Recognition of empty pelvic syndrome and its prevention and treatment / 中华胃肠外科杂志

With the development of existing surgical techniques, equipment and treatment concepts, more and more medical centers begin to carry out extensive resection for recurrent pelvic malignant tumors or those with multivisceral invasion. Exenteration may facilitate curative resection and improve the outcome of the patients. Therefore, pelvic exenteration has gradually become the standard of care for locally advanced pelvic malignancies. At present, pelvic exenteration leads to high intraoperative and postoperative complications and mortality, and therefore compromise the safety and long-term quality of life. Cumulating evidences suggest remnant cavity after exenteration might trigger the pathophysiological process and cause downstream complications which can be defined as empty pelvis syndrome. The literature related to empty pelvic syndrome was summarized, the possible cause of empty pelvic syndrome was analyzed. After the pelvic exenteration, the closed pelvic residual cavity formed continuous negative pressure with the gradual absorption of air in the cavity, bacterial propagation, and accumulation of fluid, which had an impact on the distribution of organs in the abdominal and pelvic cavity. At the same time, whether physical processes also play a role in the occurrence of empty pelvic syndrome remains to be explored. It is concluded that the diagnosis is mainly based on the patient's medical history, clinical manifestations and radiological findings, and the history of pelvic exenteration is the most important indicator in the diagnosis. In terms of prevention measures, we should identify the high-risk groups of the occurrence of empty pelvic syndrome, and then take accurate and individualized preventive measures. Various new biomaterials have more advantages in preventive pelvic cavity filling than traditional human tissue filling. Mesentery plays an important role in the morphology, peristalsis and arrangement of the small intestine. More attention should be paid to reducing the ectopic placement of the small intestine into the pelvic cavity by protecting the mesentery structure and restoring or rebuilding the mesentery morphology. In terms of treatment measures, there is still a lack of standard treatment pathway for empty pelvic syndrome.

Short-term outcome of programmed cell death protein1 (PD-1) antibody combined with total neoadjuvant chemoradiotherapy in the treatment of locally advanced middle-low rectal cancer with high risk factors / 中华胃肠外科杂志

Objective: Total neoadjuvant chemoradiotherapy is one of the standard treatments for locally advanced rectal cancer. This study aims to investigate the safety and feasibility of programmed cell death protein 1 (PD-1) antibody combined with total neoadjuvant chemoradiotherapy in the treatment of locally advanced middle-low rectal cancer with high-risk factors. Methods: A descriptive cohort study was conducted. Clinicopathological data of 24 patients with locally advanced middle-low rectal cancer with high-risk factors receiving PD-1 antibody combined with neoadjuvant chemoradiotherapy in Gastrointestinal Cancer Center, Unit III, Peking University Cancer Hospital between January 2019 and April 2021 were retrospectively analyzed. Inclusion criteria: (1) rectal adenocarcinoma confirmed by pathology; patient age of ≥ 18 years and ≤ 80 years; (2) the distance from low margin of tumor to anal verge ≤ 10 cm under sigmoidoscopy; (3) ECOG performance status score 0-1; (4) clinical stage T3c, T3d, T4a or T4b, or extramural venous invasion (EMVI) (+) or mrN2 (+) or mesorectal fasciae (MRF) (+) based on MRI; (5) no evidence of distant metastases; (6) no prior pelvic radiation therapy, no prior chemotherapy or surgery for rectal cancer; (7) no systemic infection requiring antibiotic treatment and no immune system disease. Exclusion criteria: (1) anticipated unresectable tumor after neoadjuvant treatment; (2) patients with a history of a prior malignancy within the past 5 years, or with a history of any arterial thrombotic event within the past 6 months; (3) patients received other types of antitumor or experimental therapy; (4) women who were pregnant or breast-feeding; (5) patients with any other concurrent medical or psychiatric condition or disease; (6) patients received immunotherapy (PD-1 antibody). The neoadjuvant therapy consisted of three stages: PD-1 antibody (sintilimab 200 mg, IV, Q3W) combined with CapeOx regimen for three cycles; long-course intensity modulated radiation therapy (IMRT) with gross tumor volume (GTV) 50.6 Gy/CTV 41.8 Gy/22f; CapeOx regimen for two cycles after radiotherapy. After oncological evaluation following the end of the third stage of treatment, surgery or watch and wait would be carried out. Surgical safety, histopathological changes and short-term oncological outcome were analyzed. Results: There were 15 males and 9 females with a median age of 65 (47-78) years. Median distance from the lower margin of the tumor to the anal verge was 4 (3-7) cm. The median maximal diameter of the tumor was 5.1 (2.1-7.5) cm. Twenty patients were cT3, 4 were cT4, 8 were cN1, 5 were cN2a, 11 were cN2b. Ten cases were MRF (+) and 10 were EMVI (+). All the patients were mismatch repair proficient (pMMR). During the neoadjuvant treatment period, 6 patients (25.0%) developed grade 1-2 treatment-related adverse events, including 3 immune-related adverse events. As of April 30, 2021, 20 patients (83.3%, 20/24) had received surgical resection, including 19 R0 resections and 16 sphincter-preservation operations. Morbidity of postoperative complication was 25.0% (5/20), including 2 cases of Clavien-Dindo grade II (1 of anastomotic bleeding and 1 of pseudomembranous enteritis), 3 cases of grade I anastomotic stenosis. Pathological complete response (pCR) rate was 30.0% (6/20) and major pathological response rate was 20.0% (4/20). None of Ras/Raf mutants had pCR or cCR (0/5), while 6 of 17 Ras/Raf wild-type patients had pCR and 3 had cCR, which was significantly higher than that of Ras/Raf mutants (P<0.01). Nine of 16 patients with Ras/Raf wild-type and differentiated adenocarcinoma had pCR or cCR. Among other 4 patients without surgery, 3 patients preferred watch and wait strategy because their tumors were assessed as clinical complete response (cCR), while another one patient refused surgery as the tumor remained stable. After a median follow-up of 11 (6-24) months, only 1 patient with signet ring cell carcinoma had recurrence. Conclusions: PD-1 antibody combined with total neoadjuvant chemoradiotherapy in the treatment of locally advanced rectal cancer has quite good safety and histopathological regression results. Combination of histology and genetic testing is helpful to screen potential beneficiaries.