Quantification of histologic regression of rectal cancer after irradiation: a proposal for a modified staging system

Optimal therapy for resectable rectal cancer

A lot can be gained by improving our understanding of the optimal sequence of existing therapies in rectal cancer, with the more difficult task of balancing the morbidity of recurrence with the morbidity of prescribed therapies that are particularly toxic owing to tumour location. This review aims to highlight a recent shift in treatment strategies in the opposite direction, with a focus on earlier, more intense systemic treatments with reduced local therapies. Understanding the rationale for and evidence to support this shift will help identify gaps, shape future trials, and ultimately answer the question of whether this is indeed the right path to follow with regards to maintaining local control rates and long-term outcomes for patients, and improving distal disease control and local treatment-related morbidities without compromising quality of life.

Liver metabolic activity changes over time with neoadjuvant therapy in locally advanced rectal cancer

OBJECTIVE

The aim of this study was to evaluate, using PET/computed tomography (CT), changes in liver metabolic activity in patients with locally advanced rectal cancer (LARC) after neoadjuvant chemoradiotherapy (CRT).

PATIENTS AND METHODS

A total of 29 biopsy-proven LARC patients between 2009 and 2012 were studied. Liver standardized uptake values (SUVs) and SUVs adjusted for lean body mass (SULs) were obtained from PET/CT images obtained at 1 h (early) and 2 h (late) after (18)F-fluorodeoxyglucose ((18)F-FDG) administration both before and after neoadjuvant CRT. Age, sex, BMI, lean body mass, blood glucose level, and (18)F-FDG dose, which can influence liver SUVs and SULs, were also analyzed.

RESULTS

Fourteen (48%) men and 15 (52%) women with a mean age of 62±11 years (range 34-80 years) were included in the study. The mean SUVs and SULs were significantly decreased in the late scans. Sex was significantly correlated with the mean liver SUV in early and late scans. The mean SUV differed significantly between male and female patients in early and late images (P<0.05). In a multivariate stepwise regression analysis, only liver SUVs (maximum and mean) were significantly associated with BMI before and after therapy. SUVs were significantly higher in the high (≥25) BMI group after but not before therapy. Mean SUL was not influenced by BMI.

CONCLUSION

Liver (18)F-FDG uptake is consistent before and after neoadjuvant CRT therapy in patients with LARC. When assessing response to therapy and using liver metabolic activity to indicate background activity, BMI should be considered as it can influence liver metabolic activity.

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.

Neoadjuvant FOLFOX 4 versus FOLFOX 4 with Cetuximab versus immediate surgery for high-risk stage II and III colon cancers: a multicentre randomised controlled phase II trial--the PRODIGE 22--ECKINOXE trial

Background

In patients with high risk stage II and stage III colon cancer (CC), curative surgery followed by adjuvant FOLFOX-4 chemotherapy has become the standard of care. However, for 20 to 30 % of these patients, the current curative treatment strategy of surgical excision followed by adjuvant chemotherapy fails either to clear locoregional spread or to eradicate distant micrometastases, leading to disease recurrence. Preoperative chemotherapy is an attractive concept for these CCs and has the potential to impact upon both of these causes of failure. Optimum systemic therapy at the earliest possible opportunity may be more effective at eradicating distant metastases than the same treatment given after the delay and immunological stress of surgery. Added to this, shrinking the primary tumor before surgery may reduce the risk of incomplete surgical excision, and the risk of tumor cell shedding during surgery.

Methods/Design

PRODIGE 22 - ECKINOXE is a multicenter randomized phase II trial designed to evaluate efficacy and feasibility of two chemotherapy regimens (FOLFOX-4 alone and FOLFOX-4 + Cetuximab) in a peri-operative strategy in patients with bulky CCs. Patients with CC deemed as high risk T3, T4 and/or N2 on initial abdominopelvic CT scan are randomized to either colectomy and adjuvant chemotherapy (control arm), or 4 cycles of neoadjuvant chemotherapy with FOLFOX-4 (for RAS mutated patients). In RAS wild-type patients a third arm testing FOLFOX+ cetuximab has been added prior to colectomy. Patients in the neoadjuvant chemotherapy arms will receive postoperative treatment for 4 months (8 cycles) to complete their therapeutic schedule. The primary endpoint of the study is the histological Tumor Regression Grade (TRG) as defined by Ryan. The secondary endpoints are: treatment strategy safety (toxicity, primary tumor related complications under chemotherapy, peri-operative morbidity), disease-free and recurrence free survivals at 3 years, quality of life, carcinologic quality and completeness of the surgery, initial radiological staging and radiological response to neoadjuvant chemotherapy, and the correlation between histopathological and radiological response. Taking into account a 50 % prevalence of CC without RAS mutation, accrual of 165 patients is needed for this Phase II trial.

Trial Registration

NCT01675999 (ClinicalTrials.gov)

Germline and somatic genetic predictors of pathological response in neoadjuvant settings of rectal and esophageal cancers: systematic review and meta-analysis

Oncologists have pointed out an urgent need for biomarkers that can be useful for clinical application to predict the susceptibility of patients to preoperative therapy. This review collects, evaluates and combines data on the influence of reported somatic and germline genetic variations on histological tumor regression in neoadjuvant settings of rectal and esophageal cancers. Five hundred and twenty-seven articles were identified, 204 retrieved and 61 studies included. Among 24 and 14 genetic markers reported for rectal and esophageal cancers, respectively, significant associations in meta-analyses were demonstrated for the following markers. In rectal cancer, major response was more frequent in carriers of the TYMS genotype 2 R/2 R-2 R/3 R (rs34743033), MTHFR genotype 677C/C (rs1801133), wild-type TP53 and KRAS genes. In esophageal cancer, successful therapy appeared to correlate with wild-type TP53. These results may be useful for future research directions to translate reported data into practical clinical use.

Remaining cancer cells within the fibrosis after neo-adjuvant treatment for locally advanced rectal cancer

AIM

To analyse the incidence and distribution of remaining cancer cells within the fibrosis induced by preoperative chemo-radiotherapy (CRT) for locally advanced rectal cancer.

METHODS

The histopathological specimens from 46 patients operated on with extensive surgery for locally advanced rectal cancer after CRT were examined. The extension of fibrosis in relation to the mesorectal fascia (MRF) and the distribution of cancer cells within the fibrosis was examined using routine haematoxylin-eosin staining. In addition, immunohistochemical staining with CK20 was done to examine if cancer cells were missed by routine pathological work up.

RESULTS

All specimens showed CRT induced fibrosis. Two specimens showed complete response without viable cancer cells (ypT0). The fibrosis was limited inside the MRF in three cases, adherent to or involved the MRF in ten cases and in 33 cases the fibrosis was obvious outside as well as inside the fascia. Twenty-one cases showed fibrosis on the surgical resection margin, and in 9 of these cancer cells were found on the surgical margin (R1, R2-resection). 37 patients had R0 resections and among those 24 showed fibrosis beyond the MFR and 13 had scattered cancer cells in the fibrosis along or outside the MRF.

CONCLUSIONS

The rate of remaining cancer cells within the fibrosis was high in patients with locally advanced rectal cancer treated with CRT. Frequently cancer cells were detected near the border of the fibrosis. A complete resection of the fibrosis is therefore recommended to achieve an R0 resection after neo-adjuvant treatment.

The value of liver-based standardized uptake value and other quantitative 18F-FDG PET-CT parameters in neoadjuvant therapy response in patients with locally advanced rectal cancer: correlation with histopathology

AIM

We aimed to investigate the value of PET-CT in therapy response and the correlation of quantitative PET parameters with histopathologic results in patients with locally advanced rectal cancer (LARC) before and after neoadjuvant chemoradiotherapy. We also analyzed the correlation of PET-CT parameters between Ki-67 and glucose transporter 1 (GLUT1).

PATIENTS AND METHODS

A total of 29 patients diagnosed with LARC who had undergone a biopsy between 2009 and 2012 were included in our study. Quantitative PET parameters [standardized uptake value (SUV)max-mean, lean body mass SUV(max-mean), tumor/liver SUV, retention index , and [INCREMENT]SUV(max)] were measured before and after therapy using PET-CT. Tumor regression grade (TRG) was evaluated according to Wheeler's classification. Patients in grade 1 were considered responders, whereas patients at grades 2 and 3 were considered nonresponders. Immunohistochemical staining with Ki-67 and GLUT1 was performed on biopsy and surgical specimens. The correlation between staining ratios and SUV was also investigated.

RESULTS

SUV parameters were significantly decreased after therapy (P < 0.001). Twelve (41%) patients were at TRG1, 10 (35%) were at TRG2, and seven (24%) were at TRG3. A cutoff SUV(max) of 5.05 to discriminate between responders and nonresponders after treatment revealed a sensitivity of 57%, specificity of 73%, negative predictive value of 65%, positive predictive value of 67%, and accuracy of 66%. Using a cutoff of 3.55 for the SUV(mean) (standardized measurement of SUV with 1.2-cm-diameter region of interest) revealed a sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of 67, 76, 67, 76, and 72%, respectively. For a cutoff of 1.95 for the tumor SUV(mean)/liver SUV(mean), these diagnostic values after therapy were 73, 78, 82, 67, and 76%, respectively. We found a moderate correlation between liver-based SUV(max) (r = -0.35, P = 0.019) and SUV(mean )(r = -0.31, P = 0.036) with GLUT1 after therapy. Quantitative PET parameters and retention index were moderately correlated with Ki-67.

CONCLUSION

PET-CT is a useful method for assessing the response to neoadjuvant chemoradiotherapy in patients with LARC. The most significant parameter for assessing treatment response using SUV parameters is the tumor/liver ratio.

Detection of morphologic alterations in rectal carcinoma following preoperative radiochemotherapy based on multiphoton microscopy imaging

BACKGROUND

Preoperative radiochemotherapy improves outcomes in patients with locally advanced rectal carcinoma, and has been used increasingly in patient management. However, there is a strong clinical need to assess tumor response to neoadjuvant treatment, and a non-invasive technique that allows the precise identification of morphologic changes in tumors would be of considerable clinical interest.

METHODS

In this study, we used multiphoton microscopy (MPM) to detect morphologic alterations in rectal adenocarcinomas in patients treated with preoperative radiochemotherapy.

RESULTS

MPM was able to identify histopathologic alterations in rectal cancer following preoperative radiochemotherapy, and allowed the qualitative assessment of treatment efficacy and feasibility in relation to dose or strategy.

CONCLUSION

These findings may provide the groundwork for evaluating tumor response to neoadjuvant treatment, thus allowing the tailoring of effective treatment doses and strategies.

Insulin-like growth factor receptor-1 overexpression is associated with poor response of rectal cancers to radiotherapy

AIM: To explore the potential correlation between insulin-like growth factor receptor-1 (IGF-1R) expression and rectal cancer radiosensitivity.

METHODS: Eighty-seven rectal cancer patients (cTNM I-III) treated in our department between January 2011 and December 2012 were enrolled. All subjects were treated with preoperative radiotherapy and radical resection of rectal carcinoma. Immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR) were performed to detect IGF-1R expression in pre-treatment and postoperative colorectal cancer specimens. Radiosensitivity for rectal cancer specimens was evaluated by observing rectal carcinoma mass regression combined with fibrosis on HE staining, degree of necrosis and quantity of remaining tumor cells. The relative IGF-1R expression was evaluated for association with tumor radiosensitivity.

RESULTS: Immunohistochemistry showed diffuse IGF-1R staining on rectal cancer cells with various degrees of signal density. IGF-1R expression was significantly correlated with cTNM staging (P = 0.012) while no significant association was observed with age, sex, tumor size and degree of differentiation (P = 0.424, 0.969, 0.604, 0.642). According to the Rectal Cancer Regression Grades (RCRG), there were 31 cases of RCRG1 (radiation sensitive), 28 cases of RCRG2 and 28 cases of RCRG3 (radiation resistance) in 87 rectal cancer subjects. IGF-1R protein hyper-expression was significantly correlated with a poor response to radiotherapy (P < 0.001, r = 0.401). RT-PCR results from pre-radiation biopsy specimens also showed that IGF-1R mRNA negative group exhibited a higher radiation sensitivity (P < 0.001, r = 0.497). Compared with the pre-radiation biopsy specimens, the paired post-operative specimens showed a significantly increased IGF-1R protein and mRNA expression in the residual cancer cells (P < 0.001, respectively).

CONCLUSION: IGF-1R expression level may serve as a predictive biomarker for radiosensitivity of rectal cancer before preoperative radiotherapy.

Controversies in the pathological assessment of colorectal cancer

Pathologic assessment of colorectal cancer specimens plays an essential role in patient management, informing prognosis and contributing to therapeutic decision making. The tumor-node-metastasis (TNM) staging system is a key component of the colorectal cancer pathology report and provides important prognostic information. However there is significant variation in outcome of patients within the same tumor stage. Many other histological features such as tumor budding, vascular invasion, perineural invasion, tumor grade and rectal tumor regression grade that may be of prognostic value are not part of TNM staging. Assessment of extramural tumor deposits and peritoneal involvement contributes to TNM staging but there are some difficulties with the definition of both of these features. Controversies in colorectal cancer pathology reporting include the subjective nature of some of the elements assessed, poor reporting rates and reproducibility and the need for standardized examination protocols and reporting. Molecular pathology is becoming increasingly important in prognostication and prediction of response to targeted therapies but accurate morphology still has a key role to play in colorectal cancer pathology reporting.

Global DNA methylation is altered by neoadjuvant chemoradiotherapy in rectal cancer and may predict response to treatment - A pilot study

AIM

In rectal cancer, not all tumours display a response to neoadjuvant treatment. An accurate predictor of response does not exist to guide patient-specific treatment. DNA methylation is a distinctive molecular pathway in colorectal carcinogenesis. Whether DNA methylation is altered by neoadjuvant treatment and a potential response predictor is unknown. We aimed to determine whether DNA methylation is altered by neoadjuvant chemoradiotherapy (CRT) and to determine its role in predicting response to treatment.

PATIENTS AND METHODS

Fifty-three (n = 53) patients with locally advanced rectal cancers treated with neoadjuvant CRT followed by surgery were identified from the pathology databases of 2 tertiary referral centres over a 4-year period. Immunohistochemical staining of treatment specimens was carried out using the 5-Methylcytidine (Eurogentec, Seraing, Belgium) antibody. Quantitative analysis of staining was performed using an automated image analysis platform. The modified tumour regression grading system was used to assess tumour response to neoadjuvant therapy.

RESULTS

Seven (13%) patients showed complete pathological response while 46 (87%) patients were partial responders to neoadjuvant treatment. In 38 (72%) patients, significant reduction in methylation was observed in post-treatment resection specimens compared to pre-treatment specimens (171.5 vs 152.7, p = 0.01); in 15 (28%) patients, methylation was increased. Pre-treatment methylation correlated significantly with tumour regression (p < 0.001), T-stage (p = 0.005), and was able to predict complete and partial pathological responders (p = 0.01).

CONCLUSION

Neoadjuvant CRT appears to alter the rectal cancer epigenome. The significant correlation between pre-treatment DNA methylation with tumour response suggests a potential role for methylation as a biomarker of response.

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.

Tumor Regression Grading After Preoperative Chemoradiotherapy for Locally Advanced Rectal Carcinoma Revisited: Updated Results of the CAO/ARO/AIO-94 Trial

Purpose

We previously described the prognostic impact of tumor regression grading (TRG) on the outcome of patients with rectal carcinoma treated with preoperative chemoradiotherapy (CRT) in the CAO/ARO/AIO-94 trial. Here we report long-term results after a median follow-up of 132 months.

Patients and Methods

TRG after preoperative CRT was determined in 386 surgical specimens by the amount of viable tumor cells versus fibrosis, ranging from TRG 4 (no viable tumor cells) to TRG 0 (no signs of regression). Clinicopathologic parameters and TRG were correlated to the cumulative incidence of local recurrence, distant metastasis, and disease-free survival (DFS).

Results

Ten-year cumulative incidence of distant metastasis and DFS were 10.5% and 89.5% for patients with TRG 4 (complete regression), 29.3% and 73.6% for TRG 2 and 3 (intermediate regression), and 39.6% and 63% for TRG 0 and 1 (poor regression), respectively (P = .005 and P = .008, respectively). On multivariable analysis, residual lymph node metastasis (ypN+) and TRG were the only independent prognostic factors for cumulative incidence of distant metastasis (P < .001 and P = .035, respectively) and DFS (P < .001 and P = .039, respectively), whereas local recurrence was significantly affected by ypN status (P < .001) and lymphatic invasion (P = .026).

Conclusion

Complete and intermediate tumor regressions were associated with improved long-term outcome in patients with rectal carcinoma after preoperative CRT independent of clinicopathologic parameters. This classification system needs to be prospectively tested in multiple data sets to validate its reproducibility in a wider setting.

Prognostic value of mandard and dworak tumor regression grading in rectal cancer: study of a single tertiary center

Goal. To evaluate the prognostic value of Mandard and Dworak grading systems regarding neoadjuvant chemoradiotherapy (CRT) response on rectal cancer. Materials and Methods. We queried our center's database for patients with colo rectal cancer with locally advanced rectal cancer (LARC) who received neoadjuvant CRT followed by total mesorectum excision (TME) between 2003 and 2011. After excluding 18 patients from the initial query the remaining 139 were reassessed for disease recurrence and survival; the specimens' slides were reviewed and classified according to two tumor regression grading (TRG) systems: Mandard and Dworak. Based on these TRG scores, two patient groups were created: patients with good response versus patients with bad response (Mandard TRG1+2 versus Mandard TRG3+4+5 and Dworak TRG4+3 versus Dworak TRG2+1+0). Overall survival (OS), disease-free survival (DFS), and disease recurrence were then evaluated. Results. Mean age was 64.2 years and median follow up was 56 months. No significant survival difference was found when comparing patients with Dworak TRG 4+3 versus Dworak TRG2+1+0 (P = 0.10). Mandard TRG1+2 presented with significantly better OS and DFS than Mandard TRG3+4+5 (OS P = 0.013; DFS P = 0.007). Conclusions. Mandard system provides higher accuracy over Dworak system in predicting rectal cancer prognosis when neoadjuvant CRT is applied for tumor regression.

Quantified pathologic response assessed as residual tumor burden is a predictor of recurrence-free survival in patients with rectal cancer who undergo resection after neoadjuvant chemoradiotherapy

BACKGROUND

The current study was conducted to determine whether quantified pathologic response assessed as a percentage of residual tumor cells is predictive of recurrence-free survival (RFS) in patients with rectal cancer.

METHODS

The authors studied 251 patients with rectal adenocarcinoma who were treated with neoadjuvant chemoradiation and radical resection. Quantified pathologic response was defined as an estimated percentage of residual cancer cells in relation to the tumor bed: complete, no residual cancer cells; near-complete, ≤ 5% residual cancer cells; major, > 5%, and < 50% residual cancer cells; and minor, ≥ 50% residual cancer cells. The reproducibility of quantified pathologic response between 2 pathologists was assessed using tumors from 55 randomly selected patients who did not demonstrate a complete response.

RESULTS

Pathologic response was complete in 21% of patients, near-complete in 20% of patients, major in 37% of patients, and minor in 22% of patients. Nineteen percent of patients had ypT0N0 disease, 27% had ypT1-2N0 disease, 21% had ypT3-4N0 disease, and 33% had N+ disease. The 5-year RFS rates by category of quantified pathologic response were as follows: complete, 95%; near-complete, 88%; major, 69%; and minor, 61% (P < .001). Major and minor response, high histologic grade, and perineural invasion were found to be significant predictors of decreased RFS on multivariate analysis. The 5-year RFS rates for patients with ypT3-4 or N+ disease were better for those with a near-complete response (94%) compared with those with a major (64%) or minor (61%) response (P < .02). Moderate to substantial agreement was observed between the 2 pathologists (κ = 0.72).

CONCLUSIONS

Quantified pathologic response is a predictor of RFS in patients with rectal adenocarcinoma and stratifies patients with high pathologic stage disease.

Prognostic significance of partial tumor regression after preoperative chemoradiotherapy for rectal cancer: a meta-analysis

BACKGROUND

Complete tumor regression after preoperative chemoradiotherapy for rectal cancer has been associated with better disease-free and overall survival. The survival experience for patients with partial tumor regression is less clear.

OBJECTIVE

The aim of this meta-analysis was to evaluate the prognostic significance of partial response after preoperative chemotherapy on disease-free survival in rectal cancer patients.

DATA SOURCES

Relevant studies were identified by a search of MEDLINE and EMBASE databases with no restrictions to October 31, 2012.

STUDY SELECTION

We included long-course radiotherapy that reported the association between degree of tumor regression and disease-free survival of rectal cancer.

INTERVENTIONS

Direct, indirect, and graph methods were used to extract HRs.

MAIN OUTCOME MEASURES

Study-specific HRs on the disease-free survival were pooled using a random-effects model. Eleven articles in total were selected. Analysis was performed first among the 6 studies that separated partial response from the complete response and later among all 11 of the studies.

RESULTS

Pooled HR was 0.49 (95% CI, 0.28-0.85) for the 6 studies that compared partial response with poor response. It was 0.41 (95% CI, 0.25-0.67) when all 11 of the studies were analyzed together.

LIMITATIONS

The studies were limited by not being prospective, randomized trials, and the tumor regression grades were not uniform.

CONCLUSIONS

Partial tumor response is associated with a 50% improvement in disease-free survival and should be considered as a favorable prognostic factor.

Prognostic significance of lymph node yield after long-course preoperative radiotherapy in patients with rectal cancer: a systematic review

AIM

A literature review was performed to elucidate whether long-course preoperative radiotherapy for patients with rectal cancer affects lymph node yield, and whether this influences prognosis.

METHOD

Cochrane Database, PubMed/MEDLINE, Scopus, Web of Knowledge, Embase and CINAHL databases and reference lists from published journal articles published between 1 January 1990 and 30 June 2011 were searched. Studies examining lymph node yield and prognosis were selected for review.

RESULTS

One thousand and twenty-nine articles were found, of which 11 met the inclusion criteria. None was a randomized controlled trial and all were cohort studies. Four studies showed that long-course preoperative radiotherapy reduced lymph node yield; however only one demonstrated a statistically significant survival benefit in patients with higher lymph node yields. Five-year survival was 48% in patients with fewer than and 69% in those with more than 11 lymph nodes identified in the operative specimen (P = 0.04).

CONCLUSION

Whilst long-course preoperative radiotherapy appears to reduce lymph node yield in patients with rectal cancer, no causal relationship between lymph node yield and survival can be established in this group of patients.

Radiotherapy response in microsatellite instability related rectal cancer

Preoperative radiotherapy may improve the resectability and subsequent local control of rectal cancers. However, the extent of radiation induced regression in these tumours varies widely between individuals. To date no reliable predictive marker of radiation sensitivity in rectal cancer has been identified. At the cellular level, radiation injury initiates a complex molecular network of DNA damage response (DDR) pathways that leads to cell cycle arrest, attempts at re-constituting the damaged DNA and should this fail, then apoptosis. This review presents the details which suggest the roles of DNA mismatch repair proteins, the lack of which define a distinct subset of colorectal cancers with microsatellite instability (MSI), in the DDR pathways. Hence routine assessment of the MSI status in rectal cancers may potentially serve as a predictor of radiotherapy response, thereby improving patient stratification in the administration of this otherwise toxic treatment.

Prevalence and significance of anaemia in patients receiving long-course neoadjuvant chemoradiotherapy for rectal carcinoma

AIM

The study aimed to assess the prevalence and significance of anaemia during long-course neoadjuvant radiotherapy for rectal cancer at our centre.

METHOD

Hospital coding and a prospective oncology database were used to identify all patients undergoing long-course neoadjuvant radiotherapy for rectal cancer at our centre between 2004 and 2009. A retrospective review of computerized records was used to extract individual patient data. Anaemia was defined as a haemoglobin level of < 11.5 g/dl for women and of < 13 g/dl for men. Downstaging was assessed by comparing radiological stage (rTNM) with histological stage (ypTNM). Tumour regression after radiotherapy was assessed using the Rectal Cancer Regression Group (RCRG) scores of 1-3. The results were analysed using Gnu PSPP statistical software.

RESULTS

There were 70 patients (51 men) of median age 66 (interquartile range 60-72.75) years. Of these, 24 were anaemic. Two (3%) had no haemoglobin level recorded and were excluded. Forty-two per cent of anaemic patients demonstrated mural (T) downstaging compared with 68% of nonanaemic patients (P = 0.03). There was no difference in nodal downstaging between the groups. The RCRG scores showed more tumour regression in nonanaemic patients than in anaemic patients, as follows: RCRG 1, 59%vs 30%; RCRG 2, 11%vs 17%; and RCRG 3, 38%vs 46% (P < 0.001).

CONCLUSION

The prevalence of anaemia in patients undergoing long-course neoadjuvant radiotherapy was 35%. Anaemia during long-course neoadjuvant radiotherapy was associated with significant reductions in tumour downstaging and regression.

Association between anal function and therapeutic effect after preoperative chemoradiotherapy followed by intersphincteric resection

BACKGROUND/AIMS

Preoperative chemoradiotherapy (CRT) for rectal cancer improves local control, but can also induce severe anal dysfunction after surgery. The goal of the study was to assess the relationship of the therapeutic effect of CRT with anal function and prognosis after intersphincteric resection (ISR).

METHODS

The subjects were 37 patients with lower rectal cancer who underwent ISR with preoperative CRT. The rectal cancer regression grade (RCRG) was quantified based on histologic features of surgical specimens. The relationships of RCRG with anal function (assessed by questionnaire) and incontinence (Wexner score) were examined at 12 months after surgery.

RESULTS

The median Wexner scores at 12 months after stoma closure in RCRG1, -2, and -3 cases were 18.0, 7.5, and 4.5, respectively, and anal function differed significantly among these groups (p = 0.001). Four cases had local recurrence, but 5-year local recurrence rates did not differ significantly among the groups. The 5-year disease-free survival rates were 88.9, 50.8, and 50.0% and the 5-year overall survival rates were 100, 77.3, and 66.7% in RCRG1, -2, and -3 cases, respectively, with no significant differences among the groups.

CONCLUSION

Postoperative anal function is decreased when the effect of preoperative CRT is strong in patients treated with ISR.

P53 status as a predictive biomarker for patients receiving neoadjuvant radiation-based treatment: a meta-analysis in rectal cancer

Background

Numerous studies have yielded inconsistent results regarding the relationship between p53 status and the response to neoadjuvant radiation-based therapy in patients with rectal cancer. We conducted a meta-analysis to clarify the relationship between p53 status and response to radiation-based therapy in rectal cancer.

Methods/Findings

A total of 30 previously published eligible studies including 1,830 cases were identified and included in this meta-analysis. Wild-type form of p53 status (low expression of p53 protein and/or wild-type p53 gene) was associated with pathologic response in rectal cancer patients who received neoadjuvant radiation-based therapy (good response: risk ratio [RR] = 1.30; 95% confidence intervals [CI] = 1.14–1.49; p<0.001; complete response RR = 1.65; 95% CI = 1.19–2.30; p = 0.003; poor response RR = 0.85; 95% CI = 0.75–0.96; p = 0.007). In further stratified analyses, this association remained for sub-groups of good and poor response in neoadjuvant radiotherapy (RT) setting, good and complete response in chemoradiotherapy (CRT) setting. And the association between response and the presence of p53 gene mutations was stronger than that between response and protein positivity.

Conclusion

The results of the present meta-analysis indicate that P53 status is a predictive factor for response in rectal cancer patient undergoing neoadjuvant radiation-based therapy.

Predicting the response to preoperative radiation or chemoradiation by a microarray analysis of the gene expression profiles in rectal cancer

Preoperative radiotherapy or chemoradiotherapy (CRT) has become a standard treatment for patients with locally advanced rectal cancer. However, there is a wide spectrum of responses to preoperative CRT, ranging from none to complete. There has been intense interest in the identification of molecular biomarkers to predict the response to preoperative CRT, in order to spare potentially non-responsive patients from unnecessary treatment. However, no specific molecular biomarkers have yet been definitively proven to be predictive of the response to CRT. Instead of focusing on specific factors, microarray-based gene expression profiling technology enables the simultaneous analysis of large numbers of genes, and might therefore have immense potential for predicting the response to preoperative CRT. We herein review published studies using a microarray-based analysis to identify gene expression profiles associated with the response of rectal cancer to radiation or CRT. Although some studies have reported gene expression signatures capable of high predictive accuracy, the compositions of these signatures have differed considerably, with little gene overlap. However, considering the promising data regarding gene profiling in breast cancer, the microarray analysis could still have potential to improve the management of locally advanced rectal cancer. Increasing the number of patients analyzed for more accurate prediction and the extensive validation of predictive classifiers in prospective clinical trials are necessary before such profiling can be incorporated into future clinical practice.

A prospective analysis of patient outcome following treatment of T3 rectal cancer with neo-adjuvant chemoradiotherapy and transanal excision

BACKGROUND

Local excision is an alternative to anterior or abdomino-perineal resection in patients with early rectal cancer. In more advanced disease, neo-adjuvant therapy (CRXT) can result in significant disease regression such that local excision may be considered. The primary aim was to assess oncological outcome in patients with T3 rectal cancer treated with CRXT and local excision due to unsuitability for or aversion to anterior resection and stoma. The secondary aim was to examine oncological outcomes in patients treated in a similar way in the published literature.

METHODS

Between July 2006 and July 2009, patients with rectal cancer staged T3, N0/N1, M0 who were deemed unfit for or who refused anterior resection were offered long-course CRXT. Patients were restaged 8 weeks following completion. If there was a good response (regression grade 2 or 3 clinically and radiologically), full thickness transanal excision was performed. All patients were followed regularly (monthly CT abdomen/pelvis and annual endoscopy) to assess for recurrence of disease. A literature search of PubMed was performed to identify all prospective data available of T3 rectal cancers managed with CRXT and local excision.

RESULTS

Ten patients were treated over 3 years. Six patients had complete pathological response, while four patients had a partial response. The resection margins following local excision were clear in all. There was no local recurrence (median follow-up 24 months, range 9-42 months).

CONCLUSION

Neo-adjuvant chemoradiotherapy and local excision is an option in patients unfit for or averse to major surgical resection if there is a good response to CRXT.

[Pathological staging and response evaluation of rectal carcinoma]

The application of so-called neoadjuvant therapy may induce changes in tumor tissues that have to be determined concerning the degree of severity (regression grading) and which also influence pathological staging. The extent of morphological changes (response) to be evaluated ranges from carcinomas showing no damage at all to complete disappearance of carcinomas. More than ten different systems of regression grading have been published in order to assess the dimension of morphological changes in a semiquantitative manner.

Optimal lymph node harvest in rectal cancer (UICC stages II and III) after preoperative 5-FU-based radiochemotherapy. Acetone compression is a new and highly efficient method

INTRODUCTION

Preoperative 5-fluorouracil-based radiochemotherapy (RCT), followed by total mesorectal excision, is accepted as standard therapy in rectal cancers (UICC stages II and III). The accurate evaluation of ypN status after RCT with valuable lymph node (LN) harvest is essential for postoperative risk-adapted treatment decisions. Actual numbers of assessed LNs and validity of ypN status vary extensively depending on the methods used.

MATERIAL AND METHODS

This prospective study validates the acetone compression (AC), whole mesorectal compartment embedding (WME), and fat clearance (FC) methods for LN retrieval in n=257 rectal cancer specimens obtained from 2 high-volume surgical centers. For optimal LN retrieval, the AC method (n=161 specimens: 52 cases with RCT, 109 cases without RCT) was compared with the WME (n=64 cases, with RCT) and FC methods (n=32 cases: 17 cases with RCT, 15 cases without RCT). The efficacy of LN retrieval, costs involved, and molecular diagnostics were measured.

RESULTS

Using the AC method, 41 LNs (mean; range 14 to 86 LNs) were detectable in total mesorectal excision specimens after RCT and 44 LNs (mean; range 9 to 78 LNs) in cases without RCT. The LN yield after RCT obtained by using the AC method was equivalent to that of the WME method (mean 32 LNs/specimen; range 12 to 81 LNs) but demonstrated a better time and cost-efficacy. In addition, the AC method facilitated assessment of any tumor deposits, including perineural invasion, and did not hamper molecular analyses. The AC method increased LN retrieval 4- to-6-fold as compared with the literature and 2-fold compared with manual dissection after the FC method.

DISCUSSION

The AC method is the method of choice for accurate LN staging in locally advanced rectal cancer, especially after preoperative RCT, and is well suited for routine gastrointestinal pathology workup.

Clinically relevant study end points in rectal cancer

In rectal cancer currently there are no clearly validated early end points which can serve as surrogates for long-term clinical outcome such as local control and survival. However, the use of a variety of response rates (i.e. pathological complete response, downsizing the primary tumor, tumor regression grade (TRG), radiological response) as endpoints in early (phase II) clinical trials is common since objective response to therapy is an early indication of activity. Disease-free survival (DFS) has been proposed as the most appropriate end point in adjuvant trials and is one of the most frequently used in newer rectal cancer trials. Due to the devastating nature of local recurrence in locally advanced rectal cancer, local control (which is itself a subset of the overall DFS endpoint) is still considered an important endpoint. Recently, circumferential resection margin (CRM) has been proposed as novel early end point because the CRM status can account for effects on DFS and overall survival after chemoradiation, radiation (RT), or surgery alone. Consensus is needed to define the most appropriate end points in both early and phase III trials in locally advanced cancer.

Histological grading of tumour regression and radiation colitis in locally advanced rectal cancer following neoadjuvant therapy: a critical appraisal

AIM

Locally advanced rectal cancer is commonly treated by neoadjuvant therapy and the resultant tumour response can be quantified histologically. This therapy may also induce radiation colitis, which also can be graded. The aim of this study was to assess the grading of tumour regression and of radiation colitis and their relationship to other prognostic parameters.

METHOD

Between 2000 and 2006, 75 patients (23 women; median duration of follow up, 58 months) with rectal cancer were evaluated. Sixty-three had short-course radiotherapy and 12 had long-course radiotherapy. Tumour regression was graded histologically using the three-point Ryan system: patients with grades 1 and 2 were considered as responders and patients with grade 3 were considered as nonresponders. Radiation colitis was graded histologically as mild, moderate or severe, as described previously (J Pathol 2006; 210: P25).

RESULTS

Twenty-nine patients were classified as responders and 46 as nonresponders. The former were less likely to be lymph node positive compared with the latter (P=0.001). Tumour response did not correlate with local recurrence. Responders showed a disease-free survival (not overall survival) advantage at 2 and 5 years over nonresponders. Responders showed a higher rate of postoperative abdominal complications. Histological evidence of regression was demonstrated in patients treated with short-course radiotherapy. There was no relationship between radiation colitis grade and abdominal complications.

CONCLUSION

Radiation colitis grade does not correlate with postoperative complications. More abdominal complications occurred in patients receiving long-course radiotherapy.

Perspectives on current tumor-node-metastasis (TNM) staging of cancers of the colon and rectum

Improvements in classifications of cancers based on discovery and validation of important histopathological parameters and new molecular markers continue unabated. Though still not perfect, recent updates of classification schemes in gastrointestinal oncology by the American Joint Commission on Cancer (tumor-node-metastasis [TNM] staging) and the World Health Organization further stratify patients and guide optimization of treatment strategies and better predict patient outcomes. These updates recognize the heterogeneity of patient populations with significant subgrouping of each tumor stage and use of tumor deposits to significantly "up-stage" some cancers; change staging parameters for subsets of IIIB and IIIC cancers; and introduce of several new subtypes of colon carcinomas. By the nature of the process, recent discoveries that are important to improving even routine standards of patient care, especially new advances in molecular medicine, are not incorporated into these systems. Nonetheless, these classifications significantly advance clinical standards and are welcome enhancements to our current methods of cancer reporting.

Magnetic resonance imaging-detected tumor response for locally advanced rectal cancer predicts survival outcomes: MERCURY experience

PURPOSE

To assess magnetic resonance imaging (MRI) and pathologic staging after neoadjuvant therapy for rectal cancer in a prospectively enrolled, multicenter study.

METHODS

In a prospective cohort study, 111 patients who had rectal cancer treated by neoadjuvant therapy were assessed for response by MRI and pathology staging by T, N and circumferential resection margin (CRM) status. Tumor regression grade (TRG) was also assessed by MRI. Overall survival (OS) was estimated by using the Kaplan-Meier product-limit method, and Cox proportional hazards models were used to determine associations between staging of good and poor responders on MRI or pathology and survival outcomes after controlling for patient characteristics.

RESULTS

On multivariate analysis, the MRI-assessed TRG (mrTRG) hazard ratios (HRs) were independently significant for survival (HR, 4.40; 95% CI, 1.65 to 11.7) and disease-free survival (DFS; HR, 3.28; 95% CI, 1.22 to 8.80). Five-year survival for poor mrTRG was 27% versus 72% (P = .001), and DFS for poor mrTRG was 31% versus 64% (P = .007). Preoperative MRI-predicted CRM independently predicted local recurrence (LR; HR, 4.25; 95% CI, 1.45 to 12.51). Five-year survival for poor post-treatment pathologic T stage (ypT) was 39% versus 76% (P = .001); DFS for the same was 38% versus 84% (P = .001); and LR for the same was 27% versus 6% (P = .018). The 5-year survival for involved pCRM was 30% versus 59% (P = .001); DFS, 28 versus 62% (P = .02); and LR, 56% versus 10% (P = .001). Pathology node status did not predict outcomes.

CONCLUSION

MRI assessment of TRG and CRM are imaging markers that predict survival outcomes for good and poor responders and provide an opportunity for the multidisciplinary team to offer additional treatment options before planning definitive surgery. Postoperative histopathology assessment of ypT and CRM but not post-treatment N status were important postsurgical predictors of outcome.

The prognostic value of grade of regression and oncocytic change in rectal adenocarcinoma treated with neo-adjuvant chemoradiotherapy

BACKGROUND

Pathological staging and regression grading may affect the clinical outcome in rectal carcinoma patients treated with neoadjuvant chemoradiation (NACRT). Oncocytic change (OC) has also been described in the residual tumor. This study assesses the correlation of degree of pathological response and OC with clinical outcome.

METHODS

Seventy-five cases of rectal adenocarcinoma undergoing NACRT followed by surgery were retrospectively analyzed for preoperative and post-operative staging, degree of tumor response to NACRT using the Dworak Regression score (DR) and Tumor Regression Grading (TRG) systems, as well as the proportion of cells showing OC. These parameters were correlated with overall survival (OS) and disease-free survival (DFS).

RESULTS

Significant correlation was found between post-operative T and N stage and OS (P = 0.005 and 0.002, respectively); and post-operative and preoperative T stage with DFS (P = 0.002 and 0.02, respectively). Grouping patients by TRG scores (TRG1-3 vs TRG4-5) also proved to be a significant independent prognosticator for DFS (P < 0.001). The DR score groups and OC (<35% vs. >35%) were not statistically significant predictors of clinical outcome.

CONCLUSIONS

Post-NACRT T and N staging and the TRG system are important prognostic indicators. The presence and extent of OC needs to be better understood and further investigated.

Histopathological regression grading versus staging of rectal cancer following radiotherapy

AIMS

To compare histological grading of rectal cancer radiotherapy response with pathological staging as a prognostic indicator.

METHODS

Histological tumour regression was five tier graded in 102 rectal cancer patients treated with preoperative radiotherapy [short course (n = 34), long course (n = 68)]. Differences between these grades and between the two radiotherapy regimes were assessed. These variables, pTMN staging and others were correlated with relapse free survival at 3 years.

RESULTS

22 patients suffered disease recurrence and four died during a mean post-operative follow-up of 40.3 months. There were 52 good responders (tumour regression grades 1-3) and 50 poor responders (tumour regression grades 4-5). Regression was greater following the long course regime (p < 0.0001). Otherwise, there were no significant differences between the response groups and between the two regimes, including the number of lymph nodes found in the resected bowel. Only the pN status correlated with relapse free survival on multivariate analysis (p = 0.0004; HR = 4.26, 95%CI = 1.66-10.93 for pN2 versus pN0).

CONCLUSIONS

The number of lymph nodes found for staging was not influenced by either the extent of primary tumour regression or the type of radiotherapy. pN status, but not tumour regression grade, is a reliable predictor of survival.

A pilot feasibility study of TNFerade™ biologic with capecitabine and radiation therapy followed by surgical resection for the treatment of rectal cancer

OBJECTIVE

The purpose of this pilot study was to evaluate the feasibility and tolerability of weekly intratumoral TNFerade™ injections combined with concurrent capecitabine and radiotherapy in the treatment of patients with locally advanced rectal cancer.

METHODS

Patients with T3, T4, or N+ rectal cancer received radiotherapy to a total dose of 50.4-54 Gy in combination with capecitabine 937.5 mg/m(2) p.o. b.i.d. TNFerade™ at a dose of 4 × 10(10) particle units was injected into the rectal tumor on the first day of radiotherapy and weekly for a total of 5 injections. Surgery was performed 5-10 weeks after the completion of chemoradiation.

RESULTS

Nine patients were enrolled in this pilot trial. The stage was cT2 in 2 patients, cT3 in 6 patients, cT4 in 1 patient, N- in 7 patients and N+ in 2 patients. Eight patients completed all treatments. Grade 3 hematologic toxicity was observed in 2 patients. There was no toxicity directly attributable to the injection procedure. A complete pathologic response was observed in 2 of 9 patients.

CONCLUSIONS

This study demonstrates the feasibility of weekly intratumoral TNFerade™ injections during chemoradiotherapy for locally advanced rectal cancer. Pathologic responses with this combination compare favorably to published rates.

Clinical impact of tumor regression grade after preoperative chemoradiation for locally advanced rectal cancer: subset analyses in lymph node negative patients

BACKGROUND

We investigated the prognostic significance of tumor regression grade (TRG) after preoperative chemoradiation therapy (preop-CRT) for locally advanced rectal cancer especially in the patients without lymph node metastasis.

METHODS

One-hundred seventy-eight patients who had cT3/4 tumors were given 5,040 cGy preoperative radiation with 5-fluorouracil/leucovorin chemotherapy. A total mesorectal excision was performed 4-6 weeks after preop-CRT. TRG was defined as follows: grade 1 as no cancer cells remaining; grade 2 as cancer cells outgrown by fibrosis; grade 3 as a minimal presence or absence of regression. The prognostic significance of TRG in comparison with histopathologic staging was analyzed.

RESULTS

Seventeen patients (9.6%) showed TRG1. TRG was found to be significantly associated with cancer-specific survival (CSS; P = 0.001) and local recurrence (P = 0.039) in the univariate study, but not in the multivariate analysis. The ypN stage was the strongest prognostic factor in the multivariate analysis. Subgroup analysis revealed TRG to be an independent prognostic factor for the CSS of ypN0 patients (P = 0.031). TRG had a stronger impact on the CSS of ypN (-) patients (P = 0.002) than on that of ypN (+) patients (P = 0.521). In ypT2N0 and ypT3N0, CSS was better for TRG2 than for TRG3 (P = 0.041, P = 0.048), and in ypN (-) and TRG2 tumors, CSS was better for ypT1-2 than for ypT3-4 (P = 0.034).

CONCLUSION

TRG was found to be the strongest prognostic factor in patients without lymph node metastasis (ypN0), and different survival was observed according to TRG among patients with a specific histopathologic stage. Thus, TRG may provide an accurate prediction of prognosis and may be used for f tailoring treatment for patients without lymph node metastasis.

Prognostic importance of Mandard tumour regression grade following pre-operative chemo/radiotherapy for locally advanced rectal cancer

PURPOSE

To assess the prognostic value of the Mandard tumour regression score (TRG) following pre-operative chemo/radiotherapy in patients with locally advanced rectal cancer.

METHODS AND MATERIALS

The study involved 158 patients with locally advanced rectal cancer treated with pre-operative long course chemo/radiotherapy at Nottingham University Hospital between April 2001 and December 2008. Patients were treated with radiotherapy to a dose of 50 Gy in 25 fractions over 5 weeks with or without concurrent capecitabine chemotherapy at a dose of 1650 mg/m(2)/day. Surgery was normally performed after an interval of 6-10 weeks. The response to pre-operative treatment was carefully graded by a single pathologist using the five point Mandard score. The median follow-up was 40 months (range 3-90 months).

RESULTS

Of the 158 patients 14% were TRG1, 41% were TRG2, 31% were TRG3, 13% were TRG4 and 1% were TRG5. The groups were combined into TRG1, TRG2 and TRG3-5 to simplify further analysis. The Mandard score was clearly related to both disease-free (p < 0.001) and overall survival (p = 0.012). On multivariate analysis perineural invasion, nodal status, TRG and circumferential resection margin status were the most powerful predictors of disease-free survival.

CONCLUSIONS

The Mandard tumour regression score is an independent prognostic factor and predicts for long-term outcome following pre-operative chemo/radiotherapy in rectal cancer.

Signet ring cell histology and non-circumferential tumors predict pathological complete response following neoadjuvant chemoradiation in rectal cancers

PURPOSE

Neoadjuvant chemoradiation followed by surgery is now the standard of care for patients with locally advanced rectal cancers. The aim of this study was to determine the rate of pathological complete response (pCR) following neoadjuvant treatment in patients with rectal cancers and identify the factors predicting the same.

METHODS

We conducted a retrospective analysis of patients with rectal cancers treated with neoadjuvant therapy followed by surgery at our institution from 1993 to 2008. Patients who achieved pCR were identified. Various patient, tumor, and treatment-related factors were studied for their influence on pCR by univariate and multivariate analyses. The influence of pCR on survival was also studied but was restricted to patients with a minimum follow-up of 5 years.

RESULTS

Between 1993 and 2008, 248 patients with rectal cancers received neoadjuvant therapy followed by surgery. Two hundred and twenty-seven patients received chemoradiation and 21 patients received only radiation. Pathological complete response was seen in 32 patients (12.9%). On multivariate analysis, the factors found to be independently predictive of pathological response were circumferential extent of the primary tumor (p = 0.016) and signet ring cell histology (p = 0.001). Among 116 patients with a minimum follow-up of 5 years, there was a trend towards increased overall survival (75% versus 54%) and reduced local recurrence (6.2% versus 12.3%) in the 16 patients who achieved a pCR compared to those who did not, even though the difference was not statistically significant.

CONCLUSIONS

The factors that predict a pCR after neoadjuvant treatment for rectal cancers are absence of circumferential involvement and signet ring cell histology. Pathological complete response may confer an insignificant survival advantage.

Radiation bowel disease and its clinical implication

Pre-operative radiotherapy may induce radiation colitis and tumour regression. Histological evaluation of radiation colitis needs to be reproducible to assess disease progression. The severity of radiation colitis can be assessed and graded according to its histological features. Increased severity of disease appears to be associated with a higher degree of cellular atypia and a lesser eosinophilic infiltrate. The severity of histological changes does not appear to be associated with post-operative complications. Tumour regression is an interesting phenomenon, the histological grading of which is of prognostic importance. Patients treated with long course radiotherapoy appear to have more incidences of postoperative complications. However, these are though to be related to the degree of tumour regression rather than to the type of radiotherapy.

Benchmarking circumferential resection margin (R1) resection rate for rectal cancer in the neoadjuvant era

AIM

Circumferential resection margin (CRM) involvement (R1) is used to audit rectal cancer surgical quality. However, when downsizing chemoradiation (dCRT) is used, CRM audits both dCRT and surgery, its use reflecting a high casemix of locally advanced tumours. We aimed to evaluate predictors of R1 and benchmark R1 rates in the dCRT era, and to assess the influence of failure of steps in the multidisciplinary team (MDT) process to CRM involvement.

METHOD

A retrospective analysis of prospectively collected rectal cancer data was undertaken. Patients were classified according to CRM status. Uni- and multivariate analysis was undertaken of risk factors for R1 resection. The contribution of the steps of the MDT process to CRM involvement was assessed.

RESULTS

Two hundred and ten rectal cancers were evaluated (68% T3 or T4 on preoperative staging). R1 (microscopic) and R2 (macroscopic) resections occurred in 20 (10%) and 6 patients (3%), respectively. Of several factors associated with R1 resections on univariate analysis, only total mesorectal excision (TME) specimen defects and threatened/involved CRM on preoperative imaging remained as independent predictors of R1 resections on multivariate analysis. Causes of R1 failure by MDT step classification found that less than half were associated with and only 15% solely attributable to a suboptimal TME specimen.

CONCLUSION

Total mesorectal excision specimen defects and staging-predicted threatened or involved CRM are independent strong predictors of R1 resections. In most R1 resections, the TME specimen was intact. It is important to remember the contribution of both the local staging casemix and dCRT failure when using R1 rates to assess purely surgical competence.

The pathologist's role in rectal cancer patient assessments

Since Cuthbert Dukes fundamental work linking cancer stage to prognosis, the pathologist has had an ever-expanding role in the multidisciplinary management of rectal cancer. Gross dissection techniques and histologic evaluation are reviewed. The evolving tumor size, node status, metastasis classification (TNM) staging system is outlined. The pathologist's critical role in correctly assessing circumferential margins and establishing resection adequacy and staging accuracy via lymph node assessment is emphasized.

Impact of tumor response on survival after radiochemotherapy in locally advanced rectal carcinoma

In locally advanced rectal adenocarcinoma, preoperative radiochemotherapy induces tumor response. The impact of pathologic tumor response on survival is still debated because of the numerous distinct tumor-response gradings available in the literature and the lack of standardized pathologic approach. The objective of this work was to study the impact of tumor response on survival, according to the 4 main tumor-response gradings available in the literature in locally advanced rectal adenocarcinoma after preoperative radiochemotherapy. From 1995 to 2004, 292 consecutive patients with cT3-T4 and/or N+ rectal adenocarcinoma were enrolled. Tumor response was evaluated according to ypTN-response gradings (downstaging: ypT0-2 N0 and complete pathologic response: ypT0 N0) and cellular-response gradings (ie, Mandard et al's and Rodel et al's gradings). The impact of tumor-response gradings and of different clinicopathologic variables on 5-year disease-free and overall survival were studied by univariate and multivariate analyses. We found that all tumor-response gradings were associated with survival. However, multivariate analysis showed that downstaging was the only tumor-response grading that influenced survival independently. In the subgroup of stage II patients (n=99), we also observed no difference on both 5-year disease-free and overall survival between low and high responders according to cellular response. In conclusion, in our experience, downstaging is the only tumor-response grading that influenced survival independently in locally advanced rectal adenocarcinomas. Cellular-response gradings had no impact on survival even in stage II patients.

GLUT-1 expression and response to chemoradiotherapy in rectal cancer

Preoperative chemoradiotherapy is used in locally advanced rectal cancer to reduce local recurrence and improve operability, however a proportion of tumors do not undergo significant regression. Identification of predictive markers of response to chemoradiotherapy would improve patient selection and may allow response modification by targeting of specific pathways. The aim of this study was to determine whether expression of glucose transporter-1 (GLUT-1) and p53 in pretreatment rectal cancer biopsies was predictive of tumor response to chemoradiotherapy. Immunohistochemical staining for GLUT-1 and p53 was performed on 69 pretreatment biopsies and compared to tumor response in the resected specimen as determined by the tumor regression grade (TRG) scoring system. GLUT-1 expression was significantly associated with reduced response to chemoradiotherapy and increasing GLUT expression correlated with poorer response (p=0.02). GLUT-1 negative tumors had a 70% probability of good response (TRG3/4) compared to a 31% probability of good response in GLUT-1 positive tumors. GLUT-1 may be a useful predictive marker of response to chemoradiotherapy in rectal cancer.

Rectal cancer staging post neoadjuvant therapy--how should the changes be assessed?

AIMS

To compare the utility and reproducibility of tumour regression grade scoring systems during histopathological assessment of rectal cancers resected after neoadjuvant (i.e. pre-operative) chemoradiotherapy.

METHODS AND RESULTS

The histopathological features of tumour regression were assessed independently in 54 rectal cancer resection specimens using three scoring systems: the Tumour Regression Grade (TRG), modified Rectal Cancer Regression Grade (m-RCRG) and RCPath Cancer Dataset (RCPath) methods. Good interobserver agreement was achieved for all three systems (kappa scores: TRG system 0.719, m-RCRG system 0.734, RCPath system 0.742). Both observers diagnosed complete tumour regression and little/no regression in 11 cases (20% of all cases) and four cases (11% of all cases), respectively. A mean of 5.6 tumour blocks/case were taken and the mean lymph node yield was 8.4/case.

CONCLUSIONS

All three scoring systems were usable in a diagnostic setting. The clinical significance of differing degrees of tumour regression is not yet universally agreed and, with this in mind, the m-RCRG system provided the optimum balance between applicability and the accurate recording of low, moderate and high degrees of tumour regression, thus facilitating future clinicopathological studies of moderate and high degrees of tumour regression and clinical outcome.

Molecular Response to Cetuximab and Efficacy of Preoperative Cetuximab-Based Chemoradiation in Rectal Cancer

Purpose

To characterize the molecular pathways activated or inhibited by cetuximab when combined with chemoradiotherapy (CRT) in rectal cancer and to identify molecular profiles and biomarkers that might improve patient selection for such treatments.

Patients and Methods

Forty-one patients with rectal cancer (T3-4 and/or N+) received preoperative radiotherapy (1.8 Gy, 5 days/wk, 45 Gy) in combination with capecitabine and cetuximab (400 mg/m2 as initial dose 1 week before CRT followed by 250 mg/m2 /wk for 5 weeks). Biopsies and plasma samples were taken before treatment, after cetuximab but before CRT, and at the time of surgery. Proteomics and microarrays were used to monitor the molecular response to cetuximab and to identify profiles and biomarkers to predict treatment efficacy.

Results

Cetuximab on its own downregulated genes involved in proliferation and invasion and upregulated inflammatory gene expression, with 16 genes being significantly influenced in microarray analysis. The decrease in proliferation was confirmed by immunohistochemistry for Ki67 (P = .01) and was accompanied by an increase in transforming growth factor-α in plasma samples (P < .001). Disease-free survival (DFS) was better in patients if epidermal growth factor receptor expression was upregulated in the tumor after the initial cetuximab dose (P = .02) and when fibro-inflammatory changes were present in the surgical specimen (P = .03). Microarray and proteomic profiles were predictive of DFS.

Conclusion

Our study showed that a single dose of cetuximab has a significant impact on the expression of genes involved in tumor proliferation and inflammation. We identified potential biomarkers that might predict response to cetuximab-based CRT.