To compare the characteristics of MRI signals in different therapeutic effect of desmoid-type fibromatosis (DF).

One hundred and twenty-four DF patients with pathologically proven postoperative recurrent lesions from Peking University Cancer Hospital from 2008 to 2015 were enrolled in the study. All patients had baseline MRI scans, followed by once MRI scan at least every six months, and the follow-up period was three years. All patients had MRI images at the end of the third year. The therapeutic effect was evaluated by response evaluation criteria in solid tumors (RECIST) criteria, and the patients were divided into three groups: progressive disease (PD), stable disease (SD) and partial response (PR). Differences in features in the PD, SD, and PR groups were compared using one-way analysis of variance, Kruskal-Wallis, or Chi-square test. Multiple comparisons were performed using Bonferroni to correct P values. The spearman correlation coefficient was used to test the correlation between signal score and tumor maximum diameter.

Among the 124 patients, 17 experienced PD, 37 exhibited SD and 70 exhibited PR. There were no significant differences in age, gender distribution and the location of lesion among three groups (P>0.05). The difference of treatment strategies was statistically significant (P<0.05). The difference of tumor maximum diameter of baseline and the last follow-up MRI scan was also statistically significant between three groups (P<0.05). There was no significant differences in T₂ scores and enhancement scores of baseline MRI scan among the PD, SD, and PR groups (P>0.05). At the last follow-up MRI scan, the T₂ signal scores, the changes of T₂ signal, the scores of enhancement and the changes of enhancement of the PD, SD, and PR groups were significantly different among three groups (P<0.05). At the last follow-up MRI scan, the tumor maximum diameter was positively correlated with the score of T₂ signal (r=0.434, P<0.01), and the tumor maximum diameter was positively correlated with the score of enhancement (r=0.743, P<0.01).

MRI has great value in evaluating the therapeutic effect of DF.

Magnetic resonance imaging; Desmoid-type fibromatosis; Therapeutic effect evaluation