Current debate in the oncologic management of rectal cancer

Characterization and proteomic analysis of plasma-derived small extracellular vesicles in locally advanced rectal cancer patients

BACKGROUND

Neoadjuvant chemoradiotherapy (nCRT) stands as a pivotal therapeutic approach for locally advanced rectal cancer (LARC), yet the absence of a reliable biomarker to forecast its efficacy remains a challenge. Thus, this study aimed to assess whether the proteomic compositions of small extracellular vesicles (sEVs) might offer predictive insights into nCRT response among patients with LARC, while also delving into the proteomic alterations within sEVs post nCRT.

METHODS

Plasma samples were obtained from LARC patients both pre- and post-nCRT. Plasma-derived sEVs were isolated utilizing the TIO2-based method, followed by LC-MS/MS-based proteomic analysis. Subsequently, pathway enrichment analysis was performed to the Differentially Expressed Proteins (DEPs). Additionally, ROC curves were generated to evaluate the predictive potential of sEV proteins in determining nCRT response. Public databases were interrogated to identify sEV protein-associated genes that are correlated with the response to nCRT in LARC.

RESULTS

A total of 16 patients were enrolled. Among them, 8 patients achieved a pathological complete response (good responders, GR), while the remaining 8 did not achieve a complete response (poor responders, PR). Our analysis of pretreatment plasma-derived sEVs revealed 67 significantly up-regulated DEPs and 9 significantly down-regulated DEPs. Notably, PROC (AUC: 0.922), F7 (AUC: 0.953) and AZU1 (AUC: 0.906) demonstrated high AUC values and significant differences (P value < 0.05) in discriminating between GR and PR patients. Furthermore, a signature consisting of 5 sEV protein-associated genes (S100A6, ENO1, MIF, PRDX6 and MYL6) was capable of predicting the response to nCRT, yielding an AUC of 0.621(95% CI: 0.454-0.788). Besides, this 5-sEV protein-associated gene signature enabled stratification of patients into low- and high-risk group, with the low-risk group demonstrating a longer overall survival in the testing set (P = 0.048). Moreover, our investigation identified 11 significantly up-regulated DEPs and 31 significantly down-regulated DEPs when comparing pre- and post-nCRT proteomic profiles. GO analysis unveiled enrichment in the regulation of phospholipase A2 activity.

CONCLUSIONS

Differential expression of sEV proteins distinguishes between GR and PR patients and holds promise as predictive markers for nCRT response and prognosis in patients with LARC. Furthermore, our findings highlight substantial alterations in sEV protein composition following nCRT.

Efficacy and Safety of Preoperative Radiotherapy Versus Chemoradiotherapy in Advanced Rectal Cancer: A Meta-analysis of Randomized Controlled Trials

OBJECTIVE

This meta-analysis was conducted to evaluate the safety and efficacy of preoperative radiotherapy (RT) combined with surgery and preoperative chemoradiotherapy (CRT) combined with surgery for locally advanced rectal cancer.

METHODS

PubMed, EMBASE and Cochrane Library were searched to collect published randomized controlled trials of preoperative radiotherapy or preoperative CRT combined with surgery for the treatment of locally advanced rectal cancer. Studies were screened according to inclusion and exclusion criteria, and quality was evaluated; RevMan 5.3 software was used for meta-analysis.

RESULTS

In total, 7 related studies involving 3100 patients with locally advanced rectal cancer were evaluated. The pathological complete response rate, negative lymph node rate, R0 resection rate, and incidence of grade III/IV adverse reactions were lower in the RT group than in the CRT group. In the absence of postoperative chemotherapy, the 5-year local recurrence rate of RT was higher than that of CRT, but there was no significant difference between the groups among those who underwent postoperative chemotherapy. Moreover, there was no significant difference between the groups with regard to the 5-year survival rate, anal-preserving rate, or incidence of anastomotic leakage.

CONCLUSION

Preoperative CRT is better than preoperative RT for the treatment of advanced rectal cancer, though the adverse reaction rate is higher.

Surgical outcomes in pelvic exenteration for advanced and recurrent malignancy: a high volume single institution experience

PURPOSE

Pelvic exenteration remains the only curative treatment for advanced pelvic malignancies. However, identification of predictive factors for successful surgical outcomes is still a controversial issue at present time.

METHODS

This retrospective study included data from all adult patients with colorectal or anal advanced pelvic malignancy registered for pelvic exenteration at the Leon Berard Cancer Center (Lyon, France). The primary endpoint was the surgical outcomes and aimed to define the predictive factors for postoperative complications. Secondary endpoints included overall survival and progression free survival in patients having experienced pelvic exenteration (PE).

RESULTS

Data from 141 patients with locally advanced tumor (N = 81) or recurrent malignancies (N = 60) diagnosed between May 1994 and November 2018 were collected. The median age was 63.3 years (95%CI 20.0-92.0). Malignancies included different locations (rectal: 69.5%, left colon: 17.0% and anal: 13.5%). Posterior pelvectomy was the most frequent surgery (81.6%). The median length of hospital stay was 23.3 days (95%CI 3.0-82.0). The major complication rate at 30 days was 24.8% and 38.1% at 90 days. The median overall survival was 54.5 months (95%CI 41.5-104.1) and the median PFS was 34.5 months (95%CI 19.6-NA).

CONCLUSION

In selected patients, pelvic exenteration is associated with good surgical and survival outcomes.

Overall Survival Benefit in Rectal Cancer After Neoadjuvant Radiotherapy and Adjuvant Chemotherapy: A Propensity-Matched Population-Based Study

Background

It is well known that neoadjuvant radiotherapy could reduce local recurrence followed by surgical resection. However, evidence about oncologic efficacy of radiotherapy and survival benefit of adjuvant chemotherapy after neoadjuvant radiotherapy is still lacking.

Methods

This retrospective propensity score-matched cohort study identified patients with pathologically confirmed rectal cancer and receiving surgery with curative intent from the Surveillance, Epidemiology, and End Results database from 2004 through 2014. Overall survival was compared using the stratified log-rank test. Multivariate Cox regression analysis was used for identifying risk factor and developing prediction nomogram.

Results

A total of 22,008 (11,004 for each group) propensity-matched patients were identified. In the context of receiving adjuvant chemotherapy after surgical resection, there was no significant difference in terms of overall survival between surgery alone group and neoadjuvant radiotherapy and surgery group, whether for stage I (log-rank test p = 0.467), stage II (log-rank test p = 0.310), or stage III (p = 0.994). In case of receiving a prior combination therapy of neoadjuvant radiotherapy and surgery, the following adjuvant chemotherapy could significantly improve overall survival for patients with stage I (log-rank test p <0.001), stage II (log-rank test p = 0.038), and stage III (log-rank test p = 0.014). Nomogram integrating clinicopathologic factors was developed to predict survival benefit associated with neoadjuvant radiotherapy. Calibration and ROC curves validated promising performance for the nomogram.

Conclusion

Patients with rectal cancer underwent neoadjuvant radiotherapy yield acceptable outcomes and are more likely to benefit from adjuvant chemotherapy in terms of overall survival. These data would be evidential for advocating consistency in guideline adherence to the use of adjuvant chemotherapy after neoadjuvant radiotherapy.

Surgical and Survival Outcomes Following Pelvic Exenteration for Locally Advanced Primary Rectal Cancer: Results From an International Collaboration

OBJECTIVE

The aim of the study was to analyze data from an international collaboration, and ascertain prognostic indicators that inform clinical decision-making and practices regarding the role of pelvic exenteration for locally advanced primary rectal cancer (LARC).

BACKGROUND

With improved national screening programs fewer patients present with LARC. Despite this, select cohorts of patients require pelvic exenteration. To date, the majority of outcome data are from single-center series.

METHODS

Anonymized data from 14 countries on patients who had pelvic exenteration for LARC between 2004 and 2014 were accumulated. The primary endpoint was overall survival. The impact of resection margin, nodal status, bone resection, and use of neoadjuvant therapy (before exenteration) on survival was evaluated using multivariable analysis.

RESULTS

Of 1291 patients, 778 (60.3%) were male with a median (range) age of 63 (18-90) years; 78.1% received neoadjuvant therapy. Bone resection en bloc was performed in 8.2% of patients (n = 106), and 22.6% (n = 292) had resection combined with flap reconstruction. Negative resection margin (R0 resection) was achieved in 79.9%. The 30-day postoperative mortality was 1.5%.The median overall survival following R0, R1, and R2 resection was 43, 21, and 10 months (P < 0.001) with a 3-year survival of 56.4%, 29.6%, and 8.1%, respectively (P < 0.001); 37.8% of patients experienced one or more major complication. Neoadjuvant therapy increased the risk of 30-day morbidity (P < 0.012). Multivariable analysis identified resection margin and nodal status as significant determinants of overall survival (other than advanced age).

CONCLUSIONS

Attainment of negative resection margins (R0) is the key to survival. Neoadjuvant therapy may improve survival; however, it does so at the increased risk of postoperative morbidity.

Alpinoid c analog inhibits angiogenesis and induces apoptosis in COLO205 cell line

Diarylheptanoids display an array of biological and pharmacological properties. We previously reported the synthesis of a diarylheptanoid Alpinoid c and a series of its derivatives, evaluated their cytotoxicity against various human cancer cells. We found some of these derivatives were significantly more potent than Alpinoid c in preventing the proliferation of various cancer cell lines. Among these, (S, E)-1-(3, 4 dimethoxyphenyl)-6-hydroxy-7-phenylhept-4-en-3-one (DPHP) showed most potent cytotoxicity against COLO205 cells, however, the mechanism by which DPHP prevents the growth of these colon cancer cells remains unknown. In the current study, we investigated the molecular mechanism of DPHP on colon cancer cells. DPHP inhibited the proliferation of COLO205 (IC₅₀ 7.01 ± 0.62 μM) and A549 (IC₅₀ 20.03 ± 3.11 μM) cells more specifically than normal human colon epithelial cell line NCM460 (IC₅₀ 55.6 ± 4.02 μM). In COLO205 cells, DPHP induced cell shrinkage, membrane blebbing, chromatin condensation, phosphatidylserine externalization, and an accumulation of cells at sub-G1 phase. Further analysis these cells treated with DPHP revealed a decrease in mitochondrial membrane potential, an increase in Bax/Bcl2 ratio, the release of cytochrome c, activation of caspases -9, -3/7, and cleavage of the poly-ADP-ribose polymerase. DPHP treatment resulted in inhibition of hypoxia induced VEGF downstream signaling pathway in COLO205 cells is concurrent with inhibition of angiogenesis in CAM. Based on these data we suggest that DPHP significantly induced apoptosis possibly via intrinsic mitochondrial apoptosis pathway and inhibited angiogenesis. Our study suggests DPHP could be a therapeutic agent in treating colon cancer.

The role of induction chemotherapy + chemoradiotherapy in localised pancreatic cancer: initial experience in Scotland

BACKGROUND

Despite being relatively rare pancreatic cancer is one of the highest causes of death. Even within the potentially resectable group outcomes are poor. We present our initial experiences utilising a neoadjuvant approach to localised pancreatic cancer, evaluating survival, response rates and tolerability.

METHODS

This was a retrospective analysis of a prospectively maintained database. Patients from 2012 to 2015 referred to a busy regional Hepato-Pancreatic Biliary (HPB) MDT were included. Patients were classified according to respectability criteria (utilising NCCN guidelines) and a treatment plan agreed. Systemic therapy with either FOLFIRINOX or Gem/Cap was delivered followed by chemoradiotherapy if disease remained localised. Toxicity, response, pathological outcomes and survival were all recorded.

RESULTS

A total of 85 patients were included in the study: 45 had initially resectable disease; 19 required a response for resection and 21 had locally advanced inoperable disease; 34 patients underwent resection. The median survival for the potentially resectable group was 22.2 months while for those undergoing resection it was 37 months.

CONCLUSIONS

We have demonstrated that a neoadjuvant approach is deliverable and tolerable. In addition we have demonstrated impressive survival results in patients undergoing resection with no detriment in outcome for those not proceeding to surgery.

Magnetic resonance imaging for diagnosis and neoadjuvant treatment evaluation in locally advanced rectal cancer: A pictorial review

High-resolution pelvic magnetic resonance imaging (MRI) is the primary method for staging rectal cancer. MRI is highly accurate in the primary staging of rectal cancer; however, it has not proven to be effective in re-staging, especially in complete response evaluation after neoadjuvant therapy. Neoadjuvant chemoradiotherapy produces many changes in rectal tumors and on adjacent area, as a result, local tumor extent may not be accurately determined. However, adding diffusion-weighted sequences to the standard approach can improve diagnostic accuracy. In this pictorial review, an overview of the situation of MRI in the staging and re-staging of rectal cancer is exhibited as a pictorial assay. An experience- and literature-based discussion of limitations and difficulties in interpretation are also presented.

达芬奇机器人在直肠癌手术中泌尿生殖功能保护的系统回顾

目的

研究达芬奇机器人在直肠癌术后中对于患者盆部神经功能的保护相比于腹腔镜手术的优势.

方法

利用计算器检索关于国内外发表的机器人和腹腔镜直肠癌手术的对比研究, 研究采用的方法为国际公认的国际前列腺症状评分量表和国际勃起功能指数量表, 对纳入文献进行综合分析.

结果

最终纳入7篇文献, 共673例患者, 行机器人手术患者311例, 平均年龄62.7岁, 行腹腔镜手术362例, 平均年龄69.6岁. 两种手术方式的患者术后泌尿性功能均有一定程度的下降, 但机器人手术组患者的下降程度明显低于腹腔镜手术组, 且恢复至术前水平的速度更快.

结论

达芬奇机器人相比与腹腔镜手术在直肠癌患者术后的泌尿性功能保护方面具有一定优势.