Usefulness of magnetic resonance volumetric evaluation in predicting response to preoperative concurrent chemoradiotherapy in patients with resectable rectal cancer.
OBJECTIVE
We performed magnetic resonance (MR) volumetry before and after neoadjuvant chemoradiation for evaluating response to therapy in T3 and T4 rectal cancer. To investigate the utility of MR volumetry for predicting the response to neoadjuvant chemoradiation, we compared results from MR volumetry before chemoradiation with those after chemoradiation.


METHODS
A total 112 patients with T3 or T4 rectal cancer who successfully underwent MR volumetry and completed neoadjuvant chemoradiation followed by radical resection for cure were identified. MR volumetries were performed before and after chemoradiation. We compared pre- and postchemoradiation tumor volume and % volume reduction rates of patients whose tumors were down-staged with those of patients that were not down-staged. The same analyses were also performed between those patients having a complete histologic regression and those with residual disease in the operative specimen. We assessed the difference of % volume reduction rate according to Dworak's rectal cancer regression grades.


RESULTS
Fifty-seven patients (50.9%) demonstrated a tumor down-staging after chemoradiation therapy. Both pre- and posttreatment MR tumor volumes were significantly less in patients whose tumors were down-staged than in patients that were not down-staged (p = 0.04, 0.031), and % volume reduction rates were significantly higher in patients whose tumors were down-staged (p = 0.024). Sixteen patients (14.3%) showed pathologically complete tumor regression. The differences of MR tumor volumes before and after chemoradiation and % volume reduction rates were not significantly different between patients having a complete histologic regression and those with residual disease (p = 0.688, 0.451, and 0.480). The differences of % volume reduction rates according to Dworak's grades were statistically significant (p = 0.03).


CONCLUSIONS
The MR volumetric examinations before and after chemoradiation demonstrated the significant difference of tumor volume and % volume reduction rate between patients whose tumors were down-staged and those that were not down-staged. The volume reduction rates were significantly different among groups according to Dworak's grades. However, the MR volumetric evaluation could not identify any differences between those patients having a complete histologic regression and those with residual disease.
Kim
Young Hoon
YH
Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi, South Korea.
Kim
Dae Yong
DY
Kim
Tae Hyun
TH
Jung
Kyung Hae
KH
Chang
Hee Jin
HJ
Jeong
Seung-Yong
SY
Sohn
Dae Kyung
DK
Choi
Hyo Seong
HS
Ahn
Joong Bae
JB
Kim
Dae Hyun
DH
Lim
Seok-Byung
SB
Lee
Jong Seok
JS
Park
Jae-Gahb
JG
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D012004:Rectal Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery