This prospective study aims to evaluate the feasibility and diagnostic performance of sentinel lymph node (SLN) mapping using indocyanine green (ICG) in patients undergoing surgery for early-stage epithelial ovarian cancer. Ovarian cancer is the most lethal gynecologic malignancy, and although systematic pelvic and paraaortic lymphadenectomy is considered a standard component of surgical staging. Moreover, systematic lymphadenectomy is associated with increased operative time, perioperative morbidity, and long-term complications such as lymphedema, without clear evidence of therapeutic benefit.

SLN mapping has been successfully implemented in other gynecologic malignancies and may provide a less invasive alternative for lymph node assessment. In this study, patients undergoing laparotomy for adnexal masses will receive intraoperative ICG injection into the infundibulopelvic ligament on the affected side and into the cervix (at the 3 and 9 o'clock positions) following intraoperative confirmation of malignant epithelial tumor by frozen section analysis. SLN detection rates, anatomical distribution, and feasibility will be assessed. In addition, intraoperative and postoperative outcomes and potential complications related to the procedure will be evaluated.

The results of this study are expected to contribute to the current evidence regarding the role of SLN mapping in early-stage epithelial ovarian cancer and may help reduce the need for systematic lymphadenectomy and its associated morbidity.

Epithelial ovarian cancer is the most lethal gynecologic malignancy, and accurate surgical staging plays a critical role in determining prognosis and guiding adjuvant treatment. Although systematic pelvic and paraaortic lymphadenectomy is considered a standard component of staging surgery in early-stage disease, the incidence of lymph node metastasis remains relatively low, and the procedure is associated with increased operative time and morbidity, including lymphedema and surgical complications.

Sentinel lymph node (SLN) mapping has been successfully adopted in other gynecologic cancers as a less invasive alternative for lymph node assessment. However, its role in early-stage epithelial ovarian cancer remains under investigation. This study is designed as a prospective cohort study conducted at a tertiary referral center.

Patients undergoing laparotomy for unilateral or bilateral adnexal masses will be included. Following intraoperative frozen section confirmation of malignant epithelial ovarian tumor, indocyanine green (ICG) will be injected into the infundibulopelvic ligament on the affected side and into the cervix at the 3 and 9 o'clock positions. Sentinel lymph nodes will be identified and evaluated.

The primary objective of the study is to assess the feasibility and detection rate of SLN mapping. Secondary objectives include evaluation of anatomical distribution of SLNs, intraoperative findings, perioperative outcomes, and potential complications.

The findings of this study are expected to contribute to the existing literature and may support the use of SLN mapping as an alternative to systematic lymphadenectomy in selected patients with early-stage epithelial ovarian cancer.

Inclusion Criteria:

• Female patients aged 18-90 years
• Patients undergoing laparotomy for unilateral or bilateral adnexal mass
• Intraoperative frozen section diagnosis of malignant epithelial ovarian tumor or at least borderline epithelial tumor
• Patients with bilateral adnexal masses who have undergone preoperative gastrointestinal evaluation (endoscopy/colonoscopy) with exclusion of gastrointestinal malignancies
• Patients without radiological evidence of advanced-stage ovarian cancer on preoperative imaging (PET, MRI, or CT), including absence of pleural effusion, omental cake, peritoneal carcinomatosis, malignant ascites, liver or splenic parenchymal involvement, and mesenteric involvement
• Patients who provide written informed consent

Exclusion Criteria:

• Patients with prior lymphadenectomy
• Patients with radiological or intraoperative evidence of advanced-stage ovarian cancer
• Patients planned for neoadjuvant chemotherapy without primary surgery
• Pregnant patients
• Patients with known allergy to indocyanine green (ICG) or iodine
• Patients with immunodeficiency disorders
• Patients with a history of radiotherapy
• Patients with a history of vascular surgery affecting lymphatic drainage
• Patients with a history of vascular surgery affecting lymphatic drainage
• Patients with a history of non-gynecological malignancy
• Patients younger than 18 years or older than 90 years

Individual participant data (IPD) will not be shared due to patient confidentiality and institutional data protection policies. De-identified data may be available from the corresponding author upon reasonable request.