hematology and oncology
Management of Adverse Effects of Cancer Therapy
Gastrointestinal Effects
Gastrointestinal adverse effects are common in patients with cancer. These effects may be caused by the cancer itself, cancer therapy, or both. Anorexia is common in patients with cancer and may be caused by the cancer directly or as a consequence of cancer therapy(ies). Loss of more than 10% of ideal body weight predicts an adverse prognosis. Efforts should be made to maintain reasonable nutrition. Sometimes partial or total parenteral nutrition (TPN) is needed. Patients with surgical interruption of the gastrointestinal tract may need a feeding gastrostomy. Drugs that may increase appetite include corticosteroids,megestrolacetate, androgenic steroids, anddronabinol. Whether these drugs convincingly reduce anorexia, reverse weight loss, improve quality of life, or prolong survival is unclear. Some steroids, such astestosterone, are contraindicated in patients with prostate or liver cancer. Constipation is common in patients with cancer and is often exacerbated by opioids used to treat pain. A stimulant laxative such assenna2 tablets orally at bedtime (maximum 8 tablets/day) orbisacodyl5 to 15 mg orally at bedtime should be initiated when repeated opioid use is anticipated. Established constipation can be treated with various drugs (eg,bisacodyl5 to 15 mg orally every 24 hours, milk of magnesia 15 to 30 mL orally at bedtime,lactulose15 to 30 mL (10 to 20 g) every 12 to 24 hours,magnesium citrate195 to 300 mL once every 24 hours. Enemas and suppositories should be avoided in patients with neutropenia or thrombocytopenia. 2.5 mg to 5 mg orally every 6 hours. However, doses can vary depending on various factors. Patients with cancer who are taking broad-spectrum antibiotics may become infected with Clostridioides (formerly Clostridium) difficile–Induced Diarrhea , which should be tested for and treated with Mouth lesions such as inflammation and ulcers are common in patients receiving chemotherapy drugs and/or radiation therapy. Sometimes these lesions are complicated by infection, often withCandida albicans. Candidiasis is usually treated withnystatin. Oral candidiasis can be treated withnystatinoral suspension 4 to 6 mL (400,000 to 600,000 units) 4 times a day,clotrimazoletroches 10 mg 4 times a day, orfluconazole100 mg orally once a day. Mucositis due to radiation therapy can cause pain and preclude sufficient oral intake, leading to undernutrition and weight loss. Rinses with analgesics and topical anesthetics (2% viscouslidocaine5 to 10 mL every 2 hours or other commercially available mixtures) before meals, a bland diet without citrus food or juices, and avoidance of temperature extremes may allow patients to eat and maintain weight. If not, a feeding tube may be helpful if the small intestine is functional. For severe mucositis and diarrhea or an abnormally functioning intestine, parenteral alimentation may be needed. Nausea and vomiting are common in patients with cancer whether or not they are receiving cancer therapy and decrease quality of life. Variables that predict the likelihood of causing nausea and vomiting secondary to cancer drugs are Type of drug(s) Dose How the drug is given How frequently the drug is given Interactions between cancer drugs Interactions between cancer drugs and drugs given to treat cancer-related pain Some chemotherapy drugs are especially likely to cause nausea and vomiting, including platinum-containing drugs such ascisplatinandoxaliplatin. Patients treated with other cancer modalities, including radiation therapy, hormones, targeted therapy drugs, and immune therapy can also have nausea and vomiting. Several drugs are effective in controlling and/or preventing nausea and vomiting: Serotonin-receptor antagonists are the most effective drugs but are also the most expensive. Virtually no toxicity occurs withgranisetronandondansetronaside from headache and orthostatic hypotension. A 0.15-mg/kg dose ofondansetronor a 10-mcg/kg dose ofgranisetronis given IV 30 minutes before chemotherapy. Doses ofondansetroncan be repeated 4 and 8 hours after the first dose. The efficacy against highly emetogenic drugs, such as the platinum-containing drugs, can be improved with coadministration ofdexamethasone8 mg IV given 30 minutes before chemotherapy with repeat doses of 4 mg IV every 8 hours. A substance P/neurokinin-1 antagonist,aprepitant, can limit nausea and vomiting resulting from highly emetogenic chemotherapy. Dosage is 125 mg orally 1 hour before chemotherapy on day 1, then 80 mg orally 1 hour before chemotherapy on days 2 and 3. Other traditional antiemetics, including phenothiazines (eg,prochlorperazine10 mg IV every 8 hours,promethazine12.5 to 25 mg orally or IV every 8 hours) andmetoclopramide10 mg orally or IV given 30 minutes before chemotherapy with repeated doses every 6 to 8 hours, are alternatives restricted to patients with mild to moderate nausea and vomiting. Dronabinol(Δ-9-tetrahydrocannabinol [THC]) is an alternative treatment for nausea and vomiting caused by chemotherapy. THC is the principal psychoactive component of marijuana. Its mechanism of antiemetic action is unknown, but cannabinoids bind to opioid receptors in the forebrain and may indirectly inhibit the vomiting center.Dronabinolis administered in doses of 5 mg/m2orally 1 to 3 hours before chemotherapy, with repeated doses every 2 to 4 hours after the start of chemotherapy (maximum of 4 to 6 doses/day). However, it has variable oral bioavailability, is not effective for inhibiting the nausea and vomiting of platinum-based chemotherapy regimens, and has significant adverse effects (eg, drowsiness, orthostatic hypotension, dry mouth, mood changes, visual and time sense alterations). Smoking marijuana may be more effective. Marijuana for this purpose can be obtained legally in some states, although federal law still prohibits its use. It is used less commonly because of barriers to availability and because many patients cannot tolerate smoking. Benzodiazepines, such aslorazepam1 to 2 mg orally or IV given 10 to 20 minutes before chemotherapy with repeated doses every 4 to 6 hours as needed, are sometimes helpful for refractory or anticipatory nausea and vomiting. 