ABSTRACT
In spite of a direct effect obtained in radiotherapy of lung cancer, tumor growth often resumes afterwards, metastases appear, all these causing death of most patients within the first 1-2 yrs. It is worth nothing that a considerable number of patients die from tumor recurrences in the absence of generalization. Therefore a question arises as to the therapeutic tactics for such patients, including the potentialities and appropriateness of repeated irradiation. The efficacy of repeated radiation therapy of 100 patients with lung cancer was analysed. Direct improvement was noted in 44% of x-ray findings and in 77% of clinical findings. The patients' mean survival rates were 29.7-2.6 mos. after the 1st course of treatment and 17.2 +/- 2.5 mos. after repeated irradiation. Short- and longterm results showed correlation, i.e. in x-ray improvement the mean survival after the 2nd course was 23.5 +/- 4 mos. whereas in its absence it was 13.5 +/- 4 mos. It was established that the longer the interval between the therapeutic courses the more probable an increase in a survival period after repeated radiation exposure. After 2 radiotherapy courses all the patients developed radiation pneumosclerosis of varying degree pathological rib fractures were marked in 4 patients and tumor regression in 5 patients. A conclusion has been made that repeated radiation therapy of lung cancer patients is of palliative nature.
Subject(s)
Lung Neoplasms/radiotherapy , Neoplasm Recurrence, Local/radiotherapy , Adenocarcinoma/mortality , Adenocarcinoma/radiotherapy , Adult , Aged , Carcinoma, Small Cell/mortality , Carcinoma, Small Cell/radiotherapy , Carcinoma, Squamous Cell/mortality , Carcinoma, Squamous Cell/radiotherapy , Dose-Response Relationship, Radiation , Female , Humans , Lung Neoplasms/mortality , Male , Middle Aged , Neoplasm Recurrence, Local/mortality , Radiation Injuries , Time FactorsABSTRACT
The paper is concerned with the problem of uneven irradiation of tumors using standard grid diaphragms on Soviet gamma-apparatuses. It has been shown that the utmost spatial heterogeneity is formed by using the C-4 grid with the source-surface distance (SSD) of 47 cm. The degree of spatial heterogeneity formed by the C-3, C-2, C-1 and C-5 grids is less pronounced. An increase in SSD results in the formation of more even irradiation. In uneven irradiation of tumors the nature of dose fractionation changes and it should be taken into account in the planning of radiotherapy.
Subject(s)
Neoplasms/radiotherapy , Gamma Rays , Humans , Radiation Protection , Radiotherapy DosageABSTRACT
In the paper an attempt was made to determine the optimum single therapeutic dose (otD1( in radiation treatment of 600 patients with laryngeal cancer. It is suggested to take the latter as a standard for adequate dosage in planning fractionation radiotherapy and to use it for calculating the optimum total therapeutic dose (otDt). Both the optimum single therapeutic dose and total dosage equivalent to it may provide for better chances of patients' cure. The analysis indicated that in laryngeal cancer of stage T1--2N0M0 the optimum equivalent single therapeutic dose is mostly likely to be 2700 +/- 60,0 rad while in stage T2N0M0--2850 +/- 50,0 rad.
Subject(s)
Laryngeal Neoplasms/radiotherapy , Radiotherapy Dosage , Adolescent , Adult , Aged , Female , Humans , Laryngeal Neoplasms/pathology , Male , Middle Aged , Vocal Cords/radiation effectsABSTRACT
A comparative estimation is given of the results of radiotherapy in 85 patients with cancer of the true vocal cords in stage T1--2N0M0 depending on focal dosage in rad and ret units. There was noted a distinct correlation between the results of the treatment and the dosage applied. The immediate clinical cure was gained in 88.2% of cases. In this group of patients an average focal dosage corresponded to 6448 +/- 72.8 rad and 1793 +/- 22.7 ret, whereas in unsuccessful radiotherapy these were 5963 +/- 158 rad and 1675 +/- 28.3 ret. A five-year cure was noted with an average dosage of 6525 +/- 87.0 rad and 1830 +/- 52.1 ret. In a group of patients with recurrences these doses were 6390 +/- 183.4 rad and 1720 +/- 34.4 ret accordingly.
