Time to review the role of intraluminal brachytherapy for dose escalation after concurrent chemoradiation in cancer esophagus: A retrospective audit.

Abstract

e16054 Background: Intraluminal brachytherapy (ILBT) for dose escalation after concurrent chemoradiation (CRT) in cancer esophagus is not routinely practiced. This is particularly attributable to radiotherapy toxicity in terms of strictures and fistulas. Cancer esophagus has poor locoregional control and overall survival rates in comparison to head and neck cancers. Dose escalation may be an option to counteract the high failure rates. Methods: A retrospective analysis was conducted for esophageal cancer patients treated between 2008 to 2016 planned for radical CRT to a minimum dose of 59.4 Gy in 33 fractions along with concurrent cisplatin 35 mg/m2 and 5 FU 375 mg/m2 on weekly basis. Further, the patients who received dose escalation after external beam radiotherapy (EBRT) completion by ILBT to a dose of 6 Gy in a single fraction to the pre EBRT volume were also analysed. The patient, tumor, treatment characteristics along with response rates, survival outcomes, and toxicities were evaluated and compared between the two groups - the patients who received ILBT and those who did not. Statistical significance between variables was analysed with the Chi-Square or Fischer’s exact test and t-test. Survival analysis was done by Log-Rank test. The analysis was done on a worst-case scenario basis where the patients lost to follow-up were considered dead. Results: The total number of patients treated by CRT was 69, out of which 13 patients received ILBT for dose escalation. The median age was 60 years (Range - 40 to 80 years) and the male: female ratio was 1.09, mean tumor length was 6.4 ± 2.4 cms (Range-1.5-12 cms). The commonest tumor site was the middle third observed in 58% patients. The median EBRT dose was 59.4 Gy (Range- 9 to 63 Gy). The median concurrent chemotherapy cycles were 5. The median follow-up period was 15 months (range 1-100 months). In terms of complete response rates, there was a trend towards significant improvement in patients receiving ILBT compared to those receiving EBRT alone (84.61% versus 57.49%, p=0.07). Also, the overall survival (OS) was significantly higher in the ILBT group (45.31 months versus 19.20 months; p = 0.005). The other patient, tumor, and treatment characteristics analyzed showed no significant impact on OS. There was no significant difference in the incidence of strictures (p=0.206) and severity (p=0.764) of strictures amongst both the groups. Grade ≥3 late toxicity was reported in 10 patients (17.85%) receiving EBRT alone and in 3 patients (23.07%) receiving ILBT. None of the patients receiving ILBT developed a fistula. Conclusions: The present study reveals a dramatic increase in OS by dose escalation with ILBT. The limitations of the present study were a small sample size and a lesser number of patients in the ILBT group. Recapitulating the concept of ILBT to increase the local tumoricidal dose may improve the survival rates.