Evaluating the incidence of pathological complete response in current international rectal cancer practice: the barriers to widespread safe deferral of surgery

• Published in: Colorectal disease 2018-09, Vol.20 (S6), p.58-68
• Main Authors: Frasson, Matteo, Sánchez‐Guillén, Luis, Van Belle, K., Vertruyen, M., Lombardi, B., Tercioti, V., Sotona, O., Uth Ovesen, A., Christensen, P., Bondeven, P., Alexandrovich Gameza, V., Krogh, A., Rolff, H‐C., Elhemaly, M., Elrefai, M., Omar, W., Thabet, W., Chouillard, E., Schafmayer, C., Paraskakis, S., Katsoulis, I. E., Ferreira, G., Besznyák, I., Khan, M. F., Ahmad, G., Cooke, F., Gold Deutch, R., Hermann, N., Wasserberg, N., Belluco, C., Testa, V., Mariani, N. M., De Toma, G., Barugola, G., Balducci, G., Ferri, M., Vencius, J., Lah, N. N., Zain, W. Z., Pronk, A., Smakman, N., van Loon, Y‐T., van Ruler, O., Mulder, I., Rupert, C., Martens, M., Radiya, K., Qureshi, M. S., Billah, M., Gonçalves, D., Vieira, P., Rachadell, J., Duarte, M., Lebedeva, M., Luzan, R., Klimenko, A., Katorkin, S., Andreev, P., Chernov, A., Davidova, O., Ilkanich, A., Krivokapić, Z., Pecic, V., Vila Tura, M., Turrado‐Rodriguez, V., Martin Perez, B., Paredes, J., Ladra, M. J., Montoya‐Tabares, M. J., Fermiñán, A., Hernandez Garcia, M., Navarro‐Sánchez, A., Ochogavia Segui, A., Monje Salazar, C., Orts Mico, F. J., Pastor, C., Flor‐Lorente, B., Segelman, J., Mangell, P., Carlander, J., Misteli, H., Oertli, D., Buchs, N. C., Wang, J. Y., Yavuz, E., Karagul, S., McFaul, C., Lai, C., Reddy, A., Chaudhri, S., Miller, A., Smart, C., Meylemans, D., Ahmad, N., Daniels, I., Gill, M., Patel, H., Brewer, H., Tate, S., Gregori, M.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Cancer; Cancer and Oncology; Cancer och onkologi; Chemoradiotherapy; Chemoradiotherapy, Adjuvant; Clinical Medicine; Clinical trials; Colorectal cancer; deferral of surgery; Europe; Female; Humans; Incidence; Kirurgi; Klinisk medicin; Magnetic Resonance Imaging; Male; Medical and Health Sciences; Medical Audit; Medicin och hälsovetenskap; Middle Aged; Neoadjuvant Therapy; Neoplasm Staging/methods; Pathology; Patients; Preoperative Period; Prospective Studies; radiology; rectal cancer; Rectal Neoplasms/diagnostic imaging; Rectal surgery; Rectum; Remission Induction; Reproducibility of Results; Response Evaluation Criteria in Solid Tumors; Surgery; surgical oncology; Treatment Outcome; Tumors
• ISSN: 1462-8910; 1463-1318; 1463-1318
• DOI: 10.1111/codi.14361

Introduction The mainstay of management for locally advanced rectal cancer is chemoradiotherapy followed by surgical resection. Following chemoradiotherapy, a complete response may be detected clinically and radiologically (cCR) prior to surgery or pathologically after surgery (pCR). We aim to report the overall complete pathological response (pCR) rate and the reliability of detecting a cCR by conventional pre‐operative imaging. Methods A pre‐planned analysis of the European Society of Coloproctology (ESCP) 2017 audit was performed. Patients treated by elective rectal resection were included. A pCR was defined as a ypT0 N0 EMVI negative primary tumour; a partial response represented any regression from baseline staging following chemoradiotherapy. The primary endpoint was the pCR rate. The secondary endpoint was agreement between post‐treatment MRI restaging (yMRI) and final pathological staging. Results Of 2572 patients undergoing rectal cancer surgery in 277 participating centres across 44 countries, 673 (26.2%) underwent chemoradiotherapy and surgery. The pCR rate was 10.3% (67/649), with a partial response in 35.9% (233/649) patients. Comparison of AJCC stage determined by post‐treatment yMRI with final pathology showed understaging in 13% (55/429) and overstaging in 34% (148/429). Agreement between yMRI and final pathology for T‐stage, N‐stage, or AJCC status were each graded as ‘fair’ only (n = 429, Kappa 0.25, 0.26 and 0.35 respectively). Conclusion The reported pCR rate of 10% highlights the potential for non‐operative management in selected cases. The limited strength of agreement between basic conventional post‐chemoradiotherapy imaging assessment techniques and pathology suggest alternative markers of response should be considered, in the context of controlled clinical trials.