48 - Preissitzung
Felix Largiadèr Preissitzung
16. Mai 2019, 10:15 - 11:45, Bellavista 3+4, 6. OG
Accuracy of radiological rectal cancer restaging after chemoradiotherapy
A. Kohler, B. Oberli, D. Candinas, L. Brügger, P. Studer, Presenter: A. Kohler (Bern)
Patients with rectal cancer and complete response to chemoradiotherapy (CRT) can be treated with the aim of organ preservation by applying a watch and wait strategy. However, if secondary radical surgery is needed due to cancer recurrence, this may be associated with an increased complication rate or even worse prognosis. Therefore, restaging after CRT is of paramount importance to decide whether organ preservation protocols can be applied. This study aims to assess the accuracy of radiological restaging after CRT in a cohort of patients undergoing neoadjuvant treatment followed by oncological rectal resection for cancer.
Patients undergoing surgery for rectal cancer after CRT at our institution prior to the implementation of an organ preservation program were analyzed retrospectively. For all patients radiological T and N restaging by MRI after CRT but prior to surgery was compared to final pathological T and N staging. The rates of over- and understaging and sensitivity for radiological prediction of complete response were calculated.
64 patients (mean age 65 years, 72% male) undergoing treatment for rectal cancer between 2013 and 2017 were analyzed. Radiological T stage after CRT was underestimated in 17% (11/64), correct in 45% (29/64) and overestimated in 38% (24/64) of patients. Radiological N stage was underestimated in 17% (11/64), correct in 58% (37/64) and overestimated in 25% (16/64) of patients. Five patients out of 65 patients (7.7%) showed pathological complete response after CRT. Radiologically, complete response was described in only one of these five patients (sensitivity for complete response 20%). In none of the patients complete response was described by mistake.
Radiological assessment after CRT resulted in the correct tumor and nodal stage in about half of the examined patients. Overestimation of T and N stage was more frequent than underestimation, this is most probably due to remaining scar tissue after CRT. No patient was incorrectly staged as T0 or N0. Pathological complete response could be predicted correctly in only one of five patients. Therefore, clinical staging by digital rectal examination and endoscopy remains very important in the evaluation of rectal cancer after CRT. Further, histological or molecular markers are needed to better predict response to CRT and to identify patients that qualify for organ preservation.