Radical vs Local Excision for Rectal Cancer With Clinically Complete Remission

In the present project, the investigators plan to more accurately select the rectal cancer patients with pathological complete response (pCR) to preoperative concomitant chemoradiation therapy (CCRT), taking advantage of quantification of circulating tumor DNA (ctDNA) in addition to the current available diagnostic modalities, including CT, MRI, PET and colonoscopy. The patients with suspected pCR to CCRT will be randomized to radical surgery and local excision groups, followed by the comparison of the oncologic outcomes between two treatment methods. The investigators hypothesized that if the pCR for patients with rectal cancer after CCRT can be more accurately predicted, such patients can be safely treated with limited surgery to enhance the post-treatment life quality, in comparison with patients undergoing radical surgery.

Sex

All

Minimum age

18 Years

Maximum age

75 Years

Inclusion Criteria:

1. rectal adenocarcinoma completed nCRT and the imaging studies showed no residual malignancy;
2. physical status is within American Society of Anesthesiology（ASA）class Ⅰ to Ⅲ;
3. the lesion side can be reached by the transanal local excision, generally within 6 cm above anal verge;
4. age is 18-75 years.

Exclusion Criteria:

1. Quantification of ct DNA shows residual malignancy;
2. Body mass index（BMI）\>40 kg/m2;
3. Previous abdominal or pelvic surgery;
4. abnormal hepatologic (Bil\>2.0 mg/dl), renal (Cre≧2.0) and hematologic(WBC\<3000, HB\<8.0, platelet\<50000) profiles after CCRT.