Radiation therapy adverse effects

A potentially fatal lung toxicity occurs in 10 to 20% of patients receiving bleomycin. Patients particularly at risk are those who are over 70 years of age and have had radiation therapy to the chest. Rarely, bleomycin also may cause allergic pneumonitis. Bleomycin skin toxicity is manifested by hyperpigmentation, erythematosus rashes, and thickening of the skin over the dorsum of the hands and at dermal pressure points, such as the elbows. Many patients develop a low-grade transient fever within 24 hours of receiving bleomycin. Less common adverse effects include mucositis, alopecia, headache, nausea, and arteritis of the distal extremities. 

The most common adverse effects of topical retinoic acid are erythema and dryness that occur in the first few weeks of use, but these can be expected to resolve with continued therapy. Animal studies suggest that this drug may increase the tumorigenic potential of ultraviolet radiation. In light of this, patients using retinoic acid should be advised to avoid or minimize sun exposure and use a protective sunscreen. Allergic contact dermatitis to topical retinoic acid is rare. 

When cancer is diagnosed, three primary treatment modalities are available surgery, radiation treatment, and cancer chemotherapy. The purpose of this chapter is to describe the basic rationale of cancer chemotherapy and to provide an overview of the drugs that are currently available to treat specific forms of cancer. Rehabilitation specialists will routinely work with patients undergoing cancer chemotherapy. For reasons that will become apparent in this chapter, these drugs tend to produce toxic effects that directly influence physical therapy and occupational therapy procedures. Therefore, this chapter should provide therapists with a better understanding of the pharmacodynamic principles and beneficial effects, as well as the reasons for the potential adverse effects of these important drugs. 

Adverse effects The major dose-limiting toxicity is bone marrow depression, and the drug is immunosuppressive. Other adverse reactions include nausea, vomiting, diarrhea, stomatitis, and alopecia. Extravasation during injection produces serious problems. Dactinomycin sensitizes to radiation inflammation at sites of prior radiation therapy may occur. 

Neurotoxicity is the result of improper (careless) use, handling, and negligence in the management of chemical substances such as metals, food additives, pesticides, industrial solvents, cosmetics, radiation treatment, and drug therapies. Depending upon route and dose of exposure, the symptoms of neurotoxicity appear immediately after exposure or are delayed. The symptoms include limb weakness or numbness loss of memory, vision, and/or intellect headache cognitive and behavioral problems and sexual dysfunction. Children and workers with certain existing health disorders are more vulnerable to the adverse effects of neurotoxic chemicals. 

Candidates for teriparatide treatment include women who have a history of osteoporotic fracture, who have multiple risk factors for fracture, or who failed or are intolerant of previous osteoporosis therapy. Teriparatide should not be used in patients who are at increased baseline risk for osteosarcoma (including those with Paget s disease of bone, unexplained elevations of alkaline phosphatase, open epiphyses, or prior radiation therapy involving the skeleton). Full-length PTH(l-84), which is in clinical trials, has not been associated with osteosarcomas. Other adverse effects have included exacerbation of nephrolithiasis and elevation of serum uric acid levels. 

This therapy can produce urticaria and skin rashes. In addition, there can be potentially serious adverse effects, including bone marrow depression, acute leukemia, and blood dyscrasias. Symptoms of radiation sickness as well as cardiovascular complications (e.g., angina, sinus tachycardia) can also occur. 

The adverse effects of ganciclovir are similar to those caused by radiation therapy. The major dose-limiting adverse effects—myelosuppression, gastrointestinal distress, and mucositis—occur commonly. The toxic effects of ganciclovir are enhanced by concomitant administration of other drugs that suppress bone marrow. The answer is (D). 

It is also important that the suture material is stable to radiation. This can occur when, following gynecologic cancer, a patient is prescribed abdominal radiation for palliative or curative therapy. The ionizing effect of the radiation may adversely affect suture strength, and may lead to wound dehiscence (Orr et al, 2004). The use of a knotted monofilament suture presents a high risk in such cases, since, if the suture breaks at one point, the entire length of the suture stitch is rendered ineffective in keeping the wound closed. Several small suture stitches may be used but this increases the time of operation and can lead to complications due to the presence of multiple knots. A barbed suture, however, can effectively eliminate both these risks. Since it anchors at multiple points, should the suture break it will still hold the wound tissue in closed apposition at the next barb. Secondly, since the suture stays inside the tissue there is less scar formation. 

Importantly, the toxicity of bleomycin is cumulative. Total doses in excess of 450 units are associated with a significantly increased incidence of adverse lung reactions and death. The incidence of bleomycin-induced lung toxicity has been reported between 0% and 46% with a mortality rate of 3% (5,7). As mentioned above, high cumulative dose, extreme of age, uremia, the use of supplemental oxygen, and radiation therapy are well-documented risk factors for bleomycin toxicity. Other chemotherapeutic agents (cyclophosphamide and vincristine) may also have a synergistic effect with bleomycin. Finally, bleomycin may occasionally reactivate a prior radiation-induced pneumonitis, a phenomenon known as radiation-recall. ... 

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