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K Slosarek

Publications and source records attributed to K Slosarek.

5 recordsLinked to original sources
PubMed1999

Clinical radiobiology of glottic T1 squamous cell carcinoma.

PURPOSE: Radiation therapy is the treatment of choice for early glottic squamous cell cancer in many institutions over the world. Despite a relatively homogenous clinical model of T1 glottic tumors for the fractionation studies, the relationships between dose-time parameters remain unclear. To analyze the influence of fractionation parameters and hemoglobin level on tumor cure, this study has been performed. MATERIALS AND METHODS: This is a retrospective review of 235 patients with T1N0M0 glottic cancer treated by radiation therapy alone given in a conventional schedule with 5 fractions each week. The individual total dose, dose per fraction, and overall treatment time (OTT) ranged from 51-70 Gy, 1.5-3.0 Gy, and 24-79 days, respectively. The median follow-up was 48 months. Patient data--total dose, dose per fraction, OTT, and hemoglobin level (Hb) measured before the radiation treatment--were fitted by the mixed LQ/log-logistic model. RESULTS: The 5-year local relapse-free survival rate was 84%. All parameters included in the mixed LQ/log-logistic model improved the fit significantly. The dose-response curve for 235 patients with T1 glottic cancer was well defined and steep, and showed significant decrease in tumor control probability (TCP) when total doses were below 61 Gy. The 10-day prolongation of OTT, from 45 to 55 days, decreased the TCP by 13%. The dose of 0.35 Gy/day, compensated repopulation during the 1 day of prolongation, which indicates a potential doubling time (Tpot) for glottic T1 tumor clonogens of 5.5 days. The drop of Hb level of 1 g/dl (from 13.8 g/dl to 12.8 g/dl) gave a 6% decrease of TCP, provided that OTT was 45 days. CONCLUSION: The significant correlation between the total dose, overall treatment time, hemoglobin concentration, and tumor control probability has been found for T1 glottic cancer.

Carcinoma, Squamous Cell↗
PubMed1998

[Efficiency evaluation of radiotherapy of recurrences after surgery in head and neck cancer].

An analysis of 200 consecutive patients with head and neck squamous cell cancer treated after surgery with radiation at the Centre of Oncology, Maria Sklodowska-Curie Memorial Institute in Gliwice was performed. At the beginning of radiotherapy recurrences were found in 67 (33.5%) patients. Recurrences were diagnosed at the primary site exclusively in 30 patients, in lymph nodes only in 21 patients, in both localizations in 14 patients, and in 2 patients in the tracheostomy. Conventional 60Co radiation treatment to the mean total dose of 62.5 Gy was applied. Three year disease-free survival probability was 22% for patients with recurrences comparing to 54% for patients with no relapse. In the group of patients with recurrences better prognosis was found for patients with preoperatively early stages, and with early recurrences, located in the primary tumour site, which completely responded to radiotherapy. High rate of recurrences after surgery for head and neck cancer and low probability of recurrence control with radiotherapy indicate the necessity of more careful qualification for surgical treatment.

Adult↗
PubMed1990

Dose-rate distribution under partially shielded beams.

We are presenting a method of calculating the dose-rate distributions in partially shielded field. An attenuator was placed in central beam axis and also in an off-axis geometry. The study was made with a Co-60 radiation and with photons generated by 10 and 23 MV Linac at depths, in phantom, from 5 to 30 cm. To obtain the calculated values of dose-rates; the contributions of the three components to the total dose-rate were measured. The calculated dose-rate distributions agree well with the measured data in case of 10 MV and 23 MV radiation.

Cobalt Radioisotopes↗
PubMedDate not supplied

[Use of the linear-square model for evaluation of the distribution of equivalent doses of electron irradiation].

The differences between physical absorbed dose of the electron radiation and normalized up to the total dose, fractionated by daily dose equal to 2 Gy, corresponding to "equivalent biologic dose isobio Gy 2" have been analysed. The effect of the fraction dose on the distribution of equivalent total dose in relation to the localization of the neoplastic tumor in the irradiated area has been assessed. On account of the calculations it has been found that alike as in the case of photon radiation the application of fractionated doses equal or lower than 2 Gy is more safe for healthy tissues as compared with higher fractionated doses. No distinct differences have been present between the distribution of physical and biological doses for isodoses below 80%. This fact suggests that the choice of the energy of electron radiation should be decided on account of the depth of the neoplastic tumor and the distribution of physical dose--whereas the distribution of biologic isodoses (isobio Gy 2) of electron radiation is of significant importance in the estimation of the tolerance of critical organs situated in the area between skin and the irradiated tumor.

Cobalt Radioisotopes↗