Approach Considerations
Postradiation sarcoma (PRS; also referred to as radiation-induced sarcoma [RIS]) ideally is managed with a multidisciplinary approach that includes input from the radiation oncologist, the medical oncologist, and the surgeon. Because PRS is high-grade and advanced-stage or metastatic at the time of diagnosis, patients commonly are not eligible for curative surgery, and their prognosis generally is poor. Chemotherapy is the most common treatment modality and typically is associated with poor response rates.
Inpatient care frequently is required for patients with PRS at different stages of treatment. Inpatient care may be required for diagnostic evaluation to allow surgery with general anesthesia. Most preoperative chemotherapy regimens and palliative chemotherapy regimens for advanced disease require inpatient hospitalization.
Medical Care
The selection of chemotherapy agents used to treat patients with PRS is based largely on data from clinical trials of soft-tissue and bone sarcomas. The two most active single chemotherapy agents are doxorubicin and ifosfamide. These agents have roughly equivalent activity. Dacarbazine has modest single-agent activity. MAID (a combination of mesna, Adriamycin [ie, doxorubicin], ifosfamide, and dacarbazine) has been a commonly used combination chemotherapy regimen for the treatment of soft-tissue sarcoma over the past decade.
Three randomized trials compared doxorubicin plus ifosfamide with doxorubicin alone. Two of these trials showed higher response rates in the treatment arms containing doxorubicin and ifosfamide than in those containing doxorubicin alone. However, the doxorubicin and ifosfamide combinations also were associated with significantly higher myelosuppression (including fatal neutropenic sepsis) but no survival advantage. No standard of care has been established for the choice of chemotherapy agents. Therefore, treatment typically is individualized.
Preoperative chemotherapy can be administered with or without radiation therapy and is administered either intravenously (as a bolus or as a continuous infusion) or regionally (via an intra-arterial infusion to an isolated limb). Preoperative chemotherapy generally is considered in order to facilitate a limb-sparing procedure. This approach is considered for patients who otherwise would require amputation for cure or palliation. In some instances, this approach may be considered to convert a marginally resectable lesion into one that is operable.
Consideration of preoperative chemotherapy for PRS must take into account that response rates to chemotherapy are low and that most long-term survivors with PRS are patients who have undergone successful surgical resection.
Surgical Care
Surgical options for PRS include wide or radical resection [26, 27, 28] (limb salvage) and amputation, and the choice depends on the stage and location of the tumor and the age and performance status of the patient. In patients with peripherally located tumors at Musculoskeletal Tumor Society (MSTS) stage IIB and below (see Workup, Staging), it is feasible to expect resection to provide a reasonable 5-year survival rate. (In one study, the 5-year survival rate for this group approached 68%.) Brachytherapy or postoperative external beam radiation can be added if the margins are close to the tumor.
Chan et al conducted a retrospective study that included 25 patients treated for PRS after radiation therapy (RT) for nasopharyngeal carcinoma. [29] Of the 25 patients, 20 underwent surgery with curative intent. All 25 received postoperative adjuvant chemoradiation, and six underwent brachytherapy as well. Local recurrence occurred in 71.4%. Median survival was significantly better for surgical patients with clear margins than for those with positive margins. Surgery was found to be effective in symptom palliation, including tumor pain, bleeding, and trismus.
In a systematic review of studies addressing RIS of the head and neck, Coca-Pelaz found surgery with wide margins to be the best therapeutic option, though outcomes remained poor. [26]
Diet
Nutrition is an important aspect in the care of patients receiving active cancer treatment. [30] Surgery, RT, and chemotherapy may adversely affect the patient's nutritional status and hence may alter quality of life. Cancer treatment can alter the patient's ability to eat, digest, and absorb food. Anticipation of these potential adverse effects, therefore, is necessary.
Intervention, such as with commercially available liquid nutritional supplements, may be required to maintain adequate caloric intake. Consultation with a healthcare provider qualified in nutrition also may be considered.
Activity
The impact of physical activity on treatment outcome in patients with cancer is not well defined in the literature. However, modest levels of physical activity during cancer treatment may provide benefits with respect to increasing appetite, maintaining mobility and muscle tone, and enhancing a sense of emotional well-being.
Prevention
Lowering the dosage of RT and/or adjuvant chemotherapy is the only preventive measure for PRS; however, such reductions may not be practicable. The discontinuance of radiation for benign bone and soft-tissue diseases has limited PRS to patients receiving radiation treatment for malignancies.
Consultations
A multidisciplinary approach is ideal for PRS. The surgical oncologist, who preferably has experience in treating sarcomas, should be involved at the outset for the diagnostic evaluation. In addition, input from the radiation oncologist and medical oncologist is necessary to achieve a coordinated treatment plan, particularly for patients in whom combined modality treatment is being contemplated.
Long-Term Monitoring
RT is delivered in the ambulatory setting. Follow-up of patients who have received definitive treatment for PRS is individualized according to the site of disease. Generally, follow-up should include a posttreatment imaging study to provide a baseline against which subsequent studies may be evaluated.
Subsequent follow-up should include a thorough history and physical examination, with laboratory tests and chest radiographs and other imaging performed regularly for the first 2 years. Assessments may be spaced further apart after the second year to the fifth year following definitive treatment. Annual assessments may be performed thereafter.
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Light-microscopic appearance of postradiation osteosarcoma; tumor is composed of pleomorphic plump spindle cells with focal presence of neoplastic osteoid (pink areas) in between tumor cells. This meningeal tumor occurred 10 years after radiation therapy in patient who had received such therapy for recurrent pituitary neoplasm.
