Outcomes of intermediate-risk to high-risk stage I endometrial cancer: 10-year clinical experiences of using in-house multi-channel applicators in a single center
Endometrial cancer (EC) is the second most common gynecologic malignancy in China, with approximately 63,400 new cases and 21,800 deaths reported in 2015. For women with intermediate-risk (IR) to high-risk (HR) stage I EC—early-stage disease with features that increase recurrence risk—adjuvant therapy after surgery is critical to improving survival and reducing the chance of cancer coming back. While vaginal cuff brachytherapy (VBT) is a standard adjuvant option, few studies in China have examined the long-term outcomes of using multi-channel applicators (MCA) for this treatment. A new study from Peking Union Medical College Hospital fills this gap, sharing 10 years of experience with in-house made MCAs for early-stage EC.
What We Did
The study retrospectively reviewed 390 consecutive women with stage I IR to HR EC who underwent total abdominal hysterectomy (removal of the uterus) and salpingo-oophorectomy (removal of fallopian tubes and ovaries) between January 2003 and December 2015. All patients received post-operative VBT—either alone or as a “boost” after external beam radiotherapy (EBRT, which targets larger pelvic areas like lymph nodes).
Two types of in-house MCAs were used:
- Rigid seven-channel applicator: The most common type, with a central channel and six peripheral channels to deliver uniform radiation.
- 3D-printed applicator: Introduced in 2015 for patients with irregular vaginal anatomy (e.g., a “dog-ear” cuff or narrowing), custom-made to fit their unique structure.
VBT doses were tailored to each patient:
- VBT alone: 500 cGy per fraction for 5–6 sessions (total: 2500–3000 cGy).
- VBT + EBRT: 400–600 cGy per fraction for 2–3 sessions (total: 800–1800 cGy) after EBRT (45–50.4 Gy total, 1.8–2.0 Gy per session).
Patients were followed every 3–6 months for the first 2 years, then annually. Survival rates were calculated using the Kaplan-Meier method, and factors like age, tumor grade, and stage were analyzed to identify prognostic indicators.
What We Found
Of the 390 patients, 92.8% were followed for a median of 48 months (range: 4–172 months). The results highlight the effectiveness and safety of using in-house MCAs:
Survival and Recurrence
- Overall Survival (OS): 5-year OS was 96.3%, and 10-year OS was 89.7%.
- Progression-Free Survival (PFS): 5-year PFS (time without cancer growth) was 92.1%, and 10-year PFS was 87.9%.
- Recurrence: Local recurrence (vaginal or pelvic) occurred in just 2.9% of patients, and distant metastasis (spread to organs like the lungs or brain) in 4.8%. Only two patients had isolated vaginal recurrence outside the irradiated area—both successfully treated with salvage therapy.
Prognostic Factors
Age and tumor grade were the strongest predictors of survival:
- Age: Patients under 60 had a 10-year OS of 96.0%, compared to 78.7% for those 60 and older.
- Grade: Patients with low-grade tumors (G1-2) had a 10-year OS of 92.1%, versus 83.4% for high-grade (G3) tumors.
Complications
Most side effects were mild and manageable:
- Gastrointestinal (GI): 17.2% of patients had acute grade 1–2 issues (e.g., nausea, diarrhea), with higher rates in those who received EBRT + VBT (25.5% vs. 12.2% for VBT alone).
- Genitourinary: 11.3% had mild symptoms (e.g., urinary frequency).
- Late effects: Only two patients (0.5%) had severe GI complications (bowel obstruction) requiring surgery. No treatment-related deaths occurred.
What It Means
Guidelines from the American Society for Radiation Oncology (ASTRO) and American Brachytherapy Society (ABS) recommend VBT for early-stage EC, but single-channel applicators (SCA)—the traditional choice—have limitations: their radial symmetry can miss irregular areas (like a “dog-ear” vaginal cuff) and offer less flexibility to adjust dose.
MCAs solve these problems by allowing more uniform dose coverage of the target and reducing unnecessary radiation to nearby organs (like the bladder or rectum). This study is the first to report long-term outcomes with MCAs in China, and the results are compelling:
- Rigid MCAs: Worked well for most patients, thanks to their simplicity and convenience.
- 3D-printed MCAs: Provided personalized treatment for patients with irregular anatomy, minimizing gaps between the applicator and vaginal lining.
Age and grade emerged as key prognostic factors because older patients often present with higher-grade tumors and more advanced disease, while lower-grade tumors are less aggressive. The high survival rates—even in high-risk patients—reflect the effectiveness of the treatment approach.
One limitation is that the study is retrospective (looking back at existing data), so there may be biases. Also, only 6.7% of patients used the 3D-printed MCA, so more research is needed to confirm its long-term benefits.
Conclusion
For women with intermediate- to high-risk stage I endometrial cancer, adjuvant vaginal cuff brachytherapy using in-house multi-channel applicators—either alone or with external beam radiotherapy—delivers excellent survival rates, low recurrence, and minimal serious complications. Age and tumor grade are important factors to consider when predicting overall survival, and personalized applicators (like 3D-printed models) can improve outcomes for patients with unique anatomical needs.
This 10-year study adds valuable evidence for the use of MCAs in China and reinforces the importance of tailored adjuvant therapy for early-stage EC.
This study was conducted by Xiao-Rong Hou, Lang Yu, Ke Hu, and Fu-Quan Zhang from the Department of Radiation Oncology at Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College. It was published in the Chinese Medical Journal in 2019.
doi.org/10.1097/CM9.0000000000000382
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