Prognostic significance of MR identified EMVI, tumour deposits, mesorectal nodes and pelvic side wall disease in locally advanced rectal cancer

Abstract

Aim To study the prognostic significance of MRI identified tumour deposits (TD), extramural vascular invasion (EMVI), lymph node metastases (LNM) and pelvic sidewall (PSW) disease in rectal cancer. Methods This IRB approved study was conducted on patients with stage IIA–IIIC rectal adenocarcinoma treated with neoadjuvant long course chemoradiotherapy (LCCRT) and total mesorectal excision (TME) type of surgery between 2012–2018. A radiologist blinded to outcome reviewed staging and restaging magnetic resonance imaging (MRI) for TD, EMVI, LNM and PSW. The agreement between four radiologists was studied and we obtained outcome data from a prospectively maintained database. The prognostic significance of imaging findings was assessed. Results A total of 297 (186 males) patients with a mean age of 47.3 (SD14.4) years were included in the study. The majority had T3 (n = 206) or T4 (n = 59) stage disease. The mean duration of follow‐up was 49.3 ± 25 months (6.6–101 months). 5‐year overall (OS) and disease‐free survival (DFS) was 84% and 74%, respectively. Staging and restaging MRI had EMVI in 49.5% and 31.3%; TD in 47.5% and 31.6%; LNM in 61.1% and 38.1% and PSW in 11.4% and 6.1%. OS was adversely affected by EMVI, TD and PSW with the adjusted HR (aHR) of 3.32, 3.31, 3.27 for staging MRI and 2.99, 3.1, 2.81 for restaging MRI, respectively, p < 0.05. DFS was affected by EMVI (aHR = 1.85, 2.33) and TD (aHR = 1.83, 2.19), p < 0.05. Persistence of these findings after LCCRT led to worst outcome. Intra‐ and interobserver agreement for EMVI, TD and LN was 0.789, 0.734, 0.406 and 0.449, 0.354, 0.376, respectively, p < 0.001. Conclusions MRI identified that TD, EMVI and PSW disease are independent poor prognostic indicators in rectal cancer patients. Interobserver agreement for these findings was moderate to fair.

Stage cT3 low rectal cancer: analysis of prognostic factors

“…The normal vascular wall around the rectum appears to be linear and zigzag in MRI-T2WI images. However, EMVI shows a tumor signal in the blood vessels, widened vessels, or a tumor that has expanded beyond and destroyed the wall (8).…”

“…In total, 187 patients were enrolled in the study with an average PTV of 16.2±11.1 (2.07-72.68) cm 3 . The longest distance outside the muscularis propria was 3.8±3.1 [1][2][3][4][5][6][7][8][9][10][11][12][13][14] mm; positive correlation with PTV (r=0.581, P<0.001). Based on a PTV best cutoff point of 15 cm 3 (5), the patients were divided into the PTV ≤15 cm 3 group and the PTV >15 cm 3 group, which had 3-year DFS rates of 86.6% and 64.6% (P≤0.001), distant metastasis (DM) rates of 8.9% and 23.0% (P=0.001), and LR rates of 4.7% and 16.7% (P=0.004), respectively.…”

Oncological outcome after lateral pelvic lymphadenectomy for low rectal carcinoma: not only an N‐status matter

“…Moreover MRI‐determined TDs/EMVI status is also a significant prognostic factor after neoadjuvant chemoradiotherapy 20,42 . Patients with MRI‐detected TDs/EMVI with a good preoperative treatment response had a prognosis similar to patients with negative TDs/EMVI status at baseline MRI, 20,41,43 whereas persistent TDs and /or EMVI after neoadjuvant treatment led to worse prognosis 22 . Finally, TDs in a neoadjuvant setting might result from tumour regression, reflecting fragmentation or discontinuous eradication of an original tumour with more aggressive biology and would still confer a poor prognosis 24,39,44 .…”

“…19 On the other hand it has been reported that current MRI staging based on T and N status does not adequately predict prognosis, whereas MRIdiagnosed EMVI and tumour deposit (TD) status have greater prognostic accuracy and are superior in determining treatment and follow-up protocols. [20][21][22] Then in addition to well-recognized pathological prognostic factors, namely T, N and M included in the classical TNM staging system, identification of novel pathological entities, that is, TDs, should be taken into account in predicting the regional and systemic spread of rectal carcinoma and in the evaluation of treatment strategies. 23,24 This review aims to discuss the impact of TDs on the oncological outcome of patients who undergo TME with LPLND for low rectal carcinoma.…”

Biparametric magnetic resonance imaging-based radiomics features for prediction of lymphovascular invasion in rectal cancer

“…In the detection of extramural vascular invasion(EMVI),MRI has moderate sensitivity and high specificity. However, MRI cannot definitively depict vessels with a diameter of < 3 mm, including micro-arteriovenous and lymphatic vessels [9,10]. Therefore, accurate preoperative imaging evaluation of LVI of rectal cancer is highly challenging.…”