The Effect of Dose and Storage Conditions of Indocyanine Green on Efficacy and Cost in Sentinel Lymph Node Mapping in Gynecological Cancer

Indocyanine Green (ICG) is a substance used in many areas of medicine, particularly in surgical procedures for vascular imaging, organ function assessment, and the treatment of various types of cancer. In recent years, this substance has also gained significant ground in gynecological cancers. The use of indocyanine green in gynecological cancers is particularly notable for its role in identifying cancer cells, performing lymph node biopsies, and performing minimally invasive surgeries.

Indocyanine green has become an important tool in the treatment of gynecological cancers, particularly in lymph node biopsies and minimally invasive surgeries. Its applications are increasingly expanding as it helps identify the path of cancer spread and enhances surgical precision. This substance allows surgeons to perform more accurate and effective interventions while also accelerating patient recovery.

Sentinel lymph node (SLN) mapping is increasingly used in gynecologic cancers as a less morbid staging method, an alternative to systematic pelvic and para-aortic lymphadenectomy. Numerous prospective studies have demonstrated the accuracy and reliability of the SLN technique, particularly in endometrial, cervical, and vulvar cancers. Indocyanine green (ICG), when used in conjunction with near-infrared fluorescence imaging, has become the most frequently used method due to its high sensitivity and bilateral detection rate.Patients diagnosed with endometrial, cervical, and vulvar cancer and scheduled for SLN mapping will be included in the study; potential confounding variables such as patient characteristics (age, BMI, comorbidities), tumor characteristics (histology, stage), surgical approach, and surgeon experience will also be considered in the analyses. Indocyanine green administration in gynecological cancers:

1. Standard dose (1.25 mg/mL, 4 x 1 mL)
2. A low-volume protocol (1 mL) may be tried in low-risk cases for minimal intervention, but signal may be reduced.
3. A high-volume application (8-10 mL) may be preferred in obese or signal-deficient patients; signal strength may be increased.
4. A high concentration (2.5 mg/mL) has been found effective in some studies, but should be used with caution due to the risk of suppressing ICG's own fluorescence.

Standard storage conditions:

Storage at 2-8°C (refrigerated) in dark glass vials protected from light and moisture.

Short-term storage at room temperature (15-25°C) after preparation is suitable. Use within 24 hours is recommended. In this study, sentinel lymph node mapping will be performed by injecting 1 cc of indocyanine green diluted with sterile water (25 mg + 20 mL water → 1.25 mg/mL) into the submucosa of the cervical os at the 3-9 o'clock positions.

Prepared ICGs will be stored in a dark environment at +4°C.

The data obtained will evaluate the effects of the dosage on mapping success and also reveal the potential effects of indocyanine green storage conditions on efficacy and cost. This study aims to contribute to the development of a safer, more effective, and more economical mapping method for gynecological cancers.

Parameters used in this study:

• Age (years)
• BMI (kg/m²)
• Parity
• Comorbidities (DM, HT, cardiac/AKI, COPD, renal failure)
• Drug/allergy history (especially iodine/ICG/green dye)
• Previous pelvic surgery/lymph node dissection/RT-CT history
• ASA score
• Cancer type: endometrium, cervix, vulva
• Cancer stage (clinical and/or pathological)
• Histology (endometrioid/serous/clearcell/squamous, etc.)
• Tumor size (mm), depth of myometrial invasion (%) in endometrial cancers, LVSI (present/absent), depth of stromal invasion in cervical tumors, parametrial involvement, lesion location and size in the vulva
• Need for reinjection: Present/Absent
• Injection sites and plan: 3-9 line (superficial/deep) on the cervix, clitoris level on the vulva, labia majora; cervical injection standardization for the endometrium. -Storage conditions
• Freshly prepared vs. stored for a certain period
• Temperature: Room temperature vs. Refrigerator
• Operative: Laparoscopic/Laparotomic
• Operative duration (min), time to SLN (min)
• Intraoperative complications (allergic reaction, tissue staining problems, etc.)
• Number of lymph nodes: Total SLNs removed, SLNs per side
• Anatomical distribution: Obturator, external/internal iliac, parametrial, presacral, etc.
• Micro/macrometastasis, isolated tumor cells