61. The outcomes of the conventionally fractionated radiotherapy in the prospectiive and retrosprctive studies. Is the meaning of conventionality the same?

Abstract

Aim

To discuss some problems of the “conventionality” in the prospective and retrospective studies finished last year at the RT Department in Warsaw. The phase III clinical trial. The study was conducted according to the evidence based rules. Cancer of the larynx – glottis and supragiottis T1 – T3 NO M0 WHO 0 – 1, 395 cases 196 in experimental, 199 in conventional arm. The retrospective study concerned all patients with the cancer of larynx treated radically in the II department in years 1989 to May 1995. 372 patients T1- T4, N1-N3, M0. The prospective material 150 patients were selected [age 75 and less, WHO 0–1, T1–T3, NO, M0] employing the same selection criteria as in the prospective study. The comparison was performed with the conventional arm of the clinical trial [199 cases].

Results of the study

Significant differences were recorded in the: ? performance status and in the number of T1 and T3 cases, ? compliance to protocol in the total dose and the overall treatment time, ? response to treatment in the whole group and in the particular stages These results indicate the very demanding selection of cases and much more rigorous compliance with the therapeutic protocol in the prospective study. The response to treatment was about 20% higher in the clinical trial group. The 20% difference between the outcomes in the prospective and retrospective studies recorded in the response to treatment was similar in the 1, 2, and 3 years local control observations.