Case Report: Sphincter-preserving surgery after conversion therapy and longitudinal recovery of bowel function in ultra-low rectal cancer.

BACKGROUND

KRAS-mutated ultra-low rectal cancer is associated with poor response to conventional neoadjuvant therapy, making sphincter preservation particularly challenging. In addition, effective rehabilitation strategies for severe low anterior resection syndrome (LARS) remain limited.

CASE PRESENTATION: A 55-year-old woman with KRAS-mutated ultra-low rectal adenocarcinoma experienced insufficient tumor regression after multiple lines of chemotherapy, chemoradiotherapy, and immunotherapy, complicated by oxaliplatin allergy. After referral to our center, she received bevacizumab plus XELIRI combined with traditional Chinese medicine therapies. Following five treatment cycles, the patient underwent laparoscopic radical rectal resection with transanal specimen extraction and Bacon-type pull-through reconstruction. Pathological examination demonstrated negative proximal, distal, and circumferential margins, no metastatic involvement among 12 examined lymph nodes, and a final pathological stage of ypT2N0. The patient subsequently developed major LARS and underwent a four-week rehabilitation program centered on electroacupuncture at the Baliao acupoints. Assessment was conducted using the LARS score, Memorial Sloan Kettering Cancer Center Bowel Function Instrument (MSKCC-BFI), and EORTC QLQ-C30 scales. The patient's bowel movement frequency decreased from over 30 times per day to approximately 10 times, and remained stable at 7-10 times during the 6-month follow-up.

CONCLUSION

In this patient, an individualized conversion strategy was followed by R0 sphincter-preserving resection, and postoperative bowel function improved temporally during and after multimodal rehabilitation that included electroacupuncture. This observation provide preliminary evidence in support of this treatment approach. However, high-quality studies are still required to comprehensively evaluate the efficacy of this treatment regimen.