[Radiobiologic basis for using 131I to treat patients with thyroid cancer]. / Radiobiologiczne podstawy leczenia jodem promieniotwórczym 131I chorych na raka tarczycy.

The basic biological principle for 131I treatment of patients with thyroid cancer is the ability of well-differentiated tumor cells to uptake iodine. The absorption of adequate activities of radioiodine may sterilize primary tumor cells and the metastatic deposits. The basic factors which determine the effectiveness of radioiodine treatment include the effective half-life of 131I, the discrete energy of its beta decay, the effective range of emitted beta-rays, the activity of individual therapeutic doses, the intrinsic ability of tumor to uptake radioiodine, and the absorbed total radiation dose. The biological factors, which contribute to the effectiveness of radioiodine treatment, can be referred to "five Rs" of radiobiology: radiosensitivity, repair, redistribution, reoxygenation, and repopulation. The theoretical radiobiological considerations suggest that improvements in therapeutic indexes of radioiodine treatment are possible, e.g. by unconventional fractionation of 131I, or by combining the radionuclide therapy with external-beam irradiation. The net effect of such strategies in the clinic is, however, often unpredictable, and remains investigational and controversial. This illustrates the need for improved design of new research in clinical and experimental radiobiology of radioiodine treatment.

[Early evaluation of treatment effectiveness using 131I iodine radiotherapy in patients with differentiated thyroid cancer]. / Ocena wczesnej skutecznosci leczenia uzupelniajacego jodem promieniotwórczym 131I chorych na zróznicowane raki tarczycy.

UNLABELLED: This paper presents the preliminary results of a prospective randomized trial on early effectiveness of 30 mCi versus 60 mCi for ablation of thyroid remnants in patients with WDTC after total thyroidectomy. Since April 1998 to January 2000, 220 patients with papillary thyroid cancer in stage T1b-3, N0-x, M0 had entered the study. 106 patients received 60 mCi and 114 received 30 mCi as the first ablation dose. The subject for the analysis was the uptake over the neck, post-therapeutic whole body scintigraphy and Tg level 6 months after ablation. The early effectiveness of ablation was estimated using a 5-degree scale: 0--very good effect, 1--good effect, 2--dubious effect-required repetition of WBS and Tg assessment in 6-12 months, 3--insufficient ablation--required repetition of radioiodine treatment, 4--for evident dissemination or local recurrence. RESULTS: Grades 0 were obtained in 29 (53%) after 30 mCi (group I) and in 38 patients (86%) after 60 mCi (group II). Grades 1 were obtained in group I in 15 patients (28%) and in 4 patients (9%) of group II. Grades 2 were obtained in group I in 9 patients (17%) and in group II in 1 (2.3%). Grade 3 was obtained only in 1 (2%) patient after 30 mCi. Grade 4 was obtained in one patient after 60 mCi (2.3%). The difference in uptake over the neck in the two groups was statistically significant (p < 0.05), although the differences in early effectiveness between the both groups according to the 5-degree scale were on the borderline of significance (p = 0.075). There was a correlation between uptake before and after ablation in 30 mCi group, which was not seen present in 60 mCi group. CONCLUSION: For the ablation of thyroid remnants 60 mCi should be considered as a standard dose.

Recombinant human TSH for the treatment of differentiated thyroid cancer metastatic to the spine.

The diagnostic use of recombinant human TSH (rhTSH) in follow- up of differentiated thyroid cancer (DTC) is already approved, however its application in (131)I therapy is still to be evaluated. We report results obtained in four patients with DTC metastatic to central skeleton, in whom 5 courses of rtTSH aided 131I therapy were administered.