We should not settle for low-level evidence but should always use the best available evidence

To the editor: We would like to thank Dr. Mirza [1] for his editorial in response to our paper [2] on " Ultrasound guided conformal brachytherapy of cervix cancer: survival, patterns of failure, and late complications. " He has raised several questions about our study, which we would like to address. Firstly, we would like to clarify that this study is based on data from our prospective unit database and is not, as stated by Dr. Mirza a retrospective study. This is an ethics-approved database into which baseline, treatment and outcome data about all patients referred to our unit for radiotherapy were entered prospectively. Toxicities were scored according to modified World Health Organization/Radiation Therapy Oncology Group criteria. We have reported three categories of toxicities to organs at risk, namely bladder, small and large bowel, and vagina. Q: Can we further improve local control? Patterns of failure at local site are not addressed. A: Of course we can improve local control further but the critical question is whether this will translate into improved cure rates. A straightforward way of increasing local control would be to increase the brachytherapy dose to the primary site. This is being done in some European countries by dose escalation using magnetic resonance imaging guided conformal brachytherapy where target doses in excess of 95 Gy (EQD2) leading to local control of >95% has been achieved [3]. In another study, in an ultimate effort to control local disease, 58% of treated patients had elective hysterectomy performed following the completion of curative radiotherapy [4]. However , in neither case was overall survival better than we have reported. In our earlier publication, we had compared the treatment of cervix cancer patients using low dose rate brachytherapy (LDR) and high dose rate brachytherapy (HDR) conformal brachytherapy. In that paper we had specifically discussed the dose escalation issue [5]. Prescribed dose in high dose rate conformal brachytherapy (HDRc) patients and the patients treated with LDR was 80 Gy10 to the outer contour of target and point A respectively. HDRc patients received a mean dose of 11 Gy less to point A than those treated by LDR for similar local failure rates. Because local tumor parameters were matched in both groups, it appears the brachytherapy target in LDR-treated patients received a higher dose at least in the plane of point A. This means three things: (1) In a target of variable geometry as …