Dynamic pion irradiation of unresectable soft tissue sarcomas

• Published in: International journal of radiation oncology, biology, physics Vol. 17; no. 5; p. 1077
• Main Authors: Greiner, R H, Blattmann, H J, Thum, P, Coray, A, Crawford, J F, Kann, R H, Munkel, G, Pedroni, E, von Essen, C F, Zimmermann, A
• Format: Journal Article
• Language: English
• Published: United States 01-11-1989
• Subjects: Adult; Aged; Elementary Particles; Humans; Mesons; Middle Aged; Neoplasm Metastasis; Radiotherapy Dosage; Sarcoma - diagnostic imaging; Sarcoma - pathology; Sarcoma - radiotherapy; Soft Tissue Neoplasms - diagnostic imaging; Soft Tissue Neoplasms - pathology; Soft Tissue Neoplasms - radiotherapy; Tomography, X-Ray Computed
• ISSN: 0360-3016
• DOI: 10.1016/0360-3016(89)90159-4

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.