Rectal cancer: a review of randomized trials of adjuvant radiotherapy

Predictors of Sensitivity to Preoperative Chemoradiotherapy of Rectal Adenocarcinoma

Objectives

The purpose of the study was to identify predictive factors of tumor response to preoperative chemoradiotherapy for rectal adenocarcinoma.

Methods

Ninety-eight patients with nonmetastatic rectal adenocarcinoma received preoperative concurrent chemoradiotherapy and underwent mesorectal excision. After treatment, tumor response according to tumor regression grade were evaluated. The correlation of clinicopathologic factors to tumor response was analyzed.

Results

The results from a univariate analysis indicated that pretreatment carcinoembryonic antigen level ≤3.0 ng/ml (P = 0.002), non-fixed tumor (P = 0.001), and tumor circumferential extent ≤50% (P = 0.001) were associated significantly with a good tumor response. They also indicated that pretreatment positive lymph nodes (P = 0.032) were associated significantly with a poor tumor response. In multivariate analysis, the results indicated that pretreatment carcinoembryonic antigen level (hazard ratio, 2.930; P = 0.003), tumor mobility (hazard ratio, 2.651; P = 0.002) and circumferential extent of tumor (hazard ratio, 2.394; P = 0.019) independently predicted a good pathologic response rate. Pretreatment positive lymph nodes were not significantly associated with a good response (hazard ratio, 0.361; P = 0.191).

Conclusions

Pretreatment carcinoembryonic antigen level, tumor mobility and circumferential extent of tumor may be helpful in predicting responsiveness in rectal adenocarcinoma to preoperative chemoradiotherapy, although the results should be confirmed in larger, more homogeneous studies.

Prognostic value of Smac expression in rectal cancer patients treated with neoadjuvant therapy

The objective was to evaluate expression of second mitochondria-derived activator of caspase (Smac) expression before and after treatment in patients treated with preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer and to correlate the clinicopathological characteristics and level of Smac expression with pathologic response and outcome. Expression of biomarker was evaluated by immunohistochemistry in tumor samples from 98 patients with clinical Stage II and III rectal cancer treated with preoperative pelvic radiotherapy plus concurrent chemotherapy. All patients received a standardized total mesorectal excision procedure after a long interval of 4-6 weeks. For Smac, patients with a good response to neoadjuvant CRT tended to have higher pre-therapy levels (P = 0.007). The level of Smac expression decreased after neoadjuvant therapy (P = 0.016). High expression of Smac before CRT, and high Dworak's tumor regression grade (TRG) were significantly associated with improved 5-year disease-free survival (P < 0.05). Pretreatment nodal status also was significantly associated with 5-year disease-free survival and 5-year local relapse-free survival (P < 0.05). Multivariate analysis confirmed that the pretreatment expression of Smac and Lymph nodal status were independent prognostic factors. Our study suggests that high expression of Smac before neoadjuvant CRT could predict good outcome in locally advanced rectal cancer patients.

Predictive value of Smac, VEGF and Ki-67 in rectal cancer treated with neoadjuvant therapy

The present study aimed to identify whether second mitochondria-derived activator of caspase (Smac), vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen (Ki-67) expression in pre-treatment tumor biopsies are useful predictive markers of tumor response in patients with rectal cancer undergoing pre-operative chemoradiotherapy (CRT). Paraffin-embedded tissues obtained before and after therapy were evaluated by immunohistochemical staining for Smac, VEGF and Ki-67. The study evaluated the correlation of Smac, VEGF and Ki-67 immunoreactivity in tumor biopsies before treatment of tumor response to pre-operative CRT. Regarding Smac, patients with a favorable response to neoadjuvant CRT had higher pre-therapy levels (p=0.011). The level of Smac expression decreased after neoadjuvant therapy (p=0.044). However, VEGF expression was found to be negatively and significantly correlated with a favorable tumor response to neoadjuvant CRT (p=0.010). A transient increase in VEGF expression was detected in the resected specimens following neoadjuvant therapy (p=0.030). In addition, tumors with a low Ki-67 labeling index (Ki-67-LI) expression were found to be more sensitive to neoadjuvant therapy than those with a high expression of Ki-67-LI (p=0.034). In contrast to VEGF, the Ki-67 expression level decreased after neoadjuvant therapy. Smac, VEGF and Ki-67 expression levels, assessed immunohistochemically from pre-treatment tumor biopsies, may be useful predictive markers of rectal tumor response to pre-operative CRT.

Influence of anemia on tumor response to preoperative chemoradiotherapy for locally advanced rectal cancer

PURPOSE

In rectal cancer patients treated with preoperative chemoradiotherapy (CRT) and curative resection, we evaluated the influence of anemia on tumor response to preoperative CRT.

METHODS

Between August 2001 and July 2007, 490 patients underwent preoperative CRT, followed by curative-intent surgery. Tumor responses were evaluated based on tumor regression grade (TRG), T- and N-level downstaging, and volume reduction rates.

RESULTS

The level of pretreatment hemoglobin (Hb) was 12.9 +/- 1.7 g/dl (range, 7.2-17.6 g/dl). Tumor response rates were significantly different below and above the Hb level of 9.0 g/dl. Specifically, patients with Hb levels >or=9.0 g/dl achieved better tumor responses than those with Hb levels < 9.0 g/dl (rates of TRG 3 or 4-29.0% vs. 0%, p < 0.001). In addition, there is no differences in tumor response between the nontransfusion and transfusion groups of patients with Hb levels >or=9.0 g/dl (rates of TRG 3 or 4-29.1% vs. 23.1%, p = 0.445).

CONCLUSIONS

The serum Hb level could be a one of prognostic factors that influences the pathologic tumor response, and pretreatment anemia (below 9.0 g/dl of Hb) is associated with poor response to preoperative CRT.

External beam radiotherapy for pelvic node recurrence after curative resection of colon cancer: report of a case

The role of radiotherapy in locally advanced or recurrent colon cancer has not yet been determined. A 59-year-old man undergoing curative resection for advanced descending colon cancer had pelvic lymph node metastasis detected by computed tomography 5 months postoperatively. Intravenous chemotherapy using 5-fluorouracil and CDDP was repeated bimonthly for 7 months; however, his condition deteriorated progressively. External beam radiotherapy (50 Gy) was started thereafter. His serum carcinoembryonic antigen level decreased promptly and abdominal computed tomography showed apparent shrinkage of the metastatic pelvic node with calcification. The patient maintained a partial response for at least 12 months. Radiotherapy has a more crucial role in the treatment of a subgroup of recurrent colorectal tumors.

Total mesorectal excision: evaluating the evidence

The present paper reviews information from pathological and clinical studies examining the role of total mesorectal excision (TME) in the treatment of rectal cancer. The pathological studies provide information about the spread of rectal cancer within the mesorectum, and the adequacy of excision obtained with conventional surgery and TME. The clinical studies provide information about the safety of TME and the reported local recurrence rates. Taken together, these studies provide a rationale for using TME to resect rectal cancers in the distal two-thirds of the rectum, despite the absence of direct evidence from randomized controlled trials.