Apparent diffusion coefficient for evaluating tumour response to neoadjuvant chemoradiation therapy for locally advanced rectal cancer
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To determine whether change in the apparent diffusion coefficient (ADC) before and after neoadjuvant chemoradiation therapy (CRT) for locally advanced rectal cancer (LARC) would more accurately predict pathological complete response (pCR) than analysing the pre- or post-CRT ADC individually.
76 patients with LARC (≥T3 or lymph node-positive) underwent pre- and post-CRT, 1.5-T diffusion-weighted imaging. A blinded radiologist measured the tumour ADCs. The three measures were compared with regard to CR and non-CR. To calculate accuracy for determining pCR, receiver-operating characteristic curve (ROC) analysis was applied to the three measures.
The post-CRT ADC (1.43 ± 0.10) (×10−3 mm2/s) and the percentage change (70.0 ± 23.5%) in the CR (n = 11) were significantly higher than those in the non-CR (n = 65) (1.14 ± 0.18, 30.2 ± 21.7%, respectively)(both, P < 0.0001). The pre-CRT ADC (0.85 ± 0.10) of the pCR did not differ significantly from that of the non-pCR (0.88 ± 0.14)(P = 0.4094). The post-CRT ADC showed comparable relative accuracy for determining pCR to that of the percentage change (P = 0.788). However, overall accuracy of the former (87%) was higher than that of the latter (75%) (P = 0.049).
Analyzing post-CRT ADC alone can reliably differentiate pCR from non-pCR in LARC
KeywordsRectum Neoplasms Chemoradiation Apparent diffusion coefficient Diffusion-weighted magnetic resonance imaging
We thank In Chan Song, PhD, for technical assistance with the data acquisition. This study was supported by a grant of the Korea Healthcare technology R&D Project, Ministry for Health, Welfare & Family Affairs, Republic of Korea. (A070001)
- 4.Garcia-Aguilar J, Hernandez de Anda E, Sirivongs P, Lee SH, Madoff RD, Rothenberger DA (2003) A pathologic complete response to preoperative chemoradiation is associated with lower local recurrence and improved survival in rectal cancer patients treated by mesorectal excision. Dis Colon Rectum 46:298–304PubMedCrossRefGoogle Scholar
- 7.Stipa F, Chessin DB, Shia J et al (2006) A pathologic complete response of rectal cancer to preoperative combined-modality therapy results in improved oncological outcome compared with those who achieved no downstaging on the basis of preoperative endorectal ultrasonography. Ann Surg Oncol 13:1047–1053PubMedCrossRefGoogle Scholar
- 8.Hughes R, Glynne-Jones R, Grainger J et al (2006) Can pathological complete response in the primary tumour following pre-operative pelvic chemoradiotherapy for T3–T4 rectal cancer predict for sterilisation of pelvic lymph nodes, a low risk of local recurrence and the appropriateness of local excision? Int J Colorectal Dis 21:11–17PubMedCrossRefGoogle Scholar
- 9.Byrd DR, Compton CC, Fritz AG, Trotti A III (2009) Colon and rectum. In: Edge SB (ed) AJCC Cancer Staging Manual, 7th edn. Springer, New York, pp 143–159Google Scholar
- 10.Maas M, Lambregts DMJ, Nelemans PJ, Beets GL, Beets-Tan RG (2010) Response after chemoradiation in rectal cancer is associated with improved long-term outcome: a pooled analysis (abstr). In: European Society of Gastrointestinal and Abdominal Radiology (ESGAR) Annual Meeting Program. Dresden, GermanyGoogle Scholar
- 33.Kim SH, Lee JM, Park HS, Eun HW, Han JK, Choi BI (2009) Accuracy of MRI for predicting the circumferential resection margin, mesorectal fascia invasion and tumor response to neoadjuvant chemoradiotherapy for locally advanced rectal cancer. J Magn Reson Imaging 29:1093–1101PubMedCrossRefGoogle Scholar
- 37.Norman GR, Streiner DL et al (2003) PDQ Statistics, 3rd edn. Decker Inc, Hamilton, pp 91–92Google Scholar
- 38.Heo S, Jeong S, Young J et al (2010) A comparative study of histopathologic parameters and apparent diffusion coefficient values on 3T rectal MRI in locally advanced rectal cancer following neoadjuvant chemoradiation therapy (abstr). In: European Congress of Radiology (ECR) Annual Meeting Program. Vienna, AustriaGoogle Scholar