Short Course Adjuvant Vaginal Cuff Brachytherapy (VCB) in Early Endometrial Cancer: Primary Endpoint Results of the SAVE Randomized Clinical Trial

Dosimetric evaluation of different cylinder diameters in three-dimensional vaginal brachytherapy for early-stage endometrial cancer

PURPOSE

To evaluate the dosimetric, radiobiological, and toxicity differences between different cylinder diameters (d) in high-dose-rate three-dimensional computed-tomography-guided vaginal brachytherapy (VBT) for early-stage endometrial cancer (EC).

METHODS

From January 2019 to January 2024, postoperative EC patients treated with exclusive VBT using cylinders were classified by the cylinder diameter (d ≤ 2.6 cm: small-size; d ≥ 3.0 cm: large-size) and matched according to 1:2 propensity score matching. Vaginal clinical target volume (CTV) was a 3-mm expansion around the cylinder surface. Dosimetric parameters in equivalent dose in 2 Gy (EQD2) (α/β = 3 Gy) and equivalent uniform dose (EUD) of vaginal_CTV and organs at risk (OARs) were evaluated. Urinary, gastrointestinal, and vaginal toxicities were assessed using CTCAE v5.0.

RESULTS

After matching, 132 patients (small-size: 44; large-size: 88) were analyzed. For vaginal_CTV, the small-size group had higher doses to 2%, 5%, 0.1 cc, 1 cc, and 2 cc of the volume (D2, D5, D0.1 cc, D1cc, and D2cc) than the large-size group while lower doses to the 95%, 98%, and 100% volume (D95, D98, and D100). The D2cc and D5cc of bladder and all dosimetric parameters of rectum were smaller in the small-size group. The EUD of vaginal_CTV, bladder, and rectum showed no significant differences. No significant differences in toxicities were found within the median follow-up of 26.8 months.

CONCLUSION

Cylinders with smaller diameters produced more nonuniform dose distributions in the target and delivered lower doses to bladder and rectum than large-size cylinders. However, the dosimetric differences did not translate into significant differences of radiobiological parameters or outcomes.

Financial Improvements From Short Course Adjuvant Vaginal Cuff Brachytherapy in Early Endometrial Cancer Compared With Standard of Care, "SAVE" Trial

PURPOSE

Early-stage endometrial cancer is often treated with hysterectomy followed by adjuvant vaginal cuff brachytherapy (VCB). Financial toxicity from cancer treatment can impact treatment completion. The Short Course Adjuvant Vaginal Cuff Brachytherapy in Early Endometrial Cancer Compared to Standard of Care trial is a multicenter, prospective randomized trial of standard of care (SoC) VCB doses delivered in 3 to 5 fractions per the physician's discretion compared with a 2-fraction course. We report on secondary cost endpoints, quantifying the financial impacts of shorter treatment courses on institutions and participating patients.

METHODS AND MATERIALS

Technical (TechCs), professional, and total charges (TotCs) were collected prospectively and are reported as raw and Medicare-adjusted charges per patient. Distance to the treatment center and the median income for each patient's zip code were estimated. The Mann-Whitney U statistic, t test, and X2 test were used to compare characteristics between the 2 groups.

RESULTS

One hundred eight patients were analyzed. SoC VCB was delivered in 3, 4, and 5 fractions for 27 of 54 patients (50%), 11 of 54 (20%), and 16 of 54 (30%), respectively. The median total distance traveled per patient for SoC versus experimental arms was 213 versus 137 miles (p = .12), and the median cost of commute for patients was $36.3 versus $18.0 (p = .11). Compared with 2-fraction treatment, 5-fraction treatment resulted in longer travel distances (median, 462 vs 137 miles; p < .01) and increased travel costs (median, $59.3 vs $18.0; p ≤ .01). Unadjusted raw professional charges in USD per patient did not differ between SoC versus experimental arms ($9159 vs $7532; p = .19). TechCs were significantly higher in the SoC arm ($35,734 vs $24,696; p ≤ .01), as were TotCs ($44,892 vs $32,228; p < .01;). Medicare-adjusted TechCs and TotCs were higher for the SoC arm.

CONCLUSIONS

Two-fraction VCB resulted in fewer treatments per patient, reduced cost of travel compared with longer courses, and an adjusted reduction in health care expenditures compared with SoC.

Risk-Tailoring Radiotherapy for Endometrial Cancer: A Narrative Review

Endometrial cancer is the most common gynecologic cancer in the United States and it contributes to the second most gynecologic cancer-related deaths. With upfront surgery, the specific characteristics of both the patient and tumor allow for risk-tailored treatment algorithms including adjuvant radiotherapy and systemic therapy. In this narrative review, we discuss the current radiation treatment paradigm for endometrial cancer with an emphasis on various radiotherapy modalities, techniques, and dosing regimens. We then elaborate on how to tailor radiotherapy treatment courses in combination with other cancer-directed treatments, including chemotherapy and immunotherapy. In conclusion, this review summarizes ongoing research that aims to further individualize radiotherapy regimens for individuals in an attempt to improve patient outcomes.