Ex vivo localization and immunohistochemical detection of sentinel lymph node micrometastasis in patients with colorectal cancer can upgrade tumor staging

The concept of developmental anatomy: the greater omentum should be resected in right-sided colon cancer?

BACKGROUND

The greater omentum is derived from the foregut, and the right hemicolon is derived from the midgut based on developmental anatomy. This study aimed to investigate whether the greater omentum should be resected in laparoscopic complete mesocolic excision based on developmental anatomy for right-sided colon cancer.

METHODS

A total of 183 consecutive patients with right-sided colon cancer were recruited in this study between February 2020 and July 2022. Ninety-eight patients underwent standard laparoscopic complete mesocolic excision surgery (CME group). The presence of isolated tumor cells and micrometastases was detected in resected greater omentum by the HE staining and immunohistochemistry analysis. Based on developmental anatomy, laparoscopic CME surgery with greater omentum preservation (DACME group) was proposed and performed on 85 right-sided colon cancer patients. To overcome selection bias, we performed a 1:1 match between two groups using four variables: age, sex, BMI, and ASA scores.

RESULTS

No isolated tumor cells and micrometastases were found in the resected greater omentum specimen in the CME group. After the propensity score, 81 pairs were balanced and analyzed. Patients in the DACME group showed shorter operative time (194.9 ± 16.4 min vs.201.5 ± 11.5 min, p = 0.002), less blood loss (23.5 ± 24.7 ml vs.33.6 ± 26.3 ml, p = 0.013), and the shorter hospital stays (9.6 ± 1.7 days vs.10.3 ± 2.0 days, p = 0.010) compared with patients in the CME group. In addition, patients in the DACME group had a lower incidence of postoperative complications (4.9% vs.14.8%, p = 0.035) than patients in the CME group.

CONCLUSION

The greater omentum should be preserved during right-sided colon cancer surgery, laparoscopic CME surgery based on developmental anatomy is technically safe and feasible for right-sided colon cancer.

Impact of the preoperative clinical N stage on the prognosis of patients with colon cancer

AIM

Although preoperative clinical staging (cStage) is performed for most cancer patients, limited information is currently available on the relationship with postoperative prognosis. We herein investigated the relationship between cStage and prognosis of colon cancer (CC) patients, particularly focusing on the presence or absence of clinical lymph node (LN) metastasis.

METHOD

This was a retrospective study on 840 consecutive patients with colon adenocarcinoma who underwent radical resection at our institution between January 2007 and December 2018. A Kaplan-Meier curve was used to analyse the prognosis of two groups: cN(+)pN(-); a group preoperatively diagnosed with clinical LN metastasis positive, but with no pathological LN metastasis postoperatively, and cN(-)pN(-); a group without clinical and pathological LN metastasis. We also investigated whether a clinical diagnosis is a more accurate prognostic factor than other clinical factors.

RESULTS

Among pN(-) cases, the 5-year recurrence-free survival rate was significantly lower in preoperatively diagnosed cN(+) cases than in cN(-) cases (79.4% vs. 95.6%, 3.04 years vs. 3.85 years, p < 0.01). In a multivariate analysis of various preoperative clinical factors in pStage II cases, including high risk factors for pStage II CC, cN(+) was identified as an independent prognostic factor (hazard ratio: 2.06, 95% CI: 1.02-4.27, p = 0.04).

CONCLUSION

Preoperatively over-staged cN cases had a poorer prognosis than cases without over-staging, indicating its potential as a prognostic factor. In addition to already known high risk factors in pStage II cases, the preoperative cStage may be an indication for adjuvant chemotherapy.

NCK-associated protein 1 regulates metastasis and is a novel prognostic marker for colorectal cancer

Metastatic colorectal cancer (CRC) remains a substantial problem for mortality and requires screening and early detection efforts to increase survival. Epithelial-mesenchymal transition (EMT) and circulation of tumor cells in the blood play important roles in metastasis. To identify a novel target for metastasis of CRC, we conducted a gene microarray analysis using extracted RNA from the blood of preclinical models. We found that NCK-associated protein 1 (NCKAP1) was significantly increased in the blood RNA of patient-derived xenograft (PDX) models of colon cancer. In the NCKAP1 gene knockdown-induced human colon cancer cell lines HCT116 and HT29, there was a reduced wound healing area and significant inhibition of migration and invasion. As the result of marker screening for cytoskeleton and cellular interactions, CRC treated with siRNA of NCKAP1 exhibited significant induction of CDH1 and phalloidin expression, which indicates enhanced adherent cell junctions and cytoskeleton. In HCT116 cells with a mesenchymal state induced by TGFβ1, metastasis was inhibited by NCKAP1 gene knockdown through the inhibition of migration, and there was increased CTNNB1 expression and decreased FN expression. We established metastasis models for colon cancer to liver transition by intrasplenic injection shRNA of NCKAP1-transfected HCT116 cells or by implanting tumor tissue generated with the cells on cecal pouch. In metastasis xenograft models, tumor growth and liver metastasis were markedly reduced. Taken together, these data demonstrate that NCKAP1 is a novel gene regulating EMT that can contribute to developing a diagnostic marker for the progression of metastasis and new therapeutics for metastatic CRC treatment.

Sentinel Lymph Node Analysis in Colorectal Cancer Patients Using One-Step Nucleic Acid Amplification in Combination With Fluorescence and Indocyanine Green

PURPOSE

Analysis of the sentinel lymph node (SLN) in colorectal cancer (CRC) patients was proposed for more accurate staging and tailored lymphadenectomy. The aim of this study was to assess the ability to predict lymph node (LN) involvement through analysis of the SLN with a one-step nucleic acid (OSNA) technique in combination with peritumoral injection of indocyanine green (ICG) and near-infrared (NIR) lymphangiography in CRC patients.

METHODS

A total of 34 patients were enrolled. Overall, 51 LNs were analyzed with OSNA. LNs of 17 patients (50%) were examined simultaneously with hematoxylin and eosin (H&E) and OSNA.

RESULTS

SLN analysis of 17 patients examined with H&E and OSNA revealed that OSNA had a higher sensitivity (1 vs. 0.55), higher negative predictive value (1 vs. 0.66) and higher accuracy (100% vs. 76.4%) in predicting LN involvement. Overall, OSNA showed a sensitivity of 0.69, specificity of 1, accuracy of 88.2%, and stage migration of 8.8%. Compared to those who were OSNA (-), OSNA (+) patients had a greater number of LN metastases (4.8 vs. 0.16, P = 0.04), higher G3 rate (44.4% vs. 4%, P = 0.01), more advanced stage of disease (stage III: 77.8% vs. 16%; P = 0.00) and were more rapidly subjected to adjuvant chemotherapy (39.1 days vs. 50.2 days, P = 0.01).

CONCLUSION

SLN analysis with OSNA in combination with ICG-NIR lymphangiography is feasible and can detect LN involvement in CRC patients. Furthermore, it allows for more accurate staging reducing the delay between surgery and adjuvant chemotherapy.