Comparative long-term outcomes of natural orifice specimen extraction surgery and conventional laparoscopic colectomy for left-sided colorectal cancer: a propensity score-matched analysis

BACKGROUND

Natural orifice specimen extraction surgery (NOSES) is currently widely used in left-sided colorectal cancer. Some clinical comparative studies have been conducted, providing evidence of its safety and oncological benefits. However, these studies are typically characterized by small sample sizes and short postoperative follow-up periods. Consequently, in this research, the authors adopt the propensity score matching method to undertake a large-scale retrospective comparative study on NOSES colectomy for left-sided colorectal cancer, with the goal of further augmenting the body of evidence-based medical support for NOSES.

METHODS

This retrospective study involved patients who underwent NOSES colectomy and conventional laparoscopic (CL) colectomy for left-sided colorectal cancer between January 2014 and April 2021. In the NOSES group, specimens were extracted through the anus with the help of a Cai tube (homemade invention: ZL201410168748.2). The patients were matched at a ratio of 1:1 according to age, sex, BMI, tumor diameter, tumor location (descending and splenic flexure colon/ sigmoid colon/ middle and upper rectum), tumor height from anal verge, ASA grade, previous abdominal surgery, clinical pathologic stage, preoperative CEA. After matching, 132 patients in the NOSES group and 132 patients in the CL group were eligible for analysis.

RESULTS

Compared with CL group, NOSES group was associated with decreased postoperative maximum pain score (2.6±0.7 vs. 4.7±1.7, P=0.000), less additional analgesia required (6.8 vs. 34.8%, P=0.000), faster time to passage of flatus (2.3±0.6 days vs. 3.3±0.7 days, P=0.000), less wound infection (0.0 vs. 6.1%, P=0.007), and longer operative time (212.5±45.8 min vs. 178.0±43.4 min, P=0.000). No significant differences were observed in estimated blood loss, time to resume regular diet, postoperative hospital stay, conversion to open surgery or conventional minilaparotomy, total morbidity, readmission, mortality, pathologic outcomes, and Wexner incontinence score between groups. After a median follow-up of 63.0 months, the 5-year overall survival rates were 88.3 versus 85.0% (P=0.487), disease-free survival rates were 82.9 versus 83.6% (P=0.824), and the local recurrence rates were 4.4 versus 4.0% (P=0.667) in the NOSES and CL groups, respectively.

CONCLUSIONS

This study suggests that NOSES colectomy using a Cai tube for left-sided colorectal cancer is a safe and feasible option with better cosmetic results, less pain, faster recovery of gastrointestinal function, and comparable long-term clinical and oncologic outcomes to CL colectomy.

Construction of a gut microbiota-gene-pathway network to reveal the molecular mechanisms underlying right- and left-sided colorectal cancer

Aiming to reveal the molecular mechanisms involved in right- and left-sided colorectal cancer (CRC) development, CRC gene expression data and a microorganism atlas were downloaded from The Cancer Genome Atlas and The Cancer Microbiome Atlas, respectively. The R package was used to screen differentially expressed genes (DEGs) between right- and left-sided CRC samples and identify those related to prognosis, a correlation analysis was performed between DEGs and prognosis-related microbiota, and an interaction network was created using Cytoscape. Finally, a taxon set enrichment analysis of the microbiota was performed and a gene-genus-pathway network was constructed after GO and KEGG analyses. In total, nine out of 1557 identified DEGs had a significant correlation with prognosis, whereas three out of 211 bacterial genera (Fusobacterium, Bacteroides and Parabacteroides) showed a significant correlation with prognosis. DEGs were mainly enriched in the PPAR pathway and vitamin metabolic and transport processes. According to a taxon set enrichment analysis, the microbes in the integrated network were significantly abundant in 28 host-intrinsic, two host-extrinsic and one environment taxon sets. This study provides new insights for understanding the molecular mechanisms of left- and right-CRC.

Prognostic Utility of Apical Lymph Node Metastasis in Patients With Left-sided Colorectal Cancer

BACKGROUND

Unlike the tumor nodes metastasis (TNM) lymph node classification, based solely on counts of nodal metastases, the Japanese system of classifying colorectal carcinoma (CRC) focuses on regional lymph node spread. In this study, we explored the prognostic utility of inferior mesenteric artery (IMA) apical lymph node (APN) metastasis.

PATIENTS AND METHODS

This was a retrospective study of patients with stage III left-sided CRC. All enrollees were subjected to D3 resection between April 2007 and December 2016 at the International Medical Center of Saitama Medical University and then stratified by histologic presence (APN+ group) or absence (APN- group) of tumor in APNs examined postoperatively. Ultimately, propensity score matching was invoked (1:2) and COX regression analysis was conducted, determining group rates of relapse-free survival (RFS) and cancer-specific survival (CSS).

RESULTS

A total of 498 patients were studied, grouped as APN+ (19/498, 3.8%) or APN- (479/498, 96.2%). Prior to matching, the APN+ (vs. APN-) group showed significantly more lymphatic involvement (73.7% vs. 47.8%; p=0.023), deep (T3/T4) tumor infiltration (100% vs. 78.9%; p=0.024), and nodal metastasis (N2: 84.2% vs. 27.6%; p<0.001). In addition, para-aortic nodal recurrences were significantly increased (15.7% vs. 2.0%; p<0.001), conferring worse RFS (p<0.001) and CSS (p=0.014) rates. Once baseline factors were matched, the two groups appeared similar in RFS (p=0.415) and CSS (p=0.649). Multivariate regression analysis indicated that elevated carcinoembryonic antigen (CEA) level and deep tumor infiltration were independent risk factors for RFS, whereas postoperative complications and tumor-positive node counts were independent risk factors for CSS. APN+ status was not a significant risk factor for RFS or CSS.

CONCLUSION

APN positivity may thus constitute a regional rather than systemic manifestation. The TNM staging based on the number of metastatic lymph nodes seems to be more reasonable than the regional lymph node classification method.

Molecular Profiling of Appendiceal Adenocarcinoma and Comparison with Right-sided and Left-sided Colorectal Cancer

PURPOSE

The natural history and prognosis of appendiceal adenocarcinomas differ from those of adenocarcinomas arising in other large bowel sites. We aimed to compare the molecular profiles exhibited by appendiceal adenocarcinomas and colorectal cancers, or between the histopathologic subtypes of appendiceal adenocarcinoma.

EXPERIMENTAL DESIGN

A total of 183 samples from appendiceal adenocarcinoma [46 adenocarcinoma, not otherwise specified (NOS), 66 pseudomyxoma peritonei (PMP), 44 mucinous adenocarcinoma (MU), and 27 signet ring cell carcinoma (SR)], 994 from right-sided colorectal cancer (R-CRC), and 1,080 from left-sided CRC (L-CRC) were analyzed by next-generation sequencing (NGS) and IHC markers. Microsatellite instability (MSI) and tumor mutational burden (TMB) were tested by NGS, and programmed death ligand 1 (PD-L1) by IHC.

RESULTS

We observed high mutation rates in appendiceal adenocarcinoma samples for KRAS (55%), TP53 (40%), GNAS (31%), SMAD4 (16%), and APC (10%). Appendiceal adenocarcinoma exhibited higher mutation rates in KRAS and GNAS, and lower mutation rates in TP53, APC, and PIK3CA (6%) than colorectal cancers. PMP exhibited much higher mutation rates in KRAS (74%) and GNAS (63%), and much lower mutation rates in TP53 (23%), APC (2%), and PIK3CA (2%) than NOS. Alterations associated with immune checkpoint inhibitor response (MSI-high, TMB-high, PD-L1 expression) showed similar frequency in appendiceal adenocarcinoma compared with L-CRC, but not R-CRC, and those of NOS were higher than other subtypes of appendiceal adenocarcinoma and L-CRC.

CONCLUSIONS

Molecular profiling of appendiceal adenocarcinoma revealed different molecular characteristics than noted in R-CRC and L-CRC, and molecular heterogeneity among the histopathologic subtypes of appendiceal adenocarcinoma. Our findings may be critical to developing an individualized approach to appendiceal adenocarcinoma treatment.