The effect of head-fractioned teletherapy on pulp tissue.

AIM: To evaluate the early and delayed effects of fractioned teletherapy (radiotherapy) on the dental pulps of rats using Co(60). METHODOLOGY: In group 1 - rats (n = 15) were subjected to fractioned teletherapy by 30 daily sessions fractioned in doses of 200 cGy day(-1), totaling 60 Gy and the rats were killed immediately after the final dose of irradiation; group 2 - same protocol but killed 30 days following the final irradiation dose; groups 3 (n = 7) and 4 (n = 8) - formed controls without irradiation. Following perfusion, the left mandible of each rat was dissected and processed for histopathology. Serial sections (5 microm) were obtained and stained with HE or picrosirius. Observations were recorded for the coronal pulp tissue. A blinded observer evaluated HE sections using pre-defined indices of inflammation, nuclear alterations and extracellular matrix (ECM) hyalinization. Images of sections stained with picrosirius were converted to black and white for analysis by image-pro plus; areas in black (collagen) were measured as percentage area. The pulps of mandibular incisors of the specimens prepared for transmission electron microscopy (TEM) were subjected to descriptive analysis. Magnifications of 6300 and 10000 x were used to observe 10 pulp fibroblasts from each group. RESULTS: No inflammatory reactions or modification of the ECM status were found (P = 0.428) in any specimens. The collagen content also displayed no significant changes (P = 0.067) as a result of treatment. Groups 1 and 2 displayed significantly more nuclear alterations than the control groups (P < 0.05). The bubble-like aspect was more pronounced in group 1, and the bubbles looked smaller in group 2. The ECM showed no differences in the hyalinization status and there were no differences in the collagen area within the pulps. Under TEM, the pulp fibroblasts in group 1 displayed nuclear alterations that resembled circular, oval or elongated perforations; perforations also appeared in the cytoplasm. CONCLUSION: Fractioned teletherapy is capable of producing nuclear alterations in the dental pulp tissue of rats.

Radiation therapy alone in stage III-B cancer of the uterine cervix--a 17-year old experience in southern Brazil.

PURPOSE: External irradiation followed by intracavitary therapy (EBIC) has been considered the standard treatment for stage III-B cancer of the uterine cervix. For different reasons, some patients are not suited for intracavitary therapy (ICT), and the treatment may be given entirely by external beam irradiation alone (EBRTA). The purpose of our study is to discuss treatment results and complications for patients undergoing EBIC or EBRTA. METHODS AND MATERIALS: A retrospective study was carried out on 202 eligible patients with stage III-B cancer of the uterine cervix admitted for radiotherapy from 1980-1997. Ninety-three patients were able to receive EBIC (50 Gy, 8 MV RX whole pelvis followed by one session of 38-45 Gy ICT to point A). The remaining received EBRTA (50-70 Gy for 5-9 or more weeks). Median follow-up procedure was 18.5 months (range: 4-182) for all patients and 26 months (range 4-147) for the patients at risk. RESULTS: The most frequent reason for precluding ICT was large residual tumor volume (32.1%). Ten-year overall survival rates, relapse free survival, and pelvic failure rate for the EBIC and EBRTA patients were, respectively, 22.5% x 15.6% (p = 0.0087), 23.5% x 14.8% (p = 0.005), and 51.6% x 68.8% (p = 0.005). However, when the same comparisons were performed with EBIC patients x EBRTA patients receiving a high dose schedule (60 Gy/6-8 wk to 70 Gy/7-9 wk), the results of the EBIC group remained higher, but the differences became insignificant: respectively, 22.5% x 18.9% (p = 0.17), 23.5% x 15.3% (p = 0.052), and 51.6% x 60.0% (p = 0.10). The distribution of complications was similar in both groups. CONCLUSIONS: We found that EBIC was the best treatment modality in our patients with stage III-B cancer of the uterine cervix, whereas for patients who were not candidates for ICT, EBRTA with a high dose schedule appears to be an efficient and safe alternative.