Normalized Therapy Dose (EQD2) from management of locally advanced cervical cancer: comparison with ABS recommendation.

摘要

Optimal radiotherapy dose fractionation regime (DFR) for definitive management of cervical cancer is not well known. However, several investigators have demonstrated that the biologically equivalent dose in 2-Gy fractions(EQD2) required to achieve local control probability of more than 90% for advanced disease is about 87Gy to the high risk tumour volume. Patients with locally advanced cervical cancer (LACC) have been managed at the University College Hospital, Ibadan Nigeria with combination of external beam radiation and high dose rate (HDR) intracavitary brachytherapy using different DFR. This study is aimed at calculating EQD2 received by 250 patients with LACC managed with different DFR between 2008 and 2010. Patients’ data were extracted from case files and mathematical method was used to calculate EQD2. Results obtained were compared with EQD2 values (80–90Gy) recommended by the American Brachytherapy Society (ABS) for LACC. Out of eleven different DFR employed at the centre, only five resulted in EQD2 values (81.00Gy, 87.60 Gy, 81.30 Gy, 88.80 Gy and 83.10 Gy) that are within ABS recommendation; five fell below (65.60 Gy, 70.30 Gy, 75.60 Gy, 78.40 Gy and 77.80 Gy) and one is higher (99. 80 Gy). It means out of 250 patients managed during this period, only 45% received recommended dose required to cure macroscopic disease. This study shows that to improve therapeutic ratio, total EQD2 for DFR(of choice) must be calculated before treatment. With the on-going follow-up, further study is aimed at assessment of late complications, 5- year survival and rate of recurrence in these patients.