Patterns of failure in XXXX : I. Failure at the primary site.

@entity1 @entity957 @entity5 @entity189
Between 1970 and 1980, we treated 107 previously untreated @entity1 with biopsy proven @entity189 by megavoltage external radiation therapy to the primary site, base of the skull and both sides of the neck. Fifty-three percent of the @entity1 had T4 primaries and 87% had Stage IV disease. The histology was poorly differentiated, undifferentiated or @entity189 in 81% of the @entity1 , and well differentiated or moderately well differentiated @entity957 in 19%. The dose of irradiation to the primary site ranged from 5700 to 7700 rad. Fifty-five @entity1 have suffered relapse of the @entity5 , 33 of whom (60%) relapsed at the primary site. Seventy-two percent of the relapses at the primary site appeared within two years after treatment and 91 percent within 3 years. Median survival following relapse at the primary site was 10 months. Those @entity1 who received a dose to the primary between 5700 and 6700 rad had a lower rate of local control than those who received a dose between 6700 and 7700 rad. However, regardless of the dose, those @entity1 whose radiation therapy was interrupted (for whatever reason) for a total of three weeks or longer had poorer local control than those @entity1 whose treatment was not so interrupted. The highest rate of local control (84%) was observed in those @entity1 who did not have such interruptions and received a dose of 6700-7700 rad to the primary. Improved local control with the higher doses was especially striking for T4 primaries, suggesting a dose-response relationship. The local control rate did not appear to be significantly influenced by age, sex, birthplace or histology. These data suggest that a high rate of local control is possible in @entity189 , even with T4 disease, if a sufficiently high dose of radiation therapy is delivered without undue interruptions.
