Objective To explore the cancer prehabilitation CP concept for overweight or obese breast cancer BC auxiliary during radiotherapy in patients with nutritional status the influence of the blood lipid metabolism and complications. Method A retrospective study was conducted on 118 patients with BC who received adjuvant radiotherapy in the department of radiotherapy of Nanjing Pukou People's Hospital from January 2020 to March 2022. They were divided into prehabilitation group n = 63 and control group n = 55 . The indexes of HB ALB TG TC HDL - C LDL - C FACIT - F score JSEQ score radiation dermatitis and VAS score were compared between the two groups. Result During radiotherapy the hemoglobin level of the two groups decreased without significant difference P > 0. 05 . The serum albumin level of the prehabilitation group was better than the control group P < 0. 05 . In terms of lipid metabolism the increase of TG in the prehabilitation group was lower than the control group P < 0. 05 while there was no significant difference in TC HDL-C and LDL-C P > 0. 05 . FACIT-F score JSEQ score degree of radiation dermatitis and VAS score of pain in the prehabilitation group were better P < 0. 05 . Conclusion In the adjuvant radiotherapy of overweight or obese BC patients CP may not only help to maintain nutritional status and to improve lipid metabolism but also help to improve the related complications.