104 Role of radiation therapy in management of patients with sarcoma of soft tissue

Proceedings of the 39th Annual ASTRO Meeting 104 Role of Radiation Therapy in Management of Patients with Sarcoma of Soft Tissue Ira 1. Spiro, Ph.D., M.D. Herman D. Suit, M.D., D. Phil. Dept. of Radiation Oncology, Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA Soft tissue sarcomas (STS) are relatively rare malignant neoplasms arising from the mesenchymal connective tissues. There are some 5600 newly diagnosed patients with STS per year. These tumors occur at all anatomic sites within the body and are of many histologic subtypes. Etiologic factors, including occupational risks, the role of environmental carcinogens, radiation and genetic diseases in the develooment of these tumors will be made. The molecular bioloev of soft tissue sarcomas includina the role of several will be revrewed. Cytogenetic alternations &th an emphasis on oncogenes and suppressor genes (e.g. Rb, ~53, MDM2) -” molecular diagnostic techniques will be reviewed. The natural history of these tumors will be described with reference to local invasion and spread to regional and distal sites. The evaluation of the patients suspected of having a sarcoma of soft tissue will then be considered including the relative roles of various imaging modalities. The timing and type of biopsy (including FNA, core needle biopsy, incisional biopsy or excisional biopsy) for tumors at various sites and sizes will be addressed. Assessment of histopathologic subtype of the tumor by standard H&E stains, immunohistochemistry, electron microscopy and cytogenetic studies will then be discussed. The principal role for radiation in the management of patients with sarcoma of soft tissue is in combination with surgery. This may be: 1) pm-operative and or post-operative use of external beam photons, electrons, and protons, and 2) intra-operative use of electron beam techniques, or 3) post-operative brachytherapy. Results of these various treatment options with respect to local control, disease-free survival and overall survival will be considered for each of the various techniques with respect to size, grade, histologic type, surgical margin status, anatomic site, primary vs. recurrent disease. Simdarly, the factors associated with delav in wound healine are to be considered and stratenies to reduce wound morbiditv. Functional outcome after limb-sparing p&dures will be discussed. There are new account of impressive results of treatment with perfusional TNF melphalan and interferon. The role of systemic chemotherapy in patients with MO disease will be considered. Specifically, the results of the several Phase II and Phase III trials of adjuvant chemotherapy will be reviewed with respect to outcome; trial design, patient numbers, implication for patient care. The radiation sensitivity measured in vitro for cells arising from sarcomas of soft tissue of human patients and experimental animals will be reviewed and compared with reference to clinical response patterns of epithelial tumors. Finally, there will be a brief coverage of the role of radiation desmoid tumors and dermatofibrosarcoma protuberans.

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105 Treatment of Nasopharyngeal Carcinoma and Carcinoma of the Nasal Cavity and Paranasal Sinuses James E. Marks, M.D. Missouri Baptist Medical Center, St. Louis, MO This course will address the primary and adjuvant role of ionizing radiation in the management of nasopharyngeal, nasal cavity and paranasal sinus cancers. Nasopharynx: Primary irradiation of nasopharyngeal carcinoma is technically challenging because of its proximity to the base of skull and central nervous system. Careful planning and an in-depth understanding of skull-base anatomy, patterns of local-regional spread and radiation tolerance of brain, spinal cord, optic nerves and retina are required. The theoretical advantages of three-dimensional planning and delivery of dose with modulated-intensity x-ray beams and protons, though promising, remain unsubstantiated. What has been established is that non-keratinizing WHO 2 and 3 cancers of the nasopharynx are more radiocurable than keratinizing ones and that chemotherapy in addition to radiation, though toxic, improves disease-free survival. The limited role of surgery and retreatment by external beam and endocavity brachytherapy will be discussed. Nasal Cavity: Radiation alone is preferentially used for cancers within the vestibule of the external nose because of its cosmetic importance and the impossible task of reconstructing it after rhinectomy. Cancers of the nasal cavity often behave like paranasal sinus cancers and require resection with adjuvant pre- or postoperative irradiation. Techniques of interstitial implantation and external irradiation of the nose will be described. Paranasal Sinus: Radiation is used before or after surgery for resectable cancers of the paranasal sinus or as a single modality for unresectable ones. Those which involve the maxillary suprastructure are irradiated with ethmoido-maxillary technique while those of the infrastructure, are irradiated with a classic wedge-pair technique. Dose escalation is limited by the tolerance of the retina, optic nerves and brain.