Introduction
Cervical cancer is the second most commonly diagnosed cancer and the
third leading cause of cancer-related deaths among females, with
significant upward trends in its incidence and
mortality1-2. Conventionally, women with early-stage
cervical cancer (FIGO 2009 stages Ia2–IIa2) undergo hysterectomy with
pelvic lymph node dissection (PLND). However, early-stage cervical
cancer with nodal metastases accounts for only 8–26% of
cases3, suggesting that approximately more than 75%
of those patients routinely undergo unnecessary PLND. PLND increases the
incidence of short- and long-term complications, especially leg
lymphedema, and removing “healthy” lymph nodes may negatively
influence the immune system4. All
complications markedly decrease the
quality of post-operative life. Hence, avoiding unnecessary PLND in
early-stage cervical cancer patients is clinically important.
The so-called sentinel lymph node (SLN) is the first lymph node to drain
from a primary tumour5. If SLNs are
metastasis-negative, then upstream nodes should (in theory) also be
metastasis-free. To reduce the morbidity associated with PLND, SLN
biopsy (SLNB) is diagnostically beneficial when assessing for nodal
metastases in early-stage cervical cancer6. The
National Comprehensive Cancer Network (NCCN) guidelines recommend SLNB
as an alternative to PLND (Recommendation 2A)7.
However, the implementation of SLNB is limited, especially in China,
where one-fourth of the cervical cancer cases in the world
occur1. According to an anonymous online survey
completed by all full and candidate members of the Society of
Gynaecology and Obstetrics (SGO), only 70% (n = 139) of the 198
respondents (response rate = 17.7%) indicated that they perform SLNB.
The main reason for not performing SLNB was the lack of standardized
training and technology8. Inevitable heterogeneity was
observed in patient selection and tracer application in previous
studies, which were mainly retrospective studies with small sample
sizes. Moreover, there are some disadvantages to using the most common
tracers, such as allergic reactions, radioactive pollution, and the cost
of and dependence on expensive imaging technology9-11.
Therefore, we investigated carbon
nanoparticle suspension (CNS), a new tracer that can be used in SLNB for
patients with early-stage cervical cancer. A previous study showed that
CNS permits easy identification, has good lymphatic tracer effects, and
results in increased lymph node retrieval12. Its use
in SLNB for cervical cancer is relatively new. Accordingly, the
objectives of this study were to assess the safety and feasibility of
CNS in SLNB, and to determine the diagnostic validity of the SLN status
for assessing lymphatic spread in early-stage cervical cancer.