How does preoperative radiotherapy affect the rate of sphincter-sparing surgery in rectal cancer?

Predictors for temporary stomas non-closure among non-metastatic rectal cancer patients undergoing curative resection: a retrospective analysis

BACKGROUND

The primary treatment for non-metastatic rectal cancer is curative resection. However, sphincter-preserving surgery may lead to complications. This study aims to develop a predictive model for stoma non-closure in rectal cancer patients who underwent curative-intent low anterior resection.

METHODS

Consecutive patients diagnosed with non-metastatic rectal cancer between January 2005 and December 2017, who underwent low anterior resection, were retrospectively included in the Chang Gung Memorial Foundation Institutional Review Board. A comprehensive evaluation and analysis of potential risk factors linked to stoma non-closure were performed.

RESULTS

Out of 956 patients with temporary stomas, 10.3% (n = 103) experienced non-closure primarily due to cancer recurrence and anastomosis-related issues. Through multivariate analysis, several preoperative risk factors significantly associated with stoma non-closure were identified, including advanced age, anastomotic leakage, positive nodal status, high preoperative CEA levels, lower rectal cancer presence, margin involvement, and an eGFR below 30 mL/min/1.73m2. A risk assessment model achieved an AUC of 0.724, with a cutoff of 2.5, 84.5% sensitivity, and 51.4% specificity. Importantly, the non-closure rate could rise to 16.6% when more than two risk factors were present, starkly contrasting the 3.7% non-closure rate observed in cases with a risk score of 2 or below (p < 0.001).

CONCLUSION

Prognostic risk factors associated with the non-closure of a temporary stoma include advanced age, symptomatic anastomotic leakage, nodal status, high CEA levels, margin involvement, and an eGFR below 30 mL/min/1.73m2. Hence, it is crucial for surgeons to evaluate these factors and provide patients with a comprehensive prognosis before undergoing surgical intervention.

RIOK1 mediates p53 degradation and radioresistance in colorectal cancer through phosphorylation of G3BP2

RIO Kinase 1 (RIOK1) is involved in various pathologies, including cancer. However, the role of RIOK1 in radioresistance of colorectal cancer (CRC) remains largely unknown. In this study, we reported that RIOK1 was overexpressed in rectal cancer tissue with weaker tumor regression after neoadjuvant chemoradiotherapy (neoCRT). Moreover, higher RIOK1 expression predicted a poor prognosis in patients with rectal cancer. Blockade of RIOK1 using Toyocamycin, a pharmacological inhibitor of RIOK1, or by knocking down its expression, decreased the resistance of CRC cells to radiotherapy in vitro and in vivo. A mechanistic study revealed that RIOK1 regulates radioresistance by suppressing the p53 signaling pathway. Furthermore, we found that RIOK1 and Ras-GAP SH3 domain binding protein 2 (G3BP2) interact with each other. RIOK1 phosphorylates G3BP2 at Thr226, which increases the activity of G3BP2. RIOK1-mediated phosphorylation of G3BP2 facilitated ubiquitination of p53 by murine double minute 2 protein (MDM2). Altogether, our study revealed the clinical significance of RIOK1 in CRC, and therapies targeting RIOK1 might alleviate the CRC tumor burden in patients.

Regulation of lnc-TLCD2-1 on Radiation Sensitivity of Colorectal Cancer and Comprehensive Analysis of Its Mechanism

As is well known that colorectal cancer is the third most common cancer in the world, and radiation treatment plays a vital role in colorectal cancer therapy, but radiation resistance is a significant problem in the treatment of colorectal cancer. As an important member of the non-coding RNA family, long non-coding RNAs (lncRNAs) have been found that it plays a role in the occurrence and progression of colorectal cancer in recent years. However, little is known about the effect of lncRNA on colorectal cancer sensitivity to radiotherapy. We found that lnc-TLCD2-1 was significantly differentially expressed in radiation-tolerant CCL244 cell lines and radiation-sensitive HCT116 cell lines, suggesting that lnc-TLCD2-1 may regulate the radiosensitivity of colorectal cancer, and the relevant underlying mechanism was investigated. Cell clone formation assay, flow cytometry, and cell counting kit 8 (CCK8) were used to detect radiation sensitivity, apoptosis, and proliferation of colorectal cancer cells, respectively; Quantitative real-time PCR and western blot were used to detect the expression of genes; the direct interaction between lnc-TLCD2-1 and hsa-miR-193a-5p was verified by dual luciferase reporter assays; GEPIA, Starbase, TIMER and DAVID were used to complete expression of lnc-TLCD2-1, miR-193a-5p,YY1 and NF-кB-P65 in colorectal cancer, correlation, immune cell infiltration, GO and KEGG enrichment analysis. Clinical prognostic analysis data were obtained from GSE17536 dataset. After radiotherapy for HCT116, the expression of lnc-TLCD2-1 was increased, and the expression of hsa-miR-193a-5p was significantly decreased, while that of CCL244 was the opposite, and the change range of lnc-TLCD2-1 was relatively small. HCT116 with overexpression of lnc-TLCD2-1 after radiation treatment, the number of cell colonies significantly increased, and cell apoptosis decreased compared with the negative control group. The cell colonies and apoptosis of CCL244 with disturbed expression of lnc-TLCD2-1 were opposite to those of HCT116. Lnc-TLCD2-1 can regulate the expression of YY1/NF-кB-P65 by targeting miR-193a-5p. Lnc-TLCD2-1 can promote the proliferation of colorectal cancer. High expression of lnc-TLCD2-1 independently predicted a shorter survival. Lnc-TLCD2-1 is associated with radiation resistance and short survival in colorectal cancer patients. In addition, Lnc-TLCD2-1 can promote the proliferation of colorectal cancer. Our study provides a scientific basis for targeting lnc-TLCD2-1 in colorectal cancer radiation resistance interventions and selection of prognostic biomarker.

MiR-1587 Regulates DNA Damage Repair and the Radiosensitivity of CRC Cells via Targeting LIG4

DNA is subject to a range of endogenous and exogenous insults that can impair DNA replication and lead to DNA double-strand breaks (DSBs). The repair capacity of cancer cells mediates their radiosensitivity, but the roles of miR-1587 during radiation resistance are poorly characterized. In this study, we explored whether miR-1587 regulates the growth and radiosensitivity of colorectal cancer (CRC) cells through its ability to regulate DNA Ligase4 (LIG4). We found that CRC cells in which miR-1587 was overexpressed inhibited cell growth and promoted apoptosis through increasing DSBs and promoting cell cycle arrest. We found that overexpression of miR-1587 significantly inhibited LIG4 messenger RNA and protein expression and further revealed the ability of miR-1587 to directly bind to the LIG4-3′-untranslated region through dual-luciferase reporter assays. More notably, miR-1587 mimics increased the radiosensitivity of CRC cells. Taken together, we show that miR-1587 overexpression enhances the formation of DSBs, arrests CRC cell growth, and enhances the radiosensivity of CRC cells through the direct repression of LIG4 expression. These results reveal novel roles for miR-1587 during DNA damage repair and the radiosensivity of CRC cells. This highlights miR-1587 as a novel therapeutic target for CRC.

Long noncoding RNA lnc-RI regulates DNA damage repair and radiation sensitivity of CRC cells through NHEJ pathway

A percentage of colorectal cancer (CRC) patients display low sensitivity to radiotherapy, which affects its therapeutic effect. Cancer cells DNA double-strand breaks (DSBs) repair capacity is crucial for radiosensitivity, but the roles of long noncoding RNAs (lncRNAs) in this process are largely uncharacterized. This study aims to explore whether lnc-RI regulates CRC cell growth and radiosensitivity by regulating the nonhomologous end-joining (NHEJ) repair pathway. CRC cells in which lnc-RI has been silenced showed lower cell growth and higher apoptosis rates due to increased DSBs and cell cycle arrest. We found that miR-4727-5p targets both lnc-RI and LIG4 mRNA and inhibit their expression. CRC cells showed increased radiosensitivity when lnc-RI was silenced. These results reveal novel roles for lnc-RI in both DNA damage repair and radiosensitivity regulation in CRC cells. Our study revealed that lnc-RI regulates LIG4 expression through lnc-RI/miR-4727-5p/LIG4 axis and regulates NHEJ repair efficiency to participate in DNA damage repair. The level of lnc-RI was negatively correlated with the radiosensitivity of CRC cells, indicates that lnc-RI may be a potential target for CRC therapy. We also present the first report of the function of miR-4727-5p.

Ultimate Functional Preservation With Intersphincteric Resection for Rectal Cancer

The proximity of the very low rectum rectal cancer to the anal sphincter raises a specific problem: how and until when can we preserve the anal continence without compromising the oncological result of the tumor resection? In this situation, intersphincteric resection (ISR) offers an excellent alternative to abdominoperineal resection (APR), but the selection of patients for this option must be extremely precise. This complex choice justifies the simultaneous consideration of an oncological approach with a functional approach in order to provide a full benefit to the patient. When a circumferential resection margin of at least 1 mm can be performed with a distal resection margin of at least 1 cm with or without preoperative radiotherapy, ISR ensures a safety choice. The oncological results of ISR reported in the literature when performed properly found a 5-year disease-free survival of 80.2% with a local recurrence rate of only 5.8%. In parallel to this oncological evaluation, the expected post-operative functional outcome and the resulting quality of life must be properly assessed pre-operatively, since partial or total resection of the internal sphincter impacts significantly on the functional outcome. Based on data from the literature, this work reports the essential anatomical considerations and then the oncological and functional elements indispensables when an anal continence preservation is evoked for a tumor of the very low rectum. Finally, the precise selection criteria and the major surgical principles are outlined in order to guarantee the safety of this modern choice for the patient.

Intersphincteric Resection Pushing the Envelope for Sphincter Preservation

During the last 15 years, a significant evolution has emerged in the surgical treatment of rectal cancer and restoration of bowel continuity has been one of the main goals. For many years the treatment of distal rectal cancer would necessarily require an abdominoperineal resection and end colostomy. The surgical procedure of intersphincteric resection has been proposed to offer sphincter preservation in patients with low rectal cancer and has been legitimized if executed according to adequate oncologic criteria. This article will discuss the best indications, technical aspects, functional, and oncological outcomes of intersphicteric resection in the management of rectal cancer.

XRCC2 as a predictive biomarker for radioresistance in locally advanced rectal cancer patients undergoing preoperative radiotherapy

XRCC2 has been shown to increase the radioresistance of some cancers. Here, XRCC2 expression was investigated as a predictor of preoperative radiotherapy (PRT) treatment response in locally advanced rectal cancer (LARC). XRCC2 was found to be overexpressed in rectal cancer tissues resected from patients who underwent surgery without PRT. In addition, overall survival for LARC patients was improved in XRCC2-negative patients compared with XRCC2-positive patients after treatment with PRT (P < 0.001). XRCC2 expression was also associated with an increase in LARC radioresistance. Conversely, XRCC2-deficient cancer cells were more sensitive to irradiation in vitro, and a higher proportion of these cells underwent cell death induced by G2/M phase arrest and apoptosis. When XRCC2 was knocked down, the repair of DNA double-strand breaks caused by irradiation was impaired. Therefore, XRCC2 may increases LARC radioresistance by repairing DNA double-strand breaks and preventing cancer cell apoptosis. Moreover, the present data suggest that XRCC2 is a useful predictive biomarker of PRT treatment response in LARC patients. Thus, inhibition of XRCC2 expression or activity represents a potential therapeutic strategy for improving PRT response in LARC patients.

The risk of definitive stoma formation at 10 years after low and ultralow anterior resection for rectal cancer

AIM

The long-term risk of definitive stoma after sphincter-saving resection (SSR) for rectal cancer is underestimated and has never been reported for ultralow conservative surgery. We report the 10-year risk of definitive stoma after SSR for low rectal cancer.

METHOD

From 1994 to 2008, patients with low rectal cancer who were suitable for SSR were analysed retrospectively. Patients were divided into the following four groups: low colorectal anastomosis (LCRA); coloanal anastomosis (CAA); partial intersphincteric resection (pISR); and total intersphincteric resection (tISR). The end-point was the risk of a definitive stoma according to the type of anastomosis.

RESULTS

During the study period, 297 patients had SSR for low rectal cancer. The incidence of definitive stoma increased from 11% at 1 year to 22% at 10 years. The reasons were no closure of the loop ileostomy (4.7%), anastomotic morbidity (6.5%), anal incontinence (8%) and local recurrence (5.2%). The risk of definitive stoma was not influenced by type of surgery: 26% vs 18% vs 18% vs 19% (P = 0.578) for LCRA, CAA, pISR and tISR, respectively. Independent risk factors for definitive stoma were age > 65 years and surgical morbidity.

CONCLUSION

The risk of a definitive stoma after SSR increased two-fold between 1 and 10 years after surgery, from 11% to 22%. Ultralow conservative surgery (pISR and tISR) did not increase the risk of definitive stoma compared with conventional CAA or LCRA.

Long-term effects of neoadjuvant chemoradiotherapy followed by sphincter-preserving resection on anal sphincter function in relation to quality of life among locally advanced rectal cancer patients: a cross-sectional analysis

BACKGROUND

There is growing recognition for the consequences of rectal cancer treatment to maintain an adequate functional sphincter in the long-term rather than preserving the anal sphincter itself. This study aims to evaluate long-term effects of neoadjuvant chemoradiotherapy (nCRT) followed by sphincter-preserving resection on anal sphincter function in relation to quality of life (QoL) among locally advanced rectal cancer patients.

METHODS

Twenty-nine patients treated with nCRT followed by low anterior resection surgery were included in this study. Data on patient demographics, tumor location and symptoms of urgency and fecal soiling were recorded and evaluated with respect to Wexner Fecal Incontinence Scoring Scale, European Organization for Research and Cancer (EORTC) cancer-specific (EORTC QLQ-C30) and colorectal cancer-specific (EORTC QLQ-CR38) questionnaires and anorectal manometrical findings. Correlation of manometrical findings with Wexner Scale, EORTC QLQ-CR38 scores and EORTC QLQ-C30 scores was also evaluated.

RESULTS

Median follow-up was 45.6 months (ranged 7.5-98 months. Higher scores for incontinence for gas (p = 0.001), liquid (p = 0.048) and solid (p = 0.019) stool, need to wear pad (p = 0.001) and alteration in life style (p = 0.004) in Wexner scale, while lower scores for future perspective (p = 0.010) and higher scores for defecation problems (p = 0.001) in EORTC QLQ-CR38 were noted in patients with than without urgency. Manometrical findings of resting pressure (mmHg) was positively correlated with body image (r = 0.435, p = 0.030) and sexual functioning (r = 0.479, p = 0.011) items of functional scale, while rectal sensory threshold (RST) volume (mL) was positively correlated with defecation problems (r = 0.424, p = 0.031) items of symptom scale in EORTC QLQ-CR38 and negatively correlated with social function domain (r = -0.479, p = 0.024) in EORTC QLQ-C30. RST volume was also positively correlated with Wexner scores including incontinence for liquid stool (r = 0.459, p = 0.024), need to wear pad (r = 0.466, p = 0.022) and alteration in lifestyle (r = 0.425, p = 0.038).

CONCLUSION

The high risk of developing functional anal impairment as well as the systematic registration of not only oncological but also functional and QoL related outcomes seem important in rectal cancer patients in the long-term disease follow-up.

Current concepts in rectal cancer

The history of rectal cancer management informs current therapy and points us in the direction of future improvements. Multidisciplinary team management of rectal cancer will move us to personalized treatment for individuals with rectal cancer in all stages.

Sphincter-sparing surgery in patients with low-lying rectal cancer: techniques, oncologic outcomes, and functional results

BACKGROUND

Rectal cancer management has evolved into a complex multimodality approach with survival, local recurrence, and quality of life parameters being the relevant endpoints. Surgical treatment for low rectal cancer has changed dramatically over the past 100 years.

DISCUSSION

Abdominoperineal resection, once the standard of care for all rectal cancers, has become much less frequently utilized as surgeons devise and test new techniques for preserving the sphincters, maintaining continuity, and performing oncologically sound ultra-low anterior or local resections. Progress in rectal cancer surgery has been driven by improved understanding of the anatomy and pathophysiology of the disease, innovative surgical technique, improved technology, multimodality approaches, and increased appreciation of the patient's quality of life. The patient with a low rectal cancer, once almost universally destined for impotence and a colostomy, now has the real potential for improved survival, avoidance of a permanent stoma, and preservation of the normal route of defecation.