Does neoadjuvant rectal score predict treatment outcomes better than the all grading systems used in neoadjuvantly treated rectal cancer?

BACKGROUND

/Objective: To compare the prognostic value of the yield pathologic (yp) stage, used 4 tumor regression grading (TRG) systems, and neoadjuvant rectal score(NARS) in patients with locally advanced rectal cancer (LARC) who received long-term neoadjuvant chemoradiotherapy (nCRT).

METHODS

Between 2005 and 2017, we included 302 patients with LARC who treated with nCRT. Postoperative pathological responses were graded by using Dworak, American Joint Committee on Cancer, Mandart, Memorial Sloan Kettering Cancer Center, grading systems and NARS([5ypN-3(kT-pT)+12]2/9,61) calculations. Their results were compared in terms of treatment outcomes.

RESULTS

The median follow-up time was 51 months (range 5-136). There was a significant relation between cT stage and the response in used grading systems(p < 0,001). Median overall(OS), local recurrence free(LRFS), and distant metastasis free(MFS) survival rates were 50, 48, and 45 months, respectively. 5-year OS, LRFS, and MFS rates were 71%, 92%, and 72%, respectively. According to the NARS and treatment response grating systems, a significant difference was found between the low risk and high risk groups in terms of OS, LRFS, and MFS rates. While it was not seen any difference in terms of OS and MFS, NARS was found to predict LRFS better than other grading systems. In multivariate analysis, high NARS was found to be correlated with worse OS and worse MFS. On the other hand, pCR was the another important factor affecting treatment outcomes.

CONCLUSIONS

While used systems except NARS group patients according to ypT status in surgical tissue, NARS add the value of ypN status in addition to ypT status. It could be suggested to use NARS to predict LRFS.