Phase I study of oxaliplatin in combination with capecitabine and radiotherapy as postoperative treatment for stage II and III rectal cancer

Postoperative Chemoradiotherapy With Capecitabine and Oxaliplatin vs Capecitabine for Stage II to III Rectal Cancer: A Randomized Clinical Trial

IMPORTANCE

Several studies have explored the efficacy and toxic effects of concurrent 5-fluorouracil (5-FU)- or capecitabine-based chemoradiotherapy (CRT) with or without oxaliplatin in the neoadjuvant setting. Addition of oxaliplatin to 5-FU or capecitabine elicited similar outcomes but with significantly increased toxic effects; however, there is a need for randomized clinical trials comparing 2 CRT regimens for patients receiving CRT in the adjuvant setting.

OBJECTIVE

To explore the efficacy and toxic effects of oxaliplatin combined with postoperative concurrent capecitabine and radiotherapy (RT) for pathological stage II and III rectal cancer.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter randomized clinical trial enrolled patients from 7 centers in China between April 1, 2008, and December 30, 2015. Patients with pathologically confirmed stage II and III rectal cancer were randomized (1:1) to receive concurrent CRT with capecitabine or capecitabine plus oxaliplatin. Analysis was conducted from December 31, 2019, to March 15, 2020.

INTERVENTIONS

RT comprised 45 to 50 Gy in 25 fractions of 1.8 to 2.0 Gy over 5 weeks. In the capecitabine with RT group, concurrent chemotherapy included 2 cycles of capecitabine (1600 mg/m2) on days 1 to 14 and 22 to 35. The capecitabine and oxaliplatin with RT group received identical postoperative RT to that in the capecitabine with RT group combined with capecitabine (1300 mg/m2) on days 1 to 14 and 22 to 35 and a 2-hour infusion of oxaliplatin (60 mg/m2) on weeks 1, 2, 4, and 5. Patients in both groups received adjuvant chemotherapy (capecitabine or fluorouracil and oxaliplatin) after CRT.

MAIN OUTCOMES AND MEASURES

The primary end point was 3-year disease-free survival (DFS).

RESULTS

A total of 589 patients (median [IQR] age, 55 [47-52] years; 375 [63.7%] men and 214 [36.3%] women) were enrolled, including 294 patients randomized to the capecitabine with RT group and 295 patients randomized to the capecitabine and oxaliplatin with RT group. Median (IQR) follow-up was 68 (45-96) months. Most patients had stage III disease (574 patients [75.9%]). Three-year DFS was 76.3% for the capecitabine with RT group and 74.1% for the capecitabine and oxaliplatin with RT group, and 5-year DFS was 72.0% for the capecitabine with RT group and 71.1% for the capecitabine and oxaliplatin with RT group (hazard ratio [HR], 1.07; 95% CI, 0.79-1.44; P = .68). There was no significant difference between groups in overall survival (HR, 0.93; 95% CI, 0.64-1.34; P = .70) or local recurrence (HR, 0.61; 95% CI, 0.31-1.22; P = .16). More grade 3 and 4 acute toxic effects were observed in the capecitabine and oxaliplatin with RT group than in the capecitabine with RT group (114 patients [38.6%] vs 84 patients [28.6%]; P = .01).

CONCLUSIONS AND RELEVANCE

This randomized clinical trial found that addition of oxaliplatin to capecitabine-based postoperative CRT did not improve the efficacy of treatment but increased the risk of severe acute toxic effects. This finding highlights the basic role of postoperative capecitabine with RT for patients with locally advanced rectal cancer.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00714077.

Interim analysis of postoperative chemoradiotherapy with capecitabine and oxaliplatin versus capecitabine alone for pathological stage II and III rectal cancer: a randomized multicenter phase III trial

The aim of this study is to present an interim analysis of a phase III trial (NCT00714077) of postoperative concurrent capecitabine and radiotherapy with or without oxaliplatin for pathological stage II and III rectal cancer. Patients with pathologically confirmed stage II and III rectal cancer were randomized to either radiotherapy with concurrent capecitabine (Cap-RT group) or with capecitabine and oxaliplatin (Capox-RT group). The primary endpoint was 3-year disease-free survival rate (DFS). The 3-year DFS rate was 73.9% in the Capox-RT group and 71.6% in the Cap-RT group (HR 0.92, p = 0.647), respectively. No significant difference was observed in overall survival, cumulative incidence of local recurrence and distant metastasis between the two groups (p > 0.05). More grade 3-4 acute toxicity was observed in the Capox-RT group than in the Cap-RT group (38.1% vs. 29.2%, p = 0.041). Inclusion of oxaliplatin in the capecitabine-based postoperative regimen did not improve DFS but increased toxicities for pathological stage II and III rectal cancer in this interim analysis.

Patients with pathological stage N2 rectal cancer treated with early adjuvant chemotherapy have a lower treatment failure rate

Background

In this era of oxaliplatin-based adjuvant therapy, the optimal sequence in which chemoradiotherapy should be administered for pathological stage N2 rectal cancer is unknown. The aim of this study was to investigate this sequence.

Methods

In the primary adjuvant concurrent chemoradiotherapy (A-CRT) group (n = 71), postoperative concurrent chemoradiotherapy was administered before adjuvant chemotherapy. In the primary adjuvant chemotherapy (A-CT) group (n = 43), postoperative concurrent chemoradiotherapy was administered during or after adjuvant chemotherapy. Postoperative radiotherapy comprised 45–50.4 Gy in 25–28 fractions. Concurrent chemotherapy comprised two cycles of oral capecitabine (1,600 mg/m²) on days 1–14 and 22–35. Patients receiving adjuvant chemotherapy with four or more cycles of XELOX (oxaliplatin plus capecitabine) or eight or more cycles of FOLFOX (fluorouracil, leucovorin, and oxaliplatin) were included.

Results

Between June 2005 and December 2013, data for 114 qualified rectal cancer patients were analyzed. The percentages of patients in whom treatment failed in the A-CRT and A-CT groups were 33.8% and 16.3%, respectively (p = 0.042). More patients had distant metastases in the A-CRT group than in the A-CT group (32.4% vs. 14.3%, p = 0.028). Multivariate analysis indicated that the sequence in which chemoradiotherapy was administered (A-CT vs. A-CRT) was an independent prognostic factor for both estimated disease-free survival [hazard ratio (HR) 0.345, 95% confidence interval (CI) 0.137–0.868, p = 0.024] and estimated distant metastasis-free survival (HR 0.366, 95% CI 0.143–0.938, p = 0.036).

Conclusions

In pathological stage N2 rectal cancer patients, administering adjuvant chemotherapy before chemoradiotherapy led to a lower rate of treatment failure, especially with respect to distant metastasis. Adjuvant chemotherapy prescribed as early as possible might benefit this cohort of patients in this era of oxaliplatin-based adjuvant therapy.