Neoadjuvant chemotherapy without radiotherapy for patients with locally advanced rectal cancer. Oncologic outcomes

Neoadjuvant chemotherapy for treatment patients with rectal cancer with adverse prognostic factors: A review

Rectal cancer (RC) is one of the leading tumor location in the structure of the incidence of malignant neoplasms in the Russian Federation and the world. And the standard approach to the treatment of patients with locally advanced forms of RC is preoperative chemo-radiotherapy (CRT) with delayed surgery. The use of such sort of approach in the recent decades has led to the reduction of the frequency of local recurrence up to 10% and even less. However, approximately a third of patients die of distant metastases. In this regard, one of the main tasks in the treatment of patients with locally advanced forms of RC with adverse prognostic factors is the prevention of distant metastasis formation. Early initiation of the systemic therapy before surgery is aimed at solving this issue. Conducting neoadjuvant chemotherapy (NCT) instead of CRT in RC treatment allows to avoid radiation reactions and injuries, occurring in some patients. Two-component oxaliplatin-containing regimens are the most well studied types of NCT in the treatment of patients with non-metastatic RC. In this connection, despite the differences in the treatment regimens and the number of cycles, a good tolerability of the method as well as no effect on the frequency of postoperative complications and in general a satisfactory results comparable to the effects of CRT were observed. The use of NCT in combination with targeted treatment modalities as well as three-component chemotherapy regimens are promising and encouraging treatment options for patients with RC with adverse prognostic factors.

Meta-analysis of neoadjuvant chemotherapy versus neoadjuvant chemoradiotherapy for locally advanced rectal cancer

Background and purpose

With the advent of more intensive chemotherapy regimens, neoadjuvant chemoradiotherapy (NACRT) for patients with locally advanced rectal cancer (LARC) has always been questioned due to its inevitable radiation toxicity. Hence, we conducted a meta-analysis to compare the clinical efficacy of neoadjuvant chemotherapy (NAC) and NACRT.

Materials and methods

Eligible studies were searched using PubMed, MEDLINE, Embase, the Cochrane Library, and Web of Science up to 31 July 2020, comparing the clinical efficacy of NAC versus NACRT for LARC. Short- and long-term outcomes were determined using the odds ratio (OR) with 95% confidence interval (CI).

Results

Six studies with 12,812 patients were eligible for this meta-analysis, including 677 patients in the NAC group and 12,135 patients in the NACRT group. There were no significant differences between the two groups in terms of pathological complete response rate (OR=0.62, 95%CI=0.27~1.41), N down-staging rate (OR=1.20, 95%CI=0.25~5.79), R0 resection rate (OR=1.24, 95%CI=0.78~1.98), and local relapse rate (OR=1.12, 95%CI=0.58~2.14). The pooled OR for the total response rate and T down-staging were in favor of NACRT (OR=0.41, 95%CI=0.22~0.76 versus OR=0.67 95%CI=0.52~0.87). However, the pooled OR for the sphincter preservation rate favored NAC compared with NACRT (OR=1.87, 95%CI=1.24~2.81). Moreover, NAC was found to be superior to NACRT in terms of distant metastasis (14.3% vs. 20.4%), but the difference was not significant (OR=0.84, 95%CI=0.31~2.27).

Conclusion

We concluded that NAC was superior to NACRT in terms of the sphincter preservation rate, and non-inferior to NACRT in terms of pCR, N down-staging, R0 resection, local relapse, and distant metastasis. However, the conclusion warrants further validation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02251-0.