Comparable regional therapeutic effects between neoadjuvant chemotherapy and neoadjuvant chemoradiotherapy for locally advanced lower rectal cancer in terms of histopathological analysis

Neoadjuvant chemotherapy without radiation as a potential alternative treatment for locally advanced rectal cancer: A meta-analysis

BACKGROUND

Neoadjuvant chemoradiotherapy (Neo-CRT) is the current standard strategy for treating locally advanced rectal cancer. However, it delays the administration of optimal chemotherapy and increases toxicity.

AIM

To compare the feasibility and efficacy of neoadjuvant chemotherapy (Neo-CT) and Neo-CRT for patients with locally advanced rectal cancer.

METHODS

The Cochrane, EMBASE, and PubMed databases were searched for relevant articles using MESH terms and free words. The hazard ratio of overall survival and the risk ratio (RR) for the pathological complete response, the sphincter preservation rate, and treatment-related adverse events were analyzed.

RESULTS

A total of 19 studies of 60870 patients were included in the meta-analysis. There was no significant difference in overall survival [hazard ratio = 1.09, 95% confidence interval (CI) = 0.93–1.24; P = 0.19] or the pathological complete response (RR = 0.79, 95%CI = 0.61–1.03; P = 0.086) between the Neo-CT and Neo-CRT groups. As compared to the Neo-CRT group, the incidences of anastomotic fistula (RR = 0.49, 95%CI = 0.35–0.68; P = 0.000) and temporary colostomy (RR = 0.69, 95%CI = 0.58–0.83; P = 0.000) were significantly lower in the Neo-CT group, with a simultaneous increase in the sphincter preservation rate (RR = 1.07, 95%CI = 1.01–1.13; P = 0.029). However, there was no significant difference in the tumor downstaging rate, overall complications, and urinary complications.

CONCLUSION

Neo-CT administration can lower the incidences of anastomotic fistula and temporary colostomy and increase the sphincter preservation rate as to compared to Neo-CRT and could provide an alternative to chemoradiotherapy for locally advanced rectal cancer.

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.