Though refusal of radical surgery was often happened in rectal cancer patient after neoadjuvant chemoradiotherapy, little is currently known about the actual oncologic outcome of it. Thus the investigators designed this study to compare the oncologic outcome of unintended rectal preservation with intended rectal preservation by surgeon.

The investigators identified patients whose organ were preserved by non-operative management or local excision after neoadjuvant chemoradiotherapy for mid to low rectal cancer. Then, the patients were categorized into two groups according to the agreement on omitting radical surgery (rectal preservation). When treatment decision was agreed by their surgeon, the patients were categorized as intended rectal preservation. When there was disagreement by surgeon on rectal preservation, then the patients categorized as unintended rectal preservation. Oncologic outcome was compared between two groups.

Inclusion Criteria:

• biopsy proven rectal cancer (anal verge ≤ 10cm)
• neoadjuvant radiotherapy or chemoradiotherapy
• no radical surgery after neoadjuvant therapy

Exclusion Criteria:

• other malignant disease
• other fatel disease
• incompletion of half of radiotherapy course
• metastasis on initial presentation

Intended organ preservation

• non-operative management or local excision selected by surgeon

Unintended organ preservation

• non-operative management or local excision persisted by patient and disagreed by surgeon

The row data generated during and/or analysed during the current study couldn't be shared to public or other researcher because of institutional policy.