It has been recently reported that the population of Fusobacterium, particularly Fusobacterium nucleatum (Fn), is overrepresented in colorectal cancers (CRCs) and adenomas. The promoting effects of Fn infection on adenoma and/or carcinoma formation have been shown in ApcMin/+mice. Characteristics of Fn-associated CRC were identified through studies using human CRC cohorts and include right-sided colon location, CpG island methylation phenotype (CIMP)-high, high level of microsatellite instability (MSI-H), and poor patient prognosis. A subset of Fn-associated CRC exhibits a low level of microsatellite instability (MSI-L) and elevated microsatellite alterations in selected tetra-nucleotide repeats (EMAST) induced by translocation of MSH3 from the nucleus to the cytoplasm in response to oxidative DNA damage or inflammatory signals. The association between CIMP/MSI-H and Fn infection can be explained by the role of the mismatch repair protein complex formed between MSH2 and MSH6 (MutSα) to repair aberrant bases generated by reactive oxygen species (ROS) to form 7,8-dihydro-8-oxo-guanine (8-oxoG). Clustered 8-oxoGs formed at CpG-rich regions including promoters by ROS is refractory to base excision repair. Under these conditions, MutSα initiates repair in cooperation with DNA methyltransferases (DNMTs) and the polycomb repressive complex 4. DNMTs at damaged sites methylate CpG islands to repress transcription of target genes and promote repair reactions. Thus, continuous generation of ROS through chronic Fn infection may initiate (1) CIMP-positive adenoma and carcinoma in an MSH2/MSH6-dependent manner and/or (2) MSI-L/EMAST CRC in an MSH3-dependent manner. The poor prognosis of Fn-associated CRC can be explained by Fn-induced immune-evasion and/or chemoresistance.
Current practice of neoadjuvant therapy and total mesorectal excision (TME) in rectal cancer bears the weakness in systemic disease control and long-term functional outcomes. With increasing concerns of the balance between cure and quality of life, new strategies are developed to better oncological outcomes at least cost of function damage. Attractive options to adjust neoadjuvant modality include escalation of radiotherapy, intensification of chemotherapy, and chemoradiotherapy with consolidation or full-course chemotherapy. Subsequently, organ-preserving strategies have gained the popularity. Surgical or nonsurgical approaches that spare the rectum are used as possible alternatives for radical surgery, though high-quality TME remains the last resort to offer reliable local disease control. This review discusses new strategies of neoadjuvant therapy and subsequent management, with a specific focus on the balance between oncological and functional outcomes.
Objectives: Non-surgical treatment is an acceptable approach for managing appendiceal abscess in adults. However, it is only applicable for selected patients, and conversion to surgery is mandatory for failed conservative treatment. This study aimed to determine the predictive factors for unsuccessful outcomes. Methods: Of 594 patients with acute appendicitis, 34 (5.7%) diagnosed with appendiceal abscess were initially treated conservatively. Patients were divided into two groups: the conservative group, which was successfully treated with antibiotics and percutaneous abscess drainage, and the conversion group, which comprised patients who had surgical conversion despite conservative treatment. Risk factors for the conversion group were investigated by comparing clinical and radiological parameters between the two groups. Results: Eight (23.4%) patients were converted to surgical management at an average of 5.5 days of non-surgical treatment. An abscess size greater than 40 mm and a lower rate of improvement in the white blood cell (WBC) count were significant factors for predicting conversion in multivariate analysis. The conversion group had a long operative time and high morbidity and operative conversion rates (change of proposed initial operation). Early conversion to operation group, i.e., less than 5 days of treatment, contributed to a significantly shorter hospital stay, lower hospital cost, and relatively shorter operative time (p = 0.02, p = 0.04, and p = 0.11, respectively). Conclusions: Contributing factors in predicting unsuccessful outcomes for non-surgical treatment include an abscess size greater than 40 mm and a low rate of improvement in WBC count on the first day of antibiotic treatment.
Rectovaginal fistula caused by a tension-free vaginal mesh (TVM) is a rare condition. Moreover, a rectovaginal fistula is a challenging issue to address for surgeons regardless of causes. Due to a low rate of occurrence, treatment modality for a rectovaginal fistula caused by a TVM has previously received little attention. A successful surgery using several key techniques to address a rectovaginal fistula caused by a TVM is herein reported. A 78-year-old woman who underwent a TVM for a rectocele three months ago was referred to our hospital with a two-month history of anal bleeding. Mesh protruding into both the vagina and the rectum was confirmed. The patient was operated on under diagnosis of a rectovaginal fistula caused by TVM. TVM was removed by transvaginal dissection of the rectovaginal septum with division of both anterior and posterior arms of the TVM. Layer-to-layer sutures of rectal and vaginal walls were crossly performed with a drain placed in the rectovaginal septum after saline irrigation followed by a covering sigmoid colostomy. The wound healed without infection after surgery, and a water-soluble contrast enema demonstrated the healing of the rectovaginal fistula two months after surgery. No recurrent fistula was confirmed 15 months after stoma closure.