Maxime J M van der Valk1, Floris A Vuijk2, Hein Putter3, Cornelis J H van de Velde2, Geerard L Beets4, Denise E Hilling5. 1. Department of Surgery, Leiden University Medical Centre, Leiden, The Netherlands; Department of Surgery, The Netherlands Cancer Institute, Amsterdam, The Netherlands. 2. Department of Surgery, Leiden University Medical Centre, Leiden, The Netherlands. 3. Department of Medical Statistics, Leiden University Medical Centre, Leiden, The Netherlands. 4. Department of Surgery, The Netherlands Cancer Institute, Amsterdam, The Netherlands. 5. Department of Surgery, Leiden University Medical Centre, Leiden, The Netherlands; Department of Surgery, The Netherlands Cancer Institute, Amsterdam, The Netherlands. Electronic address: d.e.hilling@lumc.nl.
Abstract
BACKGROUND: The neoadjuvant rectal score (NAR) was developed as a surrogate endpoint for overall survival in patients with rectal cancer after neoadjuvant treatment. We aimed to validate the NAR score in patients from the Netherlands Cancer Registry database. PATIENTS AND METHODS: We studied patients with rectal cancer treated with long-course neoadjuvant therapy followed by surgery in the Netherlands between 2007 and 2014. The probability of concordance with overall survival and the goodness of fit of several models were evaluated using Harrell's concordance index (c index) and the Akaike information criterion (AIC), which is used to compare the quality of statistical models. RESULTS: The NAR score resulted in a c index of 0.665. We found that single pathologic parameters (pT or pN) have similar concordance as the NAR formula (c index of 0.663 and 0.655, respectively). A combination of pT and pN resulted in better concordance with the true endpoint, overall survival (c index 0.684), and a simple Cox regression model with the 3 parameters included in the NAR formula (cT, pT, and pN) improved the concordance even more (c index 0.689). When the AIC index was compared for all models, the NAR score model showed the worst fit to the true endpoint. CONCLUSION: We found no additional value for using the NAR formula as a surrogate endpoint for overall survival in rectal cancer patients treated with neoadjuvant therapy.
BACKGROUND: The neoadjuvant rectal score (NAR) was developed as a surrogate endpoint for overall survival in patients with rectal cancer after neoadjuvant treatment. We aimed to validate the NAR score in patients from the Netherlands Cancer Registry database. PATIENTS AND METHODS: We studied patients with rectal cancer treated with long-course neoadjuvant therapy followed by surgery in the Netherlands between 2007 and 2014. The probability of concordance with overall survival and the goodness of fit of several models were evaluated using Harrell's concordance index (c index) and the Akaike information criterion (AIC), which is used to compare the quality of statistical models. RESULTS: The NAR score resulted in a c index of 0.665. We found that single pathologic parameters (pT or pN) have similar concordance as the NAR formula (c index of 0.663 and 0.655, respectively). A combination of pT and pN resulted in better concordance with the true endpoint, overall survival (c index 0.684), and a simple Cox regression model with the 3 parameters included in the NAR formula (cT, pT, and pN) improved the concordance even more (c index 0.689). When the AIC index was compared for all models, the NAR score model showed the worst fit to the true endpoint. CONCLUSION: We found no additional value for using the NAR formula as a surrogate endpoint for overall survival in rectal cancerpatients treated with neoadjuvant therapy.
Authors: Martin R Weiser; Joanne F Chou; Ajaratu Keshinro; William C Chapman; Philip S Bauer; Matthew G Mutch; Parag J Parikh; Andrea Cercek; Leonard B Saltz; Marc J Gollub; Paul B Romesser; Christopher H Crane; Jinru Shia; Arnold J Markowitz; Julio Garcia-Aguilar; Mithat Gönen Journal: JAMA Netw Open Date: 2021-11-01
Authors: Katrina A Knight; Ioanna Drami; Donald C McMillan; Paul G Horgan; James H Park; John T Jenkins; Campbell S D Roxburgh Journal: J Cancer Res Clin Oncol Date: 2021-03-12 Impact factor: 4.553