XXXX : the effect of dose-time-volume factors on local control.

@entity1 @entity957 @entity189
Between 1970 and 1979, 372 @entity1 with @entity957 were treated with primary irradiation therapy, with salvage surgery for failures. The median age was 60 years and the male to female ratio was 2:1. The staging system used was the 1974 UICC TNM system. There were 47 T1 lesions (13%), 161 T2 lesions (43%), and 164 T3 lesions (44%). Regional nodes were not palpable in 173 (46%); 122 had N1 nodes (33%), 6 had N2 nodes (2%) and 71 had N3 nodes (19%). All @entity1 received external beam radiation which was supplemented in 68 @entity1 with a radioactive implant for disease into adjacent tongue. The overall survival for all @entity1 was 38% at 5 years and 54% when corrected for intercurrent disease. Local control was 87% for T1 lesions, 68% for T2 lesions and 50% for T3 lesions. Regional control was 96% for N0, 67% for N1 and 37% for N2-3. A detailed dose-time-volume analysis revealed that increasing volume improved local control in T1 and T2 lesions (77% had local control if the volume was greater than 80 cm2 versus 53% if the volume was less than 80 cm2, p = 0.014), except for T3 lesions. Increasing the dose in the range of 5000 to 6500 rad had no significant effect on primary control in any stage of disease. The addition of a radioactive implant did not increase local control if disease extended into the tongue (57% local control if implant, 52% if no implant). This study demonstrates the significance of adequate treatment volume in local control for @entity189 . No significant dose response was found and subsequent surgery was not compromised when a moderate dose of radiation was used.
