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| The value of MRI in assessing the effect of neoadjuvant therapy for stage T3 and T4 rectal cancer before surgery |
| GAO De-pei, AI Cong-hui, FENG Jun, TAN Jing, ZHANG Da-fu, LI Zhen-hui, WANG Hong-bo |
| Department of Radiology, the 3rd Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province, Kunming 650118, China |
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Abstract Objective: To evaluate MR examination in assessing the effect of neoadjuvant therapy for stage T3 and T4 rectal cancer before surgery. Methods: MRI data of the pre- and post-neoadjuvant therapy before surgery in 45 cases pathologically confirmed to be stage T3 and T4 rectal cancer were analyzed retrospectively. The following items were assessed: the size of tumor, the extent of tumor invasion including infiltration of the intestinal circumference, the length of tumor invasion, MRI characteristics after enhanced imaging, intestinal fascia invasion, lymph nodes enlargement, conditions of the adjacent structures and the staging of tumor. Results: Pre-neoadjuvant therapy: In 15 cases the tumor was 3~≤5 cm, >5 cm in 30 cases. In 17 cases the tumor involved less than 1/2 of the whole circumference of the rectum, involved entire circumference in 28 cases. In 14 cases the length of tumor invasion was 3.0~≤5.0 cm, >5.0 cm in 31 cases. Tumor infiltrated to muscular layer in 19 cases, infiltrated the rectal mesentery 15 cases, and the mesenteric fascia in 11 cases. Tumor in all the 45 cases showed medium enhancement, the adjacent organs involved in 26 cases. On DWI, tumor in the 45 cases all showed hyperintensity. The ADC value decreased. Nineteen cases belong to stage T3 and 26 cases were T4. After neoadjuvant therapy, the size of tumor: <1.0 cm in 10 cases, 1.0~<3.0 cm in 18 cases, 3.0~<5.0 cm in 13 cases, ≥5.0 cm in 4 cases. Involvement of rectum circumference <1/3 in 7 cases, 1/3~<1/2 in 19 cases, ≥1/2 but without involvement of the entire circumference in 10 cases, involved the entire circumference in 9 cases. The length of involvement <1.0 in 8 cases, 1.0~<3.0 cm in 25 cases, 3.0~<5.0 cm in 9 cases, ≥5.0 cm in 3 cases. Invasion to mucosal and submucosal layer in 15 cases, invasion of muscular layer in 25 cases, recal mesentery in 5 cases. The tumor in 45 cases all showed mild to medium enhancement. Involvement of the adjacent organs in 5 cases. On DWI all the tumors were hypointense. ADC value increased. The change of staging: T1 in 5 cases, T2 in 28 cases, T3 in 7 cases, and T4 in 5 cases. Pathological staging after operation: T1 in 4 cases, T2 in 29 cases, T3 in 7 cases, T4a in 2 cases, and T4b in 3 cases. Conclusion: MRI is important and valuable in staging of T3 and T4 rectal cancer pre- and post-neoadjuvant therapy before surgerical operation, and in assessing the effect of the neoadjuvant therapy.
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Received: 28 June 2013
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2013, Vol. 24 
