title: Dynamic pion irradiation of unresectable soft tissue sarcomas.
abstract: Since November 1981, when pion irradiation was introduced for deep seated tumors at the Swiss Institute for Nuclear Research (SIN, now Paul Scherrer Institute, PSI) a dynamic, 3-dimensional spot scan treatment technique has been in use. To exploit this technique a special optimization treatment planning system has been designed. Of a total of 331 patients treated with pions from November 1981-December 1987, 35 were irradiated for unresectable soft tissue sarcomas. In 32/35 patients, tumor sites were retroperitoneal, pelvic or in the groin or thigh. Twenty-nine tumors had a maximum diameter of greater than 10 cm, 18 tumors of greater than 15 cm; 30 tumors had grade 2/3 and 32 Stage III B/IV A/IV B. Eight of 35 patients received a low pion total dose, 7-27 Gy. Twenty-seven patients received a total dose of 30-36 Gy, fraction size 150-170 cGy (90%-isodose), 20 fractions, 4 times per week. Of these 27 patients, severe late reactions appeared in five: 2/8 patients with extremity/groin sarcomas (1/2 caused by biopsy) and 3/19 patients with retroperitoneal/pelvic sarcomas (one a skin reaction after Actinomycin-D, one a small bowel reaction after 36 Gy, a dose no longer used). Seven of 27 patients had metastases at the beginning of irradiation. Three of 27 were treated with excisional biopsy, 9 with incisional biopsy or partial resection and in 15 patients biopsies were performed for histology only. The median follow-up of these 27 patients was 17 months (5-66). There was no progression in eight extremity/groin tumors but in 4 of 19 retroperitoneal/pelvic tumors. Three of these were marginal progressions. The actuarial 5-year rate of local tumor control is 64%; the actuarial 5-year survival rate of patients without metastases at the beginning of treatment is 58%. Dynamic spot scan pion irradiation proves to be a successful treatment technique for unresectable sarcomas with a high rate of tumor control and a very low rate of severe late reactions.
authors: Paul Scherrer Institute, Division of Radiation Medicine, Villigen-PSI, Switzerland.
authors: R H
authors: RH
authors: Greiner
authors: H J
authors: HJ
authors: Blattmann
authors: P
authors: P
authors: Thum
authors: A
authors: A
authors: Coray
authors: J F
authors: JF
authors: Crawford
authors: R H
authors: RH
authors: Kann
authors: G
authors: G
authors: Munkel
authors: E
authors: E
authors: Pedroni
authors: C F
authors: CF
authors: von Essen
authors: A
authors: A
authors: Zimmermann
mesh_terms: D000328:Adult; D000368:Aged; D004601:Elementary Particles; D006801:Humans; D008651:Mesons; D008875:Middle Aged; D009362:Neoplasm Metastasis; D011879:Radiotherapy Dosage; D012509:Sarcoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D014057:Tomography, X-Ray Computed