For a patient with recurrent endometrial cancer involving the vagina with a good response to EBRT (<5mm residual), how would you prescribe adjuvant brachytherapy with a cylinder to the entire vaginal length?

We focus on pre EBRT length, as recurrence patterns don’t support needing to treat the full length with 45Gy from EBrT sufficient, and series that have treated full length have shown higher toxicity.

See discussion of this for summary of literature for volume of treatment.

Assuming the vaginal cuff recurrence after pelvic external beam is < 5mm in depth as confirmed by pelvic MRI, we typically boost vaginal cuff with intracavitary brachytherapy. The active treatment length is dictated by the length of the upper vaginal original involvement, and it is usually the upper 4 cm unless the original tumor extends more distal. We are not routinely covering the entire vaginal length.

The required cumulative EQD2 dose to the vaginal cuff need to be more than 70 Gy for small tumors and 75-80 Gy for relatively large tumors. My HDR brachytherapy dose is usually 6 Gy x 4 or 5 fractions to the vaginal surface for radiation-naïve patients.