Initial Report of Sentinel Lymph Node Identification During Laparoscopic Radical Hysterectomy Using a New Gamma Probe Technology

Abstract

Background:

The standard surgical procedure for early-stage cervical cancer is abdominal radical hysterectomy, including pelvic lymphadenectomy. Currently, minimally invasive surgical techniques for early cervical cancer are progressing; total laparoscopic radical hysterectomy (TLRH) is a possible alternative to abdominal surgery. In addition, sentinel node navigation surgery (SNNS), which can prevent lower limb edema, has been widely used for radical hysterectomy.

Materials and Methods:

A radioisotope is injected into the uterine cervix 1 day preoperatively and surgeons carefully identify the correct sentinel lymph nodes (SLNs) to prevent picking up the cervical gamma rays during surgery.

Results:

It is difficult to identify SLNs in laparoscopic surgery compared to abdominal surgery using the traditional gamma probe, which has the sensor on the tip, since this probe picks up the gamma rays from the uterine cervix. We described 11 cases in which TLRH was combined with SNNS using a new device that accurately detects correct SLNs.

Conclusions:

The SLNs were detected using a gamma probe that has a sensor built onto the side, without picking up the cervical gamma rays. We believe that the Neoprobe plays a crucial role in SNNS for accurately detecting SLNs and helping determine whether the patient needs to undergo SNNS.

Introduction

Astandard surgical procedure for early-stage cervical cancer is abdominal radical hysterectomy (ARH), including pelvic lymphadenectomy.^1,2 Although ARH results in excellent local tumor control, it is also associated with significant morbidities, such as bladder dysfunction, massive bleeding, lymphedema, and lymphocele formation. Improvements in minimally invasive surgery for early cervical cancer have been progressing. Total laparoscopic radical hysterectomy (TLRH) was described in the 1990s by Nezhat et al.^3,4 and Canis et al.⁵ as a possible alternative to ARH. Alternatively, sentinel node navigation surgery (SNNS) is becoming a standard diagnostic procedure for early-stage cervical cancer that makes it possible to omit complete pelvic lymphadenectomy in patients who do not need it.⁶ Minimally invasive procedures, such as TLRH and SNNS, contribute to an improved quality of life for patients with early-stage cervical cancer.

However, it is difficult to detect sentinel lymph nodes (SLNs) in laparoscopic surgery compared with abdominal surgery since the movable range of a gamma probe is limited. We describe a successful approach for detecting metastatic SLNs using a new technological gamma probe.

Materials and Methods

In our institute, 11 patients with early-stage cervical cancer (International Federation of Gynecology and Obstetrics stages IB1) underwent TLRH accompanied by SNNS. TLRH was performed routinely, but SNNS for early cervical cancer was approved by the institutional review board, and all patients provided written informed consent.

An SLN was detected by injection of a radioisotope into the uterine cervix. On the day before surgery, a total of 1 mL of 99mTc-labeled phytate (4.0 mCi) was injected into four quadrants (the 3, 6, 9, and 12 o'clock regions) of the cervix. Lymphoscintigraphy was performed at 10, 20, and 30 minutes after injection, and single-photon emission computed tomography/computed tomography (SPECT-CT) was performed after the lymphoscintigraphy.

Intraoperatively, the SLNs were identified using a gamma probe for laparoscopic surgery (Neoprobe Corporation, Dublin, OH). Although the Neoprobe used in this study is a new device developed as a laparoscope, it is a device that we have much experience in laparotomy; so we performed SNNS.

Results

In the TLRH procedure, a total of four trocars were used: a 5-mm camera trocar was deployed at the navel and two operator trocars were deployed at 5 and 10 mm to the left and midline under the navel. An assistant trocar was also deployed to the right under the navel. Intraoperatively, the SLNs were identified using a gamma probe and were removed laparoscopically. We recovered the SLNs from the 10-mm port using a reducer sleeve as the outer cylinder to prevent recurrence at the port site. Biopsies of the SLN tissues were evaluated using frozen section analysis. They were cut into 2-mm serial slices to make a precise diagnosis. If no metastatic SLNs were identified on either side of the pelvis, complete pelvic lymphadenectomy was omitted. If a metastatic SLN was identified in the frozen section analysis, complete bilateral pelvic lymphadenectomy was performed.

Eleven patients underwent TLRH with SNNS for early-stage cervical cancer (Table 1). The median age was 44 years (range: 38–57 years). In all 11 cases, SLNs were detected using preoperative scintigraphy/SPECT-CT and a Neoprobe during the laparoscopy. All patients had one SLN on each pelvic side, and 10 patients had no metastasis. One patient underwent complete pelvic lymphadenectomy because of bilateral SLN metastasis. SNNS revealed that all 11 patients had SLNs, but 10 patients could avoid complete pelvic lymphadenectomy because of a lack of identifiable metastasis. There were no complications during surgery, and no patient who underwent SNNS had lymphedema after surgery.

Table 1.

Clinical Characteristics of 11 Patients with Cervical Cancer Who Underwent Total Laparoscopic Radical Hysterectomy+Sentinel Node Navigation Surgery

Patient No.	Age (years)	BMI (kg/m²)	Stage	Histologic type	Operative time (minutes)	Blood loss (mL)	Rt. sentinel node (metastasis)	Lt. sentinel node (metastasis)	Length of hospital stay (days)
1	43	17	IB1	SCC	418	140	External iliac nodes (negative)	Obturator nodes (negative)	8
2	52	17.6	IB1	SCC	263	80	Obturator nodes (negative)	Obturator nodes (negative)	8
3	43	17.4	IB1	Adenocarcinoma	386	570	Obturator nodes (negative)	Obturator nodes (negative)	8
4	44	23.2	IB1	Small cell carcinoma	319	280	External iliac nodes (negative)	Obturator nodes (negative)	8
5	46	21.3	IB1	Adenocarcinoma	334	180	Internal iliac nodes (negative)	Obturator nodes (negative)	8
6	57	17.7	IB1	SCC	292	50	External iliac nodes (positive)	External iliac nodes (positive)	8
7	41	20	IB1	SCC	260	50	Obturator nodes (negative)	Obturator nodes (negative)	8
8	41	23.9	IB1	SCC	310	170	Obturator nodes (negative)	Obturator nodes (negative)	8
9	38	18.4	IB1	SCC	207	5	Obturator nodes (negative)	External iliac nodes (negative)	8
10	50	18.5	IB1	SCC	280	30	External iliac nodes (negative)	Obturator nodes (negative)	8
11	52	30	IB1	SCC	307	5	External iliac nodes (negative)	External iliac nodes (negative)	8

BMI, body mass index; Lt., left; Rt., right; SCC, squamous cell carcinoma.

Discussion

Laparoscopic surgery in early-stage cervical cancer is standardized and practiced regularly because TLRH reduces the amount of pain the patient experiences after the surgery, minimizes bleeding, and reduces the length of hospitalization compared with laparotomy. It has also been reported that there is no significant difference between the types of surgery with regard to prognosis.^7–9 However, SNNS for early-stage cervical cancer is becoming the standard procedure. Some studies have reported that SNNS, which can prevent lower limb edema, is feasible for early-stage cervical cancer,⁶ and the combination of TLRH and SNNS could improve patients' quality of life.

To perform SNNS, it is essential to inject a radioisotope (99mTc) into the lesion a day before the surgery, so that the SLN can be identified by a gamma ray detection device. An SLN can only be detected if it is located perpendicular to the insertion point of the probe. During surgery, a gamma ray can be detected from the uterine cervix and SLNs. As these two structures are very close together, surgeons must carefully identify the correct SLNs without picking up the gamma rays from the uterine cervix. However, it is very difficult to locate the SLN under a laparoscopic view due to a lack of mobility with the probe, compared with accessibility by laparotomy, because the traditional gamma probe, which has a sensor built at the tip, picks up the gamma rays from the uterine cervix. To solve this problem, in this experiment, the Neoprobe was used, which has a sensor built onto the side of the probe rather than at the tip (Fig. 1). This configuration allows the surgeon to find the SLN more accurately by turning the probe, not to the suspicious areas of the cervix (Fig. 2). This instrument is considered to play a major role in the future of SNNS, primarily in laparoscopic and robotic surgery. In this study, we detected SLNs easily in all patients using the Neoprobe.

FIG. 1.

Gamma ray sensor on the side of the tip of the Neoprobe.

FIG. 2.

The sentinel lymph node (left external iliac node, arrow) is identified by the Neoprobe laparoscopically (arrowhead).

Moreover, the Neoprobe does not require a sterilized drape during the procedure because it has no cable attached to the control module (the probe itself can be sterilized). This feature has not only saved the hospital from purchasing sterilized drapes but also removes the need for additional cable management in the operating room. During surgery, a variety of cables may be present from various pieces of equipment, which can become entangled. This can lead to unexpected problems during the procedure.

Conclusions

Based on all the above, TLRH with SNNS are expected to become common practice for the treatment of early-stage cervical cancer. We believe that the Neoprobe plays a crucial role in SNNS for the accurate detection of SLNs, and for contributing to the decision whether the patient needs to undergo SNNS.

Footnotes

Disclosure Statement

No competing financial interests exist.

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