KEY POINTS
- This retrospective single-institution study included 255 women treated from 2009–2023 who met clinical eligibility criteria similar to the high-intermediate-risk population in PORTEC-4a. Median age was 69.5 years and median follow-up 60.1 months.
- All patients received adjuvant vaginal cuff brachytherapy without CT or MRI simulation and without verification imaging before any fraction. Consequently, applicator position, air gaps and organ-at-risk doses were not individually assessed or adapted during treatment.
- Treatment consisted of either 21 Gy in three 7-Gy fractions or 22 Gy in four 5.5-Gy fractions, prescribed 5 mm from the vaginal mucosal surface. Ovoids were used in 217 patients (85%) and cylinders in 38; the average vaginal length treated with ovoids was approximately 2.75 cm.
- There were 11 vaginal recurrences. Importantly, only one was an isolated vaginal failure; 10 of 11 (91%) occurred together with regional and/or distant recurrence, and three occurred in the distal unirradiated vagina.
- The estimated 5-year cumulative incidence of vaginal recurrence was 3.6% (95% CI 1.2–6.5%). For descriptive context, the recently reported PORTEC-4a standard brachytherapy group—with CT or MRI verification—had a 5-year incidence of 1.6% (95% CI 0–3.32%).
- The two cohorts were not randomized against each other and could not be formally statistically compared because patient-level PORTEC-4a data were unavailable. The institutional cohort also contained more lymphovascular space invasion—23% versus 8% substantial LVSI in PORTEC-4a—and predominantly used ovoids, whereas PORTEC-4a mandated cylinders.
- Applicator type and size were not significantly associated with recurrence (p=0.67 and p=0.46, respectively). The authors also estimated that adding 3D planning to a four-fraction Medicare outpatient course would increase reimbursement-related cost from approximately $3,540 to $4,572. Toxicity could not be robustly analyzed because historical documentation was not sufficiently standardized.
CLINICAL TAKEAWAY
These results suggest that carefully performed vaginal cuff brachytherapy without routine simulation can achieve low vaginal-failure rates, but they do not show that imaging is unnecessary or that the two strategies are noninferior. Verification imaging still provides information about applicator placement, air gaps and organ-at-risk dose that this study could not evaluate; a prospective randomized or rigorously matched comparison would be required before changing practice.