strontium-radioisotopes and Precancerous-Conditions

Ionizing irradiation by incorporated strontium-90 exerts two major effects: it induces tumours (mainly osteosarcomas and lymphoreticular tumours) and depresses the immune system. The interrelation between these functions, i.e. the significance of decreased immunological responsiveness in the oncogenic process, remains unclear. The influence of the 90Sr dose and the role of immune modulation on the tumour yield, were investigated in young adult CBA mice. The animals were exposed to different single doses of 90Sr and, in addition, some groups were subjected to long-term unspecific immune suppression by adult thymectomy (ATx) and/or prolonged antilymphocyteglobulin (ALG) treatment. The present paper (part I) reports on the effects of the treatments on bone tumour responses as reflected by incidence, multiplicity, latency time, histologic characteristics and growth behaviour. The histogenesis of osteosarcomas, as evidenced morphologically by preneoplastic and early neoplastic growth, is illustrated and discussed. The results demonstrate a positive dose-response relationship for osteosarcomas, in which the relative incidences of the various osteosarcoma subtypes were differentially affected. Thus, well-differentiated tumours were gradually replaced by less differentiated types as the dose decreased. A correlation was also observed between the incidence of osteosarcomas and that of assumed preneoplastic lesions in the same bones and sites. Immune suppression by ATx and/or ALG did not distinctly alter the neoplastic or preneoplastic responses at any dose-level of 90Sr.

Topics: Animals; Antilymphocyte Serum; Bone Marrow; Bone Neoplasms; Male; Mice; Mice, Inbred CBA; Neoplasms, Radiation-Induced; Osteosarcoma; Precancerous Conditions; Strontium Radioisotopes; Thymectomy

Sixty-eight patients suffering from conjunctival melanoma were treated by beta-irradiation. The dose given ranged between 15,000 and 20,000 rd at the tumor surface. In 75% the therapy was successful. In 67,4% the melanoma could be cured by beta-irradiation alone with a follow-up period between three and ten years. The lethality rate from proven metastases was only 6.2%. The regression time after beta-therapy, as a rule, exceeded several months. Beta-rays can be used either primarily or after tumor excision. Care should be taken that the applicator covers all the tissue containing tumor cells.

Topics: Adolescent; Adult; Aged; Child; Conjunctiva; Eye Neoplasms; Female; Follow-Up Studies; Humans; Male; Melanoma; Middle Aged; Nevus, Pigmented; Precancerous Conditions; Radiotherapy Dosage; Strontium Radioisotopes

The use of strontium 90 has proved to be efficient and practical, because handy, and permitting short treatment, not only, to cure benign superficial tumors and, as reported in this study, of pre-cancerous lesions such as actinic keratosis, Bowen's disease of the skin but also some carefully chosen cases of superficial carcinomas. Hundred lesions have been so treated and followed for 3 years; two only have relapsed. The cosmetic result has been excellent in 80 p. 100.

Topics: Aged; Bowen's Disease; Carcinoma, Squamous Cell; Drug Evaluation; Female; Humans; Keratosis; Male; Precancerous Conditions; Radiotherapy; Radiotherapy Dosage; Skin Neoplasms; Strontium Radioisotopes