Lymphovascular invasion in rectal cancer following neoadjuvant radiotherapy: A retrospective cohort study

Lymphovascular invasion in colorectal cancers: can we predict it preoperatively?

PURPOSE

This study aimed to investigate preoperative predictors of lymphovascular invasion (LVI), which is a poor prognostic factor usually detected postoperatively in patients with colorectal cancer.

METHODS

Results for all patients operated on for colorectal cancer between January 1, 2006, and December 31, 2021, were retrospectively analyzed. Potential preoperative factors and postoperative pathology results were recorded. The patients were categorized as those with LVI and those without LVI. Potential factors that may be associated with LVI were compared between the 2 groups.

RESULTS

The study included 335 patients. The incidence of LVI was 3.11 times higher in patients with ascending colon tumors (odds ratio [OR], 3.11; 95% confidence interval [CI], 1.34-7.23; P=0.008) and 4.28 times higher in those with metastatic tumors (OR, 4.28; 95% CI, 2.18-8.39; P<0.001). Diabetes mellitus was inversely related to LVI in colorectal cancer patients; specifically, LVI was 56% less common in colorectal cancer patients with diabetes mellitus, irrespective of its duration (OR, 0.44; 95% CI, 0.25-0.76; P<0.001).

CONCOUSION

The presence of preoperative LVI in colorectal cancer patients is difficult to predict. In particular, the effect of the effect of factors such as chronic disease accompanied by microvascular pathologies on LVI is still unclear. Advances in the neoadjuvant treatment of colorectal cancer patients, who are becoming more widespread every day, will encourage the investigation of different methods of preoperatively predicting LVI as a poor prognostic factor in these patients.

Pathologic Outcomes of Short-Course and Long-Course Radiotherapy for Locally Advanced Rectal Cancers Treated With Total Neoadjuvant Therapy

INTRODUCTION

Total neoadjuvant therapy (TNT) for patients with locally advanced rectal cancer (LARC) is now the standard of care. Randomized trials suggest the use of short-course radiotherapy (SCRT) and long-course radiotherapy (LCRT) are oncologically equivalent.

OBJECTIVE

To describe pathologic outcomes after surgical resections of patients receiving SCRT versus LCRT as part of TNT for LARC.

PARTICIPANTS

All patients with LARC treated at a single tertiary hospital who underwent proctectomy after completing TNT were included. Patients were excluded if adequate details of TNT were not available in the electronic medical record.

RESULTS

A total of 53 patients with LARC were included. Thirty-nine patients (73.5%) received LCRT and 14 (26.4%) received SCRT. Forty-nine patients (92.5%) were clinical stage III (cN1-2) prior to treatment. The average lymph node yield after proctectomy was 20.9 for SCRT and 17.0 for LCRT (P = .075). Of the 49 patients with clinically positive nodes before treatment, 76.9% of those who received SCRT and 72.2% of those who received LCRT achieved pN0 disease after TNT. Additionally, there were no significant differences in rates of pathologic complete response between patients who received SCRT and LCRT, 7.1% and 12.8%, respectively (P = .565).

CONCLUSION

Pathologic outcomes of patients with LARC treated with SCRT or LCRT, as part of TNT, may be similar. Further prospective trials are needed to assess long-term clinical outcomes and to determine best treatment protocols.

Propensity-score matched analysis of the pathologic outcomes and survival benefits of neoadjuvant therapy in stage II-III anal adenocarcinoma

BACKGROUND

Anal adenocarcinomas are a rare condition which account for less than 10% of anal cancers. The present study aimed to assess the impact of neoadjuvant therapy on the clinical and pathologic outcomes and overall survival (OS) of patients with stage II-III anal adenocarcinomas after abdominoperineal resection (APR).

METHODS

A retrospective cohort study of patients with anal adenocarcinoma in the US National Cancer Database (NCDB) (2010-2020) was conducted. Propensity-score matching was used to compare patients who received neoadjuvant therapy (neoadjuvant therapy group) to the no-neoadjuvant group. The primary outcome was 5-year OS whereas secondary outcomes included conversion to open surgery, hospital stay, surgical margins, 30-day mortality, 90-day mortality, and 30-day readmission.

RESULTS

A total of 742 patients (56% male) with a mean age of 63.6 ± 12.4 years were included. A total of 214 patients in the neoadjuvant group were matched with 107 in the no-neoadjuvant group. The mean OS was similar between the two groups (47.5 vs. 44.8 months, p = 0.253). Patients who received neoadjuvant therapy had a longer median time between diagnosis and surgery (151 vs. 54 days, p < 0.001), lower 90-day mortality (1.9% vs. 6.7%, p = 0.046), more pT0 tumors (15.7% vs. 0%), less pT3-4 tumors (28.4% vs. 36.4%, p = 0.001), less pN1-2 tumors (22.9% vs. 34.7%, p < 0.001), and less lymphovascular invasion (16.2% vs. 40%, p < 0.001) than the no-neoadjuvant group. Both groups had similar conversion rates, hospital stay, 30-day mortality, 30-day readmission, and positive surgical margins.

CONCLUSIONS

Neoadjuvant therapy before APR was associated with significant downstaging of anal adenocarcinomas and lower 90-day mortality, yet similar OS to patients who were surgically treated without neoadjuvant treatment.

CT-based radiomics nomogram for the pre-operative prediction of lymphovascular invasion in colorectal cancer: a multicenter study

OBJECTIVE

To develop and externally validate a CT-based radiomics nomogram for the pre-operative prediction of lymphovascular invasion (LVI) in patients with colorectal cancer (CRC).

METHODS

357 patients derived from 2 centers with pathologically confirmed CRC were included in this retrospective study. Two-dimensional (2D) and three-dimensional (3D) radiomics features were extracted from portal venous phase CT images. The least absolute shrinkage and selection operator algorithm and logistic regression were used for constructing 2D and 3D radiomics models. The radiomics nomogram was developed by integrating the radiomics score (rad-score) and the clinical risk factor.

RESULTS

The rad-score was significantly higher in the LVI+ group than in the LVI- group (p < 0.05). The area under the curve (AUC), accuracy, sensitivity and specificity of the 3D radiomics model were higher than those of the 2D radiomics model. The AUCs of 3D and 2D radiomics models in the training set were 0.82 (95% CI: 0.75-0.89) and 0.74 (95% CI: 0.66-0.82); in the internal validation set were 0.75 (95% CI: 0.65-0.85) and 0.67 (95% CI: 0.56-0.78); in the external validation set were 0.75 (95% CI: 0.64-0.86) and 0.57 (95% CI: 0.45-0.69); respectively. The AUCs of the nomogram integrating the optimal 3D rad-score and clinical risk factors (CT-reported T stage, CT-reported lymph node status) in the internal set and external validation set were 0.82 (95% CI: 0.73-0.91) and 0.80 (95% CI: 0.68-0.91), respectively.

CONCLUSION

Both 2D and 3D radiomics models can predict LVI status of CRC. The nomogram combining the optimal 3D rad-score and clinical risk factors further improved predictive performance.

ADVANCES IN KNOWLEDGE

This is the first study to compare the difference in performance of CT-based 2D and 3D radiomics models for the pre-operative prediction of LVI in CRC. The prediction of the nomogram could be improved by combining the 3D radiomics model with the imaging model, suggesting its potential for clinical application.

Prognostic value of CT radiomics in evaluating lymphovascular invasion in rectal cancer: Diagnostic performance based on different volumes of interest

OBJECTIVES

This study aims to evaluate diagnostic performance of radiomic analysis using computed tomography (CT) to identify lymphovascular invasion (LVI) in patients diagnosed with rectal cancer and assess diagnostic performance of different lesion segmentations.

METHODS

The study is applied to 169 pre-treatment CT images and the clinical features of patients with rectal cancer. Radiomic features are extracted from two different volumes of interest (VOIs) namely, gross tumor volume and peri-tumor tissue volume. The maximum relevance and the minimum redundancy, and the least absolute shrinkage selection operator based logistic regression analyses are performed to select the optimal feature subset on the training cohort. Then, Rad and Rad-clinical combined models for LVI prediction are built and compared. Finally, the models are externally validated.

RESULTS

Eighty-three patients had positive LVI on pathology, while 86 had negative LVI. An optimal multi-mode radiology nomogram for LVI estimation is established. The area under the receiver operating characteristic curves of the Rad and Rad-clinical combined model in the peri-tumor VOI group are significantly higher than those in the tumor VOI group (Rad: peri-tumor vs. tumor: 0.85 vs. 0.68; Rad-clinical: peri-tumor vs. tumor: 0.90 vs 0.82) in the validation cohort. Decision curve analysis shows that the peri-tumor-based Rad-clinical combined model has the best performance in identifying LVI than other models.

CONCLUSIONS

CT radiomics model based on peri-tumor volumes improves prediction performance of LVI in rectal cancer compared with the model based on tumor volumes.

Management, treatment and prognostic significance of lateral lymph node metastases in rectal cancer-a regional cohort study

PURPOSE

Lateral lymph node metastases in rectal cancer remain a clinical challenge. Different treatment regimens have been suggested. This retrospective regional cohort study examines outcome after combined oncological and surgical treatment of MRI-positive lateral lymph nodes (LLN).

METHODS

Data from the Swedish Colorectal Cancer Registry (SCRCR) and patient records were used for retrospective analysis of resected high-risk rectal cancers between 2009 and 2014. The aim was to compare tumour characteristics, neoadjuvant therapy, recurrence and outcome after lateral lymph node dissection.

RESULTS

One thousand and one hundred nineteen cases were identified and after exclusion 344 patients with cT3-T4 ≤ 10 cm from the anal verge were analysed. Thirty (8.7%) patients with MRI-positive LLN were identified. Synchronous distant metastases were associated with MRI-positive LLN (p-value 0.019). Long-course chemoradiotherapy was clinical practice in cases of MRI-positive LLN. No differences in local (p-value 0.154) or distant (p-value 0.343) recurrence rates between MRI-positive LLN patients and MRI-negative patients were detected. Only four patients underwent lateral lymph node dissection (LLND). There was no significant difference in overall survival during follow-up between the MRI-negative (CI at 95%; 99-109 months) and MRI-positive group (CI at 95%; 69-108 months; p-value 0.14).

CONCLUSION

Lateral lymph node metastases present a challenging clinical situation. The present study shows that combination of neoadjuvant therapy and selective LLND is an applicable strategy in cases of MRI-positive LLN.

A Novel Multimodal Radiomics Model for Preoperative Prediction of Lymphovascular Invasion in Rectal Cancer

Objective: To explore a new predictive model of lymphatic vascular infiltration (LVI) in rectal cancer based on magnetic resonance (MR) and computed tomography (CT).

Methods: A retrospective study was conducted on 94 patients with histologically confirmed rectal cancer, they were randomly divided into training cohort (n = 65) and validation cohort (n = 29). All patients underwent MR and CT examination within 2 weeks before treatment. On each slice of the tumor, we delineated the volume of interest on T2-weighted imaging, diffusion weighted imaging, and enhanced CT images, respectively. A total of 1,188 radiological features were extracted from each patient. Then, we used the student t-test or Mann–Whitney U-test, Spearman's rank correlation and least absolute shrinkage and selection operator (LASSO) algorithm to select the strongest features to establish a single and multimodal logic model for predicting LVI. Receiver operating characteristic (ROC) curves and calibration curves were plotted to determine how well they explored LVI prediction performance in the training and validation cohorts.

Results: An optimal multi-mode radiology nomogram for LVI estimation was established, which had significant predictive power in training (AUC, 0.884; 95% CI, 0.803–0.964) and validation (AUC, 0.876; 95% CI, 0.721–1.000). Calibration curve and decision curve analysis showed that the multimodal radiomics model provides greater clinical benefits.

Conclusion: Multimodal (MR/CT) radiomics models can serve as an effective visual prognostic tool for predicting LVI in rectal cancer. It demonstrated great potential of preoperative prediction to improve treatment decisions.

Colorectal cancer: Parametric evaluation of morphological, functional and molecular tomographic imaging

Colorectal cancer (CRC) represents one of the leading causes of tumor-related deaths worldwide. Among the various tools at physicians’ disposal for the diagnostic management of the disease, tomographic imaging (e.g., CT, MRI, and hybrid PET imaging) is considered essential. The qualitative and subjective evaluation of tomographic images is the main approach used to obtain valuable clinical information, although this strategy suffers from both intrinsic and operator-dependent limitations. More recently, advanced imaging techniques have been developed with the aim of overcoming these issues. Such techniques, such as diffusion-weighted MRI and perfusion imaging, were designed for the “in vivo” evaluation of specific biological tissue features in order to describe them in terms of quantitative parameters, which could answer questions difficult to address with conventional imaging alone (e.g., questions related to tissue characterization and prognosis). Furthermore, it has been observed that a large amount of numerical and statistical information is buried inside tomographic images, resulting in their invisibility during conventional assessment. This information can be extracted and represented in terms of quantitative parameters through different processes (e.g., texture analysis). Numerous researchers have focused their work on the significance of these quantitative imaging parameters for the management of CRC patients. In this review, we aimed to focus on evidence reported in the academic literature regarding the application of parametric imaging to the diagnosis, staging and prognosis of CRC while discussing future perspectives and present limitations. While the transition from purely anatomical to quantitative tomographic imaging appears achievable for CRC diagnostics, some essential milestones, such as scanning and analysis standardization and the definition of robust cut-off values, must be achieved before quantitative tomographic imaging can be incorporated into daily clinical practice.

DWI and T2-Weighted MRI Volumetry in Resectable Rectal Cancer: Correlation With Lymphovascular Invasion and Lymph Node Metastases

OBJECTIVE. The purpose of this study was to assess whether MR volumetric data on DW and T2-weighted MR images are correlated with lymphovascular invasion and lymph node metastases in resectable rectal cancer. MATERIALS AND METHODS. This retrospective study consisted of 50 consecutive patients with rectal cancer who underwent radical surgery within 1 week of MRI. The gross tumor volume was determined on both diffusion-weighted and T2-weighted MR images and correlated with pathologic lymphovascular invasion and lymph node metastases using univariate, multivariate, and ROC curve analyses. RESULTS. Both gross tumor volume values showed correlations with lymphovascular invasion (r = 0.750 vs r = 0.710; p < 0.0001) and lymph node metastases (r = 0.780 vs r = 0.755; p < 0.0001). Both values were associated with lymphovascular invasion and lymph node metastases in univariate analysis (all p < 0.0001), whereas only the DWI-based value was an independent risk factor for lymphovascular invasion (odds ratio = 1.207; p = 0.005) and lymph node metastases (odds ratio = 1.420; p = 0.005) in multivariate analysis. Both values could distinguish between N0 and N1, N0 and N1-N2, and N0-N1 and N2 disease (all p < 0.0001) in the Mann-Whitney U test. The area under the ROC curve was higher for the DWI-based value in lymphovascular invasion (0.899 vs 0.877), N0 vs N1 (0.865 vs 0.827), N0 vs N1-N2 (0.934 vs 0.911), and N0-N1 vs N2 (0.932 vs 0.927). CONCLUSION. Tumor volumetry data correlated with both lymphovascular invasion and lymph node metastases in resectable rectal cancer. In particular, the DWI-based gross tumor volume showed the most potential for noninvasive preoperative evaluation of lymphovascular invasion and lymph node metastases.

Whole-lesion Apparent Diffusion Coefficient First- and Second-Order Texture Features for the Characterization of Rectal Cancer Pathological Factors

OBJECTIVE

The objective of this study was to explore the value of whole-volume apparent diffusion coefficient (ADC) features in characterizing pathologic features of rectal cancer.

METHODS

A total of 50 patients who were diagnosed with rectal cancer via biopsy underwent 3-T pretreatment diffusion-weighted imaging. Apparent diffusion coefficient features, including mean, 10th-90th percentile, Entropy and Entropy(H), derived from whole-lesion volumes were compared between pathologic T1-2 and T3 stages, perineural invasion (PNI) present and absent, lymphangiovascular invasion present and absent, and pathological N0 and N+ stage groups.

RESULTS

Entropy and Entropy(H) were significantly lower in rectal cancers at T1-2 stages than T3. The 90th percentile of rectal cancers with PNI was significantly lower than that of those without PNI. All P < 0.05.

CONCLUSIONS

Whole-lesion ADC Entropy and Entropy(H) have potential in evaluating different T stages, and 90th percentile can be helpful for determining PNI presence of rectal cancers.

Rectal cancer patients after neoadjuvant radiotherapy (30Gy/10f) with negative lymph node may not benefit from postoperative adjuvant chemotherapy: a retrospective study

OBJECTIVE

The purpose of this study is to evaluate whether adjuvant chemotherapy could bring oncologic benefit to all patients who underwent neoadjuvant radiotherapy (30Gy/10f).

METHODS

Rectal cancer patients receiving preoperative radiotherapy between July 2002 and April 2009 were retrospectively identified.

RESULTS

A total of 225 patients were enrolled in this study. One hundred thirty-one patients received postoperative adjuvant chemotherapy, and 94 patients did not. The 120 ypN+ and 105 ypN- patients were divided into chemo and non-chemo groups. Two groups of patients did not show any significant difference in terms of gender, age, ypT stage, preoperative serum carcinoembryonic antigen (CEA) level, differentiation, circumferential margin (CRM), lymphovascular invasion (LVI), surgical approach, local recurrence, and distant metastasis (P > 0.05). Survival analysis showed that in ypN+ patients, the 5-year overall survival (OS) rate and 5-year disease-free survival (DFS) rate in chemo group were both significantly higher than non-chemo group (P < 0.05). In ypN- patients, the 5-year OS rate and 5-year DFS rate did not show any significant difference in the two groups (P > 0.05). Subgroup analysis showed that the 5-year OS rate and 5-year DFS rate in ypT0-2 N- patients (P > 0.05) and ypT3-4 N- patients (P > 0.05) did not show any significant difference, either.

CONCLUSIONS

Based on a Chinese protocol, patients with ypN- stage may not benefit from adjuvant chemotherapy, regardless of the ypT stage, while the ypN+ patients may benefit from adjuvant chemotherapy. More randomized clinical trials are needed in the future.

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 CD45RO(+) tumor-infiltrating lymphocytes for locally advanced rectal cancer following 30 Gy/10f neoadjuvant radiotherapy

AIM

This study aims to evaluate the prognostic value of CD45RO(+) tumor-infiltrating lymphocytes (TILs) in locally advanced rectal cancer treated with 30 Gy/10 fraction (10 f) neoadjuvant radiotherapy.

METHODS

This retrospective study involved 185 patients with locally advanced rectal cancer who underwent 30 Gy/10 f nRT (biologic equivalent dose, 30 Gy) followed by total mesorectal excision (TME) between August 2003 and October 2009. The density of CD45RO(+) TILs was assessed by immunohistochemistry using an image-analysis system and tissue microarray and was evaluated for its association with histopathologic features along with disease-free survival (DFS).

RESULTS

Following neoadjuvant radiotherapy, the median density of CD45RO(+) TILs is 654/mm(2). High density of CD45RO(+) TILs was significantly associated with increased T and N downstaging effect (p = 0.006; p = 0.014), lesser-advanced T stage (p = 0.003) and TNM stage (p = 0.022). Prolonged DFS (89.0 vs. 68.1%) was also observed in CD45RO(+Hi) cases. On multivariate regression model, CD45RO(+) TILs (p = 0.026; odds ratio (OR), 0.436 (95% confidence interval (CI), 0.209-0.907)), tumor differentiation (p = 0.057; OR, 1.878 (95% CI, 0.982-3.593)), ypT stage (p = 0.066; OR, 2.383 (95% CI, 0.943-6.025)), and ypN stage (p = 0.009; OR, 2.612 (95% CI, 1.266-5.388)) were independent factors for DFS.

CONCLUSION

The density of CD45RO(+) TILs cannot only predict tumor downstaging and ypTNM stage for rectal cancer following 30 Gy/10 f nRT but also promisingly predict long-term outcomes. These findings may be used to stratify patients and make alternative strategy of adjuvant treatment.

Assessment of aggressiveness of rectal cancer using 3-T MRI: correlation between the apparent diffusion coefficient as a potential imaging biomarker and histologic prognostic factors

BACKGROUND

Diffusion-weighted magnetic resonance imaging (DW-MRI) permits non-invasive assessment of tumor characteristics.

PURPOSE

To assess the value of DW-MRI as a potential non-invasive marker of tumor aggressiveness in rectal cancer by analyzing the relationship between tumoral apparent diffusion coefficient (ADC) values of MRI and histopathologic prognostic parameters that are not affected by preoperative chemoradiation therapy.

MATERIAL AND METHODS

Forty patients with rectal cancer were assessed with primary staging 3-T MRI, including DWI, before undergoing surgical therapy. In all patients, surgery was performed without neoadjuvant therapy. Mean tumor ADC was measured and compared between subgroups based on pretreatment carcinoembryonic antigen (CEA) levels, MRI parameters (e.g. postoperative local recurrence), and histopathologic parameters, including A (invasive distance: A1, T-stage; A2, mesorectal fascia [MRF] status), B (differentiation grade: B1, poorly differentiated; B2, moderately differentiated; B3, well differentiated), C (others: C1, N-stage; C2, lymphangiovascular invasion).

RESULTS

Mean tumor ADCs were different when comparing groups stratified by histologic differentiation grades (P=0.0192). There was no significant difference in mean ADCs when stratifying patients according to CEA levels, T-stage, N-stage, MRF status, presence of lymphangiovascular invasion, or the presence of local recurrence.

CONCLUSION

Significant correlations were found between mean ADC values and differentiation grade. ADC may be useful as an imaging biomarker of tumor aggressiveness, but it cannot serve as an independent biomarker of advanced rectal cancer.

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

AIM

To report data supporting the development of tailored treatment strategies for rectal cancer.

METHOD

A comprehensive review of the literature on the impact of prognostic factors cur-rently not included in international guidelines in rectal cancer management.

RESULTS

There is considerable variation in treatment guidelines for rectal cancer worldwide, especially for Stage II and Stage III disease. Long-term side effects of chemoradiotherapy are not considered in any guideline. Detailed knowledge, and the prognostic impact, of the circumferential resection margin, tumour grade and venous invasion should be factored into the development of a treatment strategy.

CONCLUSION

Factors additional to the TNM system should improve decision making for contemporary rectal cancer treatment. Optimized radiological and pathological evaluations, and a focus on detailed clinical factors, should be the basis for treatment decisions. International guidelines should consider all known prognostic factors for long-term oncological and functional outcomes.

Extramural depth of tumor invasion at thin-section MR in rectal cancer: associating with prognostic factors and ADC value

PURPOSE

To assess the value of maximal extramural depth (EMD) of T3 tumor spread on MRI as a potential noninvasive imaging biomarker of tumor aggressiveness in rectal cancer, by analyzing the relationship between tumoral EMD values and clinical or histological prognostic parameters. In addition, we try to investigate the relationship between EMD and apparent diffusion coefficient (ADC) values.

MATERIALS AND METHODS

Ninety rectal cancer patients who underwent primary MRI staging and diffusion weighted imaging (DWI) as T3 tumor were included. Tumor EMD was measured, and the EMD values of the subgroups based on pretreatment CEA, CA19-9 levels, N stage, and histological parameters were compared. The correlation between EMD and ADC values was compared.

RESULTS

Interobserver agreement of confidence levels for observers 1 and 2 was good for cN stage (k = 0.678) and EMD measurement(k = 0.612) and was excellent for ADC measurement (k = 0.880). Tumor EMDs differ between CEA <5 ng/mL versus ≥ 5 ng/mL (P = 0.013), CA19-9 < 27 U/mL versus ≥ 27 U/mL (P = 0.012), the groups of cN0 versus cN+ cancers (P = 0.049), and between the several groups of histological differentiation grades (P = 0.033). There was no significant difference in EMDs between the various groups of vessel carcinoma embolus and neural invasion. A significant negative correlation (r = -0.581; P = 0.001) between ADC and EMD values was found.

CONCLUSION

Significant correlations were found between EMD values and CEA, CA19-9 level, differentiation grade and ADC value. As been found, higher EMD values were associated with a more aggressive tumor profile and, therefore, EMD has the potential to become an imaging biomarker of tumor aggressiveness indicator.

Preoperative evaluation of lymphovascular invasion using high-resolution pelvic magnetic resonance in patients with rectal cancer: a 2-year follow-up study

OBJECTIVES

The objectives of this study were to preoperatively evaluate lymphovascular invasion (LVI) using pelvic magnetic resonance (MR) in patients with rectal cancer and to determine the correlation with distant metastasis rate.

METHODS

If the mesorectal perivascular infiltrative signal was visible on pelvic MR imaging, the possibility of LVI was recorded. Distant metastatic lesions were also recorded at the time of the initial diagnostic workup and over a 2-year follow-up period.

RESULTS

Fifteen (68.2%) of the 22 LVI patients showed mesorectal perivascular infiltrative signals on pelvic MRI. For the prediction of LVI in rectal cancer, MR had a sensitivity of 68.2% and a specificity of 93.2. The initial distant metastasis rate was significantly higher in patients with MR LVI (52%) than in patients without MR LVI (5.7%) (P < 0.0001).

CONCLUSIONS

On pelvic MR, the presence of mesorectal perivascular infiltration by nodes is a specific sign of LVI in rectal cancer, and the presence of LVI is a predictor of distant metastasis.

Intermediate-fraction neoadjuvant radiotherapy for rectal cancer

BACKGROUND

In China, standard neoadjuvant chemoradiation therapy has not been well accepted, not only because of financial constraints but also because of the poorly-tolerated long duration of the regimen.

OBJECTIVE

The current study aimed to evaluate the impact of a modified neoadjuvant radiation regimen on the prognosis of rectal cancer patients in China.

DESIGN

This was a nonrandomized cohort study evaluating outcomes of patients who chose to undergo preoperative radiotherapy compared with those who chose not to undergo preoperative radiotherapy (controls).

SETTINGS

The study was carried out in Peking University Cancer Hospital, a tertiary care cancer center in China.

PATIENTS

Records of patients with locally advanced, mid-to-low rectal cancer who underwent total mesorectal excision at Peking University Cancer Hospital from 2001 through 2005 were analyzed in this study.

INTERVENTION

Patients who chose preoperative radiotherapy received a total dose of 30 Gy delivered in 10 once-daily fractions of 3.0 Gy each, with at least a 14-day delay of surgery after delivery of the last fraction.

MAIN OUTCOME MEASURES

Tumor downstaging was evaluated. Local recurrence, distant metastases, and disease-free and overall survival were analyzed with the Kaplan-Meier method.

RESULTS

A total of 101 patients accepted and 162 patients declined the modified preoperative radiotherapy regimen. Of the 101 patients receiving preoperative radiotherapy, 5 (5%) had a complete response, and 50 (50%) achieved TNM downstaging. The local recurrence rate was 5% with preoperative radiotherapy and 18% in the control groups (p = 0.02). Within the preoperative radiotherapy group, 5-year disease-free survival and overall survival rates were significantly higher in patients with T-, N-, or TNM-downstaging than in patients without downstaging. Evaluation of literature reports indicated that clinical safety and effectiveness of the modified protocol are comparable to results of standard neoadjuvant procedures.

LIMITATIONS

The allocation to study groups was not randomized, and patient self-selection may have introduced bias, particularly because patients with greater financial means were more likely to choose to undergo the preoperative radiotherapy regimen.

CONCLUSIONS

Compared with surgery alone, this modified preoperative radiotherapy regimen is associated with significantly reduced local recurrence and complication rates, with improved survival in patients who show downstaging. The modified protocol offers a clinical outcome equivalent to standard preoperative radiotherapy regimens while offering an alternative for increasing the flexibility of preoperative radiation regimens in China.

The Factors Effecting Lymphovascular Invasion in Adenocarcinoma of the Colon and Rectum

Adenocarcinomas of the colon and rectum are the most common gastrointestinal malignancy, and lymph node metastases are established as a prognostic factor. Lymphovascular invasion has been recognized as an indication of lymph node metastases. This prompted us to investigate the features of primary tumor that may serve as a risk factor for lymphovascular invasion in colorectal carcinoma. Clinical and pathologic tissue data of colorectal carcinoma treated in our hospital were retrieved from the computer files at Haydarpasa Numune Education and Research Hospital, from June 1998 to December 2010, retrospectively. We excluded all patients who have two-thirds distal rectal carcinoma to rule out neoadjuvant treatment bias. Tissues from the specimens were stained with standard hematoxylin and eosin. Clinical data including age and sex of patient, location and diameter of tumor, perineural invasion, peritumoral lymphocytic infiltration, tumor grade, lymphovascular invasion, Pathologic T level (pT), and lymph node metastasis were recorded. Lymphovascular invasion was present only in 43 patients out of 108. Only pT and lymph node metastases were found to be statistically significant related to lymphovascular invasion (p = 0.04 and p < 0.001). Perineural invasion, pT, and peritumoral lymphocytic infiltration are the factors with p < 0.2 in the univariate analysis that were investigated with multivariate analysis, but no factor was found as an independent prognostic factor for lymphovascular invasion. Lymphovascular invasion is significantly related to lymph node metastases. Only pT is found as a factor that increases the lymphovascular invasion.

Diffusion-weighted MRI in rectal cancer: apparent diffusion coefficient as a potential noninvasive marker of tumor aggressiveness

PURPOSE

To assess the value of diffusion-weighted MR imaging (DWI) as a potential noninvasive marker of tumor aggressiveness in rectal cancer, by analyzing the relationship between tumoral apparent diffusion coefficient (ADC) values and MRI and histological prognostic parameters.

MATERIALS AND METHODS

Fifty rectal cancer patients underwent primary staging MRI including DWI before surgery and neo-adjuvant therapy. In 47, surgery was preceded by short-course radiation therapy (n = 28) or long-course chemoradiation therapy (n = 19). Mean tumor ADC was measured and compared between subgroups based on pretreatment CEA levels, MRI parameters (mesorectal fascia - MRF - status; T-stage; N-stage) and histological parameters (differentiation grade: poorly differentiated, poorly moderately differentiated, moderately differentiated, moderately well differentiated, well-differentiated; lymphangiovascular invasion).

RESULTS

Mean tumor ADCs differ between MRF-free versus MRF-invaded tumors (P = 0.013), the groups of cN0 versus cN+ cancers (P = 0.011), and between the several groups of histological differentiation grades (P = 0.025). There was no significant difference in mean ADCs between the various groups of CEA levels, the T stage, and the presence of lymphangiovascular invasion.

CONCLUSION

Lower ADC values were associated with a more aggressive tumor profile. Significant correlations were found between mean ADC values and radiological MRF status, N stage and differentiation grade. ADC has the potential to become an imaging biomarker of tumor aggressiveness profile.