Salvage high-dose-rate interstitial brachytherapy for locally recurrent rectal cancer: long-term follow-up results.

BACKGROUND

We retrospectively examined outcomes of salvage high-dose-rate interstitial brachytherapy (HDR-ISBT) for locally recurrent rectal cancer (LRRC).

METHODS

Nine patients with LRRC were treated with salvage HDR-ISBT. Their median age was 63 years. The median maximum diameter of LRRC was 40 mm (range 20-80 mm). Adenocarcinomas were histologically confirmed in all cases. The prescribed dose was 30 Gy/5 fractions/3 days to 50 Gy/10 fractions/6 days in the combined external-beam radiotherapy group (four patients) and 54 Gy/9 fractions/5 days to 60 Gy/10 fractions/6 days in the monotherapeutic group (five patients). Median follow-up time was 90 months (range 6-221 months).

RESULTS

Local control at final follow-up was achieved in five of nine patients. Of these five patients, one experienced a locally re-recurrent tumor in the vaginal wall 33 months after treatment and received re-HDR-ISBT as re-salvage treatment. The 8-year overall survival, local control, and progression-free survival rates were 56, 44, and 33 %, respectively. Based on the Common Terminology Criteria for Adverse Events ver. 4.03, the following Grade 3 adverse events were observed in three patients (≥3 months): Grade 3 skin ulceration in one patient who showed tumor invasion of the skin and whose V100 was 400 cc; Grade 3 vaginal perforation in one patient whose tumor had invaded the vaginal wall; and Grade 3 vagina-to-bladder fistula in one patient whose tumor received re-irradiation. Late adverse events above Grade 3 were not observed.

CONCLUSIONS

Long-term follow-up results revealed that salvage HDR-ISBT is a promising treatment for LRRC with tolerable toxicity.