This review identified the various terminology, features, and criteria used in the literature to define a near-complete response. This heterogeneity in criteria and features is probably related to... Show moreThis review identified the various terminology, features, and criteria used in the literature to define a near-complete response. This heterogeneity in criteria and features is probably related to the differences in therapeutic aim (watchful waiting versus additional treatment aiming at organ preservation). In the future, more evidence should be gathered that support the use of specific features at response evaluation to define a near-complete response.Background A uniform definition of a clinical near-complete response (near-CR) after neoadjuvant (chemo)radiotherapy for rectal cancer is lacking. A clear definition is necessary for uniformity in clinical practice and trial enrolment for organ-preserving treatments. This review aimed to provide an overview of the terminology, criteria, and features used in the literature to define a near-CR. Methods A systematic review was performed based on the PRISMA statement. PubMed and Embase were searched up to May 2021 to identify the terminology, criteria, and features used to define a near-CR after (chemo)radiotherapy for rectal cancer. Studies with no clear cut-off point between a cCR and near-CR, studies using Response Evaluation Criteria In Solid Tumours, and studies including only complete responders were excluded. Results A total of 1876 articles were found, of which 23 were included. Patients were managed by watchful waiting and/or additional local treatment in 11 and 17 of 23 studies respectively. Response evaluation included digital rectal examination (DRE) and/or endoscopy with MRI in 18 studies. The majority of studies used the term 'near-complete response'. In most studies, minor irregularities or a smooth induration with DRE and a small flat ulcer on endoscopy were considered to indicate a near-CR. On MRI, five studies used features (obvious downstaging with or without heterogeneous/irregular fibrosis on T2-weighted MRI or small spot of high signal on diffusion-weighted imaging), five studies used TNM criteria (ycT2), and four used magnetic resonance tumour regression grade (mrTRG) (mrTRG1-2/mrTRG2) to describe a near-CR. Conclusion The terminology, criteria, and features used to describe a near-CR vary substantially, which can partly be explained by the different treatment strategies patients are selected for (watchful waiting or additional local treatment). A reproducible definition of near-CR is required. Show less
Custers, P.A.; Maas, M.; Lambregts, D.M.J.; Beets-Tan, R.G.H.; Beets, G.L.; Peters, F.P.; ... ; Triest, B. van 2022
Simple Summary: Contact X-ray brachytherapy (CXB) after neoadjuvant (chemo)radiotherapy for rectal cancer is applied in selected patients aiming at organ preservation. However, limited data exist... Show moreSimple Summary: Contact X-ray brachytherapy (CXB) after neoadjuvant (chemo)radiotherapy for rectal cancer is applied in selected patients aiming at organ preservation. However, limited data exist on features observed on endoscopy and MRI after treatment with CXB. On endoscopy, features observed in most patients 6 months after CXB are a flat, white scar, indicative for a clinical complete response (cCR), or tumor mass. On MRI, features indicative for a residual tumor are a focal tumor signal on T2W-MRI and a mass-like high signal on DWI. Due to treatment-related features observed early in follow-up, an irregular ulcer on endoscopy and a diffuse "reactive" mucosal signal on DWI, the distinction between a cCR and a residual tumor generally can be made at 6 months of follow-up. These results can help clinicians to interpret imaging features following CXB, ultimately, to identify patients with a cCR for Watch-and-Wait and to identify patients with a residual tumor for subsequent total mesorectal excision. After neoadjuvant (chemo)radiotherapy for rectal cancer, contact X-ray brachytherapy (CXB) can be applied aiming at organ preservation. This explorative study describes the early features on endoscopy and MRI after CXB. Patients treated with CXB following (chemo)radiotherapy and a follow-up of >= 12 months were selected. Endoscopy and MRI were performed every 3 months. Expert readers scored all the images according to structured reporting templates. Thirty-six patients were included, 15 of whom obtained a cCR. On endoscopy, the most frequently observed feature early in follow-up was an ulcer, regardless of whether patients developed a cCR. A flat, white scar and tumor mass were common at 6 months. Focal tumor signal on T2W-MRI and mass-like high signal on DWI were generally absent in patients with a cCR. An ulceration on T2W-MRI and "reactive" mucosal signal on DWI were observed early in follow-up regardless of the final tumor response. The distinction between a cCR and a residual tumor generally can be made at 6 months. Features associated with a residual tumor are tumor mass on endoscopy, focal tumor signal on T2W-MRI, and mass-like high signal on DWI. Early recognition of these features is necessary to identify patients who will not develop a cCR as early as possible. Show less
Sande, M.E. van der; Maas, M.; Melenhorst, J.; Breukink, S.O.; Leerdam, M.E. van; Beets, G.L. 2021
Objective and Background: Watch-and-wait approach in rectal cancer relies on the identification of a clinical complete response (CR) after neoadjuvant (chemo)radiotherapy. This is mainly performed... Show moreObjective and Background: Watch-and-wait approach in rectal cancer relies on the identification of a clinical complete response (CR) after neoadjuvant (chemo)radiotherapy. This is mainly performed by rectal examination. magnetic resonance imaging, and endoscopy. Endoscopy has been less well studied, and the objective of the study is to assess the diagnostic value of endoscopy and the predictive value of endoscopic features for the identification of CR.Patients and Methods: A total of 161 patients with primary rectal cancer undergoing flexible sigmoidoscopy for response assessment after neoadjuvant (chemo)radiotherapy between January 2012 and December 2015 at a single institution were evaluated retrospectively. Three independent readers scored endoscopic features and a confidence level score for a CR. Diagnostic performance of endoscopy and positive predictive value (PPV) of endoscopic features for a CR were calculated. If available, biopsy results were revealed to the reader and a change in confidence level was noted. Reference standard was histology after surgery, or long-term outcome in a watch-and-wait policy.Results: Median time to endoscopy was 9 (interquartile range 8 12) weeks. Area under the receiver operator characteristic curve, sensitivity, specificity. PPV, and negative predictive value for a CR were 0.80 to 0.84, 72% to 94%, 61% to 85%, 63% to 78% and 80% to 89%, respectively. A flat scar was the most predictive feature of a CR (PPV 70%-80%). The PPV of small flat ulcers and large flat ulcers were 40% to 50% and 29% to 33%, respectively. The addition of biopsy results led to a significant change in confidence level score in 4% to 13% of patients.Conclusions: More than 70% of the patients with a luminal CR after neoadjuvant treatment for rectal cancer can be identified by endoscopy at +/- 9 weeks. Together with findings on digital rectal examination (DRE) and magnetic resonance imaging, specific endoscopic features can be used to select patients for an extended observation period to select for organ preservation. Show less
