Radiosurgery and stereotactic irradiation of multiple and contiguous brain metastases: A practical proposal of dose prescription methods and a literature review.

PURPOSE: In literature, there are no guidelines on how to prescribe dose in the case of radiosurgery (SRS) or stereotactic irradiation of multiple and adjacent BM. Aim of this work is to furnish practical proposals of dosimetric methods for multiple neighboring BM, and to make a literature review about the SRS treatment of multiple BM, comparing radiotherapy techniques on the basis of different dosimetric parameters. MATERIALS AND METHODS: A theoretical proposal of dosimetric approaches to prescribe dose in case of multiple contiguous BM is done. A literature review between 2010 and 2020 was performed on MEDLINE and Cochrane databases according to the PRISMA methodology, with the following keywords dose prescription, radiosurgery, multiple BM. Papers not reporting dosimetric solutions to irradiate multiple BM were excluded. RESULTS: Only one article in the literature reports a practical modality of dose prescription for multiple adjacent BM. Thus, we proposed other five practical solutions to prescribe radiation dose in case of two or more neighboring BM, describing advantages and drawbacks of each method in terms of different dosimetric parameters. The literature review about dosimetric solutions to irradiate multiple BM led to 56 titles; 14 articles met the chosen criteria and we reported their results in terms of dosimetric indexes and low doses to the normal brain tissue. CONCLUSIONS: The six dosimetric approaches here described can be used by physicians for multiple contiguous BM, depending on the clinical situation. These methods may be applied in clinical studies to better evaluate their usefulness in practice.

Effects of long-term growth hormone therapy on adrenal steroidogenesis in Turner syndrome.

It has been shown that growth hormone (GH) and insulin-like growth factor-1 (IGF1) enhance steroidogenesis responsiveness to ACTH in cultured adrenal cells. To investigate the GH effect on adrenal steroidogenesis in non-GH-deficient subjects, we studied 9 girls with Turner syndrome (chronological age 5.5-7.2 years; bone age 5-7 years). In all subjects an ACTH test (Synacthen depot, 0.25 mg i.v. with blood samples at 0 and 60 min) was performed basally at 8-9 a.m. and 6 months after GH therapy (1 IU/kg/week). 17-Hydroxypregnenolone (17PGN), 17-hydroxyprogesterone (17OHP), dehydroepiandrosterone (DHA), its sulfate (DHA-S), androstenedione and cortisol were evaluated by radioimmunoassay. Two groups of normal girls were selected as controls: group A age-matched the patients at the start of the study, and group B age-matched the patients at the end of the study. The responsiveness of each hormone to ACTH was expressed as the difference between stimulated and basal values. A p value of < 0.01 was considered to indicate significance. There were no significant differences between pre- and posttreatment basal values of 17PGN, 17OHP, DHA, androstenedione and cortisol in the Turner syndrome patients, whereas a significant increase was observed for basal DHA-S (1.57+/-0.31; 1.89+/-0.43 micromol/l, p < 0.01). Comparison of increments before and after GH treatment showed a significant increase in responsiveness to ACTH after GH therapy DHA (p < 0.01). The increase in 17PGN was evident (p < 0.02), but the established significant p value was not reached. No differences for 17OHP, androstenedione and cortisol were found. The stimulated 17PGN/17OHP ratio was significantly higher (p < 0.01) after GH, whereas the 17OHP/androstenedione ratio was considerably lower, but the p value was < 0.02. No differences between pretreatment values with the control group androstenedione was found, whereas basal and stimulated posttreatment values of DHA and stimulated values of 17PGN were higher in patients after GH therapy than in control group B. No differences between the 2 control groups were found. In conclusion our study showed that adrenal steroid responsiveness to ACTH increases in Turner syndrome after long-term treatment with high GH doses. An increase in the number of ACTH adrenal receptors and/or a modulation of enzyme activities may be suggested. The positive or negative pharmacological implications of these data remain to be determined especially when taking into consideration the wide use of GH therapy in non-GH-deficient subjects.

Adult height in short normal adolescent girls treated with gonadotropin-releasing hormone analog and growth hormone.

GnRH analog associated with GH therapy has potential importance for treatment of short stature in subjects without GH deficiency and with a normal onset of puberty. We treated 10 girls with familial short stature with the GnRH analog leuprolide (3.75 mg, im, every 25 days) and GH (0.1 IU/kg.day, sc, 6 days/week). The combined therapies were started simultaneously, and the patients were treated for 28.1 +/- 5.4 (range, 24-36) months. At the onset of treatment, chronological age was 11.6 +/- 1.4 yr, bone age was 10.6 +/- 0.9 yr, height was -2.7 +/- 0.7 SD, predicted height (PH; Bayley-Pinneau score) was 143.2 +/- 3 cm. Target height was 147.6 +/- 5.6 cm. Tanner stage was II-III for breast and genitalia. During treatment, puberty was completely suppressed in all patients. Statistical analysis was performed using Student's t test for paired data. After 12 months of treatment, we observed a significant (P < 0.02) improvement of predicted height (146.2 +/- 3.4 cm). This improvement remained significant (147.6 +/- 3.5; P < 0.001) when treatment was withdrawn. At that time, chronological age was 13.9 +/- 1.2 yr, and bone age was 12.4 +/- 0.7 yr. At the present time (3 +/- 0.97 yr after discontinuation), all of the girls have reached a final height of 144.6 +/- 3 cm (range, 140-149.3 cm). The final height is not significantly different compared with the PH at the beginning of treatment or with target height. These data show that in our patients, combined treatment with GnRH analog and GH, despite a significant improvement in PH during therapy and upon its withdrawal, does not result in a significant increase in adult stature. Larger and perhaps more prolonged studies in patients of both sexes are required to reach definitive conclusions. Nevertheless, the cost of this treatment in terms of both subject compliance and economic cost should be weighed against the small height gain, if any, that may be achieved.