Purpose: We preliminarily estimated the treatment effect on cervical cancer in terms of the tumor regression rate (TRR) achieved with chemoradiotherapy and radiotherapy alone.
Materials and methods: The study included cervical squamous cell carcinomas treated by radiotherapy alone (n=45) or chemoradiotherapy (concurrent once-a-week cisplatin 30 mg/m2, n=13). Tumors were measured three-dimensionally on pre- and mid-treatment magnetic resonance images. TRR was defined as the slope of the exponential regression curve of tumor volume (day(-1)) on the assumption that tumors regressed exponentially with time.
Results: TRR ranged widely (0.004-0.090 day-(-1)) and did not significantly differ between treatment with chemoradiotherapy (median, 0.032 day(-1)) and with radiotherapy alone (median, 0.024 day(-1)) (p = 0.361). TRR > 0.05 day(-1) was seen in four chemoradiotherapy tumors (30.8%) and in six radiotherapy-alone tumors (15.0%) (p = 0.207), whereas TRR < 0.01 day(-1) was seen in no chemoradiotherapy tumors (0.0%) and in five radiotherapy-alone tumors (11.1%) (p = 0.180). TRR for tumors > 5.0 cm in diameter was greater with chemoradiotherapy (n=5) than with radiotherapy alone (n=12) (p = 0.065).
Conclusion: Although the difference did not reach a statistically significant level, our TRR data suggest that concurrent chemotherapy heightens the radioresponse of large-size cervical cancer.