Possible poor prognosis in younger-onset Crohn's disease-associated anorectal cancer: A subanalysis of the Nationwide Japanese study.

Background and aims: Crohn's disease (CD)-associated intestinal cancers are characterized by their high incidence, particularly at the anorectal site in the Japanese population. Accumulating evidence revealed that younger-onset sporadic colorectal cancer may exhibit unique biological features. To the best of our knowledge, few previous articles reported clinicopathological features in patients with CD-associated anorectal cancer (CDAAC). Therefore, we aimed to clarify the relationship between the younger onset of cancer and clinicopathological characteristics and prognosis, and the efficacy of cancer surveillance in patients with CDAAC. Methods: CD patients who had been diagnosed with intestinal cancers from 1983 to 2020 were collected from 39 Japanese institutions in this study. Of 316 patients with CD-associated intestinal cancers, we analyzed 211 patients with CDAAC. We divided the patients into two groups according to the median age at cancer diagnosis (45 years old). Results: Younger-onset CDAAC (YO-CDAAC) patients were significantly more likely to have a poor outcome than those with older-onset CDAAC (OO-CDAAC) in terms of both disease-free survival (DFS) (p = 0.0014) and overall survival (OS) (p = 0.023). Multivariate analysis showed that age under 45 years old at diagnosis of cancer was one of the independent factors for poor DFS and OS (hazard ratios: 2.15, 95% confidence interval: 1.09-4.26, p = 0.028, hazard ratios: 1.95, 95% confidence interval: 1.05-3.60, p = 0.033, respectively). Patients detected via surveillance showed significantly better DFS and OS rates than symptomatic patients in YO-CDAAC (p = 0.012 and 0.0031, respectively). Conclusions: YO-CDAAC may have a poorer prognosis compared with OO-CDAAC. Surveillance could be important to improve cancer prognosis, especially in young CD patients with anorectal disease.

Machine learning­based radiomics models accurately predict Crohn's disease­related anorectal cancer.

The radiological diagnosis of Crohn's disease (CD)-related anorectal cancer is difficult; it is often found in advanced stages and has a poor prognosis because of the difficulty of curative surgery. However, there are no studies on predicting the diagnosis of CD-related cancer. The present study aimed to develop a predictive model to diagnose CD cancerous lesions more accurately in a way that can be interpreted by clinicians. Patients with CD who developed anorectal CD lesions at Hyogo Medical University (Nishinomiya, Japan) between March 2009 and June 2022 were included in the present study. T2-weighted and T1-weighted magnetic resonance (MR) images were utilized for our analysis. Images of anorectal lesions were segmented using open-source 3D Slicer software, and radiomic features were extracted using PyRadiomics. Six machine learning models were investigated and compared: i) Support vector machine; ii) naive Bayes; iii) random forest; iv) light gradient boosting machine; v) extremely randomized trees; vi) and regularized greedy forest (RGF). SHapley Additive exPlanations (SHAP) values were calculated to assess the extent to which each radiomic feature contributed to the model's predictions compared to baseline, represented as the average of the model's predictions for all test data. The T2-weighted images of 28 patients with anorectal cancer and 40 non-cancer patients were analyzed and the contrast-enhanced T1-weighted images of 22 cancer and 40 non-cancer patients. The model with the highest area under the curve (AUC) was the RGF-based model constructed using T2-weighted image features, achieving an AUC of 0.944 (accuracy, 0.862; recall, 0.830). The SHAP-based model explanation suggested a strong association between the diagnosis of CD-related anorectal cancer and features such as complex lesion texture; greater pixel separation within the same coronal cross-section; larger, randomly distributed clumps of pixels with the same signal intensity; and a more spherical lesion shape on T2-weighted images. The MRI radiomics-based RGF model demonstrated outstanding performance in predicting CD-related anorectal cancer. These results may affect the diagnosis and surveillance strategies of CD-related colorectal cancer.

Perianal Fistulizing Crohn's Disease-Associated Anorectal and Fistula Cancers: Systematic Review and Expert Consensus.

BACKGROUND & AIMS: Perianal fistulizing Crohn's disease (PFCD)-associated anorectal and fistula cancers are rare but often devastating diagnoses. However, given the low incidence and consequent lack of data and clinical trials in the field, there is little to no guidance on screening and management of these cancers. To inform clinical practice, we developed consensus guidelines on PFCD-associated anorectal and fistula cancers by multidisciplinary experts from the international TOpClass consortium. METHODS: We conducted a systematic review by standard methodology, using the Newcastle-Ottawa Scale quality assessment tool. We subsequently developed consensus statements using a Delphi consensus approach. RESULTS: Of 561 articles identified, 110 were eligible, and 76 articles were included. The overall quality of evidence was low. The TOpClass consortium reached consensus on 6 structured statements addressing screening, risk assessment, and management of PFCD-associated anorectal and fistula cancers. Patients with long-standing (>10 years) PFCD should be considered at small but increased risk of developing perianal cancer, including squamous cell carcinoma of the anus and anorectal carcinoma. Risk factors for squamous cell carcinoma of the anus, notably human papilloma virus, should be considered. New, refractory, or progressive perianal symptoms should prompt evaluation for fistula cancer. There was no consensus on timing or frequency of screening in patients with asymptomatic perianal fistula. Multiple modalities may be required for diagnosis, including an examination under anesthesia with biopsy. Multidisciplinary team efforts were deemed central to the management of fistula cancers. CONCLUSIONS: Inflammatory bowel disease clinicians should be aware of the risk of PFCD-associated anorectal and fistula cancers in all patients with PFCD. The TOpClass consortium consensus statements outlined herein offer guidance in managing this challenging scenario.

Anal Mucinous Adenocarcinoma Presenting as a Superficial Lesion Without Luminal Involvement.

Anal mucinous adenocarcinoma arises from mucin-secreting columnar epithelium within anal glands and is extremely rare, comprising 2%-3% of all gastrointestinal malignancies. We present a unique case of 65-year-old developmentally disabled man with complaint of rectal pain. Examination showed an excoriated erythematous perianal region with mucinous film and subdermal nodularity. Surgical pathology of the lesion revealed poorly differentiated mucinous adenocarcinoma of intestinal type. Subsequent colonoscopy was without findings of intraluminal lesions. He established with oncology and later underwent a positron emission tomography scan that showed extensive metastasis. This case highlights a unique presentation of de novo mucinous adenocarcinoma with luminal sparing.

Crohn's disease-related anal fistula cancer diagnosed by examination under anesthesia: a case report.

BACKGROUND: As the number of patients with inflammatory bowel disease (IBD) increases, the incidence of IBD-related colorectal cancer (CRC) is also on the rise. Crohn's disease (CD)-related CRC has been reported to have a poorer prognosis than sporadic CRC, and the early detection of CD-related CRC is difficult. Japanese patients with CD are reported to have a higher frequency of anorectal cancer than the Western population; however, methods for early diagnosis have not yet been established because of perianal pain during the examination. CASE PRESENTATION: We report a case of CD-related anal fistula cancer that was detected early by surveillance examination under anesthesia (EUA). The patient was a 37-year-old man, diagnosed with CD at the age of 15 years and started medical treatment. However, due to poor disease control, the intestinal tract remained highly inflamed and the patient continued to have over 10 bowel movements per day. He was referred to our hospital for surgical treatment after a colonoscopy (CS), which revealed multiple active ulcers and stenoses. Since three perianal seton drainage tubes had been placed around his anus since the age of 33 years, we decided to perform an EUA to rule out cancer coexistence in the anorectal region. After a random biopsy of the rectum by CS under general anesthesia, we resected and curetted multiple perianal fistulas as much as possible and reinserted the seton drainage tubes. Pathological examination of the fistula tract revealed adenocarcinoma in one tract, indicating the coexistence of anal fistula cancer. Based on the diagnosis of multiple intestinal stenoses and anal fistula cancer due to CD, we performed hand-assisted laparoscopic total colectomy, rectal amputation, extensive perineal resection, and reconstruction using a left rectus abdominis flap. CONCLUSION: In a long-term CD patient with anorectal lesions, we performed an EUA to diagnose the coexistence of anal fistula cancer at an early stage, and surgical resection was achieved. EUA is effective for the early detection and treatment of CD-related CRC and may contribute to an improved prognosis.

Risk of anorectal cancer in patients with Crohn's disease and perianal fistula: a nationwide Danish cohort study.

AIM: Patients with Crohn's disease (CD) often suffer from perianal fistulizing disease. Their risk of anorectal cancer remains uncertain. We aimed to examine the long-term risk of anorectal cancer in a population-based cohort of CD patients with anorectal fistula. METHOD: Our study population covered all individuals (n = 7 987 520) aged 15+ years living in Denmark from 1978 to 2018. We identified all patients with CD and anorectal fistula in the Danish National Patient Register (NPR) and 50 matched noninflammatory bowel disease (IBD) individuals from the general population. Using Cox regression analyses, we examined the risk of anorectal cancer in CD fistula patients versus non-IBD individuals. All patients with CD were identified using codes from the International Classification of Diseases and their data extracted from the NPR. The main outcome measure was cases of anorectal cancer. RESULTS: A total of 2786 CD patients with anorectal fistula and 139 300 non-IBD individuals were followed for 1 553 917 person-years. During follow-up, anorectal cancer was observed in 19 CD patients (0.68%) and 340 non-IBD individuals (0.24%), corresponding to a 2.9-fold increased hazard ratio (HR) of anorectal cancer in CD fistula patients (95% CI 1.80-4.53), with a particularly high risk of anal cancer (HR 15.13, 95% CI 6.88-33.31) and a mean time from CD fistula diagnosis to anorectal cancer of 6.7 (SD 6.5) years. The risk was slightly higher in women than men and had no apparent relation to treatment with tumour necrosis factor-α inhibitors. Sensitivity analyses using CD nonfistula patients for comparison revealed similar results. Individual data on smoking and infection with human papilloma virus were not available. CONCLUSION: Patients with CD and anorectal fistula have a three-fold increased risk of anorectal cancer compared with the general population. The number needed to surveil to detect one case of anorectal cancer in this patient population was 2160 patients per year in patients with long-standing fistula (>6 years).

A review of 14 cases of perianal Paget's disease: characteristics of anorectal cancer with pagetoid spread.

BACKGROUND: Perianal Paget's disease (PPD) is an intraepithelial invasion of the perianal skin and is frequently associated with underlying anorectal carcinoma. The relatively rare nature of this disease has made it difficult to develop treatment recommendations. This study aims to analyze the clinical and pathological features of perianal Paget's disease (PPD) and to explore rational treatment options and follow-up for this disease. METHODS: The National Cancer Center Hospital database was searched for all cases of perianal Paget's disease diagnosed between 2006 and 2021. In the 14 patients identified, we reviewed the diagnosis, management, and outcomes of adenocarcinoma with pagetoid spread, including suspected or recurrent cases. RESULTS: All 14 cases met the inclusion criteria. The median follow-up period after diagnosis was 4.5 (range, 0.1-13.0) years. Pagetoid spread before initial treatment was suspected in 12 cases (85.7%). Underlying rectal cancer was identified in 6 cases, and no primary tumor was detected in the other 6 cases. Seven patients had recurrent disease, with the median time to recurrence of 34.6 (range, 19.2-81.7) months. The time to the first relapse was 3 months, and that to the second relapse was 6 months. The overall 5-year survival rate was 90.0%. CONCLUSIONS: Endoscopic and radiologic evaluation, as well as immunohistologic examination, should be performed. is to differentiate PPD with and without underlying anorectal carcinoma. The time to first recurrence varies widely, and long-term and regular follow-up for more than 5 years is considered necessary for local recurrence and distant metastasis.

Radiation therapy for de novo anorectal cancer in patients with a history of prostate radiation therapy.

Introduction: Radiation therapy (RT) for anorectal cancer after prior prostate cancer RT is usually avoided due to concern for complications. Data on this topic is scarce. Our aim was to evaluate tolerability, toxicity, and clinical outcomes associated with a second course of pelvic radiation in men with de novo anorectal cancers previously treated with RT for prostate cancer. Materials/methods: We conducted a single-institution retrospective study of men treated with RT for rectal or anal cancer after prior prostate RT. Toxicity data were collected. Treatment plans were extracted to assess doses to organs at risk and target coverage. Cumulative incidence was calculated for local and distant progression. Kaplan-Meier curves were used to estimate overall survival (OS) and progression-free survival (PFS). Results: We identified 26 patients who received anorectal RT after prostate cancer RT: 17 for rectal cancer and 9 for anal cancer. None had metastatic disease. Prior prostate RT was delivered using low dose rate brachytherapy (LDR), external beam RT (EBRT), or EBRT + LDR. RT for rectal cancer was delivered most commonly using 50.4Gy/28 fractions (fr) or 1.5 Gy twice-daily to 30-45 Gy. The most used RT dose for anal cancer was 50Gy/25 fr. Median interval between prostate and anorectal RT was 12.3 years (range:0.5 - 25.3). 65% and 89% of rectal and anal cancer patients received concurrent chemotherapy, respectively. There were no reported ≥Grade 4 acute toxicities. Two patients developed fistulae; one was urinary-cutaneous after prostate LDR and 45Gy/25fr for rectal cancer, and the other was recto-vesicular after prostate LDR and 50Gy/25fr for anal cancer. In 11 patients with available dosimetry, coverage for anorectal cancers was adequate. With a median follow up of 84.4 months, 5-yr local progression and OS were 30% and 31% for rectal cancer, and 35% and 49% for anal cancer patients, respectively. Conclusion: RT for anorectal cancer after prior prostate cancer RT is feasible but should be delivered with caution since it poses a risk of fistulae and possibly bleeding, especially in patients treated with prior LDR brachytherapy. Further studies, perhaps using proton therapy and/or rectal hydrogel spacers, are needed to further decrease toxicity and improve outcomes.

Urinary tract diversion with gastric conduit after total pelvic exenteration for Crohn's disease-related anorectal cancer: a case report.

BACKGROUND: In Japan, Crohn's disease (CD)-related cancers occur most frequently in the anal canal. Many patients with advanced CD-related cancer require total pelvic exenteration (TPE) based on their medical history, and choosing the most effective method for urinary diversion is a major concern. We herein report the first case of CD-related cancer treatment with urinary diversion using a gastric conduit after TPE in Japan. CASE PRESENTATION: A 51-year-old man with a 25 year history of CD was referred to our institution after having been diagnosed with fistulae between the rectum and urethra. Sigmoidoscopy revealed stenosis of the anal canal, and histological examination of this lesion led to a diagnosis of mucinous adenocarcinoma. Magnetic resonance imaging showed that the tumor had invaded the prostate and left internal obturator muscle, and TPE with left internal obturator muscle resection was planned. Urinary diversion was performed with a gastric conduit. The gastric conduit was created by trimming a gastric tube to a 1.5 cm width via stapled resection of the greater curvature, and the branches of the right gastroepiploic artery were preserved as feeding vessels. The ureters were raised from the mesentery on the right side of the ligament of Treitz. Ureterogastric anastomosis was performed using the Wallace technique, and the entire anastomosis was then retroperitonealized. The anastomotic site had a bleeding tendency, but hemostasis was obtained by proton pump inhibitor administration and discontinuation of enoxaparin, which had been administered to prevent venous thrombosis. No other major complications occurred, and the patient's quality of life was recovered 6 months after surgery. CONCLUSION: Urinary diversion using a gastric conduit is a feasible treatment option for patients with CD-related anorectal cancer requiring TPE.

Proton Therapy in the Management of Luminal Gastrointestinal Cancers: Esophagus, Stomach, and Anorectum.

While the role of proton therapy in gastric cancer is marginal, its role in esophageal and anorectal cancers is expanding. In esophageal cancer, protons are superior in sparing the organs at risk, as shown by multiple dosimetric studies. Literature is conflicting regarding clinical significance, but the preponderance of evidence suggests that protons yield similar or improved oncologic outcomes to photons at a decreased toxicity cost. Similarly, protons have improved sparing of the organs at risk in anorectal cancers, but clinical data is much more limited to date, and toxicity benefits have not yet been shown clinically. Large, randomized trials are currently underway for both disease sites.

Risk of Anorectal Cancer Associated with Benign Anal Inflammatory Diseases: A Retrospective Matched Cohort Study.

PURPOSE: The purpose of our study was to evaluate the relationship between benign anal inflammatory diseases and anorectal cancer and assess its risk factors. METHODS: A retrospective matched cohort study was conducted that included data from 2002 to 2013. The National Health Insurance Service National Sample Cohort data from 2002 to 2013 was used for the study. Of a total study population of 143,884 individuals, 28,110 individuals with anal fissures were assigned to the case group, while 115,774 individuals without anal fissures were assigned to the control group based on the 1:4 propensity score matching age, sex, and year (case: diagnosed year, control: health service received year). RESULTS: The risk of anorectal cancer was higher in the case group (hazard ratio [HR]: 1.95, 95% confidence interval [CI]: 1.51-2.53) compared to the control group. After grouping anorectal cancers into anal cancer and rectal cancer, the risk remained higher in the case group (anal cancer HR: 2.79, 95% CI: 1.48-5.27; rectal cancer HR: 1.82, 95% CI; 1.37-2.42). The case group was further categorized into patients with fissures and patients with fistulas; patients with fissures showed a higher risk of developing anorectal cancer than patients with fistulas (HR: 2.05, 95% CI: 1.53-2.73 vs. HR: 1.73, 95% CI: 1.13-2.66). Study participants in their 30s and 40s had a 4.19- and 7.39-times higher risk of anorectal cancer compared to those in the higher age groups (0.64-1.84), while patients who did not have inflammatory bowel disease (IBD) had a higher risk of developing anorectal cancer (HR: 2.09, 95% CI: 1.56-2.80). CONCLUSIONS AND RELEVANCE: Patients with anal fistulas or fissures have an increased risk of being diagnosed with anorectal cancer, especially at a young age and even without IBD.

Anal canal lymphoma: Case report and literature review / Linfoma de canal anal, reporte de caso y revisión de la literatura

Abstract Introduction: Primary tumors of the anal canal other than carcinomas are rare entities; among them, anal canal lymphomas are extremely unusual and pose both a diagnostic and therapeutic challenge for the coloproctologist. Case presentation: A male patient with positive human immunodeficiency virus (HIV) with proctalgia and mass sensation at the perianal level. A concentric thickening of the walls of the lower rectum was documented by magnetic resonance imaging, with colonoscopy and biopsies with histopathology compatible with plasmablastic lymphoma. Therefore, a diverting colostomy was performed and, subsequently, the hematology service indicated chemotherapy with the EPOCH scheme. Discussion: Lymphoma of the anus represents 0.2 % of anorectal tumors, most of these are non-Hodgkin's lymphomas; Hodgkin's disease at the anorectal level is even rarer. The population with the highest risk of this entity is HIV-positive patients, such as the patient in this case, although other associated factors are described in the literature.

Resumen Introducción: los tumores primarios del canal anal diferentes a carcinomas son entidades poco frecuentes; dentro de estos, los linfomas del canal anal son extremadamente raros y generan un reto tanto diagnóstico como terapéutico para el coloproctólogo. Presentación de caso: se presenta a continuación un caso clínico de un paciente con virus de inmunodeficiencia humana (VIH) positivo con proctalgia y sensación de masa a nivel perianal, se documentó por resonancia magnética un engrosamiento concéntrico de las paredes del recto inferior, con realización de colonoscopia y biopsias con histopatología compatible con linfoma plasmablástico, por lo que se realizó una colostomía derivativa y, posteriormente, se indicó por el servicio de hematología una quimioterapia con esquema EPOCH. Discusión: el linfoma de ano representa el 0,2 % de los tumores anorrectales, la mayoría de estos corresponde a linfomas no Hodgkin, y es aún más rara la enfermedad de Hodgkin a nivel anorrectal. La población con mayor riesgo de presentar esta entidad es los pacientes con VIH positivo, como el paciente descrito en el caso, aunque existen otros factores asociados descritos en la literatura.

Clinicopathological and prognostic evaluations of anorectal cancer after fecal diversion for patients with Crohn's disease.

PURPOSE: Colorectum diversion with a proximal stoma is often the preferred surgical approach in patients with Crohn's disease-related anorectal lesions or refractory colitis. To date, few studies have assessed the incidence and prognosis of cancer in the diverted anorectal segments. This study aimed to evaluate the clinical characteristics and prognosis of anorectal cancer associated with Crohn's disease following fecal diversion. METHODS: This was a retrospective study based on medical records of patients diagnosed with Crohn's disease between 1999 and 2020. It was conducted at Yokohama Municipal Citizen's Hospital. Patients diagnosed with anorectal cancer following fecal diversion were identified, and their prognosis was the primary outcome measure. RESULTS: Among 1615 patients, 232 patients (14%) underwent colorectum diversion. Of those 232 patients, 11 were diagnosed with anorectal cancer following fecal diversion, ten were diagnosed with advanced cancer, 10 underwent abdominoperineal resection, and eight died. 1 could not undergo resection due to multiple lung metastasis and died. The overall five-year survival rate in patients diagnosed with anorectal cancer following fecal diversion was 20%. CONCLUSION: Crohn's disease-associated anorectal cancer following fecal diversion was challenging to diagnose early, and patients had a poor prognosis even after curative resection. Early abdominoperineal resection may be considered for patients with Crohn's disease who cannot benefit from cancer screening and surveillance due to difficulty accessing the anorectal stricture via endoscopy.

Intestinal cancer in patients with Crohn's disease: A systematic review and meta-analysis.

BACKGROUND AND AIM: Although surveillance colonoscopy is recommended by several guidelines for Crohn's disease (CD), the evidence is insufficient to support the validity of this recommendation. Moreover, the efficacy of surveillance colonoscopy for anorectal cancer remains unclear. Therefore, we performed a systematic review of cancer in patients with CD before considering the proper surveillance methods. METHODS: We conducted a systematic review and meta-analysis examining the incidence of intestinal cancer and a literature review to clarify the characteristic features of cancer in CD. We performed the systematic literature review of studies published up to May 2019. RESULTS: Overall, 7344 patients were included in eight studies. The standardized incidence ratios (95% confidence intervals) of colorectal cancer (CRC) and small bowel cancer (SBC) were 2.08 (1.43-3.02) and 22.01 (9.10-53.25), respectively. The prevalence of CRC and SBC was 57/7344 (0.77%) and 17/7344 (0.23%), respectively, during a median follow-up of 12.55 years. Additionally, 54 studies reporting 208 anorectal cancer cases were identified. In patients with anorectal cancer, the prognosis for survival was 2.1 ± 2.3 years, and advanced cancer greater than stage T3 occurred in 46/74 patients (62.1%). Many more reports of anorectal cancer were published in Asia than in Western countries. CONCLUSION: Although we were unable to state a recommendation for surveillance for SBC, we should perform cancer surveillance for CRC in patients with CD. However, the characteristics of cancer may differ according to geography or race. We must establish proper and effective surveillance methods that are independently suitable to detect these differences.

A case of carbon dioxide embolism during the transperineal approach in total pelvic exenteration for advanced anorectal cancer.

The transanal and transperineal endoscopic approaches are useful advanced surgical options for removing rectal and anorectal cancers. Intraoperative carbon dioxide (CO2 ) embolisms, however, have been increasingly reported as potentially fatal complications associated with surgery employing these approaches. We report our experience with a CO2 embolism that was detected because of a sudden drop in end-tidal CO2 with decreasing saturation of percutaneous arterial oxygen during total pelvic exenteration using the transperineal endoscopic approach under pneumopelvis/pneumoperitoneum. Transesophageal echocardiography confirmed that it was a CO2 embolus. We reversed the pneumopelvis and pneumoperitoneum, which alleviated the cardiopulmonary problems, and the surgery then proceeded to achieve R0 resection. The patient was discharged without severe complications other than the CO2 embolism.

A case report of anal canal cancer with pagetoid spread requiring differential diagnosis.

INTRODUCTION: Paget's disease is an intraepithelial invasion by a malignant tumour and is characterised by erythema and inflammation. It can manifest as mammary or extramammary Paget's disease (EMPD), with the latter often developing in the perianal area. Anorectal cancer can cause transepithelial invasion into the epidermis, resulting in an appearance similar to that of EMPD. This is called pagetoid spread (PS), which is completely different from EMPD. These two conditions are difficult to differentiate because of the nature of intricacy and requirements of histopathology. PRESENTATION OF CASE: We present a case in which differential diagnosis between these two conditions was not possible during the preoperative examination, resulting in difficulties in treatment. The patient was a 70-year-old woman who experienced pain in the anus since the previous month and presented with red, flat and elevated lesions. DISCUSSION: Treatment for dermatitis was ineffective, and endoscopic examination did not indicate rectal or anal cancer. However, immunohistochemical examination of the biopsy specimen suggested PS. Thus, two-stage operation was planned. Transanal surgery was performed to confirm the diagnosis of PS and intersphincteric resection was allowed as a radical surgery. CONCLUSION: Thus, when differentiation between EMPD and PS is intricacy, two-stage operation is useful in selecting an appropriate radical surgery method, leading to preservation of anal function.

Investigating epidemiologic trends and the geographic distribution of patients with anal squamous cell carcinoma throughout Canada.

Background: Anal cancer is a rare disease, constituting 0.5% of new cancer cases in the United States. The most common subtype is squamous cell carcinoma (scc). Studies in several developed nations have reported on an increasing incidence of anal cancer in recent decades, and various risk factors pertaining to the pathogenesis of the disease have been identified, including infection with the human papillomavirus, tobacco use, and immunosuppression. The epidemiology and distribution of anal scc throughout Canada remain poorly understood, however. Methods: Using 3 population-based cancer registries, a retrospective analysis of demographic data across Canada for 1992-2010 was performed. The incidence and mortality for anal scc was examined at the levels of provinces, cities, and the forward sortation area (FSA) component (first 3 characters) of postal codes. Results: During 1992-2010, 3720 individuals were diagnosed with anal scc in Canada; 64% were women. The overall national incidence rate was 6.3 cases per million population per year, with an average age at diagnosis of 60.4 years. The incidence increased over time, with significantly higher incidence rates documented in British Columbia and Nova Scotia (9.3 cases per million population each). Closer examination revealed clustering of cases in various urban centres and self-identified lgbtq communities in Toronto, Montreal, and Vancouver. Discussion: This study provides, for the first time, a comprehensive analysis of the burden of anal scc in Canada, identifying susceptible populations and shedding light onto novel avenues of research to lower the incidence of anal cancer throughout the country.

Factors associated with the use of vertical rectus abdominus myocutaneous flap reconstruction following abdominoperineal resection for anorectal cancer.

BACKGROUND AND OBJECTIVES: Following abdominoperineal resection (APR), primary closure of the perineal defect is often possible. Some patients, however, require flap reconstruction. Identifying these patients preoperatively is critical to facilitate comprehensive patient counseling and optimize surgical efficacy. METHODS: A retrospective review of patients undergoing APR over a 10-year period was performed to identify predictive factors for patients requiring reconstruction with a vertical rectus abdominis myocutaneous (VRAM) flap as opposed to primary closure. Student's t and Fisher's exact tests were utilized for statistical analysis. RESULTS: A total of 158 patients underwent APR, 29 of whom (18%) required a VRAM flap. A higher average skin resection area was seen among those requiring flap reconstruction (P < .0001). Flap reconstruction was also associated with current smoking status (P = .0197), anal tumor location (P < .0001), and neoadjuvant radiation (P = .0457). Although not statistically significant, average tumor diameter was larger in the VRAM flap group compared with the primary closure group. CONCLUSIONS: While the appropriate method of closure for those undergoing APR should be considered on an individual case basis, patients who smoke, have a tumor located at the anus, or require large skin resection are more likely to need flap reconstruction.

Proton beam radiotherapy for anal and rectal cancers.

Gastrointestinal cancers are bordered by radiosensitive visceral organs, resulting in a narrow therapeutic window. The search for more efficacious and tolerable therapies raises the possibility that proton beam therapy's (PBT) physical and dosimetric differences from conventional therapy may be better suited to treat both primary and recurrent disease, which carries its own unique challenges. Currently, the maximal efficacy of radiation plans for primary and recurrent anorectal cancer is constrained by delivery techniques and modalities which must consider feasibility challenges and toxicity secondary to exposure of organs at risk (OARs). Studies using volumetric modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) demonstrate that more precise dose delivery to target volumes improves local control rates and reduces complications. By reducing the low-to-moderate radiation dose-bath to bone marrow, small and large bowel, and skin, PBT may offer an improved side-effect profile. The potential to reduce toxicity, increase patient compliance, minimize treatment breaks, and enable dose escalation or hypofractionation is appealing. In cases where prognosis is favorable, PBT may mitigate long-term morbidity such as secondary malignancies, femoral fractures, and small bowel obstruction.