e15620 Background: Treatment of locally advanced rectal cancer is based on a combination of radiotherapy and chemotherapy, either as adjuvant, neoadjuvant or total strategies. Short course radiotherapy followed by neoadjuvant chemotherapy, as described in the RAPIDO trial, was chosen by our Oncology, Radiotherapy and Coloproctological tumor board at Hospital de Clínicas de Porto Alegre during the COVID19 pandemic as a measure to reduce hospital visits and thus the possibility of transmission and infection by the SARS-COV-2 virus. Methods: We performed an observational analysis, including all patients treated with short course radiotherapy for locally advanced rectal cancer, at the Hospital de Clínicas de Porto Alegre in the period between January 2020 and March 2023. Metastatic patients were included, either treated with curative or palliative intent. Demographic characteristics, clinical staging, timing of chemotherapy, radiotherapy and surgery were analyzed. Clinical response was evaluated through sigmoidoscopy and clinical rectal exam. Patients with complete clinical response were offered the watch and wait strategy or surgery, after careful discussion of the possible benefits and risks. Results: Ninety-six patients were submitted to short course radiotherapy in the period described. Seven (7) patients were excluded; 89 patients were included in the final analysis. Fifty-five percent were male; mean age was 62 ±12.5 years; 52.8% were ECOG 1 at the diagnosis. Median CEA value at diagnosis was 7 ng/mL (CI 95%:4.4 - 9.8). Sixty-four percent were stage III, 31.4% stage IV, 3.3% stage II. Ninety-eight percent completed the programmed radiotherapy treatment. Only two patients received less than 25Gy. Forty-nine percent of patients completed the whole planned chemotherapy treatment; 15.7% were treated with palliative intent chemotherapy and 5.6% couldn’t receive chemotherapy for other reasons. Clinical response data were available in 62 patients: the main reason for unavailable clinical response was metastatic disease. Disease control was achieved in 98.4% of the cases, with only 1 patient having progressive disease during treatment (1.6%). The overall clinical response rate was 72.6%, 25.8% had stable disease and 24.2% complete clinical response. Fifteen of the 16 patients that presented with complete clinical response opted into a watch and wait strategy, achieving a 1-year disease free survival of 86.6%. Conclusions: Adopting the RAPIDO approach had a positive outcome in our advanced rectal cancer population. Short course radiotherapy followed by chemotherapy achieved excellent rates of disease control. Almost 25% of the non-metastatic patients undergoing RAPIDO treatment achieved complete clinical response opting into a watch and wait program.