766P - A comparative study of sequential and interdigitated brachytherapy with chemoradiation in patients of locally advanced carcinoma cervix

Background

Prolongation of overall treatment time (OTT) in carcinoma cervix is well known to adversely affect local control and survival. The OTT would be unduly prolonged if brachytherapy (BT) was started only after completion of external beam radiation (EBRT) as multiple insertions are required for high-dose-rate BT. This study was carried out to compare treatment outcomes of shortening the OTT by interdigitated BT as opposed to conventional sequential BT in terms of late toxicities, disease free survival (DFS) and overall survival (OS).

Methods

The study included 70 patients of cancer cervix who met the inclusion criteria. Patients were randomized into study and control arms. All the patients received EBRT (45Gy/20 fractions over 4 weeks) with concurrent Cisplatin and 3 fractions of BT (7 Gy/fraction). Patients in the control arm received weekly BT after one week following EBRT to complete the entire treatment in 7 weeks. In the study arm, BT was interdigitated with EBRT after 15 fractions. Subsequent BT fractions were given on days 27 and 34 to complete the treatment in 5 weeks. The two groups were compared in terms of late toxicities, DFS and OS at a follow up of two years.

Results

A total of 63 patients completed the planned treatment. The OTT and mean biologically equivalent dose (BED_10Gy) after reduction for accelerated repopulation was significantly better in the study arm (p=0.001). At two years of follow up, 80% of patients in the study arm and 72.72% in the control arm had no local or distant failure. Also, death occurred in 13.33% patients and 18.18% patients in the study and control arm, respectively. No statistically significant difference was reached in terms of OS and DFS despite a trend towards better DFS in the interdigitated BT arm. The incidence of late lower gastro-intestinal toxicities was found to be higher in the study arm but this difference was not significant.

Conclusions

Interdigitated BT with chemoradiation appears to be an acceptable option for shortening OTT with similar survival outcomes and acceptable toxicities in comparison to sequential brachytherapy. Owing to a shorter OTT, this approach is radiobiologically superior with a more efficient utilization of machines at centers with heavy patient load.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.