Feasibility of Sentinel Lymph Node Mapping With Carbon Nanoparticles in Cervical Cancer: A Retrospective Study

Analysis of Lymphovascular Infiltration and Tumor-Associated Macrophages in Cervical Cancer Immunoescape

Background

Exact detection of lymphovascular infiltration (LVI) status can guide accurate surgical operation scope in cervical cancer, but LVI reduces the overall survival (OS) of patients and is not easily detected by hematoxylin-eosin (H&E) staining. The role of tumor-associated macrophages (TAMs) in this process is not well defined.

Methods

Early-stage cervical cancer patients received carbon nanoparticles for sentinel lymph-node mapping, laparotomy pelvic lymph-node dissection, and radical hysterectomy. The excised specimens were analyzed using ultrastaging, double immunohistochemical (IHC) staining, flow cytometry, and Western blot analysis. Single-cell data from the Gene Expression Omnibus for cervical cancer were obtained and analyzed.

Results

The integration of carbon nanoparticle mapping, ultrastaging, and double IHC staining enhanced the detection of tumor LVI over H&E staining (41.8% [41/98] vs. 20.4% [20/98], P=0.046). When the number of vascular invasion foci was greater than two, there was a negative correlation with OS (P<0.05). More M2 TAMs emerged surrounding the tumor vasculature labeled by double IHC staining, accompanied by a higher M2:M1 ratio detected with flow cytometry (P<0.05). M2 TAM numbers were positively correlation with the degree of tumor LVI (P=0.0024), combined with higher protein expression of MMP2, SPARC, and GNLY in the tumor LVI-positive group on Western blot analysis, and the OS of the patients decreased accordingly. Single-cell data showed that the M1:M2 ratio decreased significantly, accompanied by higher M2 TAM-related gene expression. Immunosurveillance and anti-immunoescape scores for M1 were obviously higher than for M2 TAMs. GO and KEGG analysis showed M2 TAM activity increased from precancerous lesions to cervical cancer.

Conclusion

Combining different methods may accurately determine tumor LVI status, guide exact surgical operation scope, and improve cervical cancer patient outcomes. M2 TAM activity increased in cervical cancer, forming an immunosuppressive environment, TAM-related genes could be good markers in determining cervical cancer LVI and serve as potential targets for immunotherapy.

Sentinel lymph node biopsy with carbon dye in endometrial cancer: a single center, prospective cohort study

BACKGROUND

Many agents have been used for the detection of sentinel lymph nodes in endometrial cancer. Carbon dye, which has a strong staining ability and high contrast due to its dark black color, identifies the lymph nodes efficiently. Our aim was to evaluate the safety and efficacy of carbon dye for the detection of sentinel lymph nodes in endometrial cancer.

METHODS

We conducted a single-center, prospective, cohort study in 89 patients with early-stage endometrial cancer between September 2021 and August 2022. The procedure was performed under laparoscopy.

RESULTS

The sensitivity and negative predictive value of the sentinel lymph node biopsy (SLNB) with carbon dye injection were 83.3% and 98.8%, respectively. Mapping identified at least one sentinel lymph node in 84 patients (94.4%) on one pelvic side and at least one sentinel lymph node in 73 patients (82.0%) on each pelvic side out of 89 patients. In addition, no carbon dye-associated allergic reaction was detected.

CONCLUSION

Carbon dye is a non-allergenic, inexpensive, and effective agent for SLNB with a satisfying sensitivity and a negative predictive value. In addition, both unilateral and bilateral detection rates were sufficient. Accordingly, carbon dye may be a promising tracer and a considerable option, particularly for low-income countries.