Tumor scatter after neoadjuvant therapy for rectal cancer: are we dealing with an invisible margin?

Short-term outcomes of transanal endoscopic intersphincteric resection for locally advanced rectal cancer after neoadjuvant chemoradiotherapy: A single-center retrospective cohort study

OBJECTIVE

To compare the perioperative safety and specimen characteristics after transanal endoscopic intersphincteric resection (taE-ISR) versus classical intersphincteric resection (cISR) in patients with locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (nCRT).

METHODS

Clinicopathological data of 145 patients (75 undergoing taE-ISR and 70 undergoing cISR after nCRT) were retrospectively analyzed. Baseline characteristics, perioperative details, and pathological specimen quality of the two groups were compared.

RESULTS

Intraoperative blood loss was lower in the taE-ISR group compared to cISR (50.0 (40.0-100.0) ml vs. 70.0 (50.0-100.0) ml, P = 0.034). Two patients (2.6 %) in the taE-ISR group and eight patients (11.4 %) in the cISR group sustained adjacent organ injury (P = 0.037). There was no statistically significant difference in the prevalence of postoperative complications between the two groups (17.3 % vs. 30.0 %, P = 0.072). However, pelvic abscess (1.3 % vs. 8.6 %, P = 0.042) and rectovaginal fistula (0.0 % vs. 5.7 %, P = 0.036) occurred less often in taE-ISR compared to cISR. The complete resection rate was higher in taE-ISR compared to cISR (98.7 % vs. 91.4 %, P = 0.042). No patients in taE-ISR had positive distal resection margins (DRM), while four patients in cISR had positive DRM (0.0 % vs. 5.7 %, P = 0.036).

CONCLUSION

taE-ISR after nCRT was associated with higher-quality specimens, reduced intraoperative blood loss, and fewer perioperative complications, attesting to the feasibility and safety of taE-ISR In low-LARC patients.

A new treatment strategy for mid-low rectal cancer patients exhibiting a clinical complete or near-complete response to neoadjuvant chemoradiotherapy: Transanal endoscopic microsurgery --A multicenter prospective case-control clinical trial by MONT-R

BACKGROUND

Total mesorectal excision is the standard surgery for locally advanced rectal cancer (LARC) after neoadjuvant chemoradiotherapy (nCRT), but it may lead to high complication rates and poor quality of life. This study evaluates whether transanal endoscopic microsurgery (TEM), as a partial resection procedure, can enhance quality of life for clinical complete response (cCR) or near-cCR patients without compromising survival.

METHODS

Between May 2017 to September 2021, 80 patients with T3-4N0M0 or TanyN+M0 mid-low rectal cancer achieving cCR or near-cCR post-nCRT were prospectively included at 6 Chinese centers. Patients underwent either TEM (Group A, n = 38) or radical surgery (Group B, n = 41). Clinicopathological, oncological, and functional outcomes were analyzed.

RESULTS

Postoperative histology revealed 22 ypT0 (57.9 %), 5 ypT1 (13.2 %), 10 ypT2 (26.3 %), and 1 ypT3 (2.6 %) cases in group A and 20 pCR (48.8 %), 1 T0N1 (2.4 %), 5 T1N0 (12.2 %), 12 T2-3N0 (29.3 %), 3 T2-3N1 (7.3 %) cases in group B. After a 60-month median follow-up, local recurrence occurred in 2 patients (5.26 %) in Group A and none in Group B. Distant metastases occurred in 8 patients (21.05 %) in group A and 7 (17.07 %) in group B. There was no significant difference between the two groups in 5-year disease-free survival (P = 0.658) or 5-year overall survival (P = 0.465). Group A showed significantly faster recovery (P < 0.001) and better sphincter function per Wexner (1 vs. 4, P = 0.001) and LARS (0 vs. 17, P < 0.001) scores than Group B.

CONCLUSION

TEM may be an effective approach for assessing residual tumors in LARC patients with cCR or near-cCR. This approach offers an option for those requiring sphincter preservation, with no significant compromise in long-term oncological outcomes observed in our study.

A management of patients achieving clinical complete response after neoadjuvant therapy and perspectives: on locally advanced rectal cancer

Neoadjuvant chemoradiotherapy (nCRT) followed by total mesorectal excision (TME) and selective use of adjuvant chemotherapy is currently considered the standard of care for locally advanced rectal cancer (LARC). Despite this, the concept of organ preservation is gradually challenging this approach. The management of complete clinical remission (cCR) lacks international consensus, leading scholars to develop their own perspectives based on well-designed studies and long-term data from large multicenter cohorts. To ensure appropriate treatment, this review focuses on the choice of neoadjuvant therapy, criteria for defining cCR, and treatment strategies for patients who achieve cCR after neoadjuvant therapy. By providing guidance on the accurate management of LARC patients after cCR, this review aims to prevent over- or under-treatment.

Rectal Cancer: Exploring Predictive Biomarkers Through Molecular Pathways Involved in Carcinogenesis

In 2022, colorectal cancer (CCR) had the second-highest incidence in Europe, preceded only by breast cancer [...].

Local excision versus total mesorectal excision for rectal cancer patients with clinical complete or near-complete response after neoadjuvant chemoradiotherapy

PURPOSE

Local excision is an effective approach for managing rectal cancer exhibiting substantial regression after neoadjuvant chemoradiotherapy. The purpose of this study is to compare the outcomes between local excision and total mesorectal excision in rectal cancer patients achieving clinical complete or near-complete response after neoadjuvant chemoradiotherapy.

METHODS

This is a retrospective cohort study that includes a consecutive series of rectal cancer patients who responded well to neoadjuvant chemoradiotherapy followed by surgery. A total of 180 rectal cancer patients at a single institution during a 12-year period are included. The main outcomes include short-term outcomes, oncological outcomes, and functional outcomes between the two groups.

RESULTS

A total of 180 patients were included in the study. Sixty-one (33.9%) received local excision and 119 (66.1%) received total mesorectal excision. The baseline characteristics were generally balanced between the two groups. The local excision group demonstrated a significantly shorter operative time, less blood loss, and shorter hospital stay (p < 0.001). 3-year overall survival rates were 97.5% (95% CI, 0.93-1.00) and 95.5% (95% CI, 0.91-1.00) between the two groups (p = 0.38). The local excision group exhibited significantly higher 3-year local recurrence rates 15.7% (95% CI, 0.74-0.97) vs 4.2% (95% CI, 0.92-1.00) (p = 0.017), yet lower 3-year distant metastasis rates 9.6% (95% CI, 0.82-1.00) vs 12.6% (95% CI, 0.81-0.94) (p = 0.33) and lower 3-year disease-free survival rates 76.8% (95% CI, 0.64-0.92) vs 84.7% (95% CI, 0.78-0.92) (p = 0.56) comparing with the total mesorectal excision group. The local excision group demonstrated significantly better functional outcomes compared with the total mesorectal excision group (p < 0.001).

CONCLUSION

Patients who achieve either clinical complete or near-complete response after neoadjuvant chemoradiotherapy are suitable candidates for local excision. The local excision group demonstrated superior short-term and functional outcomes, and the oncological outcomes were not compromised.

Identification of radiologic and clinicopathologic variables associated with tumor regression pattern and distribution of cancer cells after short-course radiotherapy and consolidation chemotherapy in patients with rectal cancer

Background

Knowledge of the pattern of regression and distribution of residual tumor cells may assist in the selection of candidates for rectum-sparing strategies.

Objective

To investigate and identify factors associated with tumor regression pattern and distribution of residual tumor cells.

Methods

We conducted a prospective study of patients with T3/T4 N0/N+ adenocarcinoma of the middle and lower third of the rectum (≤10 cm) treated with radiotherapy (5×5 Gy) followed by 6 cycles of CAPOX chemotherapy. The pattern of tumor regression was classified as fragmented or solid. Microscopic intramural spread was measured. We used a model of distribution of residual tumor cells not yet applied to rectal cancer, defined as follows: type I (luminal), type II (invasive front), type III (concentric), and type IV (random).

Results

Forty patients were included with a median age of 66 years; 23 (57.5%) were men. A fragmented pattern was identified in 18 patients (45.0%), and a solid pattern in 22 (55.0%). Microscopic intramural spread was identified in 25 patients (62.5%), extending from 1 to 18 mm (median, 4 mm). There were 14 cases (35.0%) of microscopic intramural spread ≥10 mm. All cases of fragmented regression pattern, except one, showed microscopic intramural spread. Within the fragmented pattern, microscopic intramural spread was 4-8 mm in 4 cases and ≥10 mm in the remaining cases. All cases of microscopic intramural spread ≥ 10 mm were within the fragmented pattern. Regarding the distribution pattern of residual tumor cells, 11 cases (31.5%) were classified as type I, 14 (40.0%) as type II, 10 (28.5%) as type III, and none as type IV. Carcinoembryonic antigen levels >5 ng/mL, downsizing <50%, residual mucosal abnormality >20 mm, and anatomopathologic lymph node involvement were significantly associated with the occurrence of fragmentation (P<0.05). Having received all 6 cycles of CAPOX chemotherapy and absence of microscopic intramural spread were significantly associated with the type I distribution pattern (P<0.05).

Conclusion

The occurrence of a fragmented regression pattern is common, as is the presence of microscopic intramural spread. We could identify radiologic and clinicopathologic factors associated with the pattern of tumor regression and a type I distribution pattern.

Surgical margins in head and neck squamous cell carcinoma: A narrative review

Head and neck squamous cell carcinoma (HNSCC), a prevalent and frequently recurring malignancy, often necessitates surgical intervention. The surgical margin (SM) plays a pivotal role in determining the postoperative treatment strategy and prognostic evaluation of HNSCC. Nonetheless, the process of clinical appraisal and assessment of the SMs remains a complex and indeterminate endeavor, thereby leading to potential difficulties for surgeons in defining the extent of resection. In this regard, we undertake a comprehensive review of the suggested surgical distance in varying circumstances, diverse methods of margin evaluation, and the delicate balance that must be maintained between tissue resection and preservation in head and neck surgical procedures. This review is intended to provide surgeons with pragmatic guidance in selecting the most suitable resection techniques, and in improving patients' quality of life by achieving optimal functional and aesthetic restoration.

Tumor regression and safe distance of distal margin after neoadjuvant therapy for rectal cancer

Neoadjuvant therapy has been widely employed in the treatment of rectal cancer, demonstrating its utility in reducing tumor volume, downstaging tumors, and improving patient prognosis. It has become the standard preoperative treatment modality for locally advanced rectal cancer. However, the efficacy of neoadjuvant therapy varies significantly among patients, with notable differences in tumor regression outcomes. In some cases, patients exhibit substantial tumor regression, even achieving pathological complete response. The assessment of tumor regression outcomes holds crucial significance for determining surgical approaches and establishing safe margins. Nonetheless, current research on tumor regression patterns remains limited, and there is considerable controversy surrounding the determination of a safe margin after neoadjuvant therapy. In light of these factors, this study aims to summarize the primary patterns of tumor regression observed following neoadjuvant therapy for rectal cancer, categorizing them into three types: tumor shrinkage, tumor fragmentation, and mucinous lake formation. Furthermore, a comparison will be made between gross and microscopic tumor regression, highlighting the asynchronous nature of regression in the two contexts. Additionally, this study will analyze the safety of non-surgical treatment in patients who achieve complete clinical response, elucidating the necessity of surgical intervention. Lastly, the study will investigate the optimal range for safe surgical resection margins and explore the concept of a safe margin distance post-neoadjuvant therapy.

Clinical Tools for Rectal Cancer Response Assessment following Neoadjuvant Treatment in the Era of Organ Preservation

Local tumor response evaluation following neoadjuvant treatment(s) in rectal adenocarcinoma requires a multi-modality approach including physical and endoscopic evaluations, rectal protocoled MRI, and cross-sectional imaging. Clinical tumor response exists on a spectrum from complete clinical response (cCR), defined as the absence of clinical evidence of residual tumor, to near-complete response (nCR), which assumes a significant reduction in tumor burden but with increased uncertainty of residual microscopic disease, to incomplete clinical response (iCR), which incorporates all responses less than nCR that is not progressive disease. This article aims to review the clinical tools currently routinely available to evaluate treatment response and offers a potential management approach based on the extent of local tumor response.

Endoscopic ultrasound-guided injection of carbon nanoparticles suspension to label rectal cancer before neoadjuvant chemoradiotherapy: a retrospective cohort study

Background

Localization of the primary tumor and ensuring safe distal surgical margins (DSMs) following neoadjuvant chemoradiotherapy (nCRT) are challenging in locally advanced rectal cancers (LARCs). This study investigated the effectiveness of carbon nanoparticles suspension (CNS) for labeling the primary tumor and allowing precise tumor resection after nCRT.

Methods

Clinicopathological data of LARC patients who underwent nCRT followed by laparoscopic radical anal preservation surgery at our center between January 2018 and February 2023 were prospectively collected. The patients were divided into the CNS tattooed (CNS) and non-tattooed (control) groups. In the CNS group, CNS was injected in four quadrants on the anal side 1 cm away from the lower tumor margin. DSMs were determined through intraoperative distal rectal examination in the control group and observation of CNS tattoos in the CNS group. DSM lengths and positive DSM rates were compared between the two groups to analyse the feasibility and effectiveness of CNS for labeling LARCs before nCRT.

Results

There was no statistically significant difference in the basic demographic data, effectiveness of nCRT, or post-operative recovery rates between the two groups (all P > 0.05). In the CNS group, CNS tattoos were observed on the outside of the rectal wall, with an overall efficiency of 87.1% (27/31). The CNS group had fewer positive DSMs and safer DSM lengths (2.73 ± 0.88 vs 2.12 ± 1.15 cm, P = 0.012) than the control group (P < 0.05).

Conclusions

Endoscopic ultrasound-guided injection of CNS tattoos before nCRT could effectively label the LARCs, ensuring safe DSMs during anus-preserving surgeries (Chictr.org.cn No.: ChiCTR2300068991).

Local tumor regrowth after clinical complete response following neoadjuvant therapy for rectal cancer: what happens when organ preservation falls short

Organ preservation strategies, especially watch and wait, after neoadjuvant treatment in locally advanced rectal cancer, have become topics that generate significant interest, for both patients and clinicians. The obvious advantage of these strategies is the avoidance of surgery with its associated risks and functional consequences. Over time, it has become evident that these strategies offer acceptable safety in oncological terms and, in most patients, allows preservation of the rectum without harming patients in terms of distant metastasis or survival. However, there is a small group of patients in whom the tumor returns after an initially diagnosed clinical complete response; patients with local tumor regrowth. The main threat in these patients is not simply local disease, which can be successfully managed in most cases, but the possible effects it may have on distant metastases. The pathophysiology of the phenomenon of local tumor regrowth is not well known and, therefore, strategies to minimize possible impact on survival are not well defined. Our aim is to review key issues in this subgroup that pose a substantial threat to the safety and viability of organ-preserving and watch-and-wait strategies. We also explore possible pathophysiologic explanations and future directions and perspectives that may improve both local and systemic disease control.

Required distal mesorectal resection margin in partial mesorectal excision: a systematic review on distal mesorectal spread

BACKGROUND

The required distal margin in partial mesorectal excision (PME) is controversial. The aim of this systematic review was to determine incidence and distance of distal mesorectal spread (DMS).

METHODS

A systematic search was performed using PubMed, Embase and Google Scholar databases. Articles eligible for inclusion were studies reporting on the presence of distal mesorectal spread in patients with rectal cancer who underwent radical resection.

RESULTS

Out of 2493 articles, 22 studies with a total of 1921 patients were included, of whom 340 underwent long-course neoadjuvant chemoradiotherapy (CRT). DMS was reported in 207 of 1921 (10.8%) specimens (1.2% in CRT group and 12.8% in non-CRT group), with specified distance of DMS relative to the tumor in 84 (40.6%) of the cases. Mean and median DMS were 20.2 and 20.0 mm, respectively. Distal margins of 40 mm and 30 mm would result in 10% and 32% residual tumor, respectively, which translates into 1% and 4% overall residual cancer risk given 11% incidence of DMS. The maximum reported DMS was 50 mm in 1 of 84 cases. In subgroup analysis, for T3, the mean DMS was 18.8 mm (range 8-40 mm) and 27.2 mm (range 10-40 mm) for T4 rectal cancer.

CONCLUSIONS

DMS occurred in 11% of cases, with a maximum of 50 mm in less than 1% of the DMS cases. For PME, substantial overtreatment is present if a distal margin of 5 cm is routinely utilized. Prospective studies evaluating more limited margins based on high-quality preoperative magnetic resonance imaging and pathological assessment are required.

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.

Transanal Local Excision of Rectal Cancer after Neoadjuvant Chemoradiation: Is There a Place for It or Should Be Avoided at All Costs?

Tumor response to neoadjuvant chemoradiation (nCRT) with tumor downsizing and downstaging has significantly impacted the number of patients considered to be appropriate candidates for transanal local excision (TLE). Some patients may harbor small residual lesions, restricted to the bowel wall. These patients, who exhibit major response ("near-complete") by digital rectal examination, endoscopic assessment, and radiological assessment may be considered for this approach. Although TLE is associated with minimal postoperative morbidity, a few clinical consequences and oncological outcomes must be evaluated in advance and with caution. In the setting of nCRT, a higher risk for clinically relevant wound dehiscences leading to a considerable risk for readmission for pain management has been observed. Worse anorectal function (still better than after total mesorectal excision [TME]), worsening in the quality of TME specimen, and higher rates of abdominal resections (in cases requiring completion TME) have been reported. The exuberant scar observed in the area of TLE also represents a challenging finding during follow-up of these patients. Local excision should be probably restricted for patients with primary tumors located at or below the level of the anorectal ring (magnetic resonance defined). These patients are otherwise candidates for abdominal perineal resections or ultra-low anterior resections with coloanal anastomosis frequently requiring definitive stomas or considerably poor anorectal function.

Rectal cancer: Maximizing local control and minimizing toxicity

Adoption of multimodality treatment approach for rectal cancer has resulted in significant improvements in oncologic outcomes. The roles of chemotherapy, radiation, and surgery in rectal cancer treatment are continuously evolving with the goal of achieving the best possible oncologic and functional outcome while minimizing treatment toxicity. The aim of this review is to summarize the most recent trials focusing on organ-sparing treatment strategies and the optimal selection of patients for neoadjuvant radiation therapy.

Impact of the distal resection margin on local recurrence after neoadjuvant chemoradiation and rectal excision for locally advanced rectal cancer

We aimed to evaluate whether a short distal resection margin (< 1 cm) was associated with local recurrence in patients with locally advanced rectal cancer who underwent preoperative chemoradiotherapy. Patients with rectal cancer who underwent preoperative chemoradiotherapy followed by curative surgery were divided into two groups based on the distal resection margin (≥ 1 cm and < 1 cm). In total, 507 patients were analyzed. The median follow-up duration was 48.9 months. The 3-year local recurrence rates were 2% and 8% in the ≥ 1 cm and < 1 cm groups, respectively (P < 0.001). Multivariable analysis revealed that a distal resection margin of < 1 cm was a significant risk factor for local recurrence (P = 0.008). Subgroup analysis revealed that a distal resection margin of < 1 cm was not an independent risk factor for local recurrence in the ypT0-1 group. However, among patients with tumor stages ypT2-4, the cumulative 3-year incidences of local recurrence were 2.3% and 9.8% in the ≥ 1 cm and < 1 cm groups, respectively (P = 0.01). A distal resection margin of < 1 cm might influence local recurrence rates in patients with locally advanced rectal cancer undergoing preoperative chemoradiotherapy, especially in patients with tumor stages ypT2-4.

Evaluation and Predictive Factors of Complete Response in Rectal Cancer after Neoadjuvant Chemoradiation Therapy

The response to neoadjuvant chemoradiation therapy is an important prognostic factor for locally advanced rectal cancer. Although the majority of the patients after neoadjuvant therapy are referred to following surgery, the clinical data show that complete clinical or pathological response is found in a significant proportion of the patients. Diagnostic accuracy of confirming the complete response has a crucial role in further management of a rectal cancer patient. As the rate of clinical complete response, unfortunately, is not always consistent with pathological complete response, accurate diagnostic parameters and predictive markers of tumor response may help to guide more personalized treatment strategies and identify potential candidates for nonoperative management more safely. The management of complete response demands interdisciplinary collaboration including oncologists, radiotherapists, radiologists, pathologists, endoscopists and surgeons, because the absence of a multidisciplinary approach may compromise the oncological outcome. Prediction and improvement of rectal cancer response to neoadjuvant therapy is still an active and challenging field of further research. This literature review is summarizing the main, currently known clinical information about the complete response that could be useful in case if encountering such condition in rectal cancer patients after neoadjuvant chemoradiation therapy, using as a source PubMed publications from 2010–2021 matching the search terms “rectal cancer”, “neoadjuvant therapy” and “response”.

Long-term oncological outcomes of the sphincter preserving total mesorectal excision with varying distal resection margins

INTRODUCTION

A subcentimeter distal resection margin (DRM) appears to be acceptable for most patients, however, long-term follow up and specific subsets where DRM would influence recurrences have not been adequately investigated.

METHODS

A retrospective analysis of all sphincter-preserving resections for mid and low rectal cancers between July 2011 and May 2015 was performed. Extended total mesorectal excisions (TME) and patients with positive pathologic circumferential margins (CRM) were excluded.

RESULTS

Two hundred and thirty-six patients fit the inclusion criteria. DRM > 20 mm was obtained in 117 patients (49.6%), between 10 and 20 mm in 78 (33%) and <10 mm in 41 (17.4%) patients. Pathological DRM was positive in 4 patients (1.7%). Sixty-five recurrences occurred at a median follow up of 78.5 months. DRM did not influence any of the oncological outcomes. In a subset analysis of patients with poor pathological response to neoadjuvant radiation, that is, tumor regression grade > 3, DRM influenced disease-free survival (DFS) but not overall survival with a hazard ratio of 4.4 (p = 0.02). This was confirmed on multivariate regression analysis in this subgroup as well where pathological nodal status and DRM < 10 mm were independent predictors of DFS.

CONCLUSIONS

A subcentimeter DRM may be acceptable in most patients except those who have an inadequate response to neoadjuvant radiation.

Endoscopic and MRI response evaluation following neoadjuvant treatment for rectal cancer: a pictorial review with matched MRI, endoscopic, and pathologic examples

A nonoperative management strategy, or Watch-and-Wait, following neoadjuvant therapies of locally advanced rectal adenocarcinoma is increasingly considered for select patients. Yet, standardized tumor response assessment to best select and surveil suitable patients remains an unmet clinical challenge. Endoscopic and MRI currently provide the most reliable tumor response estimations. However, resources illustrating variable tumor responses to neoadjuvant therapies remain limited. This pictorial review aims to provide detailed and annotated examples of common endoscopic and MRI findings of rectal cancer treatment response, while also emphasizing their respective diagnostic shortcomings and consequently, the necessity for a multidisciplinary approach to optimally manage these patients.

Local excision after neoadjuvant chemoradiotherapy versus total mesorectal excision: a case-matched study in 110 selected high-risk patients with rectal cancer

AIM

The aim of this comparative study was to report a 10-year experience of an organ preservation strategy by local excision (LE) in selected high-risk patients (aged patients and/or patients with severe comorbidity and/or indication for abdominoperineal excision) versus total mesorectal excision (TME) after neoadjuvant radiochemotherapy (RCT) for patients with locally advanced (T3-T4 and/or N+) low and mid rectal cancer with suspicion of complete tumour response (CTR) or near-CTR.

METHOD

Thirty-nine patients with rectal cancer who underwent LE after RCT for suspicion of CTR were matched to 71 patients who underwent TME according to body mass index, gender, tumour location and ypTNM stage. Operative, oncological and functional results were compared between groups.

RESULTS

In the LE group, ypT0, ypTis or ypT1N0R0 were noted in 28/39 (72%). Overall morbidity was observed in 10/39 (26%) in LE vs 46/71 in the TME group (65%) (P = 0.001). Severe morbidity (Clavien-Dindo ≥ 3) was noted in 1/39 patients from the LE group (3%) vs 3/71 (4%) from the TME group (P = 1.000). After a mean follow-up of 63 ± 4 months (range 56-70 months), local recurrence was noted in 2/39 (5%) from the LE group vs 2/71 (3%) from the TME group (P = 0.601). Definitive stoma was noted in 2/39 (6%) from the LE group vs 8/71 (12%) from the TME group (P = 0.489). Major low anterior resection syndrome was noted in 5/23 (22%) from LE group vs 11/33 (33%) from the TME group (P = 0.042).

CONCLUSION

The accuracy of response prediction after RCT was 72% after LE. In high-risk patients, LE represents a safe alternative to TME with better functional results and the same long-term oncological outcome.

Local excision following chemoradiotherapy in T2-T3 rectal cancer: current status and critical appraisal

Local excision following chemoradiotherapy in rectal cancer is an organ-preserving procedure which aims at reducing morbidity and functional disorders associated with total mesorectal excision (TME) in selected patients. Although TME after chemoradiotherapy remains the gold standard for locally advanced mid and low rectal cancer, in the last years multicenter research trials have offered encouraging oncologic results which have allowed to preserve the rectum in patients with a pathologic complete response after chemoradiotherapy. A review of the available literature on this topic was conducted to define the state of the art of this conservative approach and to focus on the most controversial aspects concerning local excision performed after chemoradiotherapy, in particular tumor scatter and lymph node status, completion and salvage surgery, morbidity and quality of life. The analysis of these topics should be considered, in trial setting or in current practice, for their clinical implications. Oncologic outcomes of recent trials are encouraging for part of the patients presenting T2 rectal cancer; however, TME still remains the standard treatment in clinical practice. In such cases, local excision should include a surgical safety margin of at least 1 cm from the resection margin to achieve a true negative margin from residual tumor cells. The selection of the patients should be carefully performed and their consensus extremely detailed because TME is necessary in about 30% of cases. Failing that, morbidity and quality of life are negatively affected. However, about half of these patients refuse radical surgery (45%), thus undergoing only palliative care.

How to measure tumour response in rectal cancer? An explanation of discrepancies and suggestions for improvement

Various methods categorize tumour response after neoadjuvant therapy, including down-staging and tumour regression grading. Response categories allow comparison of different treatments within clinical trials and predict outcome. A reproducible response categorization could identify subgroups with high or low risk for the most appropriate subsequent treatments, like watch and wait. Lack of standardization and interpretation difficulties currently limit the usability of these approaches. In this review we describe these difficulties for the evaluation of chemoradiation in rectal cancer. An alternative approach of tumour response is based on patterns of residual disease, including fragmentation. We summarise the evidence behind this alternative method of response categorisation, which explains a number of very relevant clinical discrepancies. These issues include differences between downstaging and tumour regression, high local regrowth in advanced tumours during watchful waiting procedures, the importance of resection margins, the limited value of post-treatment biopsies and the relatively poor outcome of patients with a near complete pathological response. Recognition of these patterns of response can allow meaningful development of novel biomarkers in the future.

Microscopic intramural extension of rectal cancer after neoadjuvant chemoradiation: A meta-analysis based on individual patient data

OBJECTIVE

In selected rectal cancer patients with residual local disease following neoadjuvant chemoradiation (CRT) and the preference of an organ preservation pathway, additional treatment with dose escalation by endoluminal radiotherapy (RT) may ultimately result in a clinical complete response. To date, the widespread introduction of selective endoluminal radiation techniques is hampered by a lack of evidence-based guidelines that describe the radiation treatment volume in relation to the residual tumor mass. In order to convert an incomplete response into a complete one with additional treatment such as dose-escalation with endoluminal RT from a theoretical perspective, it seems important to treat all remaining microscopic tumor cells after CRT. In this setting, residual tumor extension beneath normal appearing mucosa (microscopic intramural spread - MIS) becomes relevant for accurate tumor volume and margin estimation. With the goal of providing evidence-based guidelines that define an appropriate treatment volume and patient selection, we present results from a meta-analysis based on individual patient data of studies that have assessed the extent or range of MIS of rectal cancers after neoadjuvant CRT. This meta-analysis should provide an estimate of the residual tumor volume/extension that needs to be targeted by any additional radiation therapy boost in order to achieve complete tumor eradication after initial incomplete or near-complete response following standard CRT.

METHODS AND MATERIALS

A PubMed search was performed. Additional articles were selected based on identification from reference lists. Papers were eligible when reporting MIS in patients who were treated by total mesorectal excision or local excision/transanal endoscopic microsurgery (TEM) after neo-adjuvant long-course CRT. The mean MIS was calculated for the entire group along with the 70th until 95th percentiles. Additional exploratory subgroup analyses were performed.

RESULTS

Individual patient data from 349 patients with residual disease from five studies were analyzed. 80% of tumors showed no MIS. In order to appropriately treat MIS in 95% of rectal cancer patients after CRT, a margin of 5.5 mm around the macroscopic tumor would suffice. An exploratory subgroup analysis showed that T-stage after CRT (ypT) and time interval between neoadjuvant CRT and surgery are significant factors predicting the extent of MIS (p < 0.001.) The group of ypT1 had the smallest MIS, followed by the ypT3-4 group, while the ypT2 group had the largest MIS (p < 0.001). Regarding time interval between CRT and surgery, a statistically significant difference was seen when comparing the three time-interval groups (less than 8 weeks, 8-12 weeks, and more than 12 weeks), where waiting more than 12 weeks after CRT resulted in the largest MIS (p < 0.0001).

CONCLUSION

Based on this meta-analysis, in order to treat the MIS for 95% of rectal cancer patients after CRT, a Clinical Target Volume (CTV) margin of 5.5 mm from the lateral most edge of the macroscopic tumor would suffice. 80% of tumors showed no MIS and would not require an extra CTV margin for treatment. These findings support the feasibility of localized radiotherapy boosts for dose-escalation to improve response among patients with incomplete response after standard CRT and can also be applied in the surgical setting.

[Evidence-based surgery of rectal cancer]

Over the past four decades, the treatment algorithms for rectal cancer have fundamentally changed, which resulted in a considerable improvement of oncological outcomes. In this context, the surgical concept of total mesorectal excision and the implementation of multimodal treatment strategies represent key milestones. These improvements were complemented by a standardized histopathological work-up of the surgical specimen and the introduction of high-resolution magnetic resonance imaging (MRI) diagnostics. In addition, novel surgical techniques have been introduced, such as laparoscopic and robotic rectal resection. Other technological innovations include intraoperative pelvic neuromonitoring and fluorescence imaging. This review highlights the current evidence for selected, sometimes controversially discussed principles of surgical treatment strategies in rectal cancer.

Effect of preoperative chemotherapy on distal spread of low rectal cancer located close to the anus

PURPOSE

This study aimed to clarify the frequency of distal spread and the optimal distal margin after preoperative chemotherapy for advanced low rectal cancer.

METHODS

The study included patients with advanced lower rectal cancer who received preoperative chemotherapy and underwent surgery during 2012-2015. We investigated the distal spread of tumor cells, defined as the distal distance from the intramucosal distal tumor edge to the farthest tumor cells located under the submucosal layer. Clinical characteristics were compared for distal spreads ≥ 10 and < 10 mm, and risk factors for distal spread ≥ 10 mm were investigated.

RESULTS

Of the 71 patients, 42 (59%) showed distal spread. Distal spreads of 1-9, 10-19, and ≥ 20 mm were observed in 27 (38%), 11 (15%), and 4 (6%) patients, respectively. Multivariate analysis revealed two independent risk factors for distal spread ≥ 10 mm after preoperative chemotherapy. The first risk factor is the presence of different therapeutic effects between the mucosal and deeper layers (meaning that superficial tumor shrinkage was evident on colonoscopy, but little tumor shrinkage was evident on magnetic resonance imaging) (odds ratio, 11.6; 95% CI, 2.22-61.3). The second risk factor is poorly differentiated or mucinous adenocarcinoma (odds ratio, 8.86; 95% CI, 1.58-49.9).

CONCLUSION

A distal margin of 20 mm is required (10 mm is insufficient) for advanced lower rectal cancer patients who receive preoperative chemotherapy followed by surgery. Independent risk factors for distal spread ≥ 10 mm include (1) the presence of different therapeutic effects between mucosal and deeper layers and (2) poorly differentiated or mucinous adenocarcinomas.

Neoadjuvant therapy and subsequent treatment in rectal cancer: balance between oncological and functional outcomes

Current practice of neoadjuvant therapy and total mesorectal excision (TME) in rectal cancer bears the weakness in systemic disease control and long-term functional outcomes. With increasing concerns of the balance between cure and quality of life, new strategies are developed to better oncological outcomes at least cost of function damage. Attractive options to adjust neoadjuvant modality include escalation of radiotherapy, intensification of chemotherapy, and chemoradiotherapy with consolidation or full-course chemotherapy. Subsequently, organ-preserving strategies have gained the popularity. Surgical or nonsurgical approaches that spare the rectum are used as possible alternatives for radical surgery, though high-quality TME remains the last resort to offer reliable local disease control. This review discusses new strategies of neoadjuvant therapy and subsequent management, with a specific focus on the balance between oncological and functional outcomes.

Short-course neoadjuvant chemoradiotherapy and surgery are beneficial in Chinese patients: A retrospective study

Preoperative neoadjuvant chemoradiotherapy (NACR) is used to reduce tumor size for easier resection or improved resectability rates. Considering the difficulties regarding health insurance and health resources in China, an evidence-based short-course neoadjuvant chemoradiotherapy with surgery to cure patients was performed. This study compared the postoperative effects between short-course neoadjuvant chemoradiotherapy and surgery and surgery without neoadjuvant chemoradiotherapy.The current retrospective study was based on a rectal cancer database, including 274 patients diagnosed with rectal cancer between January 2014 and October 2016. Data were analyzed with respect to curative rate, postoperative recovery indicators (times to nasogastric tube, urinary catheter, and drainage tube removal and times to first oral feeding and passing of flatus postsurgery), chemoradiotherapy-related indicators [white blood cell count (WBC) and carcinoembryonic antigen (CEA) levels], and adverse effects indicators, evaluated according to Common Terminology Criteria for Adverse Events Version 4.0.There was no significant difference between the combined therapy and surgery groups (P > .05) in terms of radical resection rates and the times to urinary catheter removal and passing flatus (P > .05). Statistically significant differences (P < .05) in terms of earlier time for removal of the nasogastric and drainage tubes and time to first oral feeding were observed in the combined therapy group. The decreases in WBC and CEA levels in the combined therapy group were significantly greater than those in the surgery group 1 week after surgery (P < .05); after 1 month, the CEA decrease in the combined therapy group was significantly greater than that in the surgery group (P < .05). More patients in the combined therapy group experienced vomiting, indigestion, dehydration, oral mucositis, sensory neuritis, and alopecia compared with those in the surgery group 1 week after surgery (P < .05); after 1 month, only the incidence of alopecia was higher in the combined therapy group (P < .05).The combined therapy group demonstrated earlier postoperative recovery compared with the surgery group. Short-course neoadjuvant chemoradiotherapy with surgery may lead to postoperative treatment-related adverse effects of varying degrees; however, these adverse effects eventually improve with time.

Local Excision and Endoscopic Resections for Early Rectal Cancer

Radical surgery is considered as the standard treatment for rectal cancer. Transanal local excision has been considered an interesting alternative for the management of selected patients with rectal cancers for many decades. Different approaches had been considered for local excision, from endoscopic submucosal dissection to resections using platforms, such as transanal endoscopic microsurgery or transanal minimally invasive surgery. Identifying the ideal candidate for this approach is crucial, as a local failure after local excision is associated with poor outcomes, even for an initial early rectal tumor. In this article, the diagnostic tools and criteria to select patients for local excision, the different modalities used, and the outcomes are discussed.

Monitoring neoadjuvant therapy responses in rectal cancer using multimodal nonlinear optical microscopy

Most patients with rectal cancer have a better prognosis after receiving neoadjuvant therapy because of its remarkable curative effect. However, no device delivers real-time histopathologic information on treatment response to help clinicians tailor individual therapeutic strategies. We assessed the potential of multimodal nonlinear optical microscopy to monitor therapeutic responses, including tumoral and stromal responses. We found that two-photon excited fluorescence imaging can, without labeling, identify colloid response, inflammatory cell infiltration, vascular proliferation, and tumor regression. It can also directly detect rare residual tumor cells, which may be helpful for distinguishing tumor shrinkage from tumor fragmentation. In addition, second harmonic generation imaging shows the ability to monitor three types of fibrotic responses: mature, intermediate, and immature. We also determined nonlinear spectra, collagen density, and collagen orientation indexes to quantitatively analyze the histopathologic changes induced by neoadjuvant therapy in rectal cancer. Our work demonstrates that nonlinear optical microscopy has the potential to become a label-free, real-time, in vivo medical imaging technique and provides the groundwork for further exploration into the application of nonlinear optical microscopy in a clinical setting.

New Strategies in Rectal Cancer

In recent years, our understanding of rectal cancer has improved, including how locally advanced disease responds to chemotherapy and radiation. This has led to new innovations and advances in the treatment of rectal cancer, which includes organ-preserving strategies for responsive disease, and minimally invasive approaces for the performance of total mesorectal excision/protectomyh for persistently advanced disease. This article discusses new strategies for rectal cancer therapy, including Watch and Wait, local excision, minimally invasive proctectomy, and transanal total mesorectal excision particularly in the setting of preoperative multimodality treatment.

No clinical benefit from routine histologic examination of stapler doughnuts at low anterior resection for rectal cancer

BACKGROUND

The aim of this study was to evaluate the clinical utility and cost-effectiveness of routine histologic examination of the doughnuts from stapled anastomoses in patients undergoing a low anterior resection for rectal cancer.

METHODS

We performed a retrospective review of 486 patients who underwent a low anterior resection with stapled anastomosis for rectal cancer between 2002 and 2015 at 3 institutions. Pathologic findings in the doughnuts and their impact on patient management were recorded. Tumor characteristics that may influence how often doughnuts were included in the pathology report were analyzed. An approximate cost of histologic examination of doughnuts was also calculated.

RESULTS

A total of 412 patients (85%) had doughnuts included in their pathology reports. Two patients had cancer cells in their doughnuts, and both patients had a positive distal margin in their primary tumor specimen; 33 patients had benign findings in their doughnuts. Pathologic examination of the doughnut did not change clinical management in any patient. Patients with rectosigmoid tumors were less likely to have their doughnuts included in the pathology report compared to patients with low tumors (P = .003). Doughnuts were not bundled with the primary tumor specimen in 374 (77%) of our patients; in these patients, pathologic analysis of the doughnut added an additional cost of approximately $643 per specimen.

CONCLUSION

This study demonstrates no clinical benefit in sending anastomotic doughnuts for histopathologic evaluation after performing a low anterior resection with a stapled anastomosis for rectal cancer. Overall cost may be decreased if doughnuts are not analyzed or if they are bundled with the primary tumor specimen.

Local Excision Techniques for Rectal Cancer After Neoadjuvant Chemoradiotherapy: What Are We Doing?

BACKGROUND

Recent evidence shows that the majority of rectal cancers demonstrate occult tumor scatter after neoadjuvant chemoradiotherapy that can extend for several centimeters under adjacent normal-appearing mucosa beside the residual mucosal abnormality or scar.

OBJECTIVE

This systematic review aimed to determine all of the published selection criteria and technical descriptions for local excision to date with regard to this phenomenon.

DATA SOURCES

PubMed, MEDLINE, and Embase were searched using the following key words: rectal cancer, local excision, radiotherapy, and neoadjuvant.

STUDY SELECTION

Studies that assessed local excision of rectal cancer after neoadjuvant chemoradiotherapy were included. Duplicate series were excluded from final analysis.

INTERVENTION

All of the data points were tabulated and analyzed using Microsoft Excel.

MAIN OUTCOME MEASURES

Criteria for patient selection, surgical technique, clinical restaging, pathologic assessment, and indications for completion surgery were analyzed.

RESULTS

After exclusions, data from 25 studies that in total evaluated local excision in 1001 patients were included. Compared with the single accepted technique of total mesorectal excision, described techniques for local excision after neoadjuvant therapy demonstrate significant variability in many critical technical issues, such as marking/tattooing original tumor margins before neoadjuvant therapy, using pretreatment tumor size/stage as exclusion criteria, and specifically stating lateral excision margins. Where detailed, the majority of local recurrences occurred in patients with clear pathological margins, yet significant variation existed for pathological assessment and reporting, with few studies detailing R status and some not reporting margin status at all. Significant variability also existed for adverse tumor features that mandated completion surgery, and, importantly, many series describe patients refusing completion surgery where indicated.

LIMITATIONS

We were unable to perform meta-analysis because studies lacked sufficient methodologic homogeneity to synthesize.

CONCLUSIONS

The observations from this study prompt additional study, standardization of technique, and cautious use of local excision of rectal cancer in the setting of neoadjuvant chemoradiotherapy.

Organ preservation with local excision or active surveillance following chemoradiotherapy for rectal cancer

BACKGROUND

Organ preservation has been proposed as an alternative to radical surgery for rectal cancer to reduce morbidity and mortality, and to improve functional outcome.

METHODS

Locally advanced non-metastatic rectal cancers were identified from a prospective database. Patients staged ⩾T3 or any stage N+ were referred for neoadjuvant chemoradiotherapy (CRT) (50-54 Gy and 5-fluorouracil), and were reassessed 6-8 weeks post treatment. An active surveillance programme ('watch and wait') was offered to patients who were found to have a complete endoluminal response. Transanal excision was performed in patients who were found to have an objective clinical response and in whom a residual ulcer measured ⩽3 cm. Patients were followed up clinically, endoscopically and radiologically to assess for local recurrence or disease progression.

RESULTS

Of 785 patients with rectal cancer between 2005 and 2015, 362 had non-metastatic locally advanced tumours treated with neoadjuvant CRT. Sixty out of three hundred and sixty-two (16.5%) patients were treated with organ-preserving strategies - 10 with 'watch and wait' and 50 by transanal excision. Fifteen patients were referred for salvage total mesorectal excision post local excision owing to adverse pathological findings. There was no significant difference in overall survival (85.6% vs 93.3%, P=0.414) or disease-free survival rate (78.3% vs 80%, P=0.846) when the outcomes of radical surgery were compared with organ preservation. Tumour regrowth occurred in 4 out of 45 (8.9%) patients who had organ preservation.

CONCLUSIONS

Organ preservation for locally advanced rectal cancer is feasible for selected patients who achieve an objective endoluminal response to neoadjuvant CRT. Transanal excision defines the pathological response and refines decision-making.

Objective measurement of the distal resection margin by MRI of the fresh and fixed specimen after partial mesorectal excision for rectal cancer: 5 cm is not just 5 cm and depends on when measured

BACKGROUND

Most studies have directly established the optimal perioperative in situ clearance margin in surgery for rectal cancer from the histologically observed extent of distal spread, neglecting the tissue variability that occurs after resection and fixation of the rectal specimen.

PURPOSE

To measure the length of the distal resection margin in the fresh and fixed specimen following partial mesorectal excision for rectal cancer using magnetic resonance imaging (MRI) to document tissue shrinkage after surgical removal and fixation.

MATERIAL AND METHODS

The length of the distal resection margin was measured by MRI of the fresh and fixed specimen and at histopathological examination of the fixed specimen in 10 patients who underwent surgery for upper rectal cancer. In addition, tissue shrinkage was estimated by measuring the total length of the fresh and fixed specimen and distance from the peritoneal reflection anteriorly to the distal cut edge of the specimen.

RESULTS

Measured by MRI, the distal resection margin was in the range of 0.6-10.2 cm (mean, 4.6 cm) in the fresh specimen, and 0.5-6.2 cm (mean, 3.2 cm) in the fixed specimen. The tissue shrinkage ratio was a mean of 69% (interquartile range, 61-77%). Taking all ratios from MRI and histopathological examination of tissue shrinkage into account, the collective tissue shrinkage ratio was 70% (95% confidence interval, 67-73%)

CONCLUSION

The length of the distal resection margin was reduced by 30% after surgical removal and fixation of the specimen.

Transanal Endoscopic Microsurgery (TEM) Following Neoadjuvant Chemoradiation for Rectal Cancer: Outcomes of Salvage Resection for Local Recurrence

BACKGROUND

Transanal endoscopic microsurgery (TEM) has been considered an alternative for selected patients with rectal cancer following neoadjuvant chemoradiation (CRT). Immediate total mesorectal completion for all patients with unfavorable pathological features would result in unnecessary protectomies in a significant proportion of patients. Instead, salvage total mesorectal excision (TME) could be restricted for patients developing local recurrence. The aim of the present study is to determine oncological outcomes of salvage resection for local recurrences following CRT and TEM.

METHODS

Consecutive patients undergoing TEM following neoadjuvant CRT for rectal cancer were reviewed. Patients with "near" complete response to CRT (≤3 cm; ycT1-2N0) were offered TEM. Salvage surgery was attempted in the event of a local recurrence.

RESULTS

A total of 53 patients were managed by CRT followed by TEM. Unfavorable pathological features were present in 36 patients (68 %). None of the patients underwent immediate completion TME. There were 12 patients who developed local recurrence resulting in a 2-year local recurrence-free survival of 77 % (95 % CI, 53-100 %). Of these patients, 9 developed exclusively local recurrences, and all had at least 1 unfavorable pathological feature in the specimen after TEM (100 %). Eight patients (8 of 9) underwent salvage resection (abdominoperineal resection [APR] in 87 %) with CRM+ in 7 of 8 patients (87 %). Four patients developed local re-recurrence after a median 36 months of follow-up. The 2-year local re-recurrence free survival was 60 %.

CONCLUSIONS

Salvage resection for local recurrence following CRT and TEM is associated with high rates of R1 resection (CRM+) and local re-recurrence. Immediate completion of TME should be considered for patients with unfavorable pathological features after TEM.

Transanal Endoscopic Microsurgery

Transanal endoscopic microsurgery (TEM) was developed by Professor Gerhard Buess 30 years ago at the dawn of minimally invasive surgery. TEM utilizes a closed proctoscopic system whereby endoluminal surgery is accomplished with high-definition magnification, constant CO2 insufflation, and long-shafted instruments. The end result is a more precise excision and closure compared to conventional instrumentation. Virtually any benign lesion can be addressed with this technology; however, proper patient selection is paramount when using it for cancer.

The value of forceps biopsy and core needle biopsy in prediction of pathologic complete remission in locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy

Patients with pathological complete remission (pCR) after treated with neoadjuvant chemoradiotherapy (nCRT) have better long-term outcome and may receive conservative treatments in locally advanced rectal cancer (LARC). The study aimed to evaluate the value of forceps biopsy and core needle biopsy in prediction of pCR in LARC treated with nCRT. In total, 120patients entered this study. Sixty-one consecutive patients received preoperative forceps biopsy during endoscopic examination. Ex vivo core needle biopsy was performed in resected specimens of another 43 consecutive patients. The accuracy for ex vivo core needle biopsy was significantly higher than forceps biopsy (76.7% vs. 36.1%; p < 0.001). The sensitivity for ex vivo core needle biopsy was significantly lower in good responder (TRG 3) than poor responder (TRG ≤ 2) (52.9% vs. 94.1%; p = 0.017). In vivo core needle biopsy was further performed in 16 patients with good response. Eleven patients had residual cancer cells in final resected specimens, among whom 4 (36.4%) patients were biopsy positive. In conclusion, routine forceps biopsy was of limited value in identifying pCR after nCRT. Although core needle biopsy might further identify a subset of patients with residual cancer cells, the accuracy was not substantially increased in good responders.

Assessing pathological complete response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer: a systematic review

AIM

Pathological complete response to neoadjuvant chemoradiotherapy is found in 20% of patients with rectal cancer undergoing long-course chemoradiotherapy. Some authors have suggested that these patients do not need to undergo surgery and can be managed with careful follow-up, with surgery only used in the event of clinical failure. Widespread adoption of this regimen is limited by the accuracy of methods to confirm a pathological complete response (pCR).

METHOD

A systematic search of PubMed, Medline and Cochrane databases was conducted to identify clinical, histological and radiological features in those patients with rectal cancer who achieved a pCR following chemoradiotherapy. Searches were conducted with the following keywords and MeSH search terms: 'rectal neoplasm', 'response', 'neoadjuvant', 'preoperative chemoradiation' and 'tumour response'. After review of title and abstracts, 89 articles addressing the assessment of pCR were identified.

RESULTS

Histology and clinical assessment are the most effective methods of assessment of pCR, with histology considered the gold standard. Clinical assessment is limited to low rectal tumours and is open to significant inter-rater variability, while histological examination requires a surgical specimen. Diffusion-weighted MRI and (18) F-fluorodeoxyglucose positron emission tomography/CT demonstrate the greatest potential for the assessment of pCR, but both modalities have limited accuracy.

CONCLUSION

Determination of a pCR is crucial if a nonoperative approach is to be undertaken proactively. Various methods are available, but currently they lack sufficient sensitivity and specificity to define management. This is likely to be an area of further research in the future.

Organ preservation in rectal cancer: current status and future perspectives

With the introduction of population screening initiatives, more patients may be amenable to local, transanal excision (LE) of early-stage rectal cancer. The most important drawback of LE is the risk of understaging node-positive disease. The most powerful predictors of node-positive disease are lymphatic invasion, submucosal invasion depth and width, tumor budding and poor differentiation. Therefore, LE should be reserved for low-risk T1 tumors in those reluctant or unable to undergo major surgery. Neoadjuvant chemoradiation followed by LE for T2 tumors allows adequate local control, and is currently being compared with anterior resection alone in randomized trials. A mere watchful waiting approach has been proposed in clinical complete responders to chemoradiation. However, given the very poor accuracy of current imaging modalities to predict a true pathological complete response, this strategy should not be offered outside of well-controlled trials.

Assessment of Clinical Complete Response After Chemoradiation for Rectal Cancer with Digital Rectal Examination, Endoscopy, and MRI: Selection for Organ-Saving Treatment

Background

The response to chemoradiotherapy (CRT) for rectal cancer can be assessed by clinical examination, consisting of digital rectal examination (DRE) and endoscopy, and by MRI. A high accuracy is required to select complete response (CR) for organ-preserving treatment. The aim of this study was to evaluate the value of clinical examination (endoscopy with or without biopsy and DRE), T2W-MRI, and diffusion-weighted MRI (DWI) for the detection of CR after CRT.

Methods

This prospective cohort study in a university hospital recruited 50 patients who underwent clinical assessment (DRE, endoscopy with or without biopsy), T2W-MRI, and DWI at 6–8 weeks after CRT. Confidence levels were used to score the likelihood of CR. The reference standard was histopathology or recurrence-free interval of >12 months in cases of wait-and-see approaches. Diagnostic performance was calculated by area under the receiver operator characteristics curve, with corresponding sensitivities and specificities. Strategies were assessed and compared by use of likelihood ratios.

Results

Seventeen (34 %) of 50 patients had a CR. Areas under the curve were 0.88 (0.78–1.00) for clinical assessment and 0.79 (0.66–0.92) for T2W-MRI and DWI. Combining the modalities led to a posttest probability for predicting a CR of 98 %. Conversely, when all modalities indicated residual tumor, 15 % of patients still experienced CR.

Conclusions

Clinical assessment after CRT is the single most accurate modality for identification of CR after CRT. Addition of MRI with DWI further improves the diagnostic performance, and the combination can be recommended as the optimal strategy for a safe and accurate selection of CR after CRT.

Assessment of a novel, full-thickness incisional biopsy model to restage rectal tumours after neoadjuvant chemoradiotherapy: results of an ex vivo pilot study

BACKGROUND

There is currently no reliable means to restage rectal cancers after neoadjuvant chemoradiation. Recent histological evidence shows that the epicentre for residual cancer cells is focussed directly underneath any residual mucosal abnormality (RMA). This proof-of-concept study aimed to determine the utility of a novel, minimally invasive method of incisional biopsy as a restaging tool. A secondary aim was to compare its performance to clinical response assessment.

METHODS

After surgical resection, 0.5 × 0.5 cm, full-thickness incisional biopsy was performed in 15 rectal cancers. Of these, 13 had RMA and 2 had mucosal cCR but a palpable intramural abnormality. In all patients, a full-thickness incisional biopsy was taken through the centre of these areas. The ypT stage of the incisional biopsy and the final total specimen were compared. Complete mucosal clinical response was deemed to have occurred when either no residual tumour or only a flat mucosal scar remained.

RESULTS

Incisional biopsy correctly identified all patients that had been downstaged to ypT0; however, it also falsely identified 5 of 10 patients (50%) with yp residual disease as ypT0. Overall performance of incisional biopsy to detect residual cancer was 50% sensitivity, 100 % specificity, 100% PPV, and 50% NPV with an accuracy of 66%. A complete mucosal clinical response occurred in only one of five patients downstaged to ypT0 (20% sensitive). It also occurred in one patient, which was ultimately staged as ypT3.

CONCLUSION

This prospective data demonstrates that incisional biopsy is not suitable as a stand-alone method to restage rectal cancer after CRT. Alternate or complementary means of restaging are needed.

Optimizing the selection of patients with low rectal cancer for intersphincteric resection by evaluating vertical invasion to the levator and external sphincter

AIM

The indications for intersphincteric (ISR) anterior resection are not clearly defined. The aim of this study was to evaluate vertical extension of T2 or T3 low rectal cancer treated by rectal amputation to optimize patient selection for ISR.

METHOD

The abdominoperineal excision specimens of T2 or T3 low rectal cancer from 53 patients treated between 1992 and 2004 were retrospectively reviewed. Vertical invasion was quantified by measuring the shortest distance between the tumour and the striated muscle (T-SM), assuming that this represented the surgical margin that would have be achieved had an ISR been performed.

RESULTS

Involvement of the dentate line (DL) and intramural distal spread were independent risk factors for T-SM ≤ 2 mm. The T-SM was less when the inferior border of the tumour was on the distal side of the DL (r = 0.572, P < 0.001). The probability of involvement of the DL, intramural distal spread or either one of these being associated with T-SM ≤ 2 mm was 43, 46 and 43%, respectively. All patients without both intramural distal spread and involvement of the DL had T-SM > 2.

CONCLUSION

We recommend that ISR should only be performed for patients with T2 or T3 low rectal cancer in whom the lowest edge of the tumour is above the DL and there is no intramural distal spread. Such patients are relatively unlikely to have a T-SM ≤ 2 mm.