Value of endorectal elastography for predicting the downstage of infiltration depth in rectal cancer after neoadjuvant radiochemotherapy

doi:10.3877/cma.j.issn.1672-6448.2016.01.013

Abstract

Abstract:

Objective

To evaluate the value of endorectal elastography with strain ratio measurements for predicting the downstage of T stage in locally advanced rectal cancer after neoadjuvant radiochemotherapy.

Methods

62 patients receiving neoadjuvant therapy had twice examinations of conventional endorectal ultrasound (ERUS) and endorectal elastography before radiochemotherapy and surgery. The difference and decreasing amplitude of SR were calculated , the downstage of T stage was predicted by decreasing amplitude of SR. The accuracy of conventional ERUS and endorectal elastography predicting the downstage were compared.

Results

58 patients (94%) demonstrated a significant decrease in strain ratios (t=2.823, P<0.01), and 4 patients (6.5%) demonstrated a increase in strain ration. The strain ratios of pT3 rectal cancer were significantly higher than that of pT0-2 rectal cancer (3.19±0.90 vs 2.20±0.85, t=3.684, P<0.01). When the cut-off point of the decreasing amplitude of SR≥33.80%, the accuracy of diagnosis of the downstage of pT stage after chemoradiotherapy by endorectal elastography was 69% (40/58), which is higher than that of the conventional ERUS (45.1%, 28/62), but the difference was not statistically significant (P<0.05). The conventional ERUS can correctly diagnosis 28 cases of the downstage increasing from 14 cases with the decreasing amplitude of SR.

Conclusions

The endorectal elastography with the decreasing amplitude of SR can assist the conventional ERUS, improve the diagnostic accuracy of the downstage of T stage in the rectal cancer after chemoradiotherapy, thereby providing a new reliable, noninvasive and convenient imaging methods for the assessment of the efficacy and prognosis of the rectal cancer after neoadjuvant chemoradiotherapy.

Key words: Rectal neoplasms, Antineoplastic combined chemotherapy protocols, Endosonography, Elasticity imaging techniques

Guangxi Zhong, Ke Lyu, Qing Dai, Jianchu Li, Yuxin Jiang. Value of endorectal elastography for predicting the downstage of infiltration depth in rectal cancer after neoadjuvant radiochemotherapy[J]. Chinese Journal of Medical Ultrasound (Electronic Edition), 2016, 13(01): 51-55.

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URL: https://chaosheng.cma-cmc.com.cn/EN/10.3877/cma.j.issn.1672-6448.2016.01.013

https://chaosheng.cma-cmc.com.cn/EN/Y2016/V13/I01/51

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References 19

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uT分期降期	例数	pT分期降期	例数
uT₃→uT₀	2	pT₃→pT₀	22
uT₃→uT₁	0	pT₃→pT₁	4
uT₃→uT₂	12	pT₃→pT₂	22

uT分期降期	例数	pT分期降期	例数
uT₃→uT₀	2	pT₃→pT₀	22
uT₃→uT₁	0	pT₃→pT₁	4
uT₃→uT₂	12	pT₃→pT₂	22

病理降期	例数	SR差值平均值	SR降幅平均值（%）
降期	44^a	2.0±1.5	47.8±23.2
未降期	14	1.0±0.5	27.9±6.4
t值	?	3.17	3.62
P值	?	<0.01	<0.01

病理降期	例数	SR差值平均值	SR降幅平均值（%）
降期	44^a	2.0±1.5	47.8±23.2
未降期	14	1.0±0.5	27.9±6.4
t值	?	3.17	3.62
P值	?	<0.01	<0.01

SR降幅界值（%）	敏感度（%）	特异度（%）	准确性（%）
≥29.55	68.2	71.4	69.0
≥33.80	63.6	85.7	69.0
≥38.50	59.1	83.7	65.5
≥40.95	54.5	100.0	65.5

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