The metastasis rate of pelvic lymph node in early cervical cancer is low. Systemic lymph node resection is traumatic and has many complications. Sentinel lymph node (SLN) biopsy can effectively avoid unnecessary lymph node dissection, which has been recommended in clinical guidelines. Indocyanine green(ICG) fluorescence imaging as the method of SLN mapping is recommended in international guidelines. However, the imaging equipment is very expensive which limits the popularization of ICG in different medical centers of various surgical volumes. Carbon nanoparticle is an innovative tracer without any special imaging equipment for SLN mapping in China. Some retrospective researches have proved that carbon nanoparticle is effective, simple, economic and suitable for popularization in different medical centers. In this study, a prospective randomized controlled trial will be conducted to analyze the non-inferiority of carbon nanoparticles compared to ICG, and to verify the application value of carbon nanoparticles. 144 cervical cancer patients with stage IB1 (FIGO2018) will be prospectively enrolled and randomly divided into two groups (R = 1:1). 72 patients will undergo SLN biopsy with carbon nanoparticles and 72 patients will be mapped by ICG. The primary endpoint is overall SLN detection rate. The secondary endpoints include bilateral SLN detection rate, the number of SLN detected, sensitivity, false negative rate and negative predictive value of SLN biopsy. Diagnostic accuracy will be evaluated at both pelvis and patient levels. What's more, SLN pathological ultrastaging will be conducted to increase the diagnostic accuracy. The hypothesis of this study is that the overall SLN detection rate by carbon nanoparticles is not inferior to that using ICG. And the differences of bilateral SLN detection rate, sensitivity, false negative rate and negative predictive value between two groups are not significant.
This is a prospective randomized controlled non-inferiority trial. Patients with early stage cervical cancer who met the inclusion criteria are divided into carbon nanoparticle group and ICG group by block random method. It is assumed that the overall SLN detection rate was PT (90%) in experimental group(carbon nanoparticle) and was PC (85%) in control group (ICG). The non-inferiority threshold Δ is -10%. The type I error and type II error of the hypothesis test are set as 0.05 and 0.2 respectively. The sample size is 60 cases in each group calculated by"Non inferiority tests for two proportions"method of Power Analysis and Sample Size (PASS) Software 11.0. After calculation, considering the 20% shedding rate, the sample size is 144 totally. There are 72 cases in experimental group and 72 cases in control group. Radical hysterectomy and systemic pelvic lymph node dissection are conducted after SLN resection, and paraaortic lymph node biopsy is conducted when necessary. Sentinel lymph nodes will be cut at 2-mm intervals perpendicular to the long axis in a bread-loaf fashion. Sentinel lymph nodes are then fixed in formalin and embedded in paraffin. Routine hemotoxin \& eosin(H\&E) staining is used for each SLN. Subsequent ultrastaging is performed if the initial H\&E assessment is negative. SLN ultrastaging is performed by cutting three 5-μm sections at two levels, 50-μm apart, from each paraffin block of negative SLN. At the first level, two adjacent 5-μm sections are stained with H\&E and immuno-histochemistry using the anti-cytokeratin AE1:AE3, respectively. At the second level, one 5-μm section is evaluated by H\&E staining. Nonsentinel lymph nodes are bisected parallel to the long axis and stained with H\&E staining.Nodal metastases are classified as (1) isolated tumor cells (ITCs) (single cells or clusters ≤ 0.2mm in largest dimension),(2) micrometastases (tumor deposits 0.2mm-2 mm), or (3) macrometastases (tumor deposits \> 2mm). All pathological reviews will be finished by two independent gynecologic pathologists in the Department of Pathology of Cancer Hospital,Chinese Academy of Medical Sciences and Peking Union Medical College. A third senior pathologist is invited to decide the diagnosis when discordance occurs.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
144
After pneumoperitoneum is established and laparoscopic instruments are prepared, according to National Comprehensive Cancer Network (NCCN) guidelines, 1ml diluted ICG solution (25 mg /10 ml) is injected into the submucosa around tumor at 3 and 9 o'clock of the cervix (2ml totally) with 1ml syringe. ICG should be slowly injected to avoid drug leakage. Intratumoral and deep cervical stroma injection should be avoided. The retroperitoneum is dissected immediately after injection under the multimodel observation of fluorescence laparoscopy. Search the fluorescent labeled lymphatics from bilateral parametrium to iliac vessels. The diffusion of ICG is rapid , and it is easy to spread to the next stations lymph nodes. The first fluorescent labeled lymph nodes on each lymphatic drainage pathway are identified as SLNs, other than all fluorescent lymph nodes. All detectable SLNs and enlarged or suspicious nodes regardless of mapping are resected for pathological examination alone.
After pneumoperitoneum is established and laparoscopic instruments are prepared, according to NCCN guidelines, 0.5ml(25mg) carbon nanoparticle solution (the dose was from our retrospective study) is injected into the submucosa around tumor at 3 and 9 o'clock of the cervix (1ml totally) with 1ml syringe. Carbon nanoparticle should be slowly injected to avoid drug leakage. Intratumoral and deep cervical stroma injection should be avoided. The retroperitoneum is dissected immediately after injection. Search the black lymphatics from bilateral parametrium to iliac vessels. Because there is no fluorescence penetration as ICG, the black lymphatic vessels should be dissected carefully.The first black lymph nodes on each lymphatic drainage pathway are identified as SLNs, other than all black lymph nodes. All detectable SLNs and enlarged or suspicious nodes regardless of mapping are resected for pathological examination alone.
Department of Gynecological Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College
Beijing, Beijing Municipality, China
Overall SLN detection rate
The percentage of patients with successfully detected SLNs in all eligible patients.
Time frame: From date of operation to the date of completion of routine pathological examination, usually 2 weeks after operation.
Bilateral SLN detection rate
The percentage of patients with successfully detected SLNs in both sides of the pelvis in all eligible patients
Time frame: From date of operation to the date of completion of routine pathological examination, usually 2 weeks after operation.
The number of detected SLNs
The numbers of detected SLNs are calculated by the pathologist.
Time frame: From date of operation to the date of completion of routine pathological examination, usually 2 weeks after operation.
Location of SLNs
Distribution of SLNs in pelvic and abdominal cavity, including external iliac, obturator fossa, internal ilia, deep inguinal, common iliac, presacral, inferior vena cava, para-aortic, and parametrial regions.
Time frame: From date of operation to the date of completion of routine pathological examination, usually 2 weeks after operation.
Sensitivity of SLN biopsy
The percentage of patients or pelvises with positive SLNs in pathological examination among those with positive pelvic lymph nodes.
Time frame: From date of operation to the date of completion of SLNs pathological ultrastaging. 3 years.
False negative rate
The percentage of patients or pelvises with negative SLNs in pathological examination among those with positive pelvic lymph nodes.
Time frame: From date of operation to the date of completion of SLNs pathological ultrastaging. 3 years.
Negative predictive value
The percentage of patients or pelvises with negative pelvic lymph nodes among those whose SLNs were negative in pathological examination.
Time frame: From date of operation to the date of completion of SLNs pathological ultrastaging. 3 years.
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