Intrinsic radiosensitivity and prediction of patient response to radiotherapy for carcinoma of the cervix

Open Access
Publisher Website
Google Scholar
Abstract
The intrinsic radiosensitivity of cervical carcinoma has been measured using a soft agar clonogenic assay. All patients received radical radiotherapy alone with a minimum of 2 years post-treatment follow-up. Only women with stage I, II and III disease were included in the analysis. Values for cell surviving fraction at 2 Gy (SF2) were obtained for 88 tumours with an assay success rate of 73%. The 53 patients alive and well at the time of analysis had tumours with a mean SF2 that was significantly lower than the value from the 22 patients with locoregional failure (P < 0.01). Patients with radioresistant tumours (SF2 > 0.40, the median) had a significantly lower 3 year survival level than those with sensitive tumours (SF2 < or = 0.40) (P = 0.002). Also the frequency of local recurrence was higher (P = 0.001) whether these were central (P = 0.009) or peripheral (P = 0.046). Cell surviving fraction at 3.5 Gy was obtained for 46 tumours and the 3 year patient survival rate was significantly higher for those with SF3.5 values less than the median (P = 0.043). There was, however, no difference in the level of local recurrence (P = 0.24). The ability to grow in culture was not associated with significantly poorer patient survival (P = 0.56) or failure to control the primary disease (P = 0.17). While high colony forming efficiencies were associated with an increased rate of local recurrence (P = 0.029) they did not predict for overall patient survival (P = 0.32). These data suggest that, for cervical carcinoma treated with radical radiotherapy, intrinsic radiosensitivity is important in determining treatment outcome.