High-Dose-Rate brachytherapy (HDR-BT) with neoadjuvant chemoradiation for advanced rectal cancer
Abstract
Colorectal cancer is leading cancer-related public health problem. This study was conducted to determine the effect of High-Dose-Rate intraluminal brachytherapy (HDR-BT) with or without interstitial brachytherapy during neoadjuvant chemoradiation for locally advanced rectal cancer. This randomized contrial was conducted on 28 patients attended with locally advanced rectal cancer (T3, T4 or N+) treated initially with concurrent capecitabine (800 mg/m2 twice daily for 5 days per week) and pelvic external beam radiation therapy (45Gy in 25 Fractions) after one week MRI for all patients; received intraluminal HDR-BT with 4Gy x 2 Fractions with one week interval for those had gross residual disease within 1cm of rectal wall and receiveed intraluminal and interstitial brachytherapy with 4Gy x 2 Fractions with one week interval for those had gross residual disease far from 1cm of rectal wall. All patients underwent surgery within 4-8 week after completion of neoadjuvant therapy. In the control group which were not randomized, twenty-eight patients underwent neoadjuvant chemoradiation (45Gy in 25 Fraction with concurrent capecitabine 800mg/m2 twice daily for 5 days per week) followed by surgery. It was found that in HDR-BT group pathologic complete response (pCR), pathologic partial response (pPR) and pathologic response rates (pCR+pPR) based on AJCC TNM staging for colorectal cancer were %35.7, %35.7, and %71.4 respectively. The pCR, pPR, and pRR were %25, %17, and %42 in the control group respectively. pCR, pPR, and pRR were improved with HDR-BT. However, only response rate improvement was statistically significant (p=0.031). There was no a statistically significant difference in the complications between the two groups (p > 0.05). So it can be concluded that HDR intraluminal with or without interstitial brachytherapy may be an effective method of dose escalation technique in neoadjuvant chemoradiation therapy of locally advanced rectal cancer with higher response rate and manageable side effects.
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Introduction
Colorectal cancer is leading cause of cancer-related mortality and morbidity worldwide. 1-3 The incidence of colorectal cancer in Iranian population is currently very low compared with western population, the younger generation is experiencing an accelerated rate approaching the western rates and the burden of disease will increase dramatically in future. 4 Accordingly, beside the preventive approaches, use of the most recent effective treatment is of importance. 5-6 However, the surgery remains the cornerstone of rectal cancer treatment, most rectal cancer cases present at advanced stage and are not indicated to curative surgery.
Conclusion
It can be concluded from this study that HDR intraluminal with or without interstitial brachytherapy may be an effective method of dose escalation technique in neoadjuvant chemoradiation therapy of locally advanced rectal cancer with higher response rate and manageable side effects.