ACR Appropriateness Criteria on resectable rectal cancer: expert panel on radiation oncology--rectal/anal cancer

Effect of alpha-lipoic acid on radiation-induced small intestine injury in mice

Purpose

Radiation therapy is a highly effective treatment for patients with solid tumors. However, it can cause damage and inflammation in normal tissues. Here, we investigated the effects of alpha-lipoic acid (ALA) as radioprotection agent for the small intestine in a mouse model.

Materials and Methods

Whole abdomen was evenly irradiated with total a dose of 15 Gy. Mice were treated with either ALA (100 mg/kg, intraperitoneal injection [i.p.]) or saline (equal volume, i.p.) the prior to radiation as 100 mg/kg/day for 3 days. Body weight, food intake, histopathology, and biochemical parameters were evaluated.

Results

Significant differences in body weight and food intake were observed between the radiation (RT) and ALA + RT groups. Moreover, the number of crypt cells was higher in the ALA + RT group. Inflammation was decreased and recovery time was shortened in the ALA + RT group compared with the RT group. The levels of inflammation-related factors (i.e., phosphorylated nuclear factor kappa B and matrix metalloproteinase-9) and mitogen-activated protein kinases were significantly decreased in the ALA + RT group compared with those in the RT group.

Conclusions

ALA treatment prior to radiation decreases the severity and duration of radiation-induced enteritis by reducing inflammation, oxidative stress, and cell death.

Liver metastases: Contrast-enhanced ultrasound compared with computed tomography and magnetic resonance

The development of ultrasound contrast agents with excellent tolerance and safety profiles has notably improved liver evaluation with ultrasound (US) for several applications, especially for the detection of metastases. In particular, contrast enhanced ultrasonography (CEUS) allows the display of the parenchymal microvasculature, enabling the study and visualization of the enhancement patterns of liver lesions in real time and in a continuous manner in all vascular phases, which is similar to contrast-enhanced computed tomography (CT) and contrast-enhanced magnetic resonance imaging. Clinical studies have reported that the use of a contrast agent enables the visualization of more metastases with significantly improved sensitivity and specificity compared to baseline-US. Furthermore, studies have shown that CEUS yields sensitivities comparable to CT. In this review, we describe the state of the art of CEUS for detecting colorectal liver metastases, the imaging features, the literature reports of metastases in CEUS as well as its technique, its clinical role and its potential applications. Additionally, the updated international consensus panel guidelines are reported in this review with the inherent limitations of this technique and best practice experiences.

Racial and ethnic disparities in outcomes with radiation therapy for rectal adenocarcinoma

BACKGROUND

Race/ethnicity may modify cancer outcomes and manifest as survival disparities for patients with rectal cancer. Our objective was to determine whether disparate rectal cancer outcomes result from variable efficacy of radiation therapy for major racial/ethnic groups.

METHODS

The Los Angeles County Cancer Surveillance Program (CSP) identified patients with rectal adenocarcinoma between the years 1988 and 2006. Patients who underwent curative-intent surgery were grouped by race/ethnicity and by receipt (yes vs. no) and timing (neoadjuvant vs. adjuvant) of radiation therapy. The impact of receipt and timing of radiation therapy on overall survival was then assessed.

RESULTS

Of 4,961 patients in CSP, 2,229 (45%) received radiation therapy. Overall, there was no difference in survival among patients according to receipt of radiation therapy. We then examined the radiation cohort, wherein 919 (41%) and 1,310 (59%) patients received neoadjuvant or adjuvant radiation, respectively. Overall, patients who received neoadjuvant compared to adjuvant radiation had improved survival (median survival (MS), 9.4 vs. 6.8 years, respectively; p < 0.001). Among those patients who received neoadjuvant radiation, whites, Hispanics, and Asians had significantly longer survival than blacks (MS, 10.4, 10.4, and 10.4 vs. 4.4 years, respectively; p = 0.003). On multivariate analysis, race/ethnicity was an independent predictor of survival (p = 0.001).

CONCLUSIONS

To our knowledge, this is the first study examining the efficacy of radiation therapy for racial/ethnic groups with rectal cancer. Disparate outcomes were observed for the administration of radiation therapy for select racial/ethnic groups. The reasons for these disparities in outcomes should be investigated to better optimize radiation therapy for patients with rectal cancer.

A randomized controlled trial to investigate the influence of low dose radiotherapy on immune stimulatory effects in liver metastases of colorectal cancer

BACKGROUND

Insufficient migration and activation of tumor specific effector T cells in the tumor is one of the main reasons for inadequate host anti-tumor immune response. External radiation seems to induce inflammation and activate the immune response. This phase I/II clinical trial aims to evaluate whether low dose single fraction radiotherapy can improve T cell associated antitumor immune response in patients with colorectal liver metastases.

METHODS/DESIGN

This is an investigator-initiated, prospective randomised, 4-armed, controlled Phase I/II trial. Patients undergoing elective hepatic resection due to colorectal cancer liver metastasis will be enrolled in the study. Patients will receive 0 Gy, 0.5 Gy, 2 Gy or 5 Gy radiation targeted to their liver metastasis. Radiation will be applied by external beam radiotherapy using a 6 MV linear accelerator (Linac) with intensity modulated radiotherapy (IMRT) technique two days prior to surgical resection. All patients admitted to the Department of General-, Visceral-, and Transplantion Surgery, University of Heidelberg for elective hepatic resection are consecutively screened for eligibility into this trial, and written informed consent is obtained before inclusion. The primary objective is to assess the effect of active local external beam radiation dose on, tumor infiltrating T cells as a surrogate parameter for antitumor activity. Secondary objectives include radiogenic treatment toxicity, postoperative morbidity and mortality, local tumor control and recurrence patterns, survival and quality of life. Furthermore, frequencies of systemic tumor reactive T cells in blood and bone marrow will be correlated with clinical outcome.

DISCUSSION

This is a randomized controlled patient blinded trial to assess the safety and efficiency of low dose radiotherapy on metastasis infiltrating T cells and thus potentially enhance the antitumor immune response.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01191632.