High-risk stage II colon cancer to prevent recurrence after surgery.
- Stage III colon cancer to prevent recurrence after surgery.
- Stage IV or recurrent (metastatic) cancer of the colon or rectum to increase survival time, reduce tumors to permit potentially curative surgery, or prevent recurrence after surgery for metastatic tumors.
Red flags for 5-FU
Call your doctor immediately if you have
- Severe vomiting, diarrhea, mouth sores, fever, or signs of infection. Severe reactions can be life-threatening. You might be one of the 3-5 percent of people who lack a specific enzyme needed to metabolize 5-FU. You can be tested for DPD (dihydropyrimidine dehydrogenase deficiency). Those with DPD cannot use any fluorouracil-based treatment including Xeloda® (capecitabine).
- Severe diarrhea or signs of infection: When taking 5-FU with irinotecan in the FOLFIRI regimen, severe diarrhea might start immediately during an infusion or 24 hours or more after the treatment. In either case, these side effects can sometimes be life-threatening.
Common side effects with 5-FU
- Loss of appetite, nausea, and occasional vomiting. Call your doctor or nurse if vomiting is severe or if you cannot keep fluids down.
- Diarrhea. Be prepared to treat a first loose stool with Imodium® (loperamide) and call your doctor if you have cramping or vomiting along with diarrhea or if you have more than six loose stools in a 24 hour period.
- Low blood cell counts. Lowered counts are most common with bolus 5 FU injections. Symptoms that should prompt a call to your doctor are:
- Fever over 100.5 degrees or other signs of infection such as redness,swelling, sore throat, or cough. Infections can results from too few white cells (neutrophils.)
- Excessive fatigue. A lack of oxygen-carrying red blood cells will make you feel tired, short of breath, weak, and you may have pale skin. Medications or blood transfusions may be necessary to treat your anemia.
- Easy bruising, tarry black stools, or pinkish urine indicating low platelet counts so your blood can’t clot normally.
- Mouth sores (mucositis). Special mouthwashes may relieve symptoms. Avoid mouthwashes with alcohol. If you are receiving the bolus 5-FU treatment, you can reduce or even prevent mouth sores by sucking ice chips or popsicles from about five minutes before treatment begins until 30 minutes after it’s completed. However, don’t use ice if you are also receiving oxaliplatin as part of FOLFOX.
- Hand-and-Foot syndrome (palmar-plantar erythrodysesthesia). Red, painful or itchy palms or soles of feet. Untreated, skin can begin to peel or tingle. Reducing dosage or adding adding vitamin B6, may decrease the reaction so you can continue the chemotherapy treatments.
- Thinned or brittle hair is more likely than complete hair loss with 5-FU. Your hair will grow back once treatment is over.
- Skin drying or darkening on your palms or arm veins. Discoloration or loss of nails is less common, and should go away after 5-FU is discontinued.
- Sun sensitivity. Avoid long sun exposure, use sunscreen, and keep your head and skin covered with protective clothing.
- Runny nose or tearing can occur. Rarely, the tear ducts can become blocked.
How 5-FU is given
- Continuous or protracted infusion over several days or weeks. You will have a portable pump worn in a small fanny pack after you leave the oncology office that will pump the drug into your veins. FOLFOX and FOLFIRI regimens normally give the drug over 46 hours.
- Bolus regimens. A bolus injection is given into a vein over a few minutes time. A monthly bolus (Mayo Clinic) regimen is daily treatments for five days, followed by three weeks of rest. Weekly bolus (Roswell Park regimen) is treatment once a week treatments for four or six weeks, followed by two weeks rest.
- Don’t have any vaccinations, including flu shots, without talking to your doctor first.
- Women should avoid pregnancy while being treated with 5-FU because it can be harmful to the fetus. Use an effective barrier method of contraception during treatment and let your doctor know immediately if you suspect you are pregnant before beginning treatment or during treatment. Avoid breastfeeding during treatment with 5-FU.
LEUCOVORIN (folinic acid, or Wellcovorin®).
Leucovorin is a derivative of the B vitamin, folic acid.
When leucovorin is used
For treatment of colorectal cancer, leucovorin is included with 5-FU regimens. It is not used alone in colorectal cancer treatment.
Leucovorin enhances the effectiveness of 5-FU by enabling it to stay within cancer cells longer.
Side effects with leucovorin
While most side effects experienced during leucovorin treatment are due to the 5-FU or other chemo drugs, leucovorin itself can cause rare allergic reactions. If you experience any of the following side effects, call your doctor immediately or get emergency help.
- Shortness of breath or difficulty breathing.
- Swelling in your face or throat.
- Hives or rash.
How it is given
Leucovorin is given by an intravenous infusion. How often it is given depends on the schedule for 5-FU and other drugs in combination regimens.
Where Can You Go for More Information
ChemoCare.Com is an initiative of the Scott Hamilton CARES Foundation and the Cleveland Clinic. It has good information in patient-friendly language about chemotherapy drugs and management of side effects including: