Pretreatment Tumor Thickness as a Predictor of Pathologic Complete Response to Neoadjuvant Chemoradiation Therapy for Stage II/III Rectal Adenocarcinoma

Benhua Xu, Yuangui Chen, Yuyan Guo, Debao Zhou, Zhicao Yue, Qing Duan, Yinghong Yang, Guoxian Guan, Pan Chi, Chi Lin

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2 Scopus citations

Abstract

Objectives: To evaluate pretreatment tumor thickness in predicting pathologic complete response (pCR) of stage II/III rectal adenocarcinoma to neoadjuvant chemoradiation (chemoradiotherapy [CRT]). Methods: We retrospectively analyzed 185 patients who were diagnosed with stage II or III rectal adenocarcinoma from January 2011 to July 2013 and treated with neoadjuvant intensity-modulated radiation therapy (45 Gy in 1.8-Gy fractions to pelvis and 50 Gy in 2-Gy fractions to rectal tumor as an integrated boost) or 3 dimensionally conformal radiation therapy (45 Gy in 1.8-Gy fractions to pelvis followed by an additional 5.4-Gy to rectal tumor) concurrently with two 3-week cycles of chemotherapy (oxaliplatin 130 mg/m 2 on day 1 and capecitabine 825 mg/m 2, twice per day from day 1 to 14, cycle 2 starts on week 4). One week after CRT, 36% patients received 1 more cycle of the above chemotherapy and 55% received 1 to 2 cycles of FOLFOX6. Tumor response was categorized as pCR and non-pCR. Tumor thickness measured on magnetic resonance imaging was collected. A multivariate logistic regression model was used to evaluate the association of potential predictors and pCR. Results: Thirty-eight patients (20.5%) reached pCR. Multivariate analysis found the pretreatment tumor thickness to be associated with higher probability of pCR after adjusting for radiation therapy-surgery interval time and pretreatment carcino-embryonic antigen level. The pretreatment carcino-embryonic antigen level was associated with pCR in the univariate analysis but lost the association in the multivatiate model. The pretreatment T or N stage, tumor volume, distance from tumor to anal verge, craniocaudal length of tumor, radiation therapy technique, and patient age and sex were not associated with pCR. Conclusions: We concluded that pretreatment tumor thickness is an independent predictor for pCR of stage II/III rectal adenocarcinoma to the neoadjuvant CRT.

Original languageEnglish (US)
Pages (from-to)601-606
Number of pages6
JournalAmerican Journal of Clinical Oncology: Cancer Clinical Trials
Volume41
Issue number6
DOIs
StatePublished - Jan 1 2018

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Keywords

  • neoadjuvant chemoradiotherapy
  • pathologic complete response
  • predictor
  • rectal cancer
  • tumor thickness

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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