Neoadjuvant rectal (NAR) score: Value evaluating the efficacy of neoadjuvant therapy and prognostic significance after surgery?

Israa Imam,Klara Hammarström,Tobias Sjöblom,Bengt Glimelius

doi:10.1016/j.radonc.2021.01.002

Israa Imam, Klara Hammarström + Show 2 more

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https://doi.org/10.1016/j.radonc.2021.01.002

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Journal: Radiotherapy and Oncology	Publication Date: Jan 14, 2021
Citations: 11	License type: cc-by

Affiliation: Uppsala University

Abstract

IntroductionThe Neoadjuvant rectal (NAR) score is a new surrogate endpoint to be used in clinical trials for early determination of treatment response to different preoperative therapies. The aim is to further validate the NAR-score, primarily developed using chemoradiotherapy (CRT) with a delay to surgery 6–8 weeks, and explore its value using other schedules. Materials and MethodsThe study included all 9978 patients diagnosed with non-metastasized RC in 2007–2015 that had undergone surgery and was registered in the Swedish Colorectal Cancer Registry. The patients of interest had either short-course radiotherapy (scRT)/CRT + delayed surgery, long-course radiotherapy (RT) + delayed surgery, (C)RT + additional chemotherapy, primary surgery, or scRT + immediate surgery. The scRT/CRT + delayed surgery groups were further divided based on time to surgery. ResultsMean NAR-score differed significantly (p < 0.0001) between different treatments. (C)RT + additional chemotherapy had the lowest mean score of 16.3 and CRT + delayed surgery had 17.7. There was a significant difference (p < 0.05) in overall survival (OS) and time to recurrence (TTR) of patients with a Low NAR-score (<8) compared to those with a High score (>16) for both CRT- and scRT, with a stronger correlation for CRT-patients. C-index for the NAR-score model (0.623) was not superior to when only pathological T- and N-stage was used (0.646). ConclusionsThe NAR-score is prognostic, but it is not better than pT- and pN-stage. However, the NAR-score can still discriminate between two treatments that have different cell killing effect and may still be of value in clinical trials as an easier method than pT- and N-stage.

Highlights

The Neoadjuvant rectal (NAR) score is a new surrogate endpoint to be used in clinical trials for early determination of treatment response to different preoperative therapies
The highest proportion of pathological complete remission (pCR) was seen in the group receiving (C)RT + chemotherapy (11.5%, 95%CI[8.6–14.9]), followed by CRT or short-course radiotherapy (scRT) + delayed surgery (8.5%, 95%CI[7.0–10.0] vs. 5.4%, 95%CI[4.1–6.9]) and lowest in ‘‘long-course RT + delayed surgery” (3.2%, 95%CI[0.8–6.5])
Mean NAR-scores and the distribution between Low, Intermediate and High scores inversely correlated with pCR rates

Summary

Introduction

The Neoadjuvant rectal (NAR) score is a new surrogate endpoint to be used in clinical trials for early determination of treatment response to different preoperative therapies. The aim is to further validate the NAR-score, primarily developed using chemoradiotherapy (CRT) with a delay to surgery 6–8 weeks, and explore its value using other schedules. The patients of interest had either short-course radiotherapy (scRT)/CRT + delayed surgery, longcourse radiotherapy (RT) + delayed surgery, (C)RT + additional chemotherapy, primary surgery, or scRT + immediate surgery. The NARscore can still discriminate between two treatments that have different cell killing effect and may still be of value in clinical trials as an easier method than pT- and N-stage.

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Results

Conclusion