While surgery remains the standard treatment for rectal cancer, some patients still firmly refuse surgery for various reasons. Here, we conducted this retrospective observation study to discuss the feasibility of high-dose radiotherapy combined with chemotherapy in treating rectal cancer We retrospectively collect data of rectal cancer patients who were treated with high-dose radiotherapy plus chemotherapy in Sun Yat-sen University Cancer Center from April 1st, 2006 to July 30th, 2017. Patients gave up surgery before any treatment would have received one course of high dose radiotherapy (GTV60-70Gy/30-35f). Patients with tumor residual after neoadjuvant chemoradiotherapy but insisted non-operative treatment would have received 2 courses of radiotherapy (1st: GTV 45-50Gy/25f, 2nd: GTV 30/15f). The chemotherapy regimens included Capox, FOLFOX, or capecitabine at the discretion of the treating physician.

After treatment, patients were followed every 3 months for the first two years, at least every 6 months in the year thereafter. Recurrence, early and late toxicity were recorded.

Analyses were performed using SPSS software, version 19.0 (SPSS, Chicago, IL). Local recurrence and distant metastasis rate, progression free survival, and overall survival were calculated using the Kaplan Meier Method and were compared by log-rank test.

Inclusion Criteria:

1. pathologically confirmed diagnosis of rectal adenocarcinoma located within 15cm from the anal verge;
2. pelvic radiation with a total dose ≥60Gy for the treatment of rectal cancer;
3. refused surgery as the initial treatment;
4. a complete set of clinical information and follow-up data.

Exclusion Criteria:

1. patients with terminal cancer who received palliative treatment;
2. patients received any treatment before admission to Sun Yat-sen University Cancer Center;
3. patients with second primary cancer.

This retrospective study included subjects identified from the database of the Sun Yat-sen University Cancer Center in the period of April 2006 to July 2017.