Hereditary colorectal cancer accounts for less than 5% of all colorectal cancer cases. Some of the unique characteristics that are commonly encountered in cases of hereditary colorectal cancer include early age at onset, synchronous/metachronous occurrence of the cancer, and association with multiple cancers in other organs, necessitating different management from sporadic colorectal cancer. While the diagnosis of familial adenomatous polyposis might be easy because usually 100 or more adenomas that develop in the colonic mucosa are in this condition, Lynch syndrome, which is the most commonly associated disease with hereditary colorectal cancer, is often missed in daily medical practice because of its relatively poorly defined clinical characteristics. In addition, the disease concept and diagnostic criteria for Lynch syndrome, which was once called hereditary non-polyposis colorectal cancer, have changed over time with continual research, thereby possibly creating confusion in clinical practice. Under these circumstances, the JSCCR Guideline Committee has developed the "JSCCR Guidelines 2016 for the Clinical Practice of Hereditary Colorectal Cancer (HCRC)," to allow delivery of appropriate medical care in daily practice to patients with familial adenomatous polyposis, Lynch syndrome, or other related diseases. The JSCCR Guidelines 2016 for HCRC were prepared by consensus reached among members of the JSCCR Guideline Committee, based on a careful review of the evidence retrieved from literature searches, and considering the medical health insurance system and actual clinical practice settings in Japan. Herein, we present the English version of the JSCCR Guidelines 2016 for HCRC.

Previously, adjuvant chemotherapy using oxaliplatin was a standard treatment for patients with node-positive colorectal cancer (CRC) who underwent curative surgery. The factor predicting adverse events and therapeutic effect have not yet been established.

In Japan, the surgical treatment for fecal incontinence (FI) can be performed using minimally invasive surgery, such as anal sphincteroplasty and sacral neuromodulation (SNM), as well as antegrade continence enema (ACE), graciloplasty, and stoma construction. In addition, currently, several other procedures, including biomaterial injection therapy, artificial bowel sphincter (ABS), and magnetic anal sphincter (MAS), are unavailable in Japan but are performed in Western countries. The evidence level of surgical treatment for FI is generally low, except for novel procedures, such as SNM, which was covered by health insurance in Japan since 2014. Although the surgical treatment algorithm for FI has been chronologically modified, it should be sequentially selected, starting from the most minimally invasive procedure, as FI is a benign condition. Injuries to the neural system or spinal cord often cause disorders of the sensory and motor nerves that innervate the anus, rectum, and pelvic floor, leading to the difficulty in controlling bowel movement or FI and/or constipation. FI and constipation are closely associated; when one improves, the other tends to deteriorate. Patients with severe cognitive impairment may present with active soiling, referred to as "incontinence" episodes that occur as a consequence of abnormal behavior, and may also experience passive soiling.

There are several reports on the usefulness of diverting ileostomy for decreasing the incidence of anastomotic leakage and the severity of pelvic peritonitis. However, a number of complications induced by ileostomy itself have also been reported, including a special condition induced by obstruction at the outlet of the stoma known as "outlet obstruction." In this study, we examined the frequency and risk factors of this complication based on the data of ileostomy cases in our institution.

To investigate the prevalence and molecular characteristics of defective DNA mismatch repair (dMMR) in small-bowel carcinoma (SBC) in a Japanese-hospital population.

This study aimed to evaluate the long-term outcomes of neoadjuvant chemoradiotherapy with S-1 in patients with locally advanced rectal cancer.

We systematically reviewed literature regarding "Lewy body constipation", i.e., constipation due to Lewy body diseases (LBD), with minimal neurologic symptoms. Epidemiology and pathology studies showed that LBD can start with constipation alone, mostly due to neuronal loss and appearance of Lewy bodies in the myenteric plexus. Because LBD significantly increases with age, "Lewy body constipation" may also increase with age. Neuroimaging methods such as metaiodobenzylguanidine (MIBG) scintigraphy and dopamine transporter (DAT) scan provide a way to detect "Lewy body constipation." Key for "Lewy body constipation" includes minimal non-motor features such as REM sleep behavior disorder (night talking). Add-on therapy may be required to ameliorate constipation in patients. Diagnosis is not always easy; therefore, collaboration of gastroenterologists and neurologists is highly recommended to maximize patients' quality of life. In conclusion, "Lewy body constipation" might become a distinct category among geriatric constipation, regarding patients' follow-up and their management.

To evaluate 20 Kampo medicines, which comprised 6 formulas, Otsujito, Junchoto, Tokakujokito, Bofutsushosan, Mashiningan, and Keishikashakuyakudaioto, from 7 brands, to create a ranking of Kampo medicines for appropriate selection of laxatives.

Examination for fecal incontinence is performed in order to evaluate the condition of each patient. As there is no single method that perfectly assesses this condition, there are several tests that need to be conducted. These are as follows: anal manometry, recto anal sensitivity test, pudendal nerve terminal motor latency, electromyogram, anal endosonography, pelvic magnetic resonance imaging (MRI) scan, and defecography. In addition, the mental and physical stress most patients experience during all these examinations needs to be taken into consideration. Although some of these examinations mostly apply for patients with constipation, we hereby describe these tests as tools for the assessment of fecal incontinence. Conservative therapies for fecal incontinence include diet, lifestyle, and bowel habit modification, pharmacotherapy, pelvic floor muscle training, biofeedback therapy, anal insert device, trans anal irrigation, and so on. These interventions have been identified to improve the symptoms of fecal incontinence by determining the mechanisms resulting in firmer stool consistency; strengthening the pelvic floor muscles, including the external anal sphincter; normalizing the rectal sensation; or periodic emptying of the colon and rectum. Among these interventions, diet, lifestyle, and bowel habit modifications and pharmacotherapy can be performed with some degree of knowledge and experience. These two therapies, therefore, can be conducted by all physicians, including general practitioners and other physicians not specializing in fecal incontinence. However, patients with fecal incontinence who did not improve following these initial therapies should be referred to specialized institutions. Contrary to the initial therapies, specialized therapies, including pelvic floor muscle training, biofeedback therapy, anal insert device, and trans anal irrigation, should be conducted in specialized institutions as these require patient education and instructions based on expert knowledge and experience. In general, conservative therapies should be performed for fecal incontinence before surgery because its pathophysiologies are mostly attributed to benign conditions. All Japanese healthcare professionals who take care of patients with fecal incontinence are expected to understand the characteristics of each conservative therapy, so that appropriate therapies will be selected and performed. Therefore, in this chapter, the characteristics of each conservative therapy for fecal incontinence are described.

To assess the predictive values of myenteric and submucosal plexitis for postoperative endoscopic recurrence of Crohn's disease (CD).

The pathogenesis of hemorrhoids is a weakening of the anal cushion and spasm of the internal sphincter. Bowel habits and lifestyles can be risk factors for hemorrhoids. The prevalence of hemorrhoids can encompass 4 to 55% of the population. Symptoms include bleeding, pain, prolapsing, swelling, itching, and mucus soiling. The diagnosis of hemorrhoids requires taking a thorough history and conducting an anorectal examination. Goligher's classification, which indicates the degree of prolapsing with internal hemorrhoids, is useful for choosing treatment. Drug therapy for hemorrhoids is typically utilized for bleeding, pain, and swelling. Ligation and excision (LE) is considered for Grade III and IV internal and external hemorrhoids. Rubber band ligation is used to treat up to Grade III internal hemorrhoids. Phenol almond oil is effective for internal hemorrhoids up to Grade III, while aluminum potassium sulfate and tannic acid have shown efficacy in treating prolapsing in internal hemorrhoids at Grades II, III, and IV. Procedure for prolapse and hemorrhoids (PPH) is surgically effective for Grade III internal hemorrhoids; however, the long-term prognosis is not favorable, with high recurrence rates. Separating ligation is effective surgical treatment for internal/external hemorrhoids Grade III and Grade IV. The basic approach to thrombosed external hemorrhoids and incarcerated hemorrhoids is conservative treatment; however, in some acute or severe cases, surgical resection is considered. Comparing the different instruments used for hemorrhoid surgery, all reduce operating time, blood loss, post-operative pain, and length of time until the return to normal activity. They do, of course, increase the cost of the procedure.

Transanal Total Mesorectal Excision (TaTME) has recently been developed to overcome the difficulties associated with conventional laparoscopic or robotic TME. TaTME has gained popularity and becomes the center of attention among colorectal surgeons globally. The present review aims to update the literature, clarify the current status and perspectives of TaTME. Complete TaTME specimens were obtained in 85-97.1% of the case; the reported circumferential resection margin (CRM) ranged from 1.5% to 8.1%, whereas and distal resection margin (DRM) positive rates ranged from 0% to 3.2%. The conversion rate of TaTME occurred from 0 to 15%, and there was no difference between TaTME and laparoscopic or robotic TME. Intraoperative complications occurred in 5-6% of the case, which compared favorably to laparoscopic TME. The most serious intraoperative complication with this approach was urethral injury, although only small numbers were reported, which was possibly due to under-reporting. Clavien-Dindo I or II postoperative complications occurred in 22-24% of the case, and III or IV in 10-11% of the case, which did not differ between TaTME and laparoscopic or robotic TME. TaTME may be technically easier and more beneficial than laparoscopic, robotic or open TME in male patients with a narrow pelvis; in obese patients with a bulky tumor. At present two randomized controlled trials, COLOR III and GRECCAR, and comparing TaTME with laparoscopic TME are being conducted and their outcomes are awaited. TaTME is a complex procedure, but proved to be feasible, oncologically safe, and effective in difficult cases. Before this new technique is adopted, proper training with Proctor/mentorship is strongly advised. Careful case selection and audit of data are mandatory.

A retrospective, observational study was conducted to examine the efficacy and safety of elobixibat, a novel therapeutic agent for chronic constipation, in Japanese elderly patients aged ≥ 65 years with chronic constipation.

With endoscopic submucosal dissection and laparoscopic surgery, treatment for colorectal neoplasms has become minimally invasive. However, few studies have compared endoscopic submucosal dissection with laparoscopic surgery for colorectal neoplasms, excluding deeply invasive cancer on preoperative diagnosis.

Colorectal laterally spreading tumors (LSTs) are widely recognized owing to their structural characteristics. This study aims to clarify the histopathological characteristics of large colorectal LSTs according to growth pattern.

The colonoscopic identification of stigmata of recent hemorrhage (SRH) in patients with colonic diverticular bleeding (CDB) is difficult. Factors that influence the identification of SRH in the diagnosis of CDB were investigated.

Few studies have compared management and outcomes of bridge to surgery (BTS) for obstructive colonic cancer according to the location of the tumor. Additional information is needed about this procedure's characteristics and short-term and long-term outcomes. We aimed to compare patient and tumor characteristics, and outcomes of BTS for obstructive right-sided versus left-sided colonic cancers.

Fecal incontinence (FI) is defined as involuntary or uncontrollable loss of feces. Gas incontinence is defined as involuntary or uncontrollable loss of flatus, while anal incontinence is defined as the involuntary loss of feces or flatus. The prevalence of FI in people over 65 in Japan is 8.7% in the male population and 6.6% among females. The etiology of FI is usually not limited to one specific cause, with risk factors for FI including physiological factors, such as age and gender; comorbidities, such as diabetes and irritable bowel syndrome; and obstetric factors, such as multiple deliveries, home delivery, first vaginal delivery, and forceps delivery. In the initial clinical evaluation of FI, the factors responsible for individual symptoms are gathered from the history and examination of the anorectal region. The evaluation is the basis of all medical treatments for FI, including initial treatment, and also serves as a baseline for deciding the need for a specialized defecation function test and selecting treatment in stages. Following the general physical examination, together with history taking, inspection (including anoscope), and palpation (including digital anorectal and vaginal examination) of the anorectal area, clinicians can focus on the causes of FI. For the clinical evaluation of FI, it is useful to use Patient-Reported Outcome Measures (PROMs), such as scores and questionnaires, to evaluate the symptomatic severity of FI and its influence over quality of life (QoL).

Colorectal cancer (CRC) is a heterogeneous disease caused by the accumulation of multistep genetic alterations under the influence of genomic instability. Different backgrounds of genomic instability, such as chromosomal instability, microsatellite instability, hypermutated-single nucleotide variants, and genome stable-induced transformation in the colonic epithelium, can result in adenomas, adenocarcinomas, and metastatic tumors. Characterization of molecular subtypes and establishment of treatment policies based on each subtype will lead to better treatment outcomes and an improved selection of molecularly targeted agents. In Japan, cancer precision medicine has been introduced in the National Health Insurance program through the addition of the cancer genomic profiling (CGP) examination. It has also become possible to access a large amount of genomic information, including information on pathogenic somatic and germline variants, incomparable to conventional diagnostic tests. This information enables us to apply research data to clinical decision-making, benefiting patients and their healthy family members. In this article, we discuss the important molecules and signaling pathways presumed to be the driver genes of CRC progression and the signal transduction system in which they are involved. Molecular subtypes of CRC based on CGP examinations and gene expression profiles have been established in The Cancer Genome Atlas Network with the advent of next-generation sequencing technology. We will also discuss the recommended management of secondary/germline findings, pathogenic germline variants, and presumed germline pathogenic variants obtained from CGP examination and review the current challenges to better understand these data in a new era of cancer genomic medicine.

To clarify the long-term outcomes of transvaginal anterior levatorplasty with posterior colporrhaphy for symptomatic rectocele with defecographic changes.