Metastatic pattern and new primary tumours after neoadjuvant therapy and surgery in rectal cancer

Dentate line invasion is a risk factor for locoregional recurrence and distant metastasis following abdominoperineal resection in rectal cancer: a single-centre retrospective cohort study based on 1854 cases

BACKGROUND

In the context of surgical treatment for rectal cancer, the dentate line is acknowledged as a critical anatomical landmark. However, the prognostic implications of dentate line invasion (DLI) remain elusive and warrant further investigation. This study aims to evaluate and compare the outcomes of patients with rectal cancer who underwent abdominoperineal resection (APR), distinguishing between those with and without DLI.

MATERIALS AND METHODS

Between January 2006 and December 2017, this study enrolled 1854 patients with rectal cancer who underwent APR. The cohort was divided into two groups, namely the DLI group (n = 340) and the non-DLI group (n = 1514). The primary endpoints were distant relapse-free survival (DRFS) and local recurrence-free survival (LRFS). Univariate and multivariate analyses were conducted to assess the impact of DLI on DRFS, LRFS, overall survival (OS), and disease-free survival (DFS).

RESULTS

The median follow-up duration for the patients was 92.9 months, with a 5-year OS rate of 92.0% for the entire cohort. Compared to the non-DLI group, patients in the DLI group showed significantly poorer outcomes, with 5-year DRFS at 57.4% vs. 73.9% (P < 0.001), DFS at 51.2% vs. 70.7% (P < 0.001), and LRFS at 71.7% vs. 88.5% (P = 0.018). OS was the only metric that showed no significant difference(89.0% vs. 92.6%, P = 0.064). Multivariate analysis demonstrated that DLI negatively impacted DRFS (hazard ratio HR 1.319, P = 0.029), LRFS (HR 2.059, P < 0.001), and DFS (HR 1.563, P < 0.001) as an independent prognostic factor. Furthermore, distant metastasis occurred more frequently in the DLI group (30.0% vs. 23.1%, P = 0.002), along with a higher rate of locoregional recurrence. (16.8% vs. 8.3%, P < 0.001).

CONCLUSIONS

DLI correlates with a heightened likelihood of locoregional recurrence and distant metastasis among rectal cancer patients treated with APR. This association underscores the significance of DLI as a crucial prognostic factor that should be considered when developing clinical management strategies.

Neoadjuvant Modified Infusional Fluorouracil, Leucovorin, and Oxaliplatin With or Without Radiation Versus Fluorouracil Plus Radiation for Locally Advanced Rectal Cancer: Updated Results of the FOWARC Study After a Median Follow-Up of 10 Years

We present 10-year results of the phase Ⅲ FOWARC trial, which evaluated the efficacy of modified infusional fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) with or without radiation compared with fluorouracil with radiation in patients with locally advanced rectal cancer. A total of 495 patients age 18-75 years with stage Ⅱ-Ⅲ rectal cancer were randomly assigned to three treatment arms: fluorouracil plus radiotherapy, mFOLFOX6 plus radiotherapy, or mFOLFOX6 alone, followed by surgery and adjuvant chemotherapy. With a median follow-up of 10 years, the 10-year disease-free survival (DFS) rates were 52.5%, 62.6%, and 60.5%, respectively (P = .56). The 10-year locoregional recurrence (LR) rates were 10.8%, 8.0%, and 9.6% (P = .57), and the 10-year overall survival (OS) rates were 65.9%, 72.3%, and 73.4% (P = .90). Subgroup analysis identified ypTNM stage as a significant prognostic factor for DFS, LR, and OS (P < .0001, P < .006, P < .0001, respectively). Patients achieving pathologic complete response had 10-year DFS, LR, and OS rates of 84.3%, 3.0%, and 92.4%, respectively. No significant difference was observed in long-term survival outcome between mFOLFOX6 with and without radiation and fluorouracil plus radiation. These results demonstrate that neoadjuvant mFOLFOX6 chemotherapy can be considered as a therapeutic option in LARC.

Added value of DCER-features to clinicopathologic model for predicting metachronous metastases in rectal cancer patients

RATIONALE AND OBJECTIVES

The study aimed to investigate whether dynamic contrast-enhanced MRI parameters and preoperative radiological features (DCER-Features) add value to the clinicopathologic model for predicting metachronous metastases in rectal cancer patients.

MATERIALS AND METHODS

From January 2014 to December 2020, 859 patients in the PACS system were retrospectively screened. Of the initial 722 patients with surgically confirmed rectal cancer and no synchronous metastases, 579 patients were excluded for various reasons such as lack of clinicopathological or radiological information. 143 patients were finally included in this study. And 73 Patients of them developed metachronous metastasis within five years. After stepwise multiple regression analyses, we constructed three distinct models. Model 1 was developed solely based on clinicopathological factors, and model 2 incorporated clinicopathological characteristics along with DCE-MRI parameters. Finally, model 3 was built on all available factors, including clinicopathological characteristics, DCE-MRI parameters, and radiological features based on rectal magnetic resonance imaging. The radiological features assessed in this study encompass tumor imaging staging, location, and circumferential resection margin (CRM) for primary tumors, as well as the number of visible lymph nodes and suspected metastatic lymph nodes. Receiver operating characteristic (ROC) and decision curve analysis (DCA) were conducted to evaluate whether the diagnostic efficiency was improved.

RESULTS

The performance of model 3 (including clinicopathologic characteristics and DCER-Features) was the best (AUC: 0.856, 95% CI 0.778-0.886), whereas it was 0.796 (95% CI 0.720-0.828) for model 2 and 0.709 (95% CI 0.612-0.778) for model 1 (DeLong test: model 1 vs model 2, p = 0.004; model 2 vs model 3, p = 0.037; model 1 vs model 3, p < 0.001). The decision curves indicated that the net benefit of model 3 was higher than the other two models at each referral threshold. The calibration plot of the three models revealed an excellent predictive accuracy.

CONCLUSION

This study suggests that DCER-Features have added value for the clinicopathological model to predict metachronous metastasis in patients with rectal cancers.

Risk and location of distant metastases in patients with locally advanced rectal cancer after total neoadjuvant treatment or chemoradiotherapy in the RAPIDO trial

INTRODUCTION

Although optimising rectal cancer treatment has reduced local recurrence rates, many patients develop distant metastases (DM). The current study investigated whether a total neoadjuvant treatment strategy influences the development, location, and timing of metastases in patients diagnosed with high-risk locally advanced rectal cancer included in the Rectal cancer And Pre-operative Induction therapy followed by Dedicated Operation (RAPIDO) trial.

MATERIAL AND METHODS

Patients were randomly assigned to short-course radiotherapy followed by 18 weeks of CAPOX or FOLFOX4 before surgery (EXP), or long-course chemoradiotherapy with optional postoperative chemotherapy (SC-G). Assessments for metastatic disease were performed pre- and post-treatment, during surgery, and 6, 12, 24, 36, and 60 months postoperatively. From randomisation, differences in the occurrence of DM and first site of metastasis were evaluated.

RESULTS

In total, 462 patients were evaluated in the EXP and 450 patients in the SC-G groups. The cumulative probability of DM at 5 years after randomisation was 23% [95% CI 19-27] and 30% [95% CI 26-35] (HR 0.72 [95% CI 0.56-0.93]; P = 0.011) in the EXP and SC-G, respectively. The median time to DM was 1.4 (EXP) and 1.3 years (SC-G). After diagnosis of DM, median survival was 2.6 years [95% CI 2.0-3.1] in the EXP and 3.2 years [95% CI 2.3-4.1] in the SC-G groups (HR 1.39 [95% CI 1.01-1.92]; P = 0.04). First occurrence of DM was most often in the lungs (60/462 [13%] EXP and 55/450 [12%] SC-G) or the liver (40/462 [9%] EXP and 69/450 [15%] SC-G). A hospital policy of postoperative chemotherapy did not influence the development of DM.

CONCLUSIONS

Compared to long-course chemoradiotherapy, total neoadjuvant treatment with short-course radiotherapy and chemotherapy significantly decreased the occurrence of metastases, particularly liver metastases.

Dentate line invasion as a predictive factor of poor distant relapse-free survival in locally advanced lower rectal cancer with anal sphincter involvement

Background

While an important surgical landmark of the dentate line has been established for locally advanced lower rectal cancer (LALRC), the prognostic significance of dentate line invasion (DLI) has not been well defined. This study aimed to explore the impact of DLI on prognosis in LALRC patients with anal sphincter involvement after neoadjuvant chemoradiotherapy followed by surgery.

Methods

We analyzed 210 LALRC patients and classified them into DLI group (n = 45) or non-DLI group (n = 165). The exact role of DLI in survival and failure patterns was assessed before and after propensity-score matching(PSM). Finally, 50 patients were matched.

Results

Before matching, patients in the DLI group had poorer 5-year distant relapse-free survival (DRFS) (P < 0.001), disease-free survival (DFS) (P < 0.001), and overall survival (OS) (P = 0.022) than those in the non-DLI group, with the exception of local recurrence-free survival (LRFS) (P = 0.114). After PSM, the 5-year DRFS, DFS, OS, and LRFS were 51.7% vs. 79.8%(P = 0.026), 51.7% vs. 79.8%(P = 0.029), 71.6% vs. 85.4%(P = 0.126), and 85.7% vs. 92.0%(P = 0.253), respectively, between the two groups. DLI was also an independent prognostic factor for poor DRFS with (Hazard ratio [HR] 3.843, P = 0.020) or without matching (HR 2.567, P = 0.001). The DLI group exhibited a higher rate of distant metastasis before (44.4% vs. 19.4%, P < 0.001) and after matching (48.0% vs. 20.0%, P = 0.037) and similar rates of locoregional recurrence before (13.3% vs.7.9%, P = 0.729) and after matching (16.0% vs.12.0%, P = 1.000).

Conclusions

DLI may portend worse DRFS and distant metastasis in LALRC patients with anal sphincter involvement, and this may be an important variable to guide clinicians.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10299-8.

Patterns and predictors of recurrence after laparoscopic resection of rectal cancer

Purpose

This study was designed to evaluate the patterns and predictors of recurrence in patients who underwent laparoscopic resection of rectal cancer.

Methods

Patients with rectal cancer receiving laparoscopic resection between April 2009 and March 2016 were retrospectively analyzed. The association of recurrence with clinicopathological characteristics was evaluated using multivariate analyses.

Results

A total of 405 consecutive patients were included in our study. Within a median follow-up time of 62 months, 77 patients (19.0%) experienced disease recurrence: 10 (2.5%) had locoregional recurrence (LR), 61 (15.1%) had distant metastasis (DM), and 6 (1.5%) developed LR and DM synchronously. The lung was the most common site of metastasis. Multivariate analyses indicated that involved circumferential resection margin (CRM) was the only independent predictor for LR (OR=13.708, 95% CI 3.478-54.026, P&lt;0.001), whereas elevated baseline level of CA19-9 (OR=3.299, 95% CI 1.461-7.449, P=0.032), advanced pN stage (OR=2.292, 95% CI 1.177-4.462, P=0.015) and harvested lymph nodes less than 12 (OR=2.418, 95% CI 1.245-4.695, P=0.009) were independently associated with DM. Patients receiving salvage surgery showed superior 3-year survival compared with palliative treatment after relapse (90.9% vs. 20.5%; P=0.017). The estimated 5-year DFS and CSS for the entire cohort was 80.2% and 83.1%, respectively.

Conclusions

DM was more common than LR after laparoscopic resection of rectal cancer, and there were several clinicopathological factors related to LR and DM. Involved CRM and suboptimal lymph node yield were adverse surgery-related factors of tumor recurrence, which should be paid more attention to during the operation.

Identifying the long-term survival beneficiary of preoperative radiotherapy for rectal cancer in the TME era

This study was to verify the long-term survival efficacy of preoperative radiotherapy (preRT) for locally advanced rectal cancer (LARC) patients and identify potential long-term survival beneficiary. Using the Surveillance, Epidemiology, and End Results (SEER) database, 7582 LARC patients were eligible for this study between 2011 and 2015 including 6066 received preRT and 1516 received surgery alone. Initial results showed that preRT prolonged the median overall survival (OS) of LARC patients (HR 0.86, 95% CI 0.75-0.98, P < 0.05), and subgroup analysis revealed that patients with age > 65 years, stage III, T3, T4, N2, tumor size > 5 cm, tumor deposits, and lymph nodes dissection (LND) ≥ 12 would benefit more from preRT (all P < 0.05). A prognostic predicting nomogram was constructed using the independent risk factors of OS identified by multivariate Cox analysis (all P < 0.05), which exhibited better prediction of OS than the 8th American Joint Cancer Committee staging system on colorectal cancer. According to the current nomogram, patients in the high-risk subgroup had a shorter median OS than low-risk subgroup (HR 2.62, 95% CI 2.25-3.04, P < 0.001), and preRT could benefit more high-risk patients rather than low-risk patients. Hence, we concluded that preRT might bring long-term survival benefits to LARC patients, especially those with high risk.

Prognostic significance of pathological sub-classification of pT3 rectal cancer

PURPOSE

Patients with pT3 rectal cancer represent a heterogeneous prognostic group. A more accurate histological sub-classification of pT status has been suggested as an improvement of the TNM staging system. The aim of the study was to evaluate the prognostic implication of a histopathologic sub-classification of pT3 rectal cancer.

METHODS

In this retrospective single-center study, pT3 rectal cancer patients who underwent surgery from January 2000 to December 2018 were evaluated. The maximum depth of tumor invasion beyond the muscularis propria was recorded. A ROC curve identified the best prognostic cutoff value to classify patients in two prognostic groups. Survival curves were estimated by the Kaplan-Meier method, and univariate and multivariate analyses with the Cox regression model were used to find independent factors influencing survival.

RESULTS

Overall, 203 patients were included. Four millimeters was identified as the best cutoff value: 82 patients showed a depth of invasion < 4 mm (group A) and 121 ≥ 4 mm (group B). Both the estimated 5-year OS and DFS were statistically better in group A than in group B (OS: 83.9% vs 62.2%, p < 0.01; DFS: 78.3% vs 40.6%, p < 0.01). The depth of tumor invasion was an independent risk factor for OS (HR 2.25, 95% CI 1.26-3.99, p = 0.006) and DFS (HR 2.30, 95% CI 1.40-3.78, p = 0.001).

CONCLUSION

Our findings suggest that a sub-classification of pT3 rectal cancer, based on the depth of tumor invasion, should be considered to be introduced in the TNM staging system.

The Correlation Between Survival Benefit of Preoperative Radiotherapy and Pretreatment Carcinoembryonic Antigen Level in Locally Advanced Rectal Cancer

Background

Preoperative radiotherapy followed by radical surgery is the standard treatment for locally advanced rectal cancer; however, its long-term survival benefit remains controversial. This study aimed to determine the relationship between pretreatment carcinoembryonic antigen (CEA) levels and the long-term prognosis of preoperative radiotherapy in locally advanced rectal cancer (LARC) patients.

Methods

Data of LARC patients who underwent surgery between 2011 and 2015 were identified from the Surveillance, Epidemiology, and End Results (SEER) database, and patients were accordingly divided into surgery (S) group and radiotherapy followed by surgery (RT+S) group. The primary outcomes were cancer-specific survival (CSS) and cancer-specific mortality (CSM). CSS was evaluated using Kaplan-Meier analysis, while CSM was evaluated using a competitive risk model. Subgroup analysis was also conducted, which was stratified by pretreatment CEA levels.

Results

A total of 2,760 patients were eligible for this study, including 350 (12.7%) patients in the S group and 2,410 (87.3%) in the RT+S group. There were no significant differences in the CSS and CSM rates at 1, 3, and 4 years between the S and RT+S groups before and after PSM (all p > 0.05). Pretreatment CEA levels were independently associated with CSS and CSM after adjusting for age, sex, stage, pathological factors, and treatment factors (all p < 0.05). Subgroup analysis showed that preoperative radiotherapy would benefit patients with elevated CEA in terms of CSS and CSM (both p < 0.05) but not those patients with normal CEA (both p > 0.05). Further analysis showed that preoperative radiotherapy was an independent protective factor for CSS and CSM in patients with elevated CEA levels (both p < 0.05).

Conclusions

Pretreatment CEA level may be considered a potential biomarker to screen LACR patients who would benefit from preoperative radiotherapy in terms of long-term prognosis.

Impact of neoadjuvant chemoradiotherapy on the local recurrence and distant metastasis pattern of locally advanced rectal cancer: a propensity score-matched analysis

BACKGROUND

Previous studies have demonstrated different predominant sites of distant metastasis between patients with and without neoadjuvant chemoradiotherapy (NCRT). This study aimed to explore whether NCRT could influence the metastasis pattern of rectal cancer through a propensity score-matched analysis.

METHODS

In total, 1296 patients with NCRT or post-operative chemoradiotherapy (PCRT) were enrolled in this study between January 2008 and December 2015. Propensity score matching was used to correct for differences in baseline characteristics between the two groups. After propensity score matching, the metastasis pattern, including metastasis sites and timing, was compared and analyzed.

RESULTS

After propensity score matching, there were 408 patients in the PCRT group and 245 patients in the NCRT group. NCRT significantly reduced local recurrence (4.1% vs. 10.3%, P = 0.004), but not distant metastases (28.2% vs. 27.9%, P = 0.924) compared with PCRT. In both the NCRT and PCRT groups, the most common metastasis site was the lung, followed by the liver. The NCRT group developed local recurrence and distant metastases later than the PCRT group (median time: 29.2 [18.8, 52.0] months vs. 18.7 [13.3, 30.0] months, Z = -2.342, P = 0.019; and 21.2 [12.2, 33.8] vs. 16.4 [9.3, 27.9] months, Z = -1.765, P = 0.035, respectively). The distant metastases occurred mainly in the 2nd year after surgery in both the PCRT group (39/114, 34.2%) and NCRT group (21/69, 30.4%). However, 20.3% (14/69) of the distant metastases appeared in the 3rd year in the NCRT group, while this number was only 13.2% (15/114) in the PCRT group.

CONCLUSIONS

The predominant site of distant metastases was the lung, followed by the liver, for both the NCRT group and PCRT group. NCRT did not influence the predominant site of distant metastases, but the NCRT group developed local recurrence and distant metastases later than the PCRT group. The follow-up strategy for patients with NCRT should be adjusted and a longer intensive follow-up is needed.

Pathologic-Based Nomograms for Predicting Overall Survival and Disease-Free Survival Among Patients with Locally Advanced Rectal Cancer

Purpose

Preoperative neoadjuvant therapy is standard before surgery for locally advanced rectal cancer in current clinical treatment. However, patients with the same clinical TNM stage before treatment vary in clinical outcomes. More and more studies noted that pathological findings after preoperative neoadjuvant therapy are better prognostic factors to determine prognosis than clinical TNM stage in patients with locally advanced rectal cancer. The purpose of this study is to develop and validate models based on pathological findings to predict overall survival (OS) and disease-free survival (DFS).

Patients and Methods

A total of 3026 patients from two hospitals were included. The endpoint was OS and DFS. Significant predictors of OS on multivariate analysis were used to establish the nomogram.

Results

The Harrell’s C index for OS prediction was 0.72 (95% confidence interval [CI], 0.68 to 0.77) in the training cohort, 0.66 (95% CI, 0.60 to 0.72) and 0.68 (95% CI, 0.64 to 0.73) in the internal and external validation cohorts. Using this nomogram, high- and low-risk groups for OS were defined in the training cohort. The 3-year OS was 78.1% (95% CI: 72.4–84.2%) for the high-risk group and 95% (95% CI: 93.6–96.5%) in the low-risk group (HR: 4.42, 95% CI: 3.22–6.05; P<0.001). This finding was also applied in the two external cohorts. Similarly, a nomogram that contained the same indices was developed and validated to predict for DFS.

Conclusion

Nomograms based on pathological findings are a reliable tool to predict 3-year OS and DFS rate in patients with locally advanced rectal cancer.

Trans-anal total mesorectal excision in low rectal cancers: Preliminary oncological results of a comparative study

OBJECTIVE

The management of lower rectal cancers is a therapeutic challenge both from the oncological and functional viewpoints. The aim of this study is to assess the oncological results and postoperative morbidity after transanal total mesorectal excision (TaTME) for low rectal cancer.

MATERIAL AND METHODS

In this monocentric retrospective study, we compared the quality of carcinologic resection and the morbidity-mortality between a group of 20 patients undergoing TaTME and 21 patients treated by abdomino-perineal resection (APR) between 2016 to 2019.

RESULTS

More patients had a positive circumferential resection margin (CRM) (≤1mm) in the APR group (47.6% vs. 5%; P<0.0036). The difference in the rates of grades I-II and III-IV complications (Clavien-Dindo classification) between the two groups was not statistically significant (50% vs. 57.1% and 5% vs. 9.5% in TaTME and APR, respectively; P=0.7579, P=1.00). The median follow-up was longer in the TaTME group (20 months vs. 11 months; P=0.58). The local recurrence rate did not differ between the two groups (5% vs. 4.8%; P=1.00) CONCLUSION: TaTME provides a reliable total mesorectal resection with an acceptable CRM. However, like any new technique, it requires experience and the learning curve is long.

Beware of Early Relapse in Rectal Cancer Patients Treated With Preoperative Chemoradiotherapy

PURPOSE

Recurrence patterns in rectal cancer patients treated with preoperative chemoradiotherapy (PCRT) are needed to evaluate for establishing tailored surveillance protocol.

METHODS

This study included 2,215 patients with locally-advanced mid and low rectal cancer treated with radical resection between January 2005 and December 2012. Recurrence was evaluated according to receipt of PCRT; PCRT group (n = 1,258) and no-PCRT group (n = 957). Early recurrence occurred within 1 year of surgery and late recurrence after 3 years. The median follow-up duration was 65.7 ± 29 months.

RESULTS

The overall recurrence rate was similar between the PCRT and no-PCRT group (25.8% vs. 24.9%, P = 0.622). The most common initial recurrence site was the lungs in both groups (50.6% vs. 49.6%, P = 0.864), followed by the liver, which was more common in the no-PCRT group (22.5% vs. 33.6%, P = 0.004). Most of the recurrence occurred within 3 years after surgery in both groups (85.3% vs. 85.8%, P = 0.862). Early recurrence was more common in the PCRT group than in the no-PCRT group (43.1% vs. 32.4%, P = 0.020). Recurrence within the first 6 months after surgery was significantly higher in the PCRT group than in the no-PCRT group (18.8% vs. 7.6%, P = 0.003). Lung (n = 27, 44.3%) and liver (n = 22, 36.1%) were the frequent the first relapsed site within 6 months after surgery in PCRT group.

CONCLUSION

Early recurrence within the first 1 year after surgery was more common in patients treated with PCRT. This difference would be considered for surveillance protocols and need to be evaluated in further studies.

Stem Cell Marker Expression in Early Stage Colorectal Cancer is Associated with Recurrent Intestinal Neoplasia

BACKGROUND

Colorectal cancer (CRC) ranks second in cancer deaths worldwide and presents multiple management challenges, one of which is identifying high risk stage II disease that may benefit from adjuvant therapy. Molecular biomarkers, such as ones that identify stem cell activity, could better stratify high-risk cohorts for additional treatment.

METHODS

To identify possible biomarkers of high-risk disease in early-stage CRC, a discovery set (n = 66) of advanced-stage tumors were immunostained with antibodies to stemness proteins (CD166, CD44, CD26, and LGR5) and then digitally analyzed. Using a second validation cohort (n = 54) of primary CRC tumors, we analyzed protein and gene expression of CD166 across disease stages, and extended our analyses to CD166-associated genes (LGR5, ASCL2, BMI1, POSTN, and VIM) by qRT-PCR.

RESULTS

Stage III and metastatic CRC tumors highly expressed stem cell-associated proteins, CD166, CD44, and LGR5. When evaluated across stages, CD166 protein expression was elevated in advanced-stage compared to early-stage tumors. Notably, a small subset of stage I and II cancers harbored elevated CD166 protein expression, which correlated with development of recurrent cancer or adenomatous polyps. Gene expression analyses of CD166-associated molecules revealed elevated ASCL2 in primary tumors from patients who recurred.

CONCLUSIONS

We identified a protein signature prognostic of aggressive disease in early stage CRC. Stem cell-associated protein and gene expression identified a subset of early-stage tumors associated with cancer recurrence and/or subsequent adenoma formation. Signatures for stemness offer promising fingerprints for stratifying early-stage patients at high risk of recurrence.

Influence of tumor location on short- and long-term outcomes after laparoscopic surgery for rectal cancer: a propensity score matched cohort study

BACKGROUND

This study aimed to evaluate the short- and long-term outcomes after laparoscopic resection for low rectal cancer (LRC) compared with mid/high rectal cancer (M/HRC).

METHODS

Patients with rectal cancer undergoing laparoscopic resection with curative intent were retrospectively reviewed between 2009 and 2015. After matched 1:1 by using propensity score analysis, perioperative and oncological outcomes were compared between LRC and M/HRC groups. Multivariate analysis was performed to identify independent factors of overall survival (OS) and disease-free survival (DFS).

RESULTS

Of 373 patients who met the criteria for inclusion, 198 patients were matched for the analysis. Laparoscopic surgery for LRC required longer operative time (P<0.001) and more blood loss volume (P = 0.015) compared with M/HRC, and the LRC group tended to have a higher incidence of postoperative complications (16.2% vs. 8.1%, P = 0.082). There was no significant difference in local recurrence between the two groups (9.1% vs. 4.0%, P = 0.251), whereas distant metastasis was inclined to be more frequent in LRC patients compared with M/HRC (21.2% vs. 12.1%, P = 0.086). The LRC group showed significantly inferior 5-year OS (77.0% vs. 86.4%, P = 0.033) and DFS (71.2% vs. 86.2%, P = 0.017) compared with the M/HRC group. Multivariate analysis indicated that tumor location was an independent predictor of DFS (HR = 2.305, 95% CI 1.203-4.417, P = 0.012).

CONCLUSION

Tumor location of the rectal cancer significantly affected the clinical and oncological outcomes after laparoscopic surgery, and it was an independent predictor of DFS.

Translational Potential of MicroRNAs for Preoperative Staging and Prediction of Chemoradiotherapy Response in Rectal Cancer

Colorectal cancer is the third most common cancer and the second cause of cancer-related deaths. Rectal cancer presents roughly one-third of all colorectal cancer cases and differs from it on both anatomical and molecular levels. While standard treatment of colon cancer patients is radical surgery, rectal cancer is usually treated with pre-operative chemoradiotherapy followed by total mesorectal excision, which requires precise estimation of TNM staging. Unfortunately, stage evaluation is based solely on imaging modalities, and they often do not correlate with postoperative pathological findings. Moreover, approximately half of rectal cancer patients do not respond to such pre-operative therapy, so they are exposed to its toxic effects without any clinical benefit. Thus, biomarkers that could precisely predict pre-operative TNM staging, and especially response to therapy, would significantly advance rectal cancer treatment—but till now, no such biomarker has been identified. In cancer research, microRNAs are emerging biomarkers due to their connection with carcinogenesis and exceptional stability. Circulating miRNAs are promising non-invasive biomarkers that could allow monitoring of a patient throughout the whole therapeutic process. This mini-review aims to summarize the current knowledge on miRNAs and circulating miRNAs involved in the prediction of response to treatment and pre-operative staging in rectal cancer patients.