Distribution of residual cancer cells in the bowel wall after neoadjuvant chemoradiation in patients with rectal cancer

An update on the multimodality of localized rectal cancer

New strategies have reduced the local recurrence (LR) rate and extended the duration of overall survival (OS) in patients with localized rectal cancer (RC) in recent decades. The mainstay of curative treatment remains radical surgery; however, downsizing the tumor by neo-adjuvant chemo-radiotherapy and adjuvant cytotoxic therapy for systemic disease has shown significant additional benefit. The standardization of total mesorectal excision (TME), radiation treatment (RT) dose and fractionation, and optimal timing and sequencing of treatment modalities with the use of prolonged administration of fluoropyrimidine concurrent with RT have significantly decreased the rates of LR in locally advanced rectal cancer (LARC) patients. This review focuses on the optimization of multi-modality therapies in patients with localized RC.

Simultaneous integrated protection : A new concept for high-precision radiation therapy

OBJECTIVE

Stereotactic radiotherapy near serial organs at risk (OAR) requires special caution. A novel intensity-modulated radiotherapy (IMRT) prescription concept termed simultaneous integrated protection (SIP) for quantifiable and comparable dose prescription to targets very close to OAR is described.

MATERIALS AND METHODS

An intersection volume of a planning risk volume (PRV) with the total planning target volume (PTV) defined the protection volume (PTV_SIP). The remainder of the PTV represented the dominant PTV (PTV_dom). Planning was performed using IMRT. Dose was prescribed to PTV_dom according to ICRU in 3, 5, 8, or 12 fractions. Constraints to OARs were expressed as absolute and as equieffective doses at 2 Gy (EQD2). Dose to the gross risk volume of an OAR was to respect constraints. Violation of constraints to OAR triggered a planning iteration at increased fractionation. Dose to PTV_SIP was required to be as high as possible within the constraints to avoid local relapse.

RESULTS

SIP was applied in 6 patients with OAR being large airways (n = 2) or bowel (n = 4) in 3, 5, 8, and 12 fractions in 1, 3, 1, and 1 patients, respectively. PTVs were 14.5-84.9 ml and PTV_SIP 1.8-3.9 ml (2.9-13.4 % of PTV). Safety of the plans was analyzed from the absolute dose-volume histogram (dose to ml). The steepness of dose fall-off could be determined by comparing the dose constraints to the PRVs with those to the OARs (Wilcoxon test p = 0.001). Constraints were respected for the corresponding OARs. All patients had local control at a median 9 month follow-up and toxicity was low.

CONCLUSION

SIP results in a median dose of ≥100 % to PTV, to achieve high local control and low toxicity. Longer follow-up is required to verify results and a prospective clinical trial is currently testing this new approach in chest and abdomen stereotactic body radiotherapy.

Pathological Assessment of Rectal Cancer after Neoadjuvant Chemoradiotherapy: Distribution of Residual Cancer Cells and Accuracy of Biopsy

We investigated the distribution of residual cancer cells (RCCs) within different layers of the bowel wall in surgical specimens and the value of biopsies of primary rectal lesion after preoperative volumetric modulated arc therapy (VMAT) with concurrent chemotherapy in patients with rectal cancer. Between April 2011 and April 2013, 178 patients with rectal cancer who received preoperative VMAT, concurrent chemotherapy, and surgery were evaluated; 79 of the patients received a biopsy of the primary lesion after chemoradiotherapy and prior to surgery. The distribution of RCCs in the surgical specimens and the sensitivity and specificity of the biopsy of primary rectal lesions for pathological response were evaluated. Fifty-two patients had a complete pathological response in the bowel wall. Of the 120 patients with ypT2-4, the rate of detection of RCCs in the mucosa, submucosa, and muscularis propria was 20%, 36.7%, 69.2%, respectively. The sensitivity and specificity of biopsies of primary rectal lesions was 12.9% and 94.1%, respectively. After chemoradiotherapy, the RCCs were primarily located in the deeper layers of the bowel wall, and the biopsy results for primary rectal lesions were unreliable due to poor sensitivity.

A Nomogram to Predict Lymph Node Positivity Following Neoadjuvant Chemoradiation in Locally Advanced Rectal Cancer

BACKGROUND

Patients with locally advanced rectal cancer typically receive neoadjuvant chemoradiation followed by total mesorectal excision. Other treatment approaches, including transanal techniques and close surveillance, are becoming increasingly common following positive responses to chemoradiation. Lack of pathologic lymph node staging is one major disadvantage of these novel strategies.

OBJECTIVE

The purposes of this study were to determine clinicopathologic factors associated with positive lymph nodes following neoadjuvant chemoradiation for rectal cancer and to create a nomogram using these factors to predict rates of lymph node positivity.

DESIGN

This is a retrospective cohort analysis.

SETTINGS

This study used the National Cancer Database.

PATIENTS

Patients aged 18 to 90 with clinical stage T3/T4, N0, M0 or Tany, N1-2, M0 adenocarcinoma of the rectum who underwent neoadjuvant chemoradiation before total mesorectal excision from 2010 to 2012 were identified.

MAIN OUTCOME MEASURES

The primary outcome measure was lymph node positivity after neoadjuvant chemoradiation for locally advanced rectal cancer. Bivariate and multivariate analyses were used to determine the associations of clinicopathologic variables with lymph node positivity.

RESULTS

Eight thousand nine hundred eighty-four patients were included. Young age, lower Charlson score, mucinous histology, poorly differentiated and undifferentiated tumors, the presence of lymphovascular invasion, elevated CEA level, and clinical lymph node positivity were significantly predictive of pathologic lymph node positivity following neoadjuvant chemoradiation. The predictive accuracy of the nomogram is 70.9%, with a c index of 0.71. There was minimal deviation between the predicted and observed outcomes.

LIMITATIONS

This study is retrospective, and it cannot be determined when in the course of treatment the data were collected.

CONCLUSIONS

We created a nomogram to predict lymph node positivity following neoadjuvant chemoradiation for locally advanced rectal cancer that can serve as a valuable complement to imaging to aid clinicians and patients in determining the best treatment strategy.

Multimodal Rectal Cancer Treatment: In Some Cases, Less May Be More

A series of clinical trials in the last several decades has resulted in the development of multimodality treatment of locally advanced rectal cancer that includes neoadjuvant (preoperative) chemoradiotherapy, total mesorectal excision, and postoperative adjuvant chemoradiotherapy. Owing to this regimen, patients with locally advanced rectal cancer have better survival rates than patients with colon cancer, but at the cost of substantial morbidity and reduced quality of life. The challenge is to identify treatment approaches that maintain or even improve oncologic outcomes while preserving quality of life. We have identified different tumor characteristics that are associated with recurrence and probability of survival for locally advanced rectal cancer. This risk stratification, based on baseline clinical staging and tumor response to chemoradiotherapy, has led us to question whether all patients with locally advanced rectal cancer require every component of the multimodal regimen. In this article, we will review recent evidence that some patients with locally advanced rectal cancer can be spared one or more treatment modalities without compromising long-term oncologic outcomes and while preserving quality of life.

The outcome and the frequency of pathological complete response after neoadjuvant radiotherapy in curative resections for advanced rectal cancer: a population-based study

AIM

Pathological complete response (ypCR) after neoadjuvant treatment for rectal cancer is associated with favourable survival and a low rate of local recurrence. The aim of the study was to assess the incidence of ypCR among patients with advanced rectal cancer treated with neoadjuvant chemoradiotherapy and curative resection and to explore factors associated with survival.

METHOD

From 2000 to 2009, 1384 patients enrolled in the national population- based colorectal cancer registry of Norway with advanced T3 and T4 rectal cancer with N0-2, M0 received neoadjuvant long-course (chemo)radiation. The duration of follow-up was a median of 5 years.

RESULTS

ypCR was achieved in 147 (10.6%) patients. The estimated 5-year overall survival rate was 87% (confidence interval ± 5.4) among ypCR and 67% among non-ypCR (confidence interval ± 2.7) (P < 0.0001). Distant metastasis developed in 12 (8%) of 147 and 328 (26.5%) of 1237 patients respectively (P < 0.001). In a Cox proportional hazards ratio model the effect of ypCR on survival was adjusted for age [hazard ratio (HR) 1.056, P = 0.0001], metachronous metastasis (HR 4.7, P = 0.0001), local recurrence (HR 4.3, P = 0.0001) and surgical procedure (HR 1.48, P = 0.0001). The independent effect of ypCR (HR 0.65, P = 0.041) on survival almost disappeared compared with the univariate analysis.

CONCLUSION

The rate of ypCR in advanced rectal cancer was about 10%. This phenomenon seems to occur in tumours with a low risk of metastasizing. The contribution of neoadjuvant therapy to ypCR on survival was small or absent.

Is Pathologic Near-Total Regression an Appropriate Indicator of a Good Response to Preoperative Chemoradiotherapy Based on Oncologic Outcome of Disease?

We evaluated the oncologic outcomes of patients with rectal cancer who demonstrated pathologic near-total regression (NTR) after preoperative chemoradiotherapy (PCRT) and compared with total regression (TR). Pathologic NTR in rectal cancer by tumor regression grade (TRG) is usually considered to indicate a good response, when evaluating tumor response to PCRT. We retrospectively analyzed the outcomes in 263 patients who received PCRT for advanced T3/4 or N+ rectal cancer followed by radical resection. Patients were diagnosed with TR (n = 132) or NTR (n = 131) according to the TRG. Recurrence-free survival (RFS) was evaluated and compared between groups. For evaluating the consistency between the result and previously published data, meta-analysis for summing up survival curve was performed using generalized linear mixed model. ypT status was heterogeneous in the NTR group as follows; 3 Tis (2.3%), 21 T1 (16%), 72 T2 (55%), and 35 T3 (26.7%). Metastatic lymph nodes were more frequently found in the NTR group (6.8% in TR vs 24.4% in NTR patients; P = 0.003). The cumulative recurrence rate was higher in the NTR group (19.8% vs 6.1%; P = 0.003). The 5-year RFS was lower in the NTR group (94% vs 77.8%; P = 0.001). Significant differences in the RFS rate were found in comparison with the published literature. Based on differences in the oncologic outcomes between the TR and NTR groups, it might not be suitable to use NTR as an indicator of good response to PCRT together with TR.

Neoadjuvant chemoradiation therapy and pathological complete response in rectal cancer

The management of rectal cancer has evolved significantly in the last few decades. Significant improvements in local disease control were achieved in the 1990s, with the introduction of total mesorectal excision and neoadjuvant radiotherapy. Level 1 evidence has shown that, with neoadjuvant chemoradiation therapy (CRT) the rates of local recurrence can be lower than 6% and, as a result, neoadjuvant CRT currently represents the accepted standard of care. This approach has led to reliable tumor down-staging, with 15-27% patients with a pathological complete response (pCR)-defined as no residual cancer found on histological examination of the specimen. Patients who achieve pCR after CRT have better long-term outcomes, less risk of developing local or distal recurrence and improved survival. For all these reasons, sphincter-preserving procedures or organ-preserving options have been suggested, such as local excision of residual tumor or the omission of surgery altogether. Although local recurrence rate has been stable at 5-6% with this multidisciplinary management method, distal recurrence rates for locally-advanced rectal cancers remain in excess of 25% and represent the main cause of death in these patients. For this reason, more recent trials have been looking at the administration of full-dose systemic chemotherapy in the neoadjuvant setting (in order to offer early treatment of disseminated micrometastases, thus improving control of systemic disease) and selective use of radiotherapy only in non-responders or for low rectal tumors smaller than 5 cm.

Watch and wait policy after preoperative radiotherapy for rectal cancer; management of residual lesions that appear clinically benign

BACKGROUND

During an ongoing phase II observational study on watch and wait policy in rectal cancer, a substantial number of patients presented residual lesion after radiotherapy with a clinical benign appearance. This article aims to discuss the clinical significance of such findings.

MATERIALS AND METHODS

Main entry criteria were age ≥70 years and small tumour (≤5 cm and ≤60% of circumferential involvement) located in the low rectum. Patients received chemoradiation (50 Gy, 2 Gy per fraction concomitantly with a 5-Fu bolus and leucovorin) or 5 × 5 Gy if considered unfit for chemotherapy. Patients with clinical complete response (cCR) were observed. Those with persistent tumours underwent transanal endoscopic microsurgery [TEM] if the baseline tumour was ≤3 cm and cN0 or total mesorectal excision.

RESULTS

The watch and wait procedure was used in 11 out of the total 35 patients (31%) with a cCR; 17 patients (49%) with residual tumours that appeared clinically malignant were referred for TEM or abdominal surgery. In the remaining seven (20%), the residual tumour clinically appeared benign. Of these, there were two invasive cancers, four high-grade dysplasias and one low-grade dysplasia. The five patients with dysplasia, underwent local lesion resection without recurrence within a median of 11 months follow-up.

CONCLUSIONS

The majority of lesions that appeared clinically benign after radio(chemo)therapy were also benign on pathological examination. Thus, local excision of such lesions should be considered.

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.

Response to chemoradiotherapy and lymph node involvement in locally advanced rectal cancer

AIM: To establish the association between lymph node involvement and the response to neoadjuvant therapy in locally advanced rectal cancer.

METHODS: Data of 130 patients with mid and low locally advanced rectal adenocarcinoma treated with neoadjuvant chemoradiation followed by radical surgery over a 5-year period were reviewed. Tumor staging was done by endorectal ultrasound and/or magnetic resonance imaging. Tumor response to neoadjuvant therapy was determined by T-downstaging and tumor regression grading (TRG). Pathologic complete response (pCR) is defined as the absence of tumor cells in the surgical specimen (ypT0N0). The varying degrees TRG were classified according to Mandard’s scoring system. The evaluation of the response is based on the comparison between previous clinico-radiological staging and the results of pathological evaluation. χ² and Spearman’s correlation tests were used for the comparison of variables.

RESULTS: Pathologic complete response (pCR, ypT0N0, TRG1) was observed in 19 cases (14.6%), and other 18 (13.8%) had only very few residual malignant cells in the rectal wall (TRG2). T-downstaging was found in 63 (48.5%). Mean lymph node retrieval was 9.4 (range 0-38). In 37 cases (28.5%) more than 12 nodes were identified in the surgical specimen. Preoperative lymph node involvement was seen in 77 patients (59.2%), 71 N1 and 6 N2. Postoperative lymph node involvement was observed in 41 patients (31.5%), 29 N1 and 12 N2, while the remaining 89 were N0 (68.5%). In relation to ypT stage, we found nodal involvement of 9.4% in ypT0-1, 22.2% in ypT2 and 43.7% in ypT3-4. Of the 37 patients considered “responders” to neoadjuvant therapy (TRG1 and 2), there were only 4 N+ (10.8%) and the remainder N0 (89.2%). In the “non responders” group (TRG 3, 4 and 5), 37 cases were N+ (39.8%) and 56 (60.2%) were N0 (P < 0.001).

CONCLUSION: Response to neoadjuvant chemoradiation in rectal cancer is associated with lymph node involvement.

Current concepts of colorectal cancer resection pathology

The discussion of pathology results is one of the important items in the multidisciplinary meeting. These results describe not only the adequacy of earlier treatments (neoadjuvant therapy, surgery), but guide subsequent treatment decisions by providing staging information and additional prognostic and predictive factors. In the era of next-generation sequencing, every so often the emphasis is put on the molecular background of tumours, but the information that can be retrieved from the resection specimen remains essential for optimal patient care. In the current review the different surgical approaches will be described, together with the relevant macroscopic evaluations. Microscopic features will be addressed, giving an overview that is aimed at optimal information exchange in the multidisciplinary meeting. Finally, special requirements for reporting local excisions and specimen after neoadjuvant therapy will be discussed.

Endoscopic Criteria for Evaluating Tumor Stage after Preoperative Chemoradiation Therapy in Locally Advanced Rectal Cancer

Purpose

Local excision may be an another option for selected patients with markedly down-staged rectal cancer after preoperative chemoradiation therapy (CRT), and proper evaluation of post-CRT tumor stage (ypT) is essential prior to local excision of these tumors. This study was designed to determine the correlations between endoscopic findings and ypT of rectal cancer.

Materials and Methods

In this study, 481 patients with locally advanced rectal cancer who underwent preoperative CRT followed by surgical resection between 2004 and 2013 at a single institution were evaluated retrospectively. Pathological good response (p-GR) was defined as ypT ≤ 1, and pathological minimal or no response (p-MR) as ypT ≥ 2. The patients were randomly classified according to two groups, a testing (n=193) and a validation (n=288) group. Endoscopic criteria were determined from endoscopic findings and ypT in the testing group and used in classifying patients in the validation group as achieving or not achieving p-GR.

Results

Based on findings in the testing group, the endoscopic criteria for p-GR included scarring, telangiectasia, and erythema, whereas criteria for p-MR included nodules, ulcers, strictures, and remnant tumors. In the validation group, the kappa statistic was 0.965 (p < 0.001), and the sensitivity, specificity, positive predictive value, and negative predictive value were 0.362, 0.963, 0.654, and 0.885, respectively.

Conclusion

The endoscopic criteria presented are easily applicable for evaluation of ypT after preoperative CRT for rectal cancer. These criteria may be used for selection of patients for local excision of down-staged rectal tumors, because patients with p-MR could be easily ruled out.

Nonoperative management of rectal cancer: identifying the ideal patients

Neoadjuvant chemoradiation (CRT) is considered one of the preferred treatment strategies for patients with locally advanced rectal cancer. This strategy may lead to significant tumor regression, ultimately leading to a complete pathologic response in up to 42% of patients. Assessment of tumor response following CRT and before radical surgery may identify patients with a complete clinical response who could possibly be managed nonoperatively with strict follow-up (watch-and-wait strategy). The present article deals with critical issues regarding appropriate selection of patients for this approach.

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.

YKL-40/c-Met expression in rectal cancer biopsies predicts tumor regression following neoadjuvant chemoradiotherapy: a multi-institutional study

BACKGROUND

Neoadjuvant chemo-radiotherapy (CRT) followed by surgical resection is the standard treatment for locally advanced rectal cancer, although complete tumor pathological regression is achieved in only up to 30% of cases. A clinicopathological and molecular predictive stratification of patients with advanced rectal cancer is still lacking. Here, c-Met and YKL-40 have been studied as putative predictors of CRT response in rectal cancer, due to their reported involvement in chemoradioresistance in various solid tumors.

MATERIAL AND METHODS

A multicentric study was designed to assess the role of c-Met and YKL-40 expression in predicting chemoradioresistance and to correlate clinical and pathological features with CRT response. Immunohistochemistry and fluorescent in situ hybridization for c-Met were performed on 81 rectal cancer biopsies from patients with locally advanced rectal adenocarcinoma. All patients underwent standard (50.4 gy in 28 fractions + concurrent capecitabine 825 mg/m2) neoadjuvant CRT or the XELOXART protocol. CRT response was documented on surgical resection specimens and recorded as tumor regression grade (TRG) according to the Mandard criteria.

RESULTS

A significant correlation between c-Met and YKL-40 expression was observed (R = 0.43). The expressions of c-Met and YKL-40 were both significantly associated with a lack of complete response (86% and 87% of c-Met and YKL-40 positive cases, p< 0.01 and p = 0.006, respectively). Thirty of the 32 biopsies co-expressing both markers had partial or absent tumor response (TRG 2-5), strengthening their positive predictive value (94%). The exclusive predictive role of YKL-40 and c-Met was confirmed using a multivariate analysis (p = 0.004 and p = 0.007 for YKL-40 and c-Met, respectively). TRG was the sole morphological parameter associated with poor outcome.

CONCLUSION

c-Met and YKL-40 expression is a reliable predictor of partial/absent response to neoadjuvant CRT in rectal cancer. Targeted therapy protocols could take advantage of prior evaluations of c-MET and YKL-40 expression levels to increase therapeutic efficacy.

Flattened tumor requires a more careful attention for residual distal cancer spread in locally advanced lower rectal carcinoma after chemoradiotherapy

BACKGROUND/AIMS

Limited data are available on distal resection margin (DRM) for lower rectal cancer (LRC) after preoperative chemoradiotherapy (pre-CRT); thus, we aimed to establish the criteria for DRMs as estimated by the macroscopic tumor appearance.

METHODS

This was a pathological study using whole-mount sections that included the entire circumference of tumor. Residual cancer spread located most distally from the macroscopic tumor border was mainly evaluated.

RESULTS

A retrospective cohort of 42 consecutive patients with locally advanced LRC after pre-CRT was enrolled, and 38 patients were eligible for this study. According to the macroscopic tumor appearance, 18 patients had raised-type and 20 had flattened-type tumors. Patients with flattened-type tumors were closely associated with histopathological regression grade. Residual distal cancer spread (RDCS) was located ≤4.0 mm (median, 0.1 mm) in the raised-type tumors and ≤17.1 mm (median, 4.2 mm) in the flattened-type tumors. RDCS in flattened-type tumors was distributed diffusely and distally from the tumor border (p = 0.022).

CONCLUSION

Even in patients evaluated as pre-CRT responders, flattened tumors often accompanied distally located residual cancer that had spread from the tumor border and require more careful attention in order to ensure cancer clearance.

Pathologic processing of the total mesorectal excision

Total mesorectal excision (TME) is the current optimal surgical treatment for patients with rectal carcinoma. A complete TME is related to lower local recurrence rates and increased patient survival. Many confounding factors in the patient's anatomy and prior therapy can make it difficult to obtain a perfect plane, and thus a complete TME. The resection specimen can be thoroughly evaluated, grossly and microscopically, to identify substandard surgical outcomes and increased risk of local recurrence. Complete and accurate data reporting is critical for patient care and helps surgeons improve their technique.

Pathology reporting of pancreatic cancer following neoadjuvant therapy: challenges and uncertainties

An increasing number of studies investigate the use of neoadjuvant treatment for ductal adenocarcinoma of the pancreas. While a strong rationale supports this approach, study results are difficult to interpret and compare due to marked variance in multiple aspects of study design and performance. Divergence in pathology examination and reporting as a cause for heterogeneity and incomparability of study results has not been brought into this discussion yet, despite the fact that several key outcome measures for neoadjuvant treatment are pathology-based. This article discusses areas of controversy and difficulty regarding the evaluation of the extent of residual tumour tissue, grading of tumour regression and assessment of the margins, and explains the important clinical implications of the present uncertainty and divergence in pathology practice.

Tumour regression grading after chemoradiotherapy for locally advanced rectal cancer: a near pathologic complete response does not translate into good clinical outcome

BACKGROUND

After preoperative chemoradiotherapy (CRT) for rectal cancer, clinically undetectable residual tumour deposits or pathologic lymph nodes may remain in the mesorectum.

AIM

The aim of this study was to report histopathological effects of CRT and factors affecting outcome in a uniformly treated series of locally advanced rectal cancer (LARC) patients.

METHODS

Between 2004 and 2008, 107 patients with cT3 (threatening the mesorectal fascia or <5 cm from the anal verge), cT4 or cN2 rectal cancer were treated with preoperative CRT (25 × 2 Gy with capecitabine) and TME 6-8 weeks later. Central histopathological review followed. Tumour regression grade (TRG) was scored in pCR, near-pCR, response and no response. Cox regression was performed to identify prognosticators.

RESULTS

The 3-year distant metastasis-free interval, disease-free rate and overall survival rate were 82%, 73% and 87% (median 44 months follow-up). TRG consisted of 20% pCR, 11% near-pCR, 55% response and 14% no response. 6/21 pCR patients harboured nodal metastases. 5/12 near-pCR had ypT3 disease, while 6 harboured node metastases. 5/12 near-PCR patients developed distant metastases. ypN and TRG were powerful outcome discriminators.

CONCLUSION

The high number of near-pCR with ypT3 or ypN1/2 and their poor outcome demonstrates that "watch-and-wait" in LARC patients should be applied with care.

Pathological prognostic factors in locally advanced rectal carcinoma after neoadjuvant radiochemotherapy: analysis of 113 cases

AIMS

Neoadjuvant radiochemotherapy (RCT) followed by surgical resection is the treatment for locally advanced mid-rectal or low rectal cancer. The aim of this study was to evaluate postoperative histological prognostic factors in a series of surgical specimens after neoadjuvant RCT.

METHODS AND RESULTS

One hundred and thirteen patients were included. Macroscopic and microscopic examinations were performed according to CAP recommendations, with additional criteria such as tumour budding, the presence of calcifications, and response to neoadjuvant therapy assessed according to Modified Rectal Cancer Regression Grade (m-RCRG). The 3-year disease-free survival (DFS) was 67.6%. In univariate analysis, ypTN stage, tumour budding, circumferential margin, invaded margin and vascular and perineural invasion were prognostic factors. In multivariate analysis, the presence of calcifications (P = 0.04) and an involved circumferential margin (P = 0.03) were the only independent factors for worse DFS. mRCRG was not correlated with DFS. Among the 50 m-RCRG1 tumours, DFS was better in ypT0 patients than in other ypT stages (P = 0.003).

CONCLUSIONS

The presence of calcifications in the tumour bed is described for the first time as a prognostic factor in rectal cancer. The prognostic value of budding was demonstrated in this study after neoadjuvant RCT. ypT stage appears to be a more reliable predictor of oncological outcome than histological tumour regression grade, which needs to be standardized for better reproducibility.

Paradigm-shifting new evidence for treatment of rectal cancer

BACKGROUND

Treatment of rectal cancer has dramatically evolved during the last three decades shifting toward a tailored approach based on preoperative staging and response to neoadjuvant combined modality therapy (CMT).

METHODS

A literature search was performed using PubMed/Medline electronic databases.

RESULTS

Selected patients with T1 N0 rectal cancer are best treated with local excision by transanal endoscopic microsurgery (TEM). Satisfactory results have been reported after CMT and TEM for the treatment of highly selected T2 N0 rectal cancers. CMT followed by rectal resection and total mesorectal excision is considered the standard of care for the treatment of locally advanced rectal cancer. However, a subset of stage II and III patients may not require neoadjuvant radiation treatment. Finally, there are mounting data supporting a "watch and wait" approach or local excision in patients with complete clinical response after neoadjuvant CMT.

CONCLUSIONS

Current evidence shows that selected T1 N0 rectal cancers can be managed by TEM alone, while locally advanced cancers should be treated by CMT followed by radical surgery. Studies are underway to identify patients that do not benefit from neoadjuvant radiation therapy. A non-operative approach in case of complete clinical response must be validated by large prospective studies.

Neoadjuvant therapy followed by local excision and two-stage total mesorectal excision: a new strategy for sphincter preservation in locally advanced ultra-low rectal cancer

BACKGROUND

With the increased usage of neoadjuvant chemoradiotherapy, improved surgical technique and stapling devices, sphincter-preserving resection has become more frequent for patients with rectal cancer. However, as for locally advanced ultra-low rectal cancer, sphincter-preservation is still facing an enormous challenge.

OBJECTIVE

To introduce an NLT strategy of sphincter-preservation-neoadjuvant therapy (NT) followed by local excision (LE) and two-stage total mesorectal excision (TME)-into the treatment of locally advanced ultra-low rectal cancer (lesions with anal sphincter invasion).

METHODS

From October 2010 to October 2011, nine patients with locally advanced rectal cancer located less than 3 cm from the anal verge were treated by the NLT strategy. All patients had shown good clinical response to NT. The LE procedure was carried transanally 6-8 weeks after completion of the NT. TME was performed to dissect mesorectal lymph nodes 4-6 weeks after LE.

RESULTS

Of the nine patients, the lesion was assessed as T2 in two, T3 in five, and T4 in two before NT, and lymph node metastasis was detected in five patients. The median distance from the tumor to the anal verge was 2.5 cm (range: 1-3 cm). The median follow-up was 27 months (range: 24-34 months). No distant metastasis was detected. Only one patient (11.1%) developed local recurrence at 12 months post-operatively and then underwent abdomino-perineal resection. The remaining eight patients had preserved long-term continence and the median Wexner score at two years post-operation was 4 (range: 2-6).

CONCLUSION

The new NLT strategy can achieve sphincter-preservation in some patients with ultra-low rectal cancer, with favorable oncological outcome and preservation of normal anal sphincter function.