This clinical trial investigates the sentinel lymph node (SLN) technique as a less invasive alternative to conventional lymphadenectomy in patients with early-stage ovarian cancer. The primary objective is to evaluate the effectiveness, safety, and diagnostic accuracy of the SLN approach in detecting lymphatic metastases. By assessing its negative predictive value, the study aims to determine whether the SLN technique can reliably replace systematic pelvic and paraaortic lymphadenectomy. If successful, this technique could minimize surgical morbidity, shorten hospitalization stays, and lower complication rates, ultimately improving patient outcomes.

Inclusion Criteria:

• Signed informed consent prior to the performance of any procedure related to the clinical trial.
• Female, 18 years of age or older at the time of inclusion.
• Patients with a histopathological diagnosis of malignant ovarian tumor in a deferred study (any epithelial histology), in apparent early stage FIGO I-II, proposed for staging surgery, or patients with suspected malignant ovarian tumor in apparent early stage FIGO I-II, who will undergo exploratory laparotomy and operative biopsy, and if positive, will undergo staging surgery.

Exclusion Criteria:

• Failure to obtain informed consent or revocation of informed consent.
• Under 18 years of age at the time of inclusion.
• Previous history of vascular surgery on the aorta, vena cava, or pelvic vessels.
• Previous pelvic or paraaortic lymphatic surgery.
• Previous lymphoma.
• Previous abdomino-pelvic tumor.
• Previous allergy to Tc99 or ICG.
• Pregnancy/Breastfeeding.

Patients who have signed informed consent but do not meet all inclusion criteria and none of the exclusion criteria will be considered as selection failures.