Neoplastic mesorectal microfoci (MMF) following neoadjuvant chemoradiotherapy: clinical and prognostic implications

Computed Tomography-based Radiomics Nomogram for the Preoperative Prediction of Tumor Deposits and Clinical Outcomes in Colon Cancer: a Multicenter Study

RATIONALE AND OBJECTIVES

To develop and validate a computed tomography (CT)-based radiomics nomogram for the preoperative prediction of tumor deposits (TDs) and clinical outcomes in patients with colon cancer.

MATERIALS AND METHODS

This retrospective study included 383 consecutive patients with colon cancer from two centers. Radiomics features were extracted from portal venous phase CT images. Least absolute shrinkage and selection operator regression was applied for feature selection and radiomics signature construction. The multivariate logistic regression model was used to establish a radiomics nomogram. The performance of the nomogram was assessed by using receiver operating characteristic curves, calibration curves and decision curve analysis. Kaplan‒Meier survival analysis was used to assess the difference of the overall survival (OS) in the TDs-positive and TDs-negative groups.

RESULTS

The radiomics signature was composed of 11 TDs status related features. The AUCs of the radiomics model in the training cohort, internal validation and external validation cohorts were 0.82, 0.78 and 0.78, respectively. The radiomics nomogram that incorporated the radiomics signature and clinical independent predictors (CT-N, CEA and CA199) showed good calibration and discrimination with AUCs of 0.88, 0.80 and 0.81 in the training cohort, internal validation and external validation cohorts, respectively. The radiomics nomogram-predicted high-risk groups had a worse OS than the low-risk groups (p < 0.001). The radiomics nomogram-predicted TDs was an independent preoperative predictor of OS.

CONCLUSION

The radiomics nomogram based on CT radiomics features and clinical independent predictors could effectively predict the preoperative TDs status and OS of colon cancer.

IMPORTANT FINDINGS

CT-based radiomics nomogram may be applied in the individual preoperative prediction of TDs status in colon cancer. Additionally, there was a significant difference in OS between the high-risk and low-risk groups defined by the radiomics nomogram, in which patients with high-risk TDs had a significantly worse OS, compared with those with low-risk TDs.

Improved Outcomes for Rectal Cancer in the Era of Preoperative Chemoradiation and Tailored Mesorectal Excision: A Series of 338 Consecutive Cases

Neoadjuvant chemoradiation (CRT), tailored mesorectal excision, and intraoperative radiotherapy (IORT) have become the leading measures for rectal cancer treatment. The objective of this study was to evaluate early and long-term results of a multimodal treatment model for rectal cancer followed by curative surgery. Prospectively collected hospital records of 338 patients surgically treated for rectal cancer between January 1998 and December 2008 were retrospectively reviewed. Patients with high rectum level cancers and those with middle and low rectum cancers with clinical stage T1 to T2 underwent surgery, whereas those with T3 to T4 and N1 disease at the middle and low rectum received neoadjuvant CRT in 96.2 per cent of cases. Short-course neoadjuvant radiotherapy was not considered for neoadjuvant treatment. Postoperative major complications and mortality rates were 12.7 and 2.3 per cent, respectively. Overall 5-year disease-specific and disease-free survival were 80 and 73.1 per cent, respectively, whereas local recurrence rate was 6.1 per cent. At multivariate analysis, nodal status and circumferential margin status were independently associated with poor survival; local recurrence rates were independently affected by nodal and marginal status and tumor stage. The extent of mesorectal excision should be tailored depending on tumor location and the use of neoadjuvant chemotherapy, combined with IORT in advanced middle and low rectal cancer, leading to remarkable tumor downstaging with excellent prognosis in responding patients.

Pathologic Assessment of Rectal Carcinoma after Neoadjuvant Radio(chemo)therapy: Prognostic Implications

Neoadjuvant radio(chemo)therapy is increasingly used in rectal cancer and induces a number of morphologic changes that affect prognostication after curative surgery, thereby creating new challenges for surgical pathologists, particularly in evaluating morphologic changes and tumour response to preoperative treatment. Surgical pathologists play an important role in determining the many facets of rectal carcinoma patient care after neoadjuvant treatment. These range from proper handling of macroscopic specimens to accurate microscopic evaluation of pathological features associated with patients' prognosis. This review presents the well-established pathological prognostic indicators and discusses challenging features in order to provide both surgical pathologists and treating physicians with a checklist that is useful in a neoadjuvant setting.

Prognostic value of tumor shrinkage versus fragmentation following radiochemotherapy and surgery for rectal cancer

Most patients with rectal cancer receive neoadjuvant radiochemotherapy (RCT), causing a variable decrease in tumor mass. We evaluated the prognostic impact of pathologic parameters reflecting tumor response to RCT, either directly or indirectly. Seventy-six rectal cancer patients receiving neoadjuvant RCT between 2006 and 2009 were included. We studied the association between disease-free survival (DFS) and the "classical" clinicopathologic features as well as tumor deposits, circumferential resection margin (CRM), Dworak regression grade, and tumor and nodal downstaging. Patients with tumor downstaging had a longer DFS (p = 0.05), indicating a more favorable prognosis when regression was accompanied by a decrease in tumor infiltrative depth, referred to as tumor shrinkage. Moreover, tumor downstaging was significantly associated with larger CRM and nodal downstaging (p = 0.02), suggesting that shrinkage of the primary tumor was associated with a decreased nodal tumor load. Higher Dworak grade did not correlate with tumor downstaging, nor with higher CRM or prolonged DFS. This implies that tumor mass decrease was sometimes due to fragmentation rather than shrinkage of the primary tumor. Lastly, the presence of tumor deposits was clearly associated with reduced DFS (p = 0.01). Assessment of tumor shrinkage after RCT via tumor downstaging and CRM is a good way of predicting DFS in rectal cancer, and shrinkage of the primary tumor is associated with a decreased nodal tumor load. Assessing regression based on the amount of tumor in relation to stromal fibrosis does not accurately discern tumor fragmentation from tumor shrinkage, which is most likely the reason why Dworak grade had less prognostic relevance.

Predictive markers of response to neoadjuvant therapy in rectal cancer

BACKGROUND

Neoadjuvant therapy followed by radical surgery is the standard treatment in locally advanced rectal cancer. It is important to predict the response because the treatment has side effects and is costly. The aim of this study was to establish the relationship among clinical, pathologic, and molecular biomarkers and the response to neoadjuvant therapy.

METHOD

A total of 130 patients with locally advanced mid and low rectal cancer who underwent long-course radiotherapy with 5-FU based chemotherapy followed by radical surgical resection were included in the study. Clinical and pathologic data were collected. Paraffin-embedded sections obtained in diagnostic biopsies were assessed by immunohistochemical staining for molecular markers and classified using a semiquantitative method. Results were related with T-downstaging and tumor regression grade using Mandard scoring system on surgical specimens.

RESULTS

Pathologic complete response was found in 19 patients (14.6%), while in another 18 (13.8%) only minor residual disease was seen in the rectal wall. T-downstaging was observed in 63 (48.5%). The average of lymph node retrieval in the surgical specimens was 9.4. Regarding predictive markers of response, there was significant correlation between the expression of B-cell lymphoma 2 (P = 0.005), β-catenin (P = 0.03), vascular endothelial growth factor (P = 0.048) and apoptotic protease activating factor 1 (P = 0.03), tumor differentiation grade (P < 0.001), and response in the univariate analysis. T-downstaging was associated with vascular endothelial growth factor expression (P = 0.03) and tumor differentiation grade (P < 0.001). Significant parameters found in the multivariate analysis were tumor differentiation grade and Bcl-2 expression.

CONCLUSIONS

Pathologic and molecular biomarkers in the diagnostic biopsies may help us predict tumor response to chemoradiation in rectal cancer patients.

Risk factors for local recurrence following neoadjuvant chemoradiotherapy for rectal cancers

Local recurrence (LR) has an adverse impact on rectal cancer treatment. Neoadjuvant chemoradiotherapy (nCRT) is increasingly administered to patients with progressive cancers to improve the prognosis. However, LR still remains a problem and its pattern can alter. Correspondingly, new risk factors have emerged in the context of nCRT in addition to the traditional risk factors in patients receiving non-neoadjuvant therapies. These risk factors are decisive when reviewing treatment options. This review aims to elucidate the distinctive risk factors related to LR of rectal cancers in patients receiving nCRT and to clarify their clinical significance. A search was conducted on PubMed to identify original studies investigating patients with rectal cancer receiving nCRT. Outcomes of interest, especially potential risk factors for LR in patients with nCRT, were then analyzed. The clinical importance of these risk factors is discussed. Remnant cancer cells, lymph-nodes and tumor response were found to be major risk factors. Remnant cancer cells decide the status of resection margins. Local excision following nCRT is promising in ypT0-1N0M0 cases. Dissection of lateral lymph nodes should be considered in advanced low-lying cancers. Although better tumor response resulted in a relatively lower recurrence rate, the evidence available is insufficient to justify a non-operative approach in clinical complete responders to nCRT. LR cannot be totally avoided by current multidisciplinary approaches. The related risk factors resulting from nCRT should be considered when making decisions regarding treatment selection.

Delayed surgery for rectal cancer patients receiving neoadjuvant chemoradiotherapy: a promising method in its infancy

BACKGROUND

Neoadjuvant chemoradiotherapy (nCRT) is used to downstage locally advanced rectal cancer before surgery. Accumulating data suggest that tumor response to nCRT is time dependent. A delay between nCRT and surgery may increase the proportion of patients that achieve a favorable response. However, delayed surgery beyond 6-8 weeks may increase the technical difficulty, and the risks of surgical complications and recurrence or metastasis. This article briefly reviews the relevant literature to evaluate the efficiency and safety of delayed surgery.

METHODS

Two non-cohort studies and 10 cohort studies were reviewed. The results were analyzed and the limitations discussed.

RESULTS

Although debatable, the findings of the included studies are promising. Delayed surgery may increase the proportion of favorable tumor response without compromising prognosis. However, most of the studies were retrospective, which introduces bias into the evaluation.

CONCLUSION

Delayed surgery is potentially useful, but this needs to be verified by further well-designed prospective trials.

One hundred years of curative surgery for rectal cancer: 1908-2008

In 1908, William Ernest Miles published his article in the Lancet, introducing the basis of modern rectal cancer surgery. He established the basis for curative cancer treatment by combining the knowledge of anatomy and biological behaviour with improved surgical options as a result of better anaesthesiological techniques. Miles' contribution comprised the introduction of the concept of lymphatic spread of cancer cells and his consequent radical surgical resection, removing all primary lymph nodes en bloc. Miles' concept has dominated the minds of surgeons throughout the 20th century and his abdominoperineal resection has been the golden standard for several decades. However, his concept of downward spread of rectal cancer was proven wrong, which initiated the historical shift from radical abdominoperineal resection to the use of sphincter-saving surgery. Since the introduction of total mesorectal excision, abdominoperineal excision has been performed in only a minority of patients. Further improvement in surgical technique consisted of autonomic nerve preservation, improving functional outcome. From a historical overview, it can be concluded that the management of rectal cancer has been progressed tremendously over the past 100 years, mainly because of an increased understanding of the pathology and natural history of the disease, which has been initiated by Miles.

Controversies of total mesorectal excision for rectal cancer in elderly patients

The cornerstone of treatment for rectal cancer is resectional treatment according to the principles of total mesorectal excision (TME). However, population-based registries show that improvements in outcome after resectional treatment occur mainly in younger patients. Furthermore, 6-month postoperative mortality is significantly increased in elderly patients (> or = 75 years of age) compared with younger patients (< 75 years of age). Several confounding factors, such as treatment-related complications and comorbidity, are thought to be responsible for these disappointing findings. Thus, major resectional treatment is not advantageous for all older patients with rectal cancer. However, the Dutch TME trial showed a good response to a short course of neoadjuvant radiotherapy in elderly patients. Biological responses to cancer treatment seem to change with age, and, therefore, individualised cancer treatments should be used that take into account the heterogeneity of ageing. For elderly patients who retain a good physical and mental condition, treatment that is given to younger patients is deemed appropriate, whereas for those with diminished physiological reserves and comorbid conditions, alternative treatments that keep surgical trauma to a minimum and optimise the use of radiotherapy might be more suitable.