Tailored rectal cancer treatment--a time for implementing contemporary prognostic factors?

Preoperative Grading of Rectal Cancer with Multiple DWI Models, DWI-Derived Biological Markers, and Machine Learning Classifiers

Background: this study aimed to utilize various diffusion-weighted imaging (DWI) techniques, including mono-exponential DWI, intravoxel incoherent motion (IVIM), and diffusion kurtosis imaging (DKI), for the preoperative grading of rectal cancer. Methods: 85 patients with rectal cancer were enrolled in this study. Mann-Whitney U tests or independent Student's t-tests were conducted to identify DWI-derived parameters that exhibited significant differences. Spearman or Pearson correlation tests were performed to assess the relationships among different DWI-derived biological markers. Subsequently, four machine learning classifier-based models were trained using various DWI-derived parameters as input features. Finally, diagnostic performance was evaluated using ROC analysis with 5-fold cross-validation. Results: With the exception of the pseudo-diffusion coefficient (Dp), IVIM-derived and DKI-derived parameters all demonstrated significant differences between low-grade and high-grade rectal cancer. The logistic regression-based machine learning classifier yielded the most favorable diagnostic efficacy (AUC: 0.902, 95% Confidence Interval: 0.754-1.000; Specificity: 0.856; Sensitivity: 0.925; Youden Index: 0.781). Conclusions: utilizing multiple DWI-derived biological markers in conjunction with a strategy employing multiple machine learning classifiers proves valuable for the noninvasive grading of rectal cancer.

Preoperative and postoperative prognostic factors of patients with stage II/III lower rectal cancer without neoadjuvant therapy in the clinical trial (JCOG0212)

BACKGROUND

The JCOG0212 trial was a randomized controlled trial comparing mesorectal excision alone to mesorectal excision with lateral lymph node dissection for stage II/III lower rectal cancer patients without clinical lateral lymph node enlargement. This study aimed to identify clinicopathological prognostic factors for relapse-free survival and overall survival of lower rectal cancer in the trial.

METHODS

Prospective data were selected from 663 patients with complete data. Uni and multivariable Cox regression model was applied to evaluate the preoperative and the combined preoperative and postoperative factors, respectively. Preoperative factors included age, sex, performance status, clinical T, clinical N and operative procedures. Postoperative factors included histological grade, pathological T, number of metastatic lymph nodes and number of dissected lymph nodes. No patient received neoadjuvant treatment.

RESULTS

Regarding preoperative factors, multivariable analysis revealed that performance status 1 (vs. 0: HR 2.079, P = 0.0041) and cT4a (vs. cT2-3: HR 2.721, P = 0.0002) were independent risk factors for relapse-free survival, and those for overall survival were male (vs. female: HR 1.660, P = 0.0228) and cT4a (vs. cT2-3: HR 2.486, P = 0.0473). The only independent preoperative risk factor common for relapse-free survival and overall survival was cT4a. Taking preoperative and postoperative factors together, the number of metastatic lymph nodes was the only independent risk factor common for relapse-free survival and overall survival.

CONCLUSIONS

Clinical stage II/III lower rectal cancer patients with cT4a should be a target of therapeutic development of neoadjuvant therapy. Postoperatively, intensive chemotherapy should be investigated for patients with more metastatic lymph nodes.

Radiomics modelling in rectal cancer to predict disease-free survival: evaluation of different approaches

BACKGROUND

Radiomics may be useful in rectal cancer management. The aim of this study was to assess and compare different radiomics approaches over qualitative evaluation to predict disease-free survival (DFS) in patients with locally advanced rectal cancer treated with neoadjuvant therapy.

METHODS

Patients from a phase II, multicentre, randomized study (GRECCAR4; NCT01333709) were included retrospectively as a training set. An independent cohort of patients comprised the independent test set. For both time points and both sets, radiomic features were extracted from two-dimensional manual segmentation (MS), three-dimensional (3D) MS, and from bounding boxes. Radiomics predictive models of DFS were built using a hyperparameters-tuned random forests classifier. Additionally, radiomics models were compared with qualitative parameters, including sphincter invasion, extramural vascular invasion as determined by MRI (mrEMVI) at baseline, and tumour regression grade evaluated by MRI (mrTRG) after chemoradiotherapy (CRT).

RESULTS

In the training cohort of 98 patients, all three models showed good performance with mean(s.d.) area under the curve (AUC) values ranging from 0.77(0.09) to 0.89(0.09) for prediction of DFS. The 3D radiomics model outperformed qualitative analysis based on mrEMVI and sphincter invasion at baseline (P = 0.038 and P = 0.027 respectively), and mrTRG after CRT (P = 0.017). In the independent test cohort of 48 patients, at baseline and after CRT the AUC ranged from 0.67(0.09) to 0.76(0.06). All three models showed no difference compared with qualitative analysis in the independent set.

CONCLUSION

Radiomics models can predict DFS in patients with locally advanced rectal cancer.

Development of a long non-coding RNA signature for prediction of response to neoadjuvant chemoradiotherapy in locally advanced rectal adenocarcinoma

Standard treatment for locally advanced rectal adenocarcinoma (LARC) includes a combination of chemotherapy with pyrimidine analogues, such as capecitabine, and radiation therapy, followed by surgery. Currently no clinically useful genomic predictors of benefit from neoadjuvant chemoradiotherapy (nCRT) exist for LARC. In this study we assessed the expression of 8,127 long noncoding RNAs (lncRNAs), poorly studied in LARC, to infer their ability in classifying patients’ pathological complete response (pCR). We collected and analyzed, using lncRNA-specific Agilent microarrays a consecutive series of 61 LARC cases undergoing nCRT. Potential lncRNA predictors in responders and non-responders to nCRT were identified with LASSO regression, and a model was optimized using k-fold cross-validation after selection of the three most informative lncRNA. 11 lncRNAs were differentially expressed with false discovery rate < 0.01 between responders and non-responders to NACT. We identified lnc-KLF7-1, lnc-MAB21L2-1, and LINC00324 as the most promising variable subset for classification building. Overall sensitivity and specificity were 0.91 and 0.94 respectively, with an AUC of our ROC curve = 0.93. Our study shows for the first time that lncRNAs can accurately predict response in LARC undergoing nCRT. Our three-lncRNA based signature must be independently validated and further analyses must be conducted to fully understand the biological role of the identified signature, but our results suggest lncRNAs may be an ideal biomarker for response prediction in the studied setting.

Early MRI predictors of disease-free survival in locally advanced rectal cancer from the GRECCAR 4 trial

BACKGROUND

Tailored neoadjuvant treatment of locally advanced rectal cancer (LARC) may improve outcomes. The aim of this study was to determine early MRI prognostic parameters with which to stratify neoadjuvant treatment in patients with LARC.

METHODS

All patients from a prospective, phase II, multicentre randomized study (GRECCAR4; NCT01333709) were included, and underwent rectal MRI before treatment, 4 weeks after induction chemotherapy and after completion of chemoradiotherapy (CRT). Tumour volumetry, MRI tumour regression grade (mrTRG), T and N categories, circumferential resection margin (CRM) status and extramural vascular invasion identified by MRI (mrEMVI) were evaluated.

RESULTS

A total of 133 randomized patients were analysed. Median follow-up was 41·4 (95 per cent c.i. 36·6 to 45·2) months. Thirty-one patients (23·3 per cent) developed tumour recurrence. In univariable analysis, mrEMVI at baseline was the only prognostic factor associated with poorer outcome (P = 0·015). After induction chemotherapy, a larger tumour volume on MRI (P = 0·019), tumour volume regression of 60 per cent or less (P = 0·002), involvement of the CRM (P = 0·037), mrEMVI (P = 0·026) and a poor mrTRG (P = 0·023) were associated with poor outcome. After completion of CRT, the absence of complete response on MRI (P = 0·004), mrEMVI (P = 0·038) and a poor mrTRG (P = 0·005) were associated with shorter disease-free survival. A final multivariable model including all significant variables (baseline, after induction, after CRT) revealed that Eastern Cooperative Oncology Group performance status (P = 0·011), sphincter involvement (P = 0·009), mrEMVI at baseline (P = 0·002) and early tumour volume regression of 60 per cent or less after induction (P = 0·007) were associated with relapse.

CONCLUSION

Baseline and early post-treatment MRI parameters are associated with prognosis in LARC. Future preoperative treatment should stratify treatment according to baseline mrEMVI status and early tumour volume regression.

State of the Art - Rectal Cancer Surgery

Background

In an aging society, the incidence and relevance of rectal cancer as one of the most frequent gastrointestinal cancers gains in importance. Excellent surgery and up-to-date multimodal treatments are essential for adequate oncological results and good quality of life.

Summary

In this review, we describe modern developments in rectal cancer surgery and its embedment in modern multimodal therapy concepts.

Key Message

Distinguished interdisciplinary cooperation combined with an outstanding surgical expertise is the basic requirement for an optimal treatment of rectal cancer. Thus, high standards of oncological outcome and patient's quality of life can be achieved.

Intravoxel Incoherent Motion MRI of Rectal Cancer: Correlation of Diffusion and Perfusion Characteristics With Prognostic Tumor Markers

OBJECTIVE

The objective of our study was to evaluate the intravoxel incoherent motion (IVIM)-DWI derived parameters and their relationships with tumor prognostic markers using 3-T MRI in patients with rectal cancer.

SUBJECTS AND METHODS

Fifty-two patients with histopathologically proven rectal cancer who underwent preoperative pelvic MRI were prospectively enrolled in this study. Diffusion and perfusion parameters including the apparent diffusion coefficient (ADC), pure diffusion coefficient, perfusion fraction, and pseudodiffusion coefficient derived from IVIMDWI were independently measured by two radiologists. Comparisons of IVIM-DWI-derived parameters in patients with different tumor prognostic markers were made using the independent-samples t test, ANOVA, and Mann-Whitney U test. The correlations between IVIM-DWI-derived parameters and tumor grade and tumor stage were further evaluated using Spearman correlation analysis. Interobserver agreement was evaluated using the intraclass correlation coefficient (ICC).

RESULTS

Excellent interobserver reproducibility was obtained for the IVIM-DWI-derived parameters (range of ICCs with 95% limits of agreement = 0.9309-0.9948, which is narrow). ADC, pseudodiffusion coefficient, and perfusion fraction tended to rise with greater tumor differentiation (r = 0.520, p < 0.001; r = 0.447, p = 0.001; r = 0.354, p = 0.010, respectively). The pure diffusion coefficient and pseudodiffusion coefficient showed a trend of decreasing with increasing tumor stages (r = 0.479, p < 0.001; r = 0.517, p < 0.001). The group of patients with extramural vascular invasion (EMVI) showed lower pseudodiffusion coefficient values than the group of patients with no EMVI (p < 0.05).

CONCLUSION

IVIM-DWI-derived parameters in patients with rectal cancer, especially the pseudodiffusion coefficient, are associated with tumor grade and tumor stage and show statistically significant differences between subjects with EMVI and those without EMVI. IVIM-DWI-derived parameters would be helpful in predicting tumor aggressiveness and prognosis.

Pretreatment magnetic resonance imaging of regional lymph nodes with carcinoembryonic antigen in prediction of synchronous distant metastasis in patients with rectal cancer

Distant metastasis in patients with rectal cancer remains a problem influencing prognosis. Prediction of synchronous distant metastasis is important for the choice of personalized treatment strategies and postoperative follow-up protocol. So far, there are few studies about the predictive value of MRI features combined with clinical characteristics for synchronous distant metastasis in rectal cancer, especially for the lesions developed within 6 months after surgery. We retrospectively reviewed the pretreatment clinical characteristics and magnetic resonance imaging (MRI) features of 271 patients from January 2010 to December 2011with pathologically confirmed rectal adenocarcinoma and tried to identify independent risk factors for synchronous distant metastasis. Forty-nine patients (18.1%) were confirmed to have synchronous distant metastasis. Multivariate logistic regression model demonstrated that the elevated carcinoembryonic antigen (CEA), positive MRI-predicted lymph nodes staging (mrN), and MRI-predicted mesorectal fascia (mrMRF) involvement were independent risk factors. The odd ratios were 12.2 for elevated CEA, 5.4 for mrN1 and 7.6 for mrN2, and 3.8 for mrMRF involvement, respectively. The accuracy and specificity for predicting synchronous distant metastasis by evaluating the positive mrN combined with elevated CEA were improved to 87.8% and 94.6%, respectively. The accuracy, sensitivity and specificity of positive mrN assessment were 86.1%, 71.4% and 91.7%, respectively using the histopathologic results as the reference standard. Altogether, our findings suggest that pretreatment positive mrN and elevated CEA are independent risk factors for synchronous distant metastasis in rectal cancer and combination of both could help to recognize the patients with high risk for structuring personalized treatment protocol.

Protocol for a multicentre randomised feasibility trial evaluating early Surgery Alone In LOw Rectal cancer (SAILOR)

INTRODUCTION

There are 11 500 rectal cancers diagnosed annually in the UK. Although surgery remains the primary treatment, there is evidence that preoperative radiotherapy (RT) improves local recurrence rates. High-quality surgery in rectal cancer is equally important in minimising local recurrence. Advances in MRI-guided prediction of resection margin status and improvements in abdominoperineal excision of the rectum (APER) technique supports a reassessment of the contribution of preoperative RT. A more selective approach to RT may be appropriate given the associated toxicity.

METHODS AND ANALYSIS

This trial will explore the feasibility of a definitive trial evaluating the omission of RT in resectable low rectal cancer requiring APER. It will test the feasibility of randomising patients to (1) standard care (neoadjuvant long course RT±chemotherapy and APER, or (2) APER surgery alone for cT2/T3ab N0/1 low rectal cancer with clear predicted resection margins on MRI. RT schedule will be 45 Gy over 5 weeks as current standard, with restaging and surgery after 8-12 weeks. Recruitment will be for 24 months with a minimum 12-month follow-up.

OBJECTIVES

Objectives include testing the ability to recruit, consent and retain patients, to quantify the number of patients eligible for a definitive trial and to test feasibility of outcomes measures. These include locoregional recurrence rates, distance to circumferential resection margin, toxicity and surgical complications including perineal wound healing, quality of life and economic analysis. The quality of MRI staging, RT delivery and surgical specimen quality will be closely monitored.

ETHICS AND DISSEMINATION

The trial is approved by the Regional Ethics Committee and Health Research Authority (HRA) or equivalent. Written informed consent will be obtained. Serious adverse events will be reported to Swansea Trials Unit (STU), the ethics committee and trial sites. Trial results will be submitted for peer review publication and to trial participants.

TRIAL REGISTRATION NUMBER

ISRCTN02406823.

National Early Rectal Cancer Treatment Revisited

BACKGROUND

Treatment of early stage rectal cancer has excellent oncological results. To reduce treatment-related mortality and morbidity and improve functional results, a focus on local resections is increasingly important.

OBJECTIVE

The purpose of this study was to compare outcomes after transanal endoscopic microsurgery and total mesorectal excision for early stage rectal cancer (T1 + T2) in Norway.

DESIGN

This was an observational study based on prospective data from the Norwegian Colorectal Cancer Registry.

SETTINGS

The study was conducted as a national, population-based study.

PATIENTS

All 543 patients with T1 and 1593 patients with T2 rectal cancer without distant metastases that was treated by transanal endoscopic microsurgery or total mesorectal excision without radiochemotherapy during 2000-2009 were included.

MAIN OUTCOME MEASURES

The primary outcomes were 5-year relative survival and 5-year local recurrence rate.

RESULTS

Among 543 patients with T1 cancer, the 5-year overall survival rate was 65.3% after transanal endoscopic microsurgery versus 81.5% after total mesorectal excision (p = 0.012). Adjusted for age and sex there was no excess mortality for transanal endoscopic microsurgery (HR = 1.28 (95% CI, 0.8-1.9); p = 0.22). The 5-year relative survival rate was 96.8% after transanal endoscopic microsurgery versus 98.2% after total mesorectal excision (p = 0.603), and the 5-year local recurrence rate was 14.5% versus 1.4% (p < 0.001). Among 1593 patients with T2 cancer, 5-year overall survival was 42.1% versus 76.1% (p < 0.001), 5-year relative survival was 65.4% versus 93.9% (p < 0.001), and 5 year local recurrence rate was 11.4% versus 4.4% in the 2 groups.

LIMITATIONS

The study is limited by its observational design and that the 2 groups were different according to patient and tumor characteristics. Another limitation was the low number of transanal endoscopic microsurgery procedures.

CONCLUSIONS

Transanal endoscopic microsurgery had comparable 5-year relative survival to total mesorectal excision in T1 rectal cancer but inferior 5-year relative survival in T2 rectal cancer. Transanal endoscopic microsurgery was associated with higher local recurrence rates for both T1 and T2 tumors.

Elevated Cell-Free DNA Measured by a Simple Assay Is Associated With Increased Rate of Colorectal Cancer Relapse

OBJECTIVES

For patients with early stage colorectal cancer (CRC), markers of high-risk relapse are needed. In a previous study on 38 randomly selected patients with CRC, we found good correlation between presurgery cell-free DNA (CFD) concentrations and standard prognostic factors. In the current study, we revisited the same patients at 5-year survival, aiming to evaluate the predictive power of presurgery CFD levels.

METHODS

We revisited 38 patients with CRC previously analyzed for 5-year outcome. CFD was measured using a simple fluorescent assay that we developed.

RESULTS

All recurrent patients and patients who had died of cancer within 5 years were shown to have presurgery CFD values above 800 ng/mL. The negative predictive value for cancer-related disease was 100%. Cox regression analysis for disease-free survival showed a hazard ratio of 6.03 (P = .003) for CFD, which was higher than the ratio of the disease stage, 1.9 (P = .006). The survival-free curve of stage I and II patients with elevated CFD was significantly different from patients with normal levels (P = .0136); 5 (41.7%) of 12 patients had died of cancer or had experienced a recurrence.

CONCLUSIONS

CFD may possibly be a decisive criterion to identify patients with local disease who might benefit from adjuvant chemotherapy.

Complications and risk prediction in treatment of elderly patients with rectal cancer

PURPOSE

The primary aim of this study was to characterise complications, identify predictors of postoperative morbidity and mortality and to evaluate existing risk prediction models in elderly rectal cancer patients.

METHODS

An observational single-centre study of 330 consecutive patients >75 years treated in 1994-2006. Analyses were performed by age group: 75-79 years, 80-85 years and >85 years.

RESULTS

Total observed in-hospital morbidity was 48.7 %. In multivariate analysis, age (OR 1.04, 95 % CI 1.01-1.08, p = 0.04), ASA grade ≥ 3 (p = 0.01), acute presentation (OR 1.67, 95 % CI 1.2-13.2, p = 0.02) and major surgery (APR OR 3.72, 95 % CI 1.37-10.15, p = 0.01, LAR OR 2.98, 95 % CI 1.14-7.79, p = 0.03, Hartmann OR 5.46, 95 % CI 1.60-19.28, p = 0.02) were independent risk factors for postoperative morbidity. The 30-day mortality was 6.3, 6.4 and 14.3 % (p = 0.146) in the three age groups, and the 100-day mortality was 8.7, 10.1 and 22.2 % (p = 0.03), respectively. ASA group 3 (OR 6.21, 95 % CI 4.39-27.69, p = 0.017), ASA group 4 (OR 32.6, 95 % CI 5.12-207.75, p < 0.001) and acute presentation (OR 6.48, 95 % CI 1.62-25.99, p = 0.008) increased the risk of 100-day mortality. The Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity (POSSUM) observed/estimated (O/E) ratio for morbidity was 1.05. For 30-day mortality, the colorectal POSSUM (Cr-POSSUM) O/E ratio was 0.74, Surgical Risk Scale 0.61 and the Association of Coloproctology of Great Britain and Ireland (ACPGBI) mortality model 0.63, and for 100-day mortality, ratios were 1.12, 0.91 and 0.95, respectively.

CONCLUSION

In this series, age increased the risk of in-hospital morbidity and 100-day mortality. Cr-POSSUM, SRS and ACPGBI overestimated 30-day mortality but predicted 100-day mortality with a high degree of accuracy. POSSUM correctly predicted in-hospital morbidity.

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.

Outcomes in locally advanced rectal cancer with highly selective preoperative chemoradiotherapy

BACKGROUND

This study compared outcomes after surgery alone for stage II/ III rectal cancer in a tertiary cancer unit versus highly selective use of preoperative chemoradiotherapy (CRT).

METHODS

This was a single-centre retrospective cohort study of consecutive patients receiving potentially curative surgery for stage II and III primary rectal cancer. CRT was given only for magnetic resonance imaging-predicted circumferential resection margin (CRM) involvement and nodal disease (at least N2). Primary endpoints were CRM involvement and local recurrence rates. Secondary endpoints were systemic recurrence and overall survival. Data were analysed by log rank test, and univariable and multivariable analysis.

RESULTS

Between 2002 and 2012, 363 patients were treated for rectal cancer. After applying exclusion criteria, 266 patients with stage II/III mid or low rectal cancer were analysed. Of these, 103 received neoadjuvant CRT and 163 proceeded directly to surgery, seven of whom required postoperative radiotherapy; the latter patients were included in the neoadjuvant CRT group for analysis. There was a significant difference in local recurrence between the CRT and surgery-alone groups (6·5 versus 0 per cent at 5 years; P = 0·040), but not in CRM involvement (7·2 versus 5·1 per cent; P = 0·470), 5-year systemic recurrence (37·2 versus 43·0 per cent; P = 0·560) and overall survival (64·2 versus 64·6 per cent; P = 0·628) rates. Metastatic disease developed more frequently in low rectal cancers (odds ratio 0·14; P < 0·001), regardless of whether neoadjuvant treatment was delivered.

CONCLUSION

Locally advanced rectal cancer does not necessarily require neoadjuvant CRT.

An umbrella protocol for standardized data collection (SDC) in rectal cancer: a prospective uniform naming and procedure convention to support personalized medicine

Predictive models allow treating physicians to deliver tailored treatment moving from prescription by consensus to prescription by numbers. The main features of an umbrella protocol for standardizing data and procedures to create a consistent dataset useful to obtain a trustful analysis for a Decision Support System for rectal cancer are reported.