1. Patterns of failure and implications for clinical target volume definition of locally advanced T4b rectal cancer identified with magnetic resonance imaging and treated using neoadjuvant chemoradiotherapy and surgery
- Author
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Yong Cai, Yangzi Zhang, Shuai Li, Weihu Wang, Yongheng Li, Jianhao Geng, Maxiaowei Song, and Xianggao Zhu
- Subjects
medicine.medical_specialty ,Colorectal cancer ,Planning target volume ,Locally advanced ,External iliac lymph nodes ,Disease ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Neoplasm Staging ,Retrospective Studies ,medicine.diagnostic_test ,Rectal Neoplasms ,business.industry ,Genitourinary system ,Magnetic resonance imaging ,Chemoradiotherapy ,Hematology ,medicine.disease ,Magnetic Resonance Imaging ,Neoadjuvant Therapy ,Surgery ,medicine.anatomical_structure ,Oncology ,030220 oncology & carcinogenesis ,Neoplasm Recurrence, Local ,business ,Neoadjuvant chemoradiotherapy - Abstract
Background and purpose Elective irradiation of the external iliac lymph nodes (EIN) has always been advocated for T4b rectal cancer with anterior organ invasion without convincing evidence. This study aimed to explore the patterns of treatment failure for locally advanced T4b rectal cancer treated using neoadjuvant chemoradiotherapy (NCRT) and surgery. This information may help to clarify whether the current definition of the clinical target volume (CTV) is still appropriate. Materials and methods We retrospectively analyzed data from 126 patients with locally advanced T4b rectal cancer who received NCRT, without elective EIN irradiation, followed by surgery between January 2010 and October 2018. Pretreatment magnetic resonance imaging was used to identify the T4b disease in all cases. The locoregional recurrence (LRR) rate and EIN failure rate were evaluated, and the LRR locations were identified using a three-dimensional model. Results After a median follow-up of 53.9 months, LRR occurred in 11.1% of patients (14/126). All LRRs were located in the previously irradiated fields and below the S2–S3 junction. The EIN failure rate was 0.8% (1/126) among all patients and 1.8% (1/56) in the group with anterior genitourinary organ invasion. The estimated 4-year distant relapse-free survival, disease-free survival and overall survival were 79.3%, 73.2% and 86.9%, respectively. Conclusions It may be feasible to exclude the external iliac region from the CTV during NCRT for locally advanced T4b rectal cancer. However, further studies are needed to clarify whether the cranial border of the CTV can be lowered.
- Published
- 2021