A Distal Resection Margin of ≤1 mm and Rectal Cancer Recurrence After Sphincter-Preserving Surgery: The Role of a Positive Distal Margin in Rectal Cancer Surgery

Risk factors for local recurrence of rectal cancer after curative surgery: A single-center retrospective study

PURPOSE

Approximately 7% of patients with rectal cancer experience local recurrence within 5 years of curative surgery. A positive circumferential resection margin (CRM) is among the most significant risk factors. Other reported risk factors include histopathologic type, anastomotic leakage, positive distal margins, and more recently, the anterior localization of the tumor. In this retrospective cohort study, we aimed to assess risk factors for local recurrence in our institution, with a focus on tumor localization as an independent negative predictive factor.

PATIENTS AND METHODS

From 2007 to 2018, all patients with stage II or III rectal cancer were included in this study. Patients underwent neoadjuvant chemoradiotherapy followed by surgical resection with total mesorectal excision. The tumor's anterior or posterior localization was assessed by preoperative endosonography or magnetic resonance imaging. Risk factors for local recurrence were assessed using univariate and multivariate regression analyses.

RESULTS

A total of 128 patients were included. The 3-year and 5-year local recurrence rates were 4.7% and 7%, respectively. In univariate and multivariate analyses, the histologic type of a poorly differentiated tumor (P=0.001) and a positive CRM (P=0.001) were correlated with local recurrence. Tumor localization (anterior or posterior) was not identified as a statistically significant factor associated with local recurrence.

CONCLUSION

Positive CRM and a poorly differentiated tumor histological subtype were found to be independent risk factors for local recurrence. In contrast to previous findings, anterior localization was not identified as an independent risk factor for local recurrence in our patient cohort.

Real-time classification of tumour and non-tumour tissue in colorectal cancer using diffuse reflectance spectroscopy and neural networks to aid margin assessment

BACKGROUND

Colorectal cancer is the third most commonly diagnosed malignancy and the second leading cause of mortality worldwide. A positive resection margin following surgery for colorectal cancer is linked with higher rates of local recurrence and poorer survival. We investigated diffuse reflectance spectroscopy (DRS) to distinguish tumour and non-tumour tissue in ex vivo colorectal specimens, to aid margin assessment and provide augmented visual maps to the surgeon in real-time.

METHODS

Patients undergoing elective colorectal cancer resection surgery at a London-based hospital were prospectively recruited. A hand-held DRS probe was used on the surface of freshly resected ex vivo colorectal tissue. Spectral data was acquired for tumour and non-tumour tissue. Binary classification was achieved using conventional machine learning classifiers and a convolutional neural network (CNN), which were evaluated in terms of sensitivity, specificity, accuracy and the area under the curve.

RESULTS

A total of 7692 mean spectra were obtained for tumour and non-tumour colorectal tissue. The CNN-based classifier was the best performing machine learning algorithm, when compared to contrastive approaches, for differentiating tumour and non-tumour colorectal tissue, with an overall diagnostic accuracy of 90.8% and area under the curve of 96.8%. Live on-screen classification of tissue type was achieved using a graduated colourmap.

CONCLUSION

A high diagnostic accuracy for a DRS probe and tracking system to differentiate ex vivo tumour and non-tumour colorectal tissue in real-time with on-screen visual feedback was highlighted by this study. Further in vivo studies are needed to ensure integration into a surgical workflow.

Close distal margin is associated with locoregional rectal cancer recurrence: A multicenter study

BACKGROUND AND OBJECTIVES

The importance of the radial margin for rectal cancer resection is well understood. However, surgeons have deemphasized the distal margin, accepting very close distal margins to perform sphincter-preserving surgery. We hypothesized that distal margins < 1 cm would be an independent risk factor for locoregional recurrence. The objective was to determine whether close distal margins are associated with increased locoregional recurrence risk.

METHODS

This was a multi-institutional retrospective cohort study conducted at six academic medical centers including patients who received low anterior resection surgery for primary rectal cancer between 2007 and 2018.

RESULTS

Of 556 low anterior resection patients, the rate of close distal margin was 12.8% (n = 71), and the locoregional recurrence rate was 5.0% (n = 28). The locoregional recurrence rate for close distal margin cases was 9.9% (n = 7) compared to 4.3% (n = 21) for distal margins ≥1.0 cm. In multivariable analysis, the only factor significantly associated with locoregional recurrence was close distal margin (adjusted odds ratio: 2.80, confidence interval: 1.08-7.25, p = 0.035).

CONCLUSIONS

Rectal cancer patients with close distal margins (<1 cm) following low anterior resection had a significantly higher risk for locoregional recurrence. Therefore, the decision to perform low anterior resection with margins < 1 cm should be taken with caution.

Changes in Oncological Surgical Principles Driven by Advances in Preoperative Treatments

From a surgical point of view, the development of preoperative oncological treatment has had a profound effect on the surgical treatment trends of cancer as well as on the outcomes of cancer patients. Consequently, these changes have challenged formerly entrenched oncological surgical principles. In our short report, we aimed to summarize the main shifts regarding the surgical principles of cancer treatment due to the development of preoperative oncological therapy in recent years. As a result of successful preoperative treatment, surgeons may perform less radical surgeries, the required free resection margin has been narrowed down to a few millimeters in dimension and preoperative treatment is justified in both definitely resectable tumors and in oligometastatic tumors as well. For prognosis assessment, the post-preoperative oncological treatment stage is now considered decisive, rather than the pretreatment stage as previously thought. Other changes include the introduction of the watch and wait strategy and the reverse order of treatment of the primary tumor and metastasis. Observing the continuously improving outcomes of cancer patients and the developments in oncological treatment modalities, a further expansion of the indication of preoperative treatments is to be expected.

In Vitro Antibody Quantification with Hyperspectral Imaging in a Large Field of View for Clinical Applications

Hyperspectral imaging (HSI) is a non-invasive, contrast-free optical-based tool that has recently been applied in medical and basic research fields. The opportunity to use HSI to identify exogenous tumor markers in a large field of view (LFOV) could increase precision in oncological diagnosis and surgical treatment. In this study, the anti-high mobility group B1 (HMGB1) labeled with Alexa fluorophore (647 nm) was used as the target molecule. This is the proof-of-concept of HSI’s ability to quantify antibodies via an in vitro setting. A first test was performed to understand whether the relative absorbance provided by the HSI camera was dependent on volume at a 1:1 concentration. A serial dilution of 1:1, 10, 100, 1000, and 10,000 with phosphatase-buffered saline (PBS) was then used to test the sensitivity of the camera at the minimum and maximum volumes. For the analysis, images at 640 nm were extracted from the hypercubes according to peak signals matching the specificities of the antibody manufacturer. The results showed a positive correlation between relative absorbance and volume (r = 0.9709, p = 0.0013). The correlation between concentration and relative absorbance at min (1 µL) and max (20 µL) volume showed r = 0.9925, p < 0.0001, and r = 0.9992, p < 0.0001, respectively. These results demonstrate the HSI potential in quantifying HMGB1, hence deserving further studies in ex vivo and in vivo settings.

Impact of Microscopically Positive (≤1 mm) Distal Margins on Disease Recurrence in Rectal Cancer Treated by Neoadjuvant Chemoradiotherapy

BACKGROUND

The adequate distal resection margin is still controversial in rectal cancer treated by neoadjuvant chemoradiotherapy (nCRT). The aim of this study was to assess the impact of a distal margin of ≤1 mm on locoregional recurrence-free survival (LRRFS).

METHODS

Among 255 patients treated with nCRT and surgery at the National Cancer Institute of Milan, 83 (32.5%) had a distal margin of ≤1 mm and 172 (67.5%) had a distal margin of >1 mm. Survival analyses were performed to assess the impact of distal margin on 5-year LRRFS, as well as Cox survival analysis. The role of distal margin on survival was analyzed according to different tumor regression grades (TRGs).

RESULTS

The overall 5-year LRRFS rate was 77.6% with a distal margin of ≤1 mm vs. 88.3% with a distal margin of >1 mm (Log-rank p = 0.09). Only stage ypT4 was an independent predictor of worse LRRFS (HR 15.14, p = 0.026). The 5-year LRRFS was significantly lower in TRG3-5 patients with a distal margin of ≤1 mm compared to those with a distal margin of >1 mm (68.5% vs. 84.2%, p = 0.027), while no difference was observed in case of TRG1-2 (p = 0.77).

CONCLUSIONS

Low-responder rectal cancers after nCRT still require a distal margin of >1 mm to reduce the high likelihood of local relapse.

Real-time in vivo distal margin selection using confocal laser endomicroscopy in transanal total mesorectal excision for rectal cancer

BACKGROUND

Transanal total mesorectal excision (TaTME) allows patients with ultralow rectal cancer to be treated with sphincter-saving surgery. However, accurate delineation of the distal resection margin (DRM), which is essential to achieve R0 resection for low rectal cancer in TaTME, is technically demanding.

AIM

To assess the feasibility of optical biopsy using probe-based confocal laser endomicroscopy (pCLE) to select the DRM during TaTME for low rectal cancer.

METHODS

A total of 43 consecutive patients who were diagnosed with low rectal cancer and scheduled for TaTME were prospectively enrolled from January 2019 to January 2021. pCLE was used to determine the distal edge of the tumor as well as the DRM during surgery. The final pathological report was used as the gold standard. The diagnostic accuracy of pCLE examination was calculated.

RESULTS

A total of 86 pCLE videos of 43 patients were included in the analyses. The sensitivity, specificity and accuracy of real-time pCLE examination were 90.00% [95% confidence interval (CI): 76.34%-97.21%], 86.96% (95%CI: 73.74%-95.06%) and 88.37% (95%CI: 79.65%-94.28%), respectively. The accuracy of blinded pCLE reinterpretation was 86.05% (95%CI: 76.89%-92.58%). Furthermore, our results show satisfactory interobserver agreement (κ = 0.767, standard error = 0.069) for the detection of cancer tissue by pCLE. There were no positive DRMs (≤ 1 mm) in this study. The median DRM was 7 mm [interquartile range (IQR) = 5-10 mm]. The median Wexner score was 5 (IQR = 3-6) at 6 mo after stoma closure.

CONCLUSION

Real-time in vivo pCLE examination is feasible and safe for selecting the DRM during TaTME for low rectal cancer (clinical trial registration number: NCT04016948).

The Impact of Narrow and Infiltrated Distal Margin After Proctectomy for Rectal Cancer on Patients' Outcomes: a Systematic Review and Meta-analysis

Rectal cancer is a common tumor within a difficult anatomic constraint. Total mesorectal excision with longitudinal and circumferential free margins is considered imperative for good prognosis. In this article, the authors systematically reviewed all published literature with specific Mesh terms until the end of year 2019. Thereafter, retrieved articles were assessed using the Newcastle-Ottawa Scale and meta-analysis was conducted comparing local recurrence among 1-cm, 5-mm, and narrow (< 1-mm)/infiltrated margins. Thirty-nine articles were included in the study. Macroscopic distal margin < 1 cm carried a higher incidence of recurrence for those who did not receive neoadjuvant radiation, without affecting neither estimated overall nor disease-free survival. Less than 5-mm margin after radiation therapy is accepted oncologically. Infiltrated margins and narrow margins (< 1 mm) microscopically are associated with higher incidence of local recurrence and shorter overall and disease-free survival. Surgeons should aim at 1-cm safety margin in radiotherapy-naïve patients and microscopic free margin > 1 mm for those who received neoadjuvant therapy. The cost/benefit of reoperation for patients with infiltrated margins is still inadequately studied.

Association of levels of metabolites with the safe margin of rectal cancer surgery: a metabolomics study

Background

Rectal cancer is one of the most lethal of gastrointestinal malignancies. Metabonomics has gradually developed as a convenient, inexpensive and non-destructive technique for the study of cancers.

Methods

A total of 150 tissue samples from 25 rectal cancer patients were analyzed by liquid chromatography–mass spectrometry (LC–MS), and 6 tissue samples were collected from each patient (group 1: tumor; group 2: 0.5 cm from tumor; group 3:1 cm from tumor; group 4:2 cm from tumor; group 5:3 cm from tumor and group 6:5 cm from tumor). The differential metabolites of tumor tissues and 5 cm from the tumor (normal tissues) were first selected. The differential metabolites between tumor tissues and normal tissues were regrouped by hierarchical clustering analysis, and further selected by discriminant analysis according to the regrouping of clustering results. The potential safe margin of clinical T(cT)1,cT2 stage rectal cancer and cT3,cT4 stage rectal cancer at the metabolomic level was further identified by observing the changes in the level of differential metabolites within the samples from group 1 to group 6.

Results

We found 22 specific metabolites to distinguish tumor tissue and normal tissue. The most significant changes in metabolite levels were observed at 0.5 cm (cT1, cT2) and 2.0 cm (cT3, cT4) from the tumor, while the changes in the tissues afterwards showed a stable trend.

Conclusions

There are differential metabolites between tumor tissues and normal tissues in rectal cancer. Based on our limited sample size, the safe distal incision margin for rectal cancer surgery in metabolites may be 0.5 cm in patients with cT1 and cT2 stage rectal cancer and 2.0 cm in patients with cT3 and cT4 stage rectal cancer.

Predictors of Definitive Treatment Interruptions of Long-Course Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer

Introduction To identify predictors of definitive treatment interruptions (DTI) of the neoadjuvant long-course radiotherapy (LCRT) in locally advanced rectal cancer (LARC), and to determine their impact on clinical outcomes. Methods Patients with stage II-III LARC treated between 2009-2018 were retrospectively analyzed (n=101, median FU 49.5 months). Logistic regression models evaluated the impact of relevant clinical variables on grade 3 or greater (G3+) acute toxicity, definitive treatment interruption (DTI), pCR, and definitive ostomy (dOST) rates. The secondary outcomes were LRC, MFS, PFS, CSS, and OS. Results The incidences of grade 3 and 4 toxicities were 25.3%, and 1.1%, respectively. The most common G3+ toxicities were peri-anal dermatitis (14.7%) and diarrhea (7.4%), which were more frequent in females (p=0.040) and tumors close to the anal verge (p=0.019). In this study, 11 patients (10.9%) developed DTI, which was associated with these G3+ events (p<0.001). Resection occurred after 7.1 weeks (median, IQR:6.1-8.9). Downstaging occurred in 57.4% (17.8% pCR), 88% achieved negative margins and the dOST rate was 56.4%. The five-year LRC, MFS, PFS, CSS and OS were: 94.4%, 78.9%, 74.7%, 85.2% and 81.6%, respectively. DTI events did not impact any outcome. The factors associated with loco-regional failure were close/positive margins (p<0.001) and stage ypIII (p=0.002). Conclusions: Tumors close to the anal verge and female sex were associated with increased G3+ toxicity, which was predictive of DTI. The resultant partial/complete omission of the planned boost, however, dose did not increase the chance of LR. Further studies to clarify the benefit and optimal timing to deliver the boost are warranted, especially for positive margins.

Artificial Intelligence in Colorectal Cancer Surgery: Present and Future Perspectives

Artificial intelligence (AI) and computer vision (CV) are beginning to impact medicine. While evidence on the clinical value of AI-based solutions for the screening and staging of colorectal cancer (CRC) is mounting, CV and AI applications to enhance the surgical treatment of CRC are still in their early stage. This manuscript introduces key AI concepts to a surgical audience, illustrates fundamental steps to develop CV for surgical applications, and provides a comprehensive overview on the state-of-the-art of AI applications for the treatment of CRC. Notably, studies show that AI can be trained to automatically recognize surgical phases and actions with high accuracy even in complex colorectal procedures such as transanal total mesorectal excision (TaTME). In addition, AI models were trained to interpret fluorescent signals and recognize correct dissection planes during total mesorectal excision (TME), suggesting CV as a potentially valuable tool for intraoperative decision-making and guidance. Finally, AI could have a role in surgical training, providing automatic surgical skills assessment in the operating room. While promising, these proofs of concept require further development, validation in multi-institutional data, and clinical studies to confirm AI as a valuable tool to enhance CRC treatment.

Intraoperative adverse events as a risk factor for local recurrence of rectal cancer after resection surgery

AIM

Failure to achieve a radical resection as well as intraoperative rectal perforation are important risk factors for local recurrence after rectal cancer surgery, but the importance of other intraoperative adverse events for the prognosis is unknown. The aim of this study was to assess the occurrence of intraoperative adverse events during rectal cancer surgery, and to determine whether these were associated with an increased risk of local recurrence.

METHODS

A retrospective population-based cohort study was undertaken, including all patients in Region Västra Götaland, Sweden, who had undergone primary resection surgery for rectal cancer diagnosed between 2010 and 2014, registered in the Swedish Colorectal Cancer Registry. Data were retrieved from the registry and through review of the medical records.

RESULTS

In total, 1208 patients were included in the study of whom 78 (6%) developed local recurrence during the follow-up period of at least 5 years. Intraoperative adverse events were common and occurred in 62/78 (79%) of patients with local recurrence compared to 604/1130 (53%) of patients without local recurrence. In multivariate analysis intraoperative adverse events were found to be an independent risk factor for local recurrence of rectal cancer, as were nonradical resection, a high pathological T stage, the presence of lymph node metastases, type of surgery and refraining from rectal washout during anterior resection and Hartmann's procedure.

CONCLUSIONS

Intraoperative adverse events were found to be an independent risk factor for local recurrence of rectal cancer and could possibly be used together with other known risk factors to select patients for intensified postoperative surveillance.

Oncological results in rectal cancer patients with a subcentimetre distal margin after laparoscopic-assisted sphincter-preserving surgery

Background

Distal resection margin (DRM) is closely associated with sphincter‐preserving surgery and oncological safety for patients with mid‐low rectal cancers. However, the optimal DRM has not been determined.

Methods

Data of 378 rectal cancer patients who underwent laparoscopic‐assisted sphincter‐preserving surgery from 2009 to 2015 were retrospectively analysed. Patients were divided into two groups based on DRM: ≤1 cm (n = 74) and >1 cm (n = 304). To minimize the differences between the two groups, propensity‐score matching on baseline features was performed.

Results

Before propensity‐score matching, no significant differences in 5‐year disease‐free survival (DFS) (92.8% versus 81.3%, P = 0.128) and 5‐year overall survival (OS) (83.7% versus 82.2%, P = 0.892) were observed in patients with DRMs of ≤1 cm (n = 74) and >1 cm (n = 304), respectively. After propensity‐score matching (1:1), there were also no significant differences in DFS (88.1% versus 78.2%, P = 0.162) and OS (84.5% versus 84.9%, P = 0.420) between the DRM of ≤1 cm group (n = 65) and >1 cm group (n = 65), respectively. A total of 44 patients received preoperative chemoradiotherapy (CRT). In this cohort, the 5‐year local recurrence (LR) rates (P = 0.118) and the 5‐year DFS rates (P = 0.298) were not significantly different between the two groups. A total of 334 patients received surgery without neoadjuvant CRT. There were also no significant differences in the 5‐year LR rates (P = 0.150) and 5‐year DFS rates (P = 0.172) between the two groups.

Conclusions

When aiming to achieve at least a 1–2 cm distal clinical resection margin, a histological resection margin of <1 cm on the DRM gave equivalent clinical outcomes to a DRM of >1 cm.

An anatomical study on intersphincteric space related to intersphincteric resection for ultra-low rectal cancer

BACKGROUND

Intersphincteric resection (ISR) has been proposed to offer sphincter-sparing solution for patients with ultra-low rectal cancer. However, complete and accurate concepts about the intersphincteric space (ISS) related anatomy are not demonstrated clearly. This study aimed to provide a comprehensive description about the anatomic structure of ISS related to ISR.

METHODS

This was a descriptive morphological study. 28 pelvic specimens were obtained from body donors. Macroscopic and microscopic observation of ISS was performed via gross anatomy, plastinated sections and histologic staining. The anatomical parameters of the anal canal were measured. Images of laparoscopic ISS dissection procedures were real-timely captured during ISR.

RESULTS

The hiatal ligament, microvessels on supra fascia of LAM and rectal longitudinal muscle at the level of anorectal ring, especially at 1, 5, 7, and 11o'clock, could be the preferred entrance of ISS. The conjoint longitudinal muscle (CLM), the major component of ISS, was the continuum of the rectal longitudinal muscle and got reinforcement from the elastic fibers from LAM and EAS. Microvessels and neuro tissues were also found in ISS. The ISS was split into two spaces by the CLM in the middle and might subjectively be divided into three segments according to its different compositions. The length and width of ISS varied from different segments and directions.

CONCLUSIONS

We provided a systemic description of boundaries, contents and topographic structure of ISS, which may help proper determination of surgical approaches and dissection planes during ISR.

Treatment outcomes of patients with involved resection margin after rectal cancer surgery: A nationwide population-based cohort study in South Korea

BACKGROUND

The involvement of resection margins after rectal cancer surgery by malignant tumors is a negative prognostic factor. Therefore, it is important to analyze treatment outcomes and establish adjuvant therapy.

METHODS

The Health Insurance Review and Assessment Service collects data from medical institutions in South Korea. We reviewed the database of this prospectively collected cohort for patients who underwent curative resection for rectal cancer.

RESULTS

Of the 5,620 patients, 113 (2.0%) were diagnosed with resection margin involvement after surgery. The resection margins of patients with mid-rectal cancer, pathologic stage III, mucinous/signet ring cell carcinoma, and undergoing emergency surgery were more frequently involved. Neoadjuvant chemoradiotherapy was a significant preventive factor for resection margin involvement (odds ratio = 0.53; 95% confidence interval [CI], 0.32-0.87; p = 0.012). The OS of patients with adjuvant treatment was better than that of patients without adjuvant treatment (5-year overall survival [OS]: 62.8% vs. 46.3%, p = 0.02). The administration of chemoradiotherapy was also significantly associated with better OS (hazard ratio = 0.36; 95% CI, 0.17-0.77; p = 0.009).

CONCLUSION

Efforts to acquire wider resection margins are necessary for patients with mid-rectal cancer, pathologic stage III, mucinous/signet ring cell carcinoma, and emergency surgery. Neoadjuvant chemoradiotherapy was a significant preventive factor for involved resection margin. Patients with resection margin involvement showed better OS after adjuvant treatment than those without adjuvant treatment. The adjuvant chemoradiotherapy was helpful to prevent the worse prognosis of these patients.

Stent as a bridge to surgery versus urgent surgery for malignant right colonic obstruction: A multicenter retrospective study

BACKGROUND

The impact of self-expandable metal stent (SEMS) for malignant right colonic obstruction remains undefined. The aim of this study was to compare short-term postoperative and long-term oncologic outcomes of colonic stenting as a bridge to surgery (SBTS) and urgent colectomy for patients with malignant right-sided obstruction.

METHODS

A total of 98 consecutive patients who underwent SEMS placement during the period 2004-2015 from three hospitals were included. For comparative analyses, patients were matched (1:2) with 196 patients treated with emergency colectomy from our prospective database.

RESULTS

The two groups were comparable in terms of demographics and tumor characteristics. The proportion of patients who underwent laparoscopic colectomy was higher in SBTS group than urgent colectomy group (75.5% vs. 37.2%; p < 0.001). Patients treated with SBTS were less likely to have a temporary stoma constructed (3.1% vs. 10.7%; p = 0.024). SBTS was associated with significantly less median estimated blood loss (90 vs. 100 ml; p = 0.029), shorter length of hospital stay (11 vs. 12 days; p < 0.001), lower overall postoperative complication rate (18.4% vs. 31.3%; p = 0.018), and wound-related complication rate (5.1% vs. 14.3%; p = 0.019) compared with urgent surgery. Reoperation rate, 30-day mortality, and lymph nodes harvested were not significantly different between two groups. Disease-free survival rate and overall survival rate were similar between the two groups.

CONCLUSIONS

SEMS insertion is safe and feasible for treating malignant right-sided obstruction. SBTS is associated with better short-term outcomes and equivalent long-term oncologic results compared with urgent colectomy.

The risk factors of local recurrence and distant metastasis on pT1/T2N0 mid-low rectal cancer after total mesorectal excision

Background

Radical resection is associated with good prognosis among patients with cT1/T2Nx rectal cancer. However, still some of the patients experienced cancer recurrence following radical resection. This study tried to identify the postoperative risk factors of local recurrence and distant metastasis separately.

Methods

This retrospective, single-center study comprised of 279 consecutive patients from Linkou branch of Chang Gung Memorial Hospital in 2005–2016 with rectal adenocarcinoma, pT1/T2N0M0 at distance from anal verge ≤ 8cm, who received curative radical resection.

Results

The study included 279 patients with pT1/pT2N0 mid-low rectal cancer with median follow-up of 73.5 months. Nineteen (6.8%) patients had disease recurrence in total. Nine (3.2%) of them had local recurrence, and fourteen (5.0%) of them had distant metastasis. Distal resection margin < 0.9 (cm) (hazard ratio = 4.9, p = 0.050) was the risk factor of local recurrence. Preoperative carcinoembryonic antigen (CEA) ≥ 5 ng/mL (hazard ratio = 9.3, p = 0.0003), lymph node yield (LNY) < 14 (hazard ratio = 5.0, p = 0.006), and distal resection margin < 1.4cm (hazard ratio = 4.0, p = 0.035) were the risk factors of distant metastasis.

Conclusion

For patients with pT1/pT2N0 mid-low rectal cancer, current multidisciplinary treatment brings acceptable survival outcome. Insufficient distal resection margin attracted the awareness of risk factors for local recurrence and distant metastasis as a foundation for future research.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02223-4.

Postoperative chemotherapy improves survival in patients with resected high-risk Stage II colorectal cancer: results of a systematic review and meta-analysis

AIM

The aim was to assess the benefit of adjuvant chemotherapy in high-risk Stage II colorectal cancer.

METHOD

A systematic literature review and meta-analysis was performed comparing survival in patients with resected Stage II colorectal cancer and high-risk features having postoperative chemotherapy vs no chemotherapy.

RESULTS

Of 1031 articles screened, 29 were included, reporting on 183 749 participants. Adjuvant chemotherapy significantly improved overall survival [hazard ratio (HR) 0.61, P < 0.0001], disease-specific survival (HR = 0.73, P = 0.05) and disease-free survival (HR = 0.59, P < 0.0001) compared to no chemotherapy. Adjuvant chemotherapy significantly increased 5-year overall survival (OR = 0.53, P = 0.0008) and 5-year disease-free survival (OR = 0.50, P = 0.001). Overall survival and disease-free survival remained significantly prolonged during subgroup analysis of studies published from 2015 onwards (HR = 0.60, P < 0.0001; HR = 0.65, P = 0.0001; respectively), in patients with two or more high-risk features (HR = 0.59, P = 0.0001; HR = 0.70, P = 0.03; respectively) and in colon cancer (HR = 0.61, P < 0.0001; HR = 0.51, P = 0.0001; respectively). Overall survival, disease-specific survival and disease-free survival during subgroup analysis of individual high-risk features were T4 tumour (HR = 0.58, P < 0.0001; HR = 0.50, P = 0.003; HR = 0.75, P = 0.05), < 12 lymph nodes harvested (HR = 0.67, P = 0.0002; HR = 0.80, P = 0.17; HR = 0.72, P = 0.02), poor differentiation (HR = 0.84, P = 0.35; HR = 0.85, P = 0.23; HR = 0.61, P = 0.41), lymphovascular or perineural invasion (HR = 0.55, P = 0.05; HR = 0.59, P = 0.11; HR = 0.76, P = 0.05) and emergency surgery (HR = 0.60, P = 0.02; HR = 0.68, P = 0.19).

CONCLUSION

Adjuvant chemotherapy in high-risk Stage II colorectal cancer results in a modest survival improvement and should be considered on an individual patient basis. Due to potential heterogeneity and selection bias of the included studies, and lack of separate rectal cancer data, further large randomized trials with predefined inclusion criteria and standardized chemotherapy regimens are required.

Optimising functional outcomes in rectal cancer surgery

Background

By improved surgical technique such as total mesorectal excision (TME), multimodal treatment and advances in imaging survival and an increased rate of sphincter preservation have been achieved in rectal cancer surgery. Minimal-invasive approaches such as laparoscopic, robotic and transanal-TME (ta-TME) enhance recovery after surgery. Nevertheless, disorders of bowel, anorectal and urogenital function are still common and need attention.

Purpose

This review aims at exploring the causes of dysfunction after anterior resection (AR) and the accordingly preventive strategies. Furthermore, the indication for low AR in the light of functional outcome is discussed. The last therapeutic strategies to deal with bowel, anorectal, and urogenital disorders are depicted.

Conclusion

Functional disorders after rectal cancer surgery are frequent and underestimated. More evidence is needed to define an indication for non-operative management or local excision as alternatives to AR. The decision for restorative resection should be made in consideration of the relevant risk factors for dysfunction. In the case of restoration, a side-to-end anastomosis should be the preferred anastomotic technique. Further high-evidence clinical studies are required to clarify the benefit of intraoperative neuromonitoring. While the function of ta-TME seems not to be superior to laparoscopy, case-control studies suggest the benefits of robotic TME mainly in terms of preservation of the urogenital function. Low AR syndrome is treated by stool regulation, pelvic floor therapy, and transanal irrigation. There is good evidence for sacral nerve modulation for incontinence after low AR.

Predictive Factors of Positive Circumferential and Longitudinal Margins in Early T3 Colorectal Cancer Resection

Background

Malignant involvement of circumferential resection margin (CRM) and longitudinal resection margin (LRM) after surgical resection of colorectal cancer (CRC) are associated with higher rates of recurrence and development of distant metastasis. This can influence the overall patient's prognosis. The aim of the current study was to identify pathological factors as predictors for the involvement of resection margins in early T3 CRC. Patients and Methods. Fifty patients radiologically diagnosed to have cT3a/b (CRC) were included in the study. After resection, the pathological examination was performed to identify patients with positive CRM and/or LRM. Relations between the different pathological parameters and the CMR and LRM involvements were assessed.

Results

Positive CRM was present in 17 cases (34%), while positive LRM was found in 6 cases (12%). The involvement of both margins was significantly associated with rectal tumors and tumors with infiltrative gross appearance, grade III, deeper invasion, and positive lymph node metastases. Also, there was a significant association between both margins' positivity and other pathological parameters as signet ring carcinoma, tumor budding, perineural and vascular invasion, high microvessel density (MVD), and sinusoidal vascular pattern, while the presence of necrosis and infiltrative advancing tumor front was significantly associated with CRM involvement only. The depth of tumor invasion and signet ring carcinoma were identified as independent predictor factors for positive CRM and LRM, respectively.

Conclusion

Preoperative identification of these pathological parameters can be a guide to tailor the management plan accordingly.

Quicker, deeper and stronger imaging: A review of tumor-targeted, near-infrared fluorescent dyes for fluorescence guided surgery in the preclinical and clinical stages

Cancer is a public health problem and the main cause of human mortality and morbidity worldwide. Complete removal of tumors and metastatic lymph nodes in surgery is significantly beneficial for the prognosis of patients. Tumor-targeted, near-infrared fluorescent (NIRF) imaging is an emerging field of real-time intraoperative cancer imaging based on tumor-targeted NIRF dyes. Targeted NIRF dyes contain NIRF fluorophores and specific binding ligands such as antibodies, peptides and small molecules. The present article reviews recently updated tumor-targeted NIRF dyes for the molecular imaging of malignant tumors in the preclinical stage and clinical trials. The strengths and challenges of NIRF agents with tumor-targeting ability are also summarized. Smaller ligands, near infrared II dyes, dual-modality dyes and activatable dyes may contribute to quicker, deeper, stronger imaging in the nearest future. In this review, we highlighted tumor-targeted NIRF dyes for fluorescence-guided surgery and their potential clinical translation.

Analysing the impact of living in a rural setting on the presentation and outcome of colorectal cancer. A prospective single centre observational study

INTRODUCTION

Approximately 17% of the Scottish population lives in a remote or rural location. Current research is contradictory as to whether living a rural location leads to poorer outcomes or affects survival from colorectal cancer (CRC). We aimed to assess if living in a rural location influences outcome of CRC patients in 21st century UK medicine.

METHODS

A prospective single-centre observational study was conducted. All patients who underwent resection for colorectal cancer 2005-2016 in NHS Grampian were included. Patients were split into two groups for comparison (urban post-code vs rural) using the Scottish government two-tier classification system. Tumour location, one-year survival, lymph node involvement and extra-mural vascular invasion was recorded and compared between the groups.

RESULTS

Of 2463 patients, 843 (34.2%) lived in a rural area. Rural patients were more likely to be detected through screening (17.4% versus 14.6%, p = 0.04). There were no differences in pathology between rural and urban groups if detected through screening. However, rural patients detected through symptomatic pathways were more likely to be node positive p = 0.015. On multivariable analysis, rurality did not independently predict for node positive presentation. Furthermore, there were no differences in cumulative survival between the two groups.

CONCLUSION

Although there were some differences in pathological characteristics between rural and urban patients, place of residence did not independently predict for outcome in this cohort. Rurality had previously been shown to impact on outcome up to 20 years ago. Improvements in infrastructure and rural healthcare may have influenced this change.

Anal function and quality of life analysis after laparoscopic modified Parks for ultra-low rectal cancer patients

Background

To assess postoperative anal function and quality of life of ultra-low rectal cancer patients treated by laparoscopic modified Parks surgery.

Methods

From February 2017 to March 2019, 114 patients with ultra-low rectal cancer above T2 were treated respectively with ultra-low anterior resection (Dixon), modified coloanal anastomosis (modified Parks), and Miles according to the preoperative stage and anastomotic position. The postoperative anal function and Fecal Incontinence Quality of Life Scale (FIQL) of each patient were collected and synthetically analyzed.

Results

Compared with the Dixon group, the postoperative anal function and FIQL in the Parks group were poor at the early stage. However, from 6 to 12 months after surgery, the scores of anal function and FIQL in the Parks group were similar to those in the Dixon group (P > 0.05). Compared with the Miles group, the FIQL of the two groups were similar in the early postoperative stage. However, with the passage of time, from 3 to 9 months after surgery, the four domains of FIQL in the Parks group were higher than those in the Miles group successively (P < 0.05).

Conclusions

Laparoscopic modified Parks is a safe, effective, and economical anus-preserving surgery. Although its early anal function and FIQL were poor, it could gradually recover to the similar level as Dixon. Moreover, it can save the anus and obtain a better postoperative quality of life for some patients who previously could only undergo Miles.

Rectal cancer MRI: protocols, signs and future perspectives radiologists should consider in everyday clinical practice

Abstract

Magnetic resonance imaging (MRI) allows to non-invasively evaluate rectal cancer staging and to assess the presence of “prognostic signs” such as the distance from the anorectal junction, the mesorectal fascia infiltration and the extramural vascular invasion. Moreover, MRI plays a crucial role in the assessment of treatment response after chemo-radiation therapy, especially considering the growing interest in the new conservative policy (wait and see, minimally invasive surgery). We present a practical overview regarding the state of the art of the MRI protocol, the main signs that radiologists should consider for their reports during their clinical activity and future perspectives.

Teaching Points

• MRI protocol for rectal cancer staging and re-staging.

• MRI findings that radiologists should consider for reports during everyday clinical activity.

• Perspectives regarding the development of latest technologies.

Rectal cancer and the pathologist

Examination of the rectum by pathologists is instrumental in the management of patients affected by rectal carcinoma. That role includes evaluation of multiple gross and microscopic features that convey prognostic implications. The analysis is based on the authors' experience handling rectal specimens along with review of the pertinent literature in these areas: margins of excision, quality of the mesorectum, diligence and techniques to sample lymph nodes, tumor budding, grading of residual amount of carcinoma after preoperative therapy, vascular/perineural invasion, and staging the tumor. Pathologists must communicate the findings in a clear manner. Evaluation of margins and completeness of mesorectum are markers of the quality of surgical excision. The number of lymph nodes obtained and examined is dependent in great part on the diligence of the pathologist finding them in the mesenteric adipose tissue. There are grades for budding and response to prior chemoradiation therapy. The location of vascular invasion (extramural vs. intramural) may predict aggressive behavior. Pathologists proactively are to choose sections of tumor for molecular testing. Meticulous macro- and microscopic evaluation of specimens for rectal carcinoma by pathologist is needed to determine an accurate assessment of staging and other prognostic factors. The modern pathologists play a pivotal part in the care and management of patients suffering from rectal adenocarcinoma. That role goes from the initial histological diagnosis to the gross and microscopic examination of the excised specimens. Based on that examination pathologists issue statements that not only evaluate the quality of the surgical procedure, but also through the application of molecular tests they give light on prognostic factors and information for therapeutic purposes.