Michael Reza Torkzad MD, PhD, Presenter: Speaker, Bayer AG Speaker, Initios Medical AB

Faoz Dranichnikov, Abstract Co-Author: Nothing to Disclose

Hakan Ahlstrom, Abstract Co-Author: Nothing to Disclose

Peter Nygren, Abstract Co-Author: Nothing to Disclose

Lars Pahlman, Abstract Co-Author: Nothing to Disclose

Haile Mahteme MD, PhD, Abstract Co-Author: Nothing to Disclose

To investigate the correlation between radiologic and pathologic assessment of serosa involvement in patient with rectal cancer, and also compare the impact of serosa involvement on survival, local recurrence and metachronous peritoneal carcinomatosis (MPC).

100 consecutive patients diagnosed with T3 and T4 primarily rectal cancer between 2007 and 2008 made the basis of this study. Detailed radiologic analysis of magnetic resonance imaging (MRI) of rectum at the time of diagnosis of rectal cancer was performed by an experienced radiologist blinded to the clinical data. T4s was defined as tumor growing locally into the serosal layer; rT4s was when the radiologist made such an assessment and pT4s when the pathologist made such assessment. The clinical data at the time of diagnosis and surgery, and 4-5 years postoperative follow-up regarding survival and adverse outcomes (cancer-related mortality and recurrence) and development of MPC were recorded. 

94 patients had complete clinical data of which 63 had MRI prior to treatment. 11 patients showed radiologic signs of local peritoneal involvement (rT4s), while 6 patients showed this at pathology (pT4s). Only two of these were assessed as T4s by both the radiologist and the pathologist. Cancer-related mortality and local recurrence rate were higher among rT4s patients than pT4s (55% vs. 33% and 58% vs. 17%, respectively with odds ratio of 1.67 and 3.49). The only two cases of MPC were seen among rT4s patients. Step-wise multivariate regression showed higher impact by rT4s than pT4s classification on survival, recurrence rate and MPC with adjusted correlation coefficients (R2) of 0.04, 0.15 and 0.14. rT4s staging was the only factor with adjusted R2 > 0.03 for development of MPC.

There seems to be a large discrepancy between rT4s and pT4s though the latter was usually after neoadjuvant therapy. rT4s showed higher impact on development of MPC, local recurrence and even cancer-related survival.

Involvement of serosal layer in rectal cancer denotes a higher risk for metachronus development of peritoneal carcinomatosis, local recurrence and cancer-related mortality than pathologic assessment.

Torkzad, M, Dranichnikov, F, Ahlstrom, H, Nygren, P, Pahlman, L, Mahteme, H, The Correlation of Radiologic Serosal Involvement in Rectal Cancer to Pathologic Assessment, and Comparison of Impact on Survival, Local Recurrence and Metachronous Peritoneal Carcinomatosis.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13014479.html