Restaging locally advanced rectal cancer by different imaging modalities after preoperative chemoradiation: a comparative study

A prospective study on using shear wave elastography to predict the ypT0 stage of rectal cancer after neoadjuvant therapy: a new support for the watch-and-wait approach?

Introduction

The diagnostic accuracy of traditional imaging examination in predicting ypT stage of rectal cancer after neoadjuvant therapy is significantly reduced, which would affect patients' subsequent treatment choices. This study aimed to investigate the use of endorectal shear wave elastography (SWE) for diagnosing ypT0 stage of rectal cancer after neoadjuvant chemoradiotherapy (nCRT).

Methods

Sixty patients with rectal cancer were prospectively recruited in this study. Data on endorectal ultrasound (ERUS) and SWE parameters were collected before nCRT and 6-8 weeks after nCRT. Postoperative pathological results were the gold standard for evaluating the diagnostic accuracy of SWE and ERUS in predicting the ypT0 stage of rectal cancer after nCRT. Receiver operating characteristic (ROC) curve analysis was used to determine the cut-off values of the SWE parameters that best corresponded to the ypT0 stage and analyze the sensitivity, specificity, and accuracy.

Results

The diagnostic accuracies of using ERUS to predict the ypT and ypT0 stages of rectal cancer after nCRT were 58.1% (18/31) and 64.3% (9/14), respectively. The ROC curve was constructed with the lesion's Emean, Emean corrected (EC), Emean difference (ED), Emean corrected differencede (ECD), Emean descendding rate (EDR) and Emean corrected descendding rate (ECDR) values after nCRT, the cut-off values of diagnosing the ypT0 stage were 64.40 kPa, 55.45 kPa, 72.55 kPa, 73.75 kPa, 50.15%, and 55.93%, respectively; the area under the curve (AUC) for diagnosing the ypT0 stage was 0.924, 0.933, 0.748, 0.729, 0.857 and 0.861, respectively. The EC value showed the best diagnostic performance.

Conclusion

SWE could improve the accuracy of conventional ERUS in diagnosing the ypT0 stage of rectal cancer after nCRT. It is expected to become a new method to help predict pathological complete responses in clinical practice and provide new evidence for the watch-and-wait approach.

Application of ultrasound in the diagnosis of gastrointestinal tumors

Gastrointestinal tumors are common tumors in the digestive system. Early diagnosis of gastrointestinal tumors is the key to improve prognosis and curative effect of patients with tumors. Compared with other methods of examination and diagnosis, ultrasound examination has the advantages of simple operation, non-invasive, economical, and repeatable operation. With the advancement of ultrasound technology and the development of ultrasound contrast agents, ultrasound examination is more and more applied to gastrointestinal examination. Ultrasound cannot only observe the gastrointestinal wall, but also evaluate the surrounding lesions and metastases, as well as preoperative analysis and postoperative follow-up of gastrointestinal tumors. We reviewed the diagnostic applications of ultrasound in gastrointestinal tumors.

Limited Role for Routine Restaging After Neoadjuvant Therapy in Locally Advanced Rectal Cancer

BACKGROUND

Although many patients with locally advanced rectal cancer undergo restaging imaging after neoadjuvant chemoradiotherapy and before surgery, the benefit of this practice is unclear. The purpose of this study was to examine the impact of reimaging on outcomes.

MATERIALS AND METHODS

We performed a retrospective analysis of consecutive patients with stage 2 and 3 rectal adenocarcinoma treated with neoadjuvant chemoradiotherapy between May 2005 and April 2018. Patient and disease characteristics, imaging, treatment, and oncologic outcomes were compared between those who underwent restaging and those who went directly to surgery. Predictors of outcomes and cost effectiveness of restaging were determined.

RESULTS

Of 224 patients, 146 underwent restaging. Six restaged patients had findings leading to a change in management. There was no difference in freedom from recurrence (P = 0.807) and overall survival (P = 0.684) based on restaging. Pretreatment carcinoembryonic antigen level >3 ng/mL (P = 0.010), clinical T stage 4 (P = 0.016), and pathologic T4 (P = 0.047) and N2 (P = 0.002) disease increased the risk of death, whereas adjuvant chemotherapy decreased the risk of death (P < 0.001) on multivariate analysis. Disease recurrence was lower with pelvic exenteration (P = 0.005) and in females (P = 0.039) and higher with pathologic N2 (P = 0.003) and N3 (P = 0.002) disease. The average cost of reimaging is $40,309 per change in management; however, $45 is saved per patient when downstream surgical costs are considered.

CONCLUSIONS

Imaging restaging after neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer rarely changes treatment and does not improve survival. In a subset of patients at higher risk for worse outcome, reimaging may be beneficial.

Molecular Predictors of Response to Neoadjuvant Chemoradiation for Rectal Cancer

OBJECTIVES

To determine whether the expression of specific molecular markers in the rectal cancer biopsies prior to treatment, can correlate with complete tumor response to chemoradiotherapy (CRT) as determined by the pathology of the surgical specimen.

METHODS

We retrospectively examined pretreatment rectal biopsies of patients aged 18 years or older with locally advanced rectal cancer who had been treated with neoadjuvant CRT and surgical resection in our tertiary-care, university-affiliated medical center, between January 2001 and December 2011. Samples were analyzed for expression of B-cell lymphoma 2, P53, Ki67, epidermal growth factor receptor (EGFR), vascular endothelial growth factor receptor, and the tumor regression grade after CRT and radical surgery.

RESULTS

Forty-seven patients were included in the final analysis. Main outcome measures were the correlation between the expression of the molecular markers tested in the pretreatment biopsy, and complete tumor response. Complete pathologic response after CRT was attained in 27% of the patients. Percentage of cells expressing EGFR in the pretreated biopsies of patients having complete pathologic response after CRT and surgery was 33.08±7.87% compared to 19±15.36% (P=0.38), 6.66±2.83% (P<0.003), and 12.5±4.93% (P=0.033) in patients with partial response and tumor regression grades of 2, 3, and 4, respectively. The other molecular markers tested in the pretreatment biopsy did not corresponded with complete pathologic response.

CONCLUSIONS

EGFR expression pattern in the pretreatment biopsies of rectal tumors can assist in identifying patients who will benefit from neoadjuvant CRT.

Accuracy of endoscopic ultrasound in rectal cancer and its use in transanal endoscopic microsurgery

Introduction: This study evaluated the accuracy of endoscopic ultrasound (EUS) for preoperative staging of rectal cancer and guiding the treatment of transanal endoscopic microsurgery (TEM) in early rectal cancer.Material and methods: One-hundred-twenty-six patients with rectal cancer were staged preoperatively using EUS and the results were compared with postoperative histopathology results. Radical surgeries, including low anterior resection (LAR), abdominal-perineal resection (APR) and Hartmann surgeries, were performed on patients with advanced rectal cancers, and TEM was performed on patients with stage T1. The Kappa statistic was used to determine agreement between EUS-based staging and pathology staging.Results: The overall accuracies of EUS for T and N stage were 90.8% (Kappa = 0.709) and 76.7% (Kappa = 0.419), respectively. The accuracies of EUS for uT1, uT2, uT3, and uT4 stages were 96.8%, 92.1%, 84.1%, and 88.9%, respectively, and for uN0, uN1, and uN2 stages, they were 71.9%, 64.9%, and 93.0%, respectively. Twelve patients underwent TEM and received confirmed pathology results of early rectal cancer. After postoperative follow-up, there were no local recurrences or distant metastases.Conclusion: EUS is a good and comparable technique for postoperative staging of rectal cancer. Moreover, EUS is used as indicator for preoperative staging and tumor assessment strategy when considering TEM.

Junior E, Machado AM, Mamede M. Individualized threshold for tumor segmentation in 18F-FDG PET/CT imaging: The key for response evaluation of neoadjuvant chemoradiation therapy in patients with rectal cancer?

Summary Introduction: The standard treatment for locally advanced rectal cancer (RC) consists of neoadjuvant chemoradiation followed by radical surgery. Regardless the extensive use of SUVmax in 18F-FDG PET tumor uptake as representation of tumor glycolytic consumption, there is a trend to apply metabolic volume instead. Thus, the aim of the present study was to evaluate a noninvasive method for tumor segmentation using the 18F-FDG PET imaging in order to predict response to neoadjuvant chemoradiation therapy in patients with rectal cancer. Method: The sample consisted of stage II and III rectal cancer patients undergoing 18F-FDG PET/CT examination before and eight weeks after neoadjuvant therapy. An individualized tumor segmentation methodology was applied to generate tumor volumes (SUV2SD) and compare with standard SUVmax and fixed threshold (SUV40%, SUV50% and SUV60%) pre- and post-therapy. Therapeutic response was assessed in the resected specimens using Dworak's protocol recommendations. Several variables were generated and compared with the histopathological results. Results: Seventeen (17) patients were included and analyzed. Significant differences were observed between responders (Dworak 3 and 4) and non-responders for SUVmax-2 (p<0.01), SUV2SD-2 (p<0.05), SUV40%-2 (p<0.05), SUV50%-2 (p<0.05) and SUV60%-2 (p<0.05). ROC analyses showed significant areas under the curve (p<0.01) for the proposed methodology with sensitivity and specificity varying from 60% to 83% and 73% to 82%, respectively. Conclusion: The present study confirmed the predictive power of the variables using a noninvasive individualized methodology for tumor segmentation based on 18F-FDG PET/CT imaging for response evaluation in patients with rectal cancer after neoadjuvant chemoradiation therapy.

Re-Staging Following Long-Course Chemoradiotherapy For Rectal Cancer: Does It Influence Management?

BACKGROUND

In patients with locally advanced or low rectal cancers, long-course chemoradiotherapy (LCCRT) is recommended prior to surgical management.¹ The need for restaging afterwards has been questioned as it may be difficult to interpret imaging due to local tissue effects of chemoradiotherapy. The purpose of this study was to determine if restaging affected the management of patients receiving long-course chemoradiotherapy for rectal cancer.

METHODS

A retrospective review of patients with rectal cancer discussed at the South Eastern Health and Social Care Trust Lower Gastrointestinal Multi-Disciplinary Team Meeting (LGIMDT) in 2013 who had received long-course chemoradiotherapy was performed. Patients were identified from the Trust Audit Department, LGIMDT notes and patient records. Imaging results and outcomes from meetings were obtained through the Northern Ireland Picture Archiving and Communications System^® (NIPACS) and Electronic Care Record^® (ECR). Data including patient demographics, initial radiological staging and LGIMDT discussion, restaging modality and result, outcome from post-treatment LGIMDT discussion and recorded changes in management plans were documented using a proforma.

RESULTS

Seventy-one patients with rectal cancer were identified as having LCCRT in 2013 (M:F 36:35; age range 31 - 85 years). Fifty-nine patients were restaged following long-course treatment with computed tomography (CT) and magnetic resonance imaging (MRI). Twelve patients did not undergo restaging. Data was not available for 6 patients, one patient underwent emergency surgery, two patients were not fit for treatment, one failed to attend for restaging and two patients died prior to completion of treatment. Of the 59 patients restaged, 19 patients (32%) had their management plan altered from that which had been proposed at the initial LGIMDT discussion. The most common change in plan was not to operate. Ten patients had a complete clinical and radiological response to treatment and have undergone intensive follow-up. Nine patients had disease progression, with 3 requiring palliative surgery and 6 referred for palliative care.

CONCLUSION

Of those patients who were restaged, 32% had their management plan altered from that recorded at the initial LGIMDT discussion. Seventeen per cent of patients in this group had a complete clinical and radiological response to treatment. Fifteen percent demonstrated disease progression. We recommend, therefore, that patients with rectal cancer be restaged with CT and MRI following long-course chemoradiotherapy as surgery may be avoided in up to 27% of cases.

Preoperative Prediction of Lymph Node Status by Circulating Mir-18b and Mir-20a During Chemoradiotherapy in Patients with Rectal Cancer

BACKGROUND

In locally advanced rectal cancer, therapeutic success of preoperative chemoradiotherapy (CRT) ranges from resistance to complete regression. For those patients that respond well to CRT, local resection (LR) procedures are currently under investigation to minimize surgical morbidity and to improve functional outcome. To maintain the oncologic benefit appropriate staging procedures are essential. However, current clinical assessment and imaging techniques need further improvement.

METHODS

Five miRNAs associated with rectal cancer (miR-17, miR-18b, miR-20a, miR-31, and miR-193-3p) were analyzed in the plasma of rectal cancer patients (n = 42) using qPCR. Expression levels were assessed before, during and after CRT and analyzed in regard to patients' lymph node status obtained after total mesorectal excision and intensive histopathological work-up.

RESULTS

Four of the five miRNAs revealed reliable results in the plasma. miR-31 was excluded due to its low expression. MicroRNA-17, 18b, 20a, and 193-3p showed altering expression levels at different time points. Only 43% (miR-17), 43% (miR-18b), 53% (miR-20a), and 60% (miR-193-3p) showed a continuous in- or decrease of miRNA expression. The reduced expression of miR-18b and miR-20a during CRT was found to be significantly associated with postoperative lymph node negativity (p < 0.05).

CONCLUSION

MicroRNA expression in patient plasma changes during preoperative CRT. The alteration is not continuous and the meaning requires additional analysis on a larger patient cohort. The co-occurrence of reduced miR-18b and miR-20a expression with lymph node negativity after preoperative CRT could help to stratify the surgical procedure with respect to total mesorectal excision and LR if validated prospectively.

Adjuvant chemotherapy for rectal cancer: Is it needed?

Adjuvant chemotherapy has become a standard treatment of advanced rectal cancer in the West. The benefits of adjuvant chemotherapy after surgery alone have been well established. However, controversy surrounds the use adjuvant chemotherapy in patients who received preoperative chemoradiotherapy, despite it being recommended by a number of international guidelines. Results of recent multicentre randomised control trials showed no benefit of adjuvant chemotherapy in terms of survival and rates of distant metastases. However, concerns exist regarding the quality of the studies including inadequate staging modalities, out-dated chemotherapeutic regimens and surgical approaches and small sample sizes. It has become evident that not all the patients respond to adjuvant chemotherapy and more personalised approach should be employed when considering the benefits of adjuvant chemotherapy. The present review discusses the strengths and weaknesses of the current evidence-base and suggests improvements for future studies.

T4 rectal cancer: do we always need an exenteration?

The management of rectal cancer has changed dramatically over the last few decades. Due to improvements in the multimodality treatment and the introduction of neoadjuvant chemoradiation, previously irresectable tumours can nowadays be cured by extensive multivisceral resections. These highly complex operations are associated with significant morbidity and mortality. Due to optimization of chemoradiotherapy, the introduction of IORT, increasing knowledge of tumour pathology and patterns of recurrence the need for extensive surgery diminishes. The question arises which patients with T4 rectal cancer really need extensive surgery and who can safely be considered for an organ preserving approach.