This is an investigator-initiated, prospective, national multi-center, phase III, randomized, open-label, non-inferiority clinical study. The hypothesis is that using online adaptive radiotherapy technology for moderately fractionated radiotherapy in post-operative patients with cervical/endometrial cancer may reduce radiotherapy-related toxicity and improve quality of life while ensuring target coverage. The objective is to evaluate treatment-related toxicity and efficacy of moderately fractionated online adaptive radiotherapy compared to conventionally fractionated intensity-modulated radiotherapy in post-operative cervical and endometrial cancer patients, aiming to provide a more precise, convenient, and cost-effective treatment option for patients.

Randomization:

Intervention Group: Moderately fractionated radiotherapy using online adaptive radiotherapy technology.

Control Group: Conventionally fractionated radiotherapy using image-guided intensity-modulated radiotherapy technology.

Stratification Factors for Randomization:Participating study center; Disease type (Cervical cancer / Endometrial cancer); Receipt of concurrent chemotherapy

Study Objectives:

Primary Endpoint: Acute adverse reactions/toxicity Secondary Endpoints: Late adverse reactions/toxicity, 3-year local control rate, 3-year distant metastasis rate, 3-year progression-free survival (PFS), 3-year overall survival (OS), 3-year disease-free survival (DFS), quality of life, cost-effectiveness analysis related to treatment.

Study Population:

Planned Sample Size: 228 participants

Inclusion Criteria:

1. Participants must be fully voluntary and have decision-making capacity, providing written informed consent within 30 days prior to enrollment.
2. Age ≥18 years and ≤75 years.
3. ECOG performance status of 0-1, and expected to tolerate lying supine for half an hour.
4. Have undergone radical surgery for cervical cancer (procedure: radical hysterectomy + pelvic lymphadenectomy ± para-aortic lymphadenectomy) or surgery for endometrial cancer (procedure: total hysterectomy + bilateral salpingo-oophorectomy ± pelvic and/or para-aortic lymph node dissection/sampling or sentinel lymph node biopsy).
5. For participants with cervical cancer, the following criteria must be met:

(1)Pathologically diagnosed with cervical squamous cell carcinoma or adenocarcinoma.

(2)Must have at least one of the following high-risk factors; or have other risk factors requiring postoperative radiotherapy: High-risk factors: Pelvic lymph node metastasis, or positive surgical margin, or parametrial invasion.

Other risk factors: Middle or deep one-third stromal invasion, regardless of tumor size and LVSI status; Tumor size ≥4cm, regardless of depth of stromal invasion and LVSI status; Adenocarcinoma: Tumor size ≥2cm, or positive LVSI, regardless of depth of stromal invasion.

6.For participants with endometrial cancer, the following criteria must be met: Endometrioid adenocarcinoma: Grade 3 with superficial myometrial invasion, accompanied by substantial LVSI or age ≥70 years; Grade 2 with deep myometrial invasion, accompanied by substantial LVSI or age ≥60 years; Grade 3 with deep myometrial invasion; FIGO 2009 Stage II-IIIC1.

Non-endometrioid adenocarcinoma: FIGO 2009 Stage I-IIIC1 (serous carcinoma, clear cell carcinoma, mixed type).

7.Participants with high-risk factors may receive a vaginal brachytherapy boost following the completion of external beam radiotherapy.

8.Participants with high-risk cervical cancer must receive concurrent sensitizing chemotherapy for ≥4 cycles.

9.Participants must be eligible to receive sequential or sandwich adjuvant chemotherapy as planned.

Study Duration: September 2025 to September 2030 Participant Involvement Period: Follow-up for over 3 years after radiotherapy

Inclusion Criteria:

1. Participants must be fully voluntary and have decision-making capacity, providing written informed consent within 30 days prior to enrollment.
2. Age ≥18 years and ≤75 years.
3. ECOG performance status of 0-1, and expected to tolerate lying supine for half an hour.
4. Have undergone radical surgery for cervical cancer (procedure: radical hysterectomy + pelvic lymphadenectomy ± para-aortic lymphadenectomy) or surgery for endometrial cancer (procedure: total hysterectomy + bilateral salpingo-oophorectomy ± pelvic and/or para-aortic lymph node dissection/sampling or sentinel lymph node biopsy).
5. For participants with cervical cancer, the following criteria must be met:

(1)Pathologically diagnosed with cervical squamous cell carcinoma or adenocarcinoma.

(2)Must have at least one of the following high-risk factors; or have other risk factors requiring postoperative radiotherapy: High-risk factors: Pelvic lymph node metastasis, or positive surgical margin, or parametrial invasion.

Other risk factors: Middle or deep one-third stromal invasion, regardless of tumor size and LVSI status; Tumor size ≥4cm, regardless of depth of stromal invasion and LVSI status; Adenocarcinoma: Tumor size ≥2cm, or positive LVSI, regardless of depth of stromal invasion.

6.For participants with endometrial cancer, the following criteria must be met: Endometrioid adenocarcinoma: Grade 3 with superficial myometrial invasion, accompanied by substantial LVSI or age ≥70 years; Grade 2 with deep myometrial invasion, accompanied by substantial LVSI or age ≥60 years; Grade 3 with deep myometrial invasion; FIGO 2009 Stage II-IIIC1.

Non-endometrioid adenocarcinoma: FIGO 2009 Stage I-IIIC1 (serous carcinoma, clear cell carcinoma, mixed type).

7.Participants with high-risk factors may receive a vaginal brachytherapy boost following the completion of external beam radiotherapy.

8.Participants with high-risk cervical cancer must receive concurrent sensitizing chemotherapy for ≥4 cycles.

9.Participants must be eligible to receive sequential or sandwich adjuvant chemotherapy as planned.

Exclusion Criteria:

1. Presence of confirmed distant metastasis or para-aortic lymph node metastasis;
2. Requirement for extended-field radiotherapy encompassing the para-aortic region;
3. Initiation of radiotherapy exceeds the specified time limit after surgery: exceeding 6 months post-surgery if adjuvant chemotherapy was administered, or exceeding 3 months post-surgery if no adjuvant chemotherapy was administered;
4. History of previous abdominal or pelvic radiotherapy;
5. History of or concurrent secondary primary malignancy (except for non-melanoma skin cancer, papillary/follicular thyroid carcinoma, or carcinoma in situ of the breast);
6. History of underlying intestinal diseases such as ulcerative colitis or Crohn's disease;
7. Cervical cancer with pathological types such as adenosquamous carcinoma, small cell carcinoma, clear cell carcinoma, or other special types; Endometrial cancer with pathological types such as undifferentiated carcinoma, carcinosarcoma, or other special types;
8. Pregnant or lactating women;
9. Presence of active infection or fever;
10. Other severe comorbidities that may significantly compromise protocol compliance, such as uncontrolled cardiac disease requiring treatment, renal disease, chronic hepatitis, poorly controlled diabetes, psychiatric disorders, etc.