Proceedings of the 38th Annual ASTRO Meeting
&Emmon MalIgnant Tumors in Childhood (Pe~Iiatric Sarcoma, Patric& s swift, A4 D. University of California, San Francisco, CA
129
Wllmr’, and Neuroblastoma)
As survival rates improve in pediatric malignancies through the introduction of intensified chemotherapeutic regimens with stem cell support, the role of local therapies must continually be refined and redefined. The risks of increasing acute and delayed toxicities due to concurrent or sequential therapies;especially in long-term survivors, must be understood by the treating radiation oncologist at the time of treatment planning. Target volumes and doses necessary to control these malignancies may or may not decrease with increasingly effective systemic therapies -these are questions currently being addressed in large scale cooperative trials. The ability of conformal treatment approaches to diminish morbidity must also be considered in these discussions. Current radiotherapeutic guidelines of the major cooperative studies for pediatric sarcomas rhabdomyosarcoma, other soft tissue sarcomas), neuroblastoma and Wilms’ tumor will be reviewed, as radiotherapy study questions of the next generation of studies. Recommended techniques, including brachytherapy and 3D conformal approaches, will be discussed. Expected interactions chemotherapeutic approaches with radiation will also be addressed.
Role of Radiation Therapy in Management kc7J. $90, Ph.D., M.D. Herman
D. Suit, MD.,
Dept. of Radiation MA
of Patients with Sarcoma
(Ewings’, well as the the role of of novel
of Soft Tissue
D. PM
Oncology,
Massachusetts
General
Hospital Cancer
Center, Harvard
Medical
School, Boston,
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 sttes 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 development of these tumors will be made. The molecular biology of soft tissue sarcomas including the role of several oncogenes and suppressor genes (e.g. Rb, ~53. MDM2) will be reviewed. Cytogenetic alternations with an emphasis on 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 cy-togenetic 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) preoperative 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. Similarly, the factors associated with delay in wound healing are to be considered and strategies to reduce wound morbidity. Functional outcome after limb-sparing procedures will be discussed. There are new accounts 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 Ill 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 in the treatment tumors, including desmoid tumors and dermatofibrosarcoma protuberans.
of several benign
mesenchymal