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Tolerance of surgery after radical radiotherapy of carcinoma of the oropharynx
We investigated CEA levels over an approximately 10 week period, preradiotherapy through five weeks after completion of therapy, in 31 patients. Four patients were excluded due to incomplete information. Twenty-three patients had a significant increase or decrease in CEA levels during this period, while four patients had no change in CEA levels. Analysis of the data shows that patients having a progressive decrease in CEA levels during this period had a longer survival (median = 1 year) than patients who displayed a progressive increase in CEA levels (median = 3 months) (p < .03), regardlesss of the magnitude of initial CEA levels. Among the patients in whom CEA levels did not change, there was no correlation with survival. Additional determinations after the interval studied increased the correlation of CEA levels with survival if the levels continued to decline or if the levels increased after an initial decline. However, in patients in whom levels did not fluctuate, no correlation with prognosis was evident. CEA levels prior to commencement of treatment alone did not appear to be a prognostic indicator of survival. This study indicates that determination of CEA levels spanning the period from preradiotherapy to five weeks after treatment is a useful screen
for predicting subsequent clinical course. Subsequent determinations at intervals thereafter may increase the correlations with prognosis. The
complementary information provided by CEA levels in addition to physical status, chest x-rays, parameters of immunity, and serum glycoproteins will be presented.
(69) TOLERANCE OF SURGERY AFTER RADICAL RADIOTHERAPY OF CARCINOMA OF THE OROPHARYNX Victor A. Martial, M.D.,* James Hanley, Ph.D.,** Arturo Ydrach, M.D.,** and Luis A. Vallecillo, M.D.* *University of Puerto Rico **Harvard University Surgery is frequently needed after radical irradiation of carcinoma of the oropharynx for persistent or recurrent primary or metastatic neck node tumor, or on a prophylactic basis for the neck area. Surgical morbidity is expected to increase with the dose of irradiation; as a consequence, most surgeons expect significant complications with doses higher than 5,000 rad in 5 weeks. The split-course project of the Radiation Therapy Oncology Group registered 142 base of tongue and 131 tonsillar fossa patients. These cases received protocol radiotherapy or a minor deviation of it. On registration, the patients were randomly assigned to a splitcourse regime (300 x 3 wks. rest, then 300 x 10) or a continuous course of irradiation (220 x 30). This report will analyze surgical morbidity
72
(delayed healing, fistulas,
mortality, etc.) and tumor control' achieved at the operative site in fifty patients who required surgery after radical irradiation. The operations performed were: to the primary tumor-17, to the primary tumor and neck-15, In three cases the information was not complete and to the nodes only-15. by the time the abstract was submitted.
( 70) ENHANCED EFFECT OF RADIATION ON THE CHROMOSOMES OF HYPOXIC CELLS TREATED WITH METRONIDAZOLE Timothy Merz, Ph.D., * Chairman, Radiation Biology, Department of Radiology, Medical College of Virginia, Richmond, Virginia Tapan Hazra, M.D., Chairman, Radiation Therapy, Department of Radiology, Medical College of Virginia, Richmond, Virginia The many reported studies of the effect of flagyl and other nitrohetrocyclic drugs in combination with radiation have demonstrated that it is an adjuvant of clinical significance. It is therefore important to know more about the biological mechanisms of its effect on cells treated with these compounds and subsequently irradiated. We report here a study of the effect of flagyl on the frequency of radiation-induced chromosome aberrations (an assay traditionally correlated with radiation-induced cell death) produced in human lymphocytes which have been irradiated in air and under hypoxic conditions. Human leukocytes were treated with Zmg:: flagyl and irradiated either in a normal air environment or in a nitrogen environment. The cells were cultured as standard lymphocyte cultures for 56 hours and the chromosomes from the cells in each group were scored for chromosome aberrations (dicentric and rings). The data demonstrate that the presence of flagyl results in an increase in aberration rates in cells irradiated in the hypoxic state but not those irradiated in normal air environments. These increases are in the range reported by other authors who have assayed tumor cell survival.
(71) EXPERIENCE OF Ir-192 INTERSTITIAL
IMPLANT
Edward C. Mok, M.Sc., Charles H. Feitl, R.T., Virenda S. Saxena, M.D. Christ Hospital, Oak Lawn,
IL
Iridium 192 has been used as a radium substitute for head and neck, floor of mouth, breast and as a surface applicator. It is found that the dosimetry for the implant are complicated by: (1) the uncertainty of the exposure rate constant, therefore no satisfactory method to specify the activity of commercial made iridium sources, (2) effect of absorption and scattered correction is uncertain for distance over 10 cm. from the source, (3) the localization of a large number of sources is difficult. The application of computer to the problems has made it possible to evaluate the dose distribution produced by the iridium sources. The method of dosimetry will be discussed. A large variety of seed implants were studied and rules and tables have been developed to predict the dose of different arrangements of the radioactive sources with specific tumor volume. Actual cases will be presented to indicate the application.
73
for predicting subsequent clinical course. Subsequent determinations at intervals thereafter may increase the correlations with prognosis. The
complementary information provided by CEA levels in addition to physical status, chest x-rays, parameters of immunity, and serum glycoproteins will be presented.
(69) TOLERANCE OF SURGERY AFTER RADICAL RADIOTHERAPY OF CARCINOMA OF THE OROPHARYNX Victor A. Martial, M.D.,* James Hanley, Ph.D.,** Arturo Ydrach, M.D.,** and Luis A. Vallecillo, M.D.* *University of Puerto Rico **Harvard University Surgery is frequently needed after radical irradiation of carcinoma of the oropharynx for persistent or recurrent primary or metastatic neck node tumor, or on a prophylactic basis for the neck area. Surgical morbidity is expected to increase with the dose of irradiation; as a consequence, most surgeons expect significant complications with doses higher than 5,000 rad in 5 weeks. The split-course project of the Radiation Therapy Oncology Group registered 142 base of tongue and 131 tonsillar fossa patients. These cases received protocol radiotherapy or a minor deviation of it. On registration, the patients were randomly assigned to a splitcourse regime (300 x 3 wks. rest, then 300 x 10) or a continuous course of irradiation (220 x 30). This report will analyze surgical morbidity
72
(delayed healing, fistulas,
mortality, etc.) and tumor control' achieved at the operative site in fifty patients who required surgery after radical irradiation. The operations performed were: to the primary tumor-17, to the primary tumor and neck-15, In three cases the information was not complete and to the nodes only-15. by the time the abstract was submitted.
( 70) ENHANCED EFFECT OF RADIATION ON THE CHROMOSOMES OF HYPOXIC CELLS TREATED WITH METRONIDAZOLE Timothy Merz, Ph.D., * Chairman, Radiation Biology, Department of Radiology, Medical College of Virginia, Richmond, Virginia Tapan Hazra, M.D., Chairman, Radiation Therapy, Department of Radiology, Medical College of Virginia, Richmond, Virginia The many reported studies of the effect of flagyl and other nitrohetrocyclic drugs in combination with radiation have demonstrated that it is an adjuvant of clinical significance. It is therefore important to know more about the biological mechanisms of its effect on cells treated with these compounds and subsequently irradiated. We report here a study of the effect of flagyl on the frequency of radiation-induced chromosome aberrations (an assay traditionally correlated with radiation-induced cell death) produced in human lymphocytes which have been irradiated in air and under hypoxic conditions. Human leukocytes were treated with Zmg:: flagyl and irradiated either in a normal air environment or in a nitrogen environment. The cells were cultured as standard lymphocyte cultures for 56 hours and the chromosomes from the cells in each group were scored for chromosome aberrations (dicentric and rings). The data demonstrate that the presence of flagyl results in an increase in aberration rates in cells irradiated in the hypoxic state but not those irradiated in normal air environments. These increases are in the range reported by other authors who have assayed tumor cell survival.
(71) EXPERIENCE OF Ir-192 INTERSTITIAL
IMPLANT
Edward C. Mok, M.Sc., Charles H. Feitl, R.T., Virenda S. Saxena, M.D. Christ Hospital, Oak Lawn,
IL
Iridium 192 has been used as a radium substitute for head and neck, floor of mouth, breast and as a surface applicator. It is found that the dosimetry for the implant are complicated by: (1) the uncertainty of the exposure rate constant, therefore no satisfactory method to specify the activity of commercial made iridium sources, (2) effect of absorption and scattered correction is uncertain for distance over 10 cm. from the source, (3) the localization of a large number of sources is difficult. The application of computer to the problems has made it possible to evaluate the dose distribution produced by the iridium sources. The method of dosimetry will be discussed. A large variety of seed implants were studied and rules and tables have been developed to predict the dose of different arrangements of the radioactive sources with specific tumor volume. Actual cases will be presented to indicate the application.
73