Concomitant boost IMRT-based neoadjuvant chemoradiotherapy for clinical stage II/III rectal adenocarcinoma: results of a phase II study

Abstract

AimThis study was designed to evaluate the efficacy and toxicities of concomitant boost intensity-modulated radiation therapy (IMRT) along with capecitabine and oxaliplatin, followed by a cycle of Xelox, in neoadjuvant course for locally advanced rectal cancer.Materials and methodsPatients with histologically confirmed, newly diagnosed, locally advanced rectal adenocarcinoma (cT3-T4 and/or cN+) located within 12 cm of the anal verge were included in this study. Patients received IMRT to the pelvis of 50 Gy and a concomitant boost of 5 Gy to the primary tumor in 25 fractions, and concurrent with oxaliplatin (50 mg/m2 d1 weekly) and capecitabine (625 mg/m2 bid d1–5 weekly). One cycle of Xelox (oxaliplatin 130 mg/m2 on d1 and capecitabine 1000 mg/m2 twice daily d1–14) was given two weeks after the completion of chemoradiation, and radical surgery was scheduled eight weeks after chemoradiation. Tumor response was evaluated by tumor regression grade (TRG) system and acute toxicities were evaluated by NCI-CTC 3.0 criteria. Survival curves were estimated using the Kaplan-Meier method and compared with Log-rank test.ResultsA total of 78 patients were included between March 2009 and May 2011 (median age 54 years; 62 male). Seventy-six patients underwent surgical resection. Twenty-eight patients underwent sphincter-sparing lower anterior resection and 18 patients (23.7%) were evaluated as pathological complete response (pCR). The incidences of grade 3 hematologic toxicity, diarrhea, and radiation dermatitis were 3.8%, 10.3%, and 17.9%, respectively. The three-year LR (local recurrence), DFS (disease-free survival) and OS (overall survival) rates were 14.6%, 63.8% and 77.4%, respectively. Initial clinical T stage and tumor regression were independent prognostic factors to DFS.ConclusionAn intensified regimen of concomitant boost radiotherapy plus concurrent capecitabine and oxaliplatin, followed by one cycle of Xelox, can be safely administered in patients with locally advanced rectal cancer, and produces a high rate of pCR. A prognostic score model is helpful to distinguish different long-term prognosis groups in early stage.

Predictors of Pathologic Complete Response Following Neoadjuvant Chemoradiotherapy for Rectal Cancer

“…34 The application of intensity-modulated radiation therapy (IMRT), while not yet standard treatment, may help to reduce this toxicity further without compromising response rates. 25,33,48–50 Similar to previous studies, we did not identify a lower likelihood of pCR in patients who received IMRT relative to standard external beam therapy.…”

A retrospective comparison of outcome and toxicity of preoperative image-guided intensity-modulated radiotherapy versus conventional pelvic radiotherapy for locally advanced rectal carcinoma

“…In the current study, patients underwent radiotherapy in the supine position, which could reduce set-up uncertainty. Certain studies have suggested that the prone position for the treatment of rectal cancer patients had the advantage of small-bowel sparing [ 4 , 8 , 32 ]. However, Beriwal et al .…”

Can dosimetric parameters predict acute hematologic toxicity in rectal cancer patients treated with intensity-modulated pelvic radiotherapy?

“…The clinical target volume (CTV) was defined as the GTV plus areas considered at significant risk of harboring microscopic disease, including the mesorectum (perirectal fascia), presacral region, and internal iliac lymph node region. Based on our institution set-up data, the planning target volume (PTV) was generated by adding a 6-mm margin around the CTV in lateral and anterior-posterior directions, and an 8-mm margin in the superiorinferior direction [ 26 ] (Fig. 1 ).…”