Pelvic phased-array MR imaging of anal carcinoma before and after chemoradiation

Insights into gastrointestinal manifestation of human immunodeficiency virus: A narrative review

Human immunodeficiency virus (HIV) modifies CD4-positive cells, resulting in immunodeficiency and a wide range of gastrointestinal (GI) manifestations. The burden of HIV-related GI illnesses has significantly evolved with the widespread use of antiretroviral therapy (ART). While ART has effectively reduced the occurrence of opportunistic infections, it has led to an increase in therapy-related GI illnesses. Common esophageal conditions in HIV patients include gastroesophageal reflux disease, idiopathic esophageal ulcers, herpes simplex virus, cytomegalovirus (CMV), and candidal esophagitis. Kaposi’s sarcoma, a hallmark of acquired immunodeficiency syndrome, may affect the entire GI system. Gastritis and peptic ulcer disease are also frequently seen in patients with HIV. Diarrhea, often linked to both opportunistic infections and ART, requires careful evaluation. Bloody diarrhea, often a sign of colitis caused by bacterial infections such as Shigella or Clostridium difficile, is prevalent. Small bowel lymphoma, although rare, is increasing in prevalence. Anorectal disorders, including proctitis, fissures, and anal squamous cell carcinoma, are particularly relevant in homosexual men, underlining the importance of timely diagnosis. This review comprehensively explores the epidemiology, pathogenesis, and treatment considerations for the various GI disorders associated with HIV, highlighting the importance of accurate diagnosis and effective treatment to improve outcomes for HIV-infected patients.

Brazilian Society of Surgical Oncology: Guidelines for the management of anal canal cancer

BACKGROUND

Anal canal squamous cell carcinoma (SCC) is a relatively uncommon neoplasia, and it is mostly a local-regional cancer, of low metastatic potential (only 15%), resulting in cure in most cases treated with definitive chemoradiation. On the other hand, its incidence has been steadily increasing over the last decades, which makes it an important public health problem. In an effort to provide surgeons and oncologists who treat patients with anal cancer with the most updated information based on the best scientific evidence, the Brazilian Society of Surgical Oncology (SBCO) has produced the present guideline for the management of anal canal SCC, focused on the main topics related to daily clinical practice.

OBJECTIVES

The SBCO developed the present guidelines to provide recommendations on the main topics related to the management of anal canal squamous cell carcinoma (SCC) based on current scientific evidence.

METHODS

Between October 2022 and January 2023, 14 experts met to develop the guidelines for the management of anal canal cancer. A total of 30 relevant topics were distributed among the participants. The methodological quality of a final list with 121 sources was evaluated, all the evidence was examined and revised, and the management guidelines were formulated by the 14-expert committee. To reach a final consensus, all the topics were reviewed in a meeting that was attended by all the experts.

RESULTS

The proposed guidelines contained 30 topics considered to be highly relevant in the management of anal canal cancer, covering subjects related to screening recommendations, preventive measures, tests required for diagnosing and staging, treatment strategies, response assessment after chemoradiotherapy, surgical technique-related aspects, and follow-up recommendations. In addition, screening and response assessment algorithms, and a checklist were proposed to summarize the important information and offer an updated tool to assist surgeons and oncologists who treat anal canal cancer and in providing the best care to their patients.

CONCLUSION

These guidelines summarize recommendations based on the most current scientific evidence on relevant aspects of anal canal cancer management and are a practical guide to help surgeons and oncologists who treat anal canal cancer make the best therapeutic decisions.

Accuracy and Clinical Impact of Persistent Disease Diagnosed on Diffusion-Weighted Imaging and Accuracy of Pelvic Nodal Assessment on Magnetic Resonance Imaging for Squamous Cell Carcinoma of the Anus in the 6-Month Interval Post Chemoradiotherapy

PURPOSE

To evaluate the diagnostic performance of diffusion-weighted imaging (DWI) in the 6-month interval post chemoradiation therapy (CRT) in determining persistent disease and whether persistent diffusion restriction on DWI at 6 months is associated with overall survival; and secondarily, to investigate the accuracy of pelvic lymph node assessment on T2-weighted imaging and DWI in the 6-month interval post CRT, in patients with squamous cell carcinoma of the anus.

METHODS AND MATERIALS

This retrospective study included patients with squamous cell carcinoma of the anus who underwent CRT followed by restaging rectal MRI from January 2010 to April 2020, with ≥1 year of follow-up after CRT. DW images were qualitatively evaluated by 2 junior and 2 senior abdominal radiologists to determine anal persistent disease. The reference standard for anal persistent disease was digital rectal examination/endoscopy and histopathology. Diagnostic performance was estimated using sensitivity, specificity, negative predictive value, and positive predictive value. Survival outcomes were evaluated via Kaplan-Meier analysis, and associations between survival outcomes and DWI status were tested for significance using the log-rank test. Additionally, DW and T2-weighted images were evaluated to determine lymph node status.

RESULTS

Among 84 patients (mean age, 63 ± 10.2 years; 64/84 [76%] female), 14 of 84 (17%) had confirmed persistent disease. Interreader agreement on DWI between all 4 radiologists was moderate (Light's κ = 0.553). Overall, DWI had a sensitivity of 71.4%, specificity of 72.1%, positive predictive value of 34.5%, and negative predictive value of 92.5%. Patients with a negative DWI showed better survival than patients with a positive DWI (3-year overall survival of 92% vs 79% and 5-year overall survival of 87% vs 74%), although the difference did not reach statistical significance (P = .063). All patients with suspicious lymph nodes (14/14, 100%) showed negative pathology or decreased size during follow-up.

CONCLUSIONS

At 6 months post CRT, DWI showed value in excluding anal persistent disease. Persistent diffusion restriction on DWI was not significantly associated with overall survival. Pelvic nodal assessment on DWI and T2-weighted imaging was limited in predicting persistent nodal metastases.

An Updated Review on Imaging and Staging of Anal Cancer-Not Just Rectal Cancer

Anal cancer is a rare disease, but its incidence has been increasing steadily. Primary staging and assessment after chemoradiation therapy are commonly performed using MRI, which is considered to be the preferred imaging modality. CT and PET/CT are useful in evaluating lymph node metastases and distant metastatic disease. Anal squamous-cell carcinoma (ASCC) and rectal adenocarcinoma are typically indistinguishable on MRI, and a biopsy prior to imaging is necessary to accurately stage the tumor and determine the treatment approach. This review discusses the histology, MR technique, diagnosis, staging, and treatment of anal cancer, with a particular focus on the differences in TNM staging between anal and rectal carcinomas.

PURPOSE

This review discusses the histology, MR technique, diagnosis, staging, and treatment of anal cancer, with a particular focus on the differences in TNM staging between anal squamous-cell carcinoma (ASCC) and rectal adenocarcinoma.

METHODS AND MATERIALS

To conduct this updated review, a comprehensive literature search was performed using prominent medical databases, including PubMed and Embase. The search was limited to articles published within the last 10 years (2013-2023) to ensure their relevance to the current state of knowledge.

INCLUSION CRITERIA

(1) articles that provided substantial information on the diagnostic techniques used for ASCC, mainly focusing on imaging, were included; (2) studies reporting on emerging technologies; (3) English-language articles.

EXCLUSION CRITERIA

articles that did not meet the inclusion criteria, case reports, or articles with insufficient data. The primary outcome of this review is to assess the accuracy and efficacy of different diagnostic modalities, including CT, MRI, and PET, in diagnosing ASCC. The secondary outcomes are as follows: (1) to identify any advancements or innovations in diagnostic techniques for ASCC over the past decade; (2) to highlight the challenges and limitations of the diagnostic process.

RESULTS

ASCC is a rare disease; however, its incidence has been steadily increasing. Primary staging and assessment after chemoradiation therapy are commonly performed using MRI, which is considered to be the preferred imaging modality. CT and PET/CT are useful in evaluating lymph node metastases and distant metastatic disease.

CONCLUSION

ASCC and rectal adenocarcinoma are the most common histological subtypes and are typically indistinguishable on MRI; therefore, a biopsy prior to imaging is necessary to stage the tumor accurately and determine the treatment approach.

Imaging of Anal Squamous Cell Carcinoma: Survey Results and Expert Opinion from the Rectal and Anal Cancer Disease-Focused Panel of the Society of Abdominal Radiology

The role and method of image-based staging of anal cancer has evolved with the rapid development of newer imaging modalities and the need to address the rising incidence of this rare cancer. In 2014, the European Society of Medical Oncology mandated pelvic magnetic resonance imaging (MRI) for anal cancer and subsequently other societies such as the National Comprehensive Cancer Network followed suit with similar recommendations. Nevertheless, great variability exists from center to center and even within individual centers. Notably, this is in stark contrast to the imaging of the anatomically nearby rectal cancer. As participating team members for this malignancy, we embarked on a comprehensive literature review of anal cancer imaging to understand the relative merits of these new technologies which developed after computed tomography (CT), e.g., MRI and positron emission tomography/computed tomography (PET/CT). The results of this literature review helped to inform our next stage: questionnaire development regarding the imaging of anal cancer. Next, we distributed the questionnaire to members of the Society of Abdominal Radiology (SAR) Rectal and Anal Disease-Focused Panel, a group of abdominal radiologists with special interest, experience, and expertise in rectal and anal cancer, to provide expert radiologist opinion on the appropriate anal cancer imaging strategy. In our expert opinion survey, experts advocated the use of MRI in general (65% overall and 91-100% for primary staging clinical scenarios) and acknowledged the superiority of PET/CT for nodal assessment (52-56% agreement for using PET/CT in primary staging clinical scenarios compared to 30% for using MRI). We therefore support the use of MRI and PET and suggest further exploration of PET/MRI as an optimal combined evaluation. Our questionnaire responses emphasized the heterogeneity in imaging practice as performed at numerous academic cancer centers across the United States and underscore the need for further reconciliation and establishment of best imaging practice guidelines for optimized patient care in anal cancer.

Follow-up imaging of anal cancer after treatment

Anal cancer treatment response assessment can be challenging with both magnetic resonance imaging (MRI) and clinical evaluation considered essential. MRI, in particular, has shown to be useful for the assessment of treatment response, the detection of recurrent disease in follow up and surveillance, and the evaluation of possible post-treatment complications as well as complications from the tumor itself. In this review, we focus on the role of imaging, mainly MRI, in anal cancer treatment response assessment. We also describe the treatment complications that can occur, and the imaging findings associated with those complications.

Combined PET-CT and MRI for response evaluation in patients with squamous cell anal carcinoma treated with curative-intent chemoradiotherapy

OBJECTIVES

To assess the effectiveness of fluorine-18 fluorodeoxyglucose (FDG) positron-emission tomography-computed tomography (PET-CT) and magnetic resonance imaging (MRI) for response assessment post curative-intent chemoradiotherapy (CRT) in anal squamous cell carcinoma (ASCC).

METHODS

Consecutive ASCC patients treated with curative-intent CRT at a single centre between January 2018 and April 2020 were retrospectively identified. Clinical meta-data including progression-free survival (PFS) and overall survival (OS) outcomes were collated. Three radiologists evaluated PET-CT and MRI using qualitative response assessment criteria and agreed in consensus. Two-proportion z test was used to compare diagnostic performance metrics (sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy). Kaplan-Meier analysis (Mantel-Cox log-rank) was performed.

RESULTS

MRI (accuracy 76%, PPV 44.8%, NPV 95.7%) and PET-CT (accuracy 69.3%, PPV 36.7%, NPV 91.1%) performance metrics were similar; when combined, there were statistically significant improvements (accuracy 94.7%, PPV 78.9%, NPV 100%). Kaplan-Meier analysis demonstrated significant differences in PFS between responders and non-responders at PET-CT (p = 0.007), MRI (p = 0.005), and consensus evaluation (p < 0.001). Cox regression analysis of PFS demonstrated a lower hazard ratio (HR) and narrower 95% confidence intervals for consensus findings (HR = 0.093, p < 0.001). Seventy-five patients, of which 52 (69.3%) were females, with median follow-up of 17.8 months (range 5-32.6) were included. Fifteen of the 75 (20%) had persistent anorectal and/or nodal disease after CRT. Three patients died, median time to death 6.2 months (range 5-18.3).

CONCLUSION

Combined PET-CT and MRI response assessment post-CRT better predicts subsequent outcome than either modality alone. This could have valuable clinical benefits by guiding personalised risk-adapted patient follow-up.

KEY POINTS

• MRI and PET-CT performance metrics for assessing response following chemoradiotherapy (CRT) in patients with anal squamous cell carcinoma (ASCC) were similar. • Combined MRI and PET-CT treatment response assessment 3 months after CRT in patients with ASCC was demonstrated to be superior to either modality alone. • A combined MRI and PET-CT assessment 3 months after CRT in patients with ASCC has the potential to improve accuracy and guide optimal patient management with a greater ability to predict outcome than either modality alone.

Radiology of anal and lower rectal cancers

Lower rectal and anal cancers are distinct from neoplasms involving rest of the rectum. These are relatively difficult to manage owing to important relationships with the sphincter muscles. Involvement of the latter portends a poorer prognosis and increased chance of recurrence. Lymphatic drainage of these tumours is into the systemic circulation and the exact set of lymph nodes involved depends on the precise location of the tumour. The role of imaging includes assessment of local invasion, infiltration of adjacent pelvic organs, assessment of locoregional lymphatic spread and metastasis, post-chemoradiation restaging as well as post-treatment surveillance.

Hellenic society of medical oncology (HESMO) guidelines for the management of anal cancer

Despite considerable improvement in the management of anal cancer, there is a great deal of variation in the outcomes among European countries, and in particular among different hospital centres in Greece and Cyprus. The aim was to elaborate a consensus on the multidisciplinary management of anal cancer, based on European guidelines (European Society of Medical Oncologists-ESMO), considering local special characteristics of our healthcare system. Following discussion and online communication among members of an executive team, a consensus was developed. Guidelines are proposed along with algorithms of diagnosis and treatment. The importance of centralisation, care by a multidisciplinary team (MDT) and adherence to guidelines are emphasised.

A 2020 update of anal cancer: the increasing problem in women and expanding treatment landscape

INTRODUCTION

Anal cancer is a rare malignancy with increasing incidence, notably in women. This disease is highly associated with HPV infection and its incidence and mortality are currently rising. Most patients present with localized disease which has a high survival after definitive treatment with chemoradiation. For patients who develop metastatic disease or present with this de novo, survival is poor.

AREAS COVERED

This review provides a summary of current literature on anal cancer. With a focus on women, this includes current epidemiological trends, role of HPV, and the current and future treatment landscape, including HPV vaccination and immunotherapy. Screening currently focusses on HIV-positive men, missing most female cases. In curative disease, trials are investigating treatment de-intensification in good prognostic groups. Immunotherapy is showing early promise in the advanced disease setting.

EXPERT OPINION

Similar to cervical cancer, anal cancer is strongly associated with HPV, and therefore, broader implementation of screening programs may reduce its incidence. HPV vaccination is expected to reduce the development of (pre)malignant anal lesions. The emergence of biomarkers will assist patient treatment selection, allowing optimal balance of treatment efficacy and morbidity. It is hoped that new treatment approaches, including immunotherapy, will improve outcomes. International collaboration is needed.

Physiological 18F-FDG uptake in the normal adult anal canal: evaluation by PET/CT

OBJECTIVE

Despite their benefit for detecting primary tumors, data for normal ¹⁸F-fluoro-2-deoxy-D-glucose (FDG) uptake in the anal canal are insufficient. Here we used positron emission tomography-computed tomography (PET/CT) to determine the uptake of FDG in the normal adult anal canal (AC) and to evaluate its clinical significance compared with that of anal cancer.

METHODS

We conducted a retrospective study of-PET/CT images in the anal region, of 201 consecutive patients without symptoms or pathology taken from January 2015 to August 2019, after excluding two patients (one each with Crohn's disease and hemorrhoid). These patients were included in the normal group, and data of eight patients with anal cancer were collected from January 2011 to August 2019 for comparison. FDG uptake was quantitatively evaluated (compared with the maximum standardized uptake value [SUV_max] to the SUV_max values of liver and distal rectum) and qualitatively (compared with background) in early and delayed phases. Normal grade 3 uptake was qualitatively defined as FDG uptake higher than the surrounding muscles.

RESULTS

In the normal group, mean anal canal SUV_max of early phase was: 2.26 (range 1.00-6.30), and delayed phase: 2.52 (range 1.00-8.80). Their ratios to liver SUV_max were early: 0.74 (range 0.24-2.25), and delayed: 0.81 (range 0.23-2.32); ratios to rectal SUV_max were early: 0.87 (range 0.30-1.89), and delayed: 0.90 (range 0.30-1.27). Qualitatively, 25 patients (15.4%) had normal grade 3 uptake during the early and delayed phases. In contrast, qualitative data showed that all patients with anal cancer exhibited high FDG uptake in the anal canal. The mean early- and delayed-phase values of SUV_max of the anal canal and anal cancer group were 11.09 (range 5.40-17.73) and 14.23 (range 6.70-22.85), respectively. There was a significant difference between the mean-early and -delayed anal SUV_max values of the normal grade 3 and anal cancer groups. Furthermore, the ratios to liver SUV_max were significantly different between the two groups.

CONCLUSIONS

PET/CT scans occasionally showed high FDG uptake in the anal canal of healthy adults. Comparing the SUV_max values of liver FDG uptake may help differentiate between normal tissue and anal cancer.

MRI anatomy and pathology of the anal canal

The normal function of the anal sphincter complex is crucial for quality of life, as it is the mechanism by which fecal continence is maintained. Additionally, the anal sphincter complex is an integral part of the coordinated effort of defecation. As imaging plays an important role in assessment of pathologic conditions involving the anal region, understanding the normal anatomy of the anal sphincter complex is important for correct image interpretation and accurate diagnosis. This review discusses the anatomy and function of the anal sphincter complex, important technical considerations for MRI, and various inflammatory, infectious, and neoplastic processes, as well as pathologic structural conditions that affect the anal region. Level of Evidence: 5 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2019;50:1018-1032.

MRI evaluation of anal and perianal diseases

Anal and perianal region is a commonly affected area in the course of several inflammatory, infectious, and neoplastic diseases. Several imaging modalities may be used in imaging evaluation of this area and magnetic resonance imaging (MRI) emerges as the imaging modality of choice due to its superb soft tissue resolution. MRI is not only useful for initial detection of anal/perianal pathologies but also in the follow-up of these disorders. In this article, we aimed to illustrate MRI findings of several diseases affecting this area including perianal fistula as well as anal fissure, hypertrophic myopathy of internal anal sphincter, hidradenitis suppurativa, pilonidal sinus, rectovaginal/anovaginal fistula and anal canal carcinoma. We think that this article will serve to familiarize the imaging specialists to the MRI findings of these diseases.

The impact of MRI sequence on tumour staging and gross tumour volume delineation in squamous cell carcinoma of the anal canal

OBJECTIVES

To compare maximum tumour diameter (MTD) and gross tumour volume (GTV) measurements between T2-weighted (T2-w) and diffusion-weighted (DWI) MRI in squamous cell carcinoma of the anal canal (SCCA) and assess sequence impact on tumour (T) staging. Second, to evaluate interobserver agreement and reader delineation confidence.

METHODS

The staging MRI scans of 45 SCCA patients (25 females) were assessed retrospectively by two independent radiologists (0 and 5 years' experience of anal cancer MRI). MTD and GTV were delineated on both T2-w and high-b-value DWI images and compared between sequences; T staging was derived from MTD. Interobserver agreement was assessed and delineation confidence scored (1 to 5) by each observer.

RESULTS

GTV and MTD were significantly and systematically lower on DWI versus T2-w sequences by 14.80%/9.98% (MTD) and 29.70%/12.25% (GTV) for each reader, respectively, causing T staging discordances in approximately a quarter of cases. Bland-Altman limits of agreement were narrower and intraclass correlation coefficients higher for DWI. Delineation confidence was greater on DWI: 40/42 cases were scored confidently (4 or 5) by each reader, respectively, versus 31/36 cases based on T2-w images.

CONCLUSIONS

Sequence selection affects SCCA measurements and T stage. DWI yields higher interobserver agreement and greater tumour delineation confidence.

KEY POINTS

• MTD and GTV measurements are significantly lower on DWI than on T 2 -w MRI. • Such differences cause T staging discordances in up to a quarter of cases. • DWI results in higher agreement between inexperienced and experienced observers. • DWI offers greater tumour delineation confidence to inexperienced readers.

The HIV manifestations within the gastrointestinal tract: A pictorial review

The aim of the pictorial review are to review the HIV manifestations within the gastrointestinal tract. We have detailed five conditions, with reference to the patients’ CD4 count – gastrointestinal tuberculosis, Kaposi’s sarcoma, small bowel lymphoma, cytomegalovirus colitis and anal carcinoma.

Cancer of the Anal Canal: Diagnosis, Staging and Follow-Up with MRI

Although a rare disease, anal cancer is increasingly being diagnosed in patients with risk factors, mainly anal infection with the human papilloma virus. Magnetic resonance imaging (MRI) with external phased-array coils is recommended as the imaging modality of choice to grade anal cancers and to evaluate the response assessment after chemoradiotherapy, with a high contrast and good anatomic resolution of the anal canal. MRI provides a performant evaluation of size, extent and signal characteristics of the anal tumor before and after treatment, as well as lymph node involvement and extension to the adjacent organs. MRI is also particularly helpful in the assessment of complications after treatment, and in the diagnosis for relapse of the diseases.

Anal cancer: French Intergroup Clinical Practice Guidelines for diagnosis, treatment and follow-up (SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, SNFCP)

INTRODUCTION

This document is a summary of the French Intergroup guidelines regarding the management of anal carcinomas, published in November 2016.

METHODS

It is a collaborative work produced under the auspices of the majority of the French medical societies involved in the management of anal cancer. It is based on the previous guidelines published in 2010. Recommendations are graded in three categories, according to the amount of evidence found in the literature.

RESULTS

Non-metastatic anal carcinomas can be divided into two risk groups, according to magnetic resonance imaging (MRI) or endorectal-ultrasonograpy. Localized small cancers (T1N0) are mainly treated by exclusive radiation therapy in the case of cancers of the anal canal, or by surgery in the case of cancers of the anal margin. The recommended treatment of locally advanced tumours (T2-T4, N0-N2) is definitive concomitant radio-chemotherapy. Salvage surgery should be reserved for patients with poor response, tumour progression or local relapse after radio-chemotherapy, or in cases of persistent vaginal fistula or total anal incontinence after the cessation of radio-chemotherapy. In the case of metastatic tumours, current therapeutic recommendations are based on less robust evidence; with chemotherapy playing a major role.

CONCLUSION

These recommendations are permanently being reviewed, and each individual case must be discussed inside a multidisciplinary team.

The assessment of local response using magnetic resonance imaging at 3- and 6-month post chemoradiotherapy in patients with anal cancer

OBJECTIVES

To assess the use of MRI-determined tumour regression grading (TRG) in local response assessment and detection of salvageable early local relapse after chemoradiotherapy (CRT) in patients with anal squamous cell carcinoma (ASCC).

METHODS

From a prospective database of patients with ASCC managed through a centralised multidisciplinary team, 74 patients who completed routine post-CRT 3- and 6-month MRIs (2009-2012) were reviewed. Two radiologists blinded to the outcomes consensus read and retrospectively assigned TRG scores [1 (complete response) to 5 (no response)] and related these to early local relapse (within 12 months) and disease-free survival (DFS).

RESULTS

Seven patients had early local relapse. TRG 1/2 scores at 3 and 6 months had a 100 % negative predictive value; TRG 4/5 scores at 6 months had a 100 % positive predictive value. All seven patients underwent salvage R0 resections. We identified a novel 'tram-track' sign on MRI in over half of patients, with an NPV for early local relapse of 83 % at 6 months. No imaging characteristic or TRG score independently prognosticated for late relapse or 3-year DFS.

CONCLUSIONS

Post-CRT 3- and 6-month MRI-determined TRG scores predicted salvageable R0 early local relapses in patients with ASCC, challenging current clinical guidelines.

KEY POINTS

• Post-chemoradiotherapy MRI (3 and 6 months) helps local response assessment in ASCC. • The MRI-TRG system can be used reproducibly in patients with ASCC. • The TRG system facilitates patient selection for examination under anaesthesia and biopsy. • The use of MRI-TRG predicts for detection of salvageable early local relapses. • The TRG system allows for a standardised follow-up pathway.

Background and Current Treatment of Squamous Cell Carcinoma of the Anus

In this review, a summary of our current understanding of squamous cell carcinoma of the anus (SCCA) and the advances in our knowledge of SCCA regarding screening, prevention, the role of the immune system, current treatment and the potential for novel targets are discussed. The present standard of care in terms of treatment is 5-fluorouracil (5-FU) and mitomycin C (MMC) concurrently with radiation, which results in a high level of disease control for small early cancers. Preservation of the anal sphincter is achieved in the majority, although anorectal function is often impaired. Although evidence from prospective studies to support a change in the treatment strategy is lacking, patients with HPV-negative SCCA appear to be less responsive to chemoradiation (CRT) and relapse more frequently. In contrast, HPV-positive tumours usually fare better, but oncological outcomes are modified by smoking and immune incompetence. There is current interest in escalating the radiotherapy dose for larger, more advanced tumours, and de-escalating treatment for HPV-positive tumours. The use of novel immunological treatments to target the underlying different molecular pathways of HPV-positive cancers is exciting.

[Follow-up after radiotherapy of anal canal carcinoma]

Anal canal carcinoma is a rare and curable disease for which the standard of care is radiation therapy with concurrent 5-fluoro-uracil and mitomycine-based chemotherapy. Post-treatment follow-up however is rather poorly defined. This article offers a review of the various post-treatment surveillance options both for early diagnosis of relapse and care for late treatment effects. While follow-up remains mostly clinical, we will discuss morphologic (endorectal echoendoscopy, pelvic magnetic resonance imaging, tomodensitometry and positron emission tomography) and biologic (squamous cell carcinoma antigen and pathology) follow-up so as to determine their diagnostic and prognostic value.

Update and current status of diffusion-weighted MRI in anorectal malignancy

SUMMARY 

Diffusion-weighted imaging (DWI) is an MRI technique that yields unique information regarding the movement of water molecules at the cellular level. Now widely available and rapid to perform the sequence is increasingly utilized within abdominopelvic oncology, including anorectal cancer imaging. Unfortunately, the diffusion properties of anorectal tumors are complex and not fully understood, with areas of cellular tumor, necrosis and fibrosis co-existing. While DWI shows promise both for staging and in assessing treatment response in anorectal cancer, there remains a lack of consensus regarding its role and integration into standard MRI protocols. This article outlines the basic science behind DWI and reviews the current evidence base for its use in anorectal cancer.

The role of MRI in the assessment of the local status of anal carcinomas and in their management

This study aims to define the role of Magnetic Resonance (MR) examinations in the assessment and therapy of anal cancer (AC), and to present the main features of the MR examinations and the typical tumor spread pattern. The MR examinations of 67 anal cancer patients with histologically confirmed planocellular cancer were analyzed retrospectively. The tumor size and the signal intensity, the nodal status were examined before and after the treatment, and in recidive tumors (N = 13). At the time of the diagnosis the primary tumor was in early stage (Tis, T1, T2) in 71.5 % of the cases, and it was localized in 97 %. In 97.4 % of the cases the tumor had relatively increased signal intensities compared to the adjacent muscles. Patients received chemo-radiotherapy (CRT). After CRT in 26 out of 39 patients (66.7 %) the size of the tumor decreased (in 75 %), and the signal intensity decreased on the T2 weighted (T2w) images. In the residual tumor cases (19/39) verified 6 patients out of 19 had further decrease in size, and signal intensity a year after the end of the therapy. The MR examination plays a key role in the therapy of AC, by assessing the precise local status, the possible recidive tumors, and monitoring the therapy.

Diagnostic performance of positron emission tomography/computed tomography using fluorine-18 fluorodeoxyglucose in detecting locoregional nodal involvement in patients with anal canal cancer: a systematic review and meta-analysis

Purpose. The diagnostic performance of positron emission tomography using ¹⁸F-fluorodeoxyglucose (FDG-PET) in detecting nodal involvement in patients with anal canal cancer (ACC) has been investigated by several studies with conflicting results. The aim of our study is to systematically review and meta-analyze published data about this topic. Methods. A comprehensive computer literature search of PubMed/MEDLINE, Scopus, and Embase databases was carried out on July 10 to find relevant articles concerning the diagnostic performance of FDG-PET in detecting locoregional nodal involvement in patients with ACC. No language restriction was used. Pooled diagnostic performance on a lesion-based analysis was calculated. Results. Seven retrospective and five prospective studies have been reviewed. Six studies allowed assessing pooled sensitivity; five studies allowed assessing pooled specificity. Sensitivity and specificity values of FDG-PET/CT on a lesion-based analysis ranged from 31 to 100% and from 53 to 98%, with pooled estimates of 56% (95% CI: 45–67%) and 90% (95% CI: 86–93%), respectively. Conclusions. Our meta-analysis demonstrates that FDG-PET is a specific diagnostic tool in detecting locoregional lymph node involvement in patients with ACC. Low sensitivity is a major concern; however, higher sensitivity could be reached combining FDG-PET with MR scan.

MRI of anal cancer: assessing response to definitive chemoradiotherapy

Anal cancer is an uncommon malignancy of the gastrointestinal tract but has a relatively good prognosis with an 80% 5-year overall survival. In this article, we review the role of MRI for assessing treatment response in anal cancer after completion of definitive chemoradiotherapy. New generation MRI scanners with optimal-phased array body coils, resulting in better signal to noise and improved contrast and spatial resolution, have contributed to high-resolution imaging in clinical practice enabling visualization of relevant anatomy including the sphincter complex, adjacent structures, mesorectal and pelvic lymph nodes with a diameter down to 2 mm. Multiplanar, high-resolution T2-weighted and diffusion-weighted sequences have a role in initial locoregional staging of anal SCC, assisting radiotherapy planning, as well as in assessing response to treatment and treatment-related complications.

Management of persistent anal canal carcinoma after combined-modality therapy: a clinical review

Anal canal carcinoma is a rare gastro-intestinal cancer. Radiochemotherapy is the recommended primary treatment for patients with non-metastatic carcinoma; surgery is generally reserved for persistent or recurrent disease. Follow-up and surveillance after primary treatment is paramount to classify patients in those with complete remission, persistent or progressive disease. Locally persistent disease represents a clinically significant problem and its management remains subject of some controversy.The aim of this systematic review is to summarise recommendations for the primary treatment of anal canal carcinoma, to focus on the optimal time to consider residual disease as genuine persistence to proceed with salvage treatment, and to discern how this analysis might inform future clinical trials in management in this class of patients.

Anorectal opportunistic diseases in human immunodeficiency virus/acquired immunodeficiency syndrome patients: spectrum of cross-sectional imaging findings

Patients infected with the human immunodeficiency virus, particularly male homosexuals, are prone to develop disorders involving the anorectal and perineal structures. Cross-sectional imaging techniques, such as multidetector computed tomography with multiplanar reformations and magnetic resonance imaging performed with phased-array coils, are increasingly adopted to detect and stage infectious and neoplastic diseases, and to assess posttreatment modifications. Pyogenic perianal sepsis may be usefully investigated with imaging, particularly to assess the presence and topography of abscess collections to allow a correct surgical choice. Rectal inflammatory involvement is frequently detected during intestinal opportunistic infections, such as cytomegalovirus, pseudomembranous, and amebic colitides, including primary and secondary imaging signs consistent with proctocolitis. Anal carcinoma and intestinal lymphoma are increasingly diagnosed; therefore, special attention should be paid to the identification of solid tissue consistent with tumor; furthermore, MRI provides optimal staging and posttreatment follow-up of neoplastic lesions. Knowledge of this varied spectrum of anorectal and perineal opportunistic abnormalities and their imaging appearances should help radiologists to propose appropriate differential diagnoses, suggest correlation with laboratory and microbiological assays or biopsy, and reliably assess therapeutic response.

MRI and CT of anal carcinoma: a pictorial review

BACKGROUND

Squamocellular anal carcinoma is increasingly diagnosed in patients with risk factors.

METHODS

State-of-the-art imaging with magnetic resonance imaging (MRI) using phased-array coils and volumetric multidetector computed tomography (CT) provides detailed visualisation of anal disorders, identification and extent assessment of neoplastic tissue, detection and characterisation of nodal and visceral metastases. MRI has been recommended by the European Society for Medical Oncology (ESMO) as the preferred modality of choice to stage anal cancer, taking into account the maximum tumour diameter, invasion of adjacent structures and regional lymph node involvement.

RESULTS

Cross-sectional imaging techniques allow the identification of coexisting complications, and differentiation from other perineal abnormalities.

CONCLUSION

Cross-sectional imaging is useful for planning radiotherapy, surgical drainage or salvage abdomino-perineal resection. After chemo-radiotherapy, MRI follow-up provides confident reassessment of therapeutic response, persistent or recurrent disease. TEACHING POINTS : • Anal carcinoma is increasingly diagnosed in patients with human immunodeficiency virus (HIV), anoreceptive intercourse, chronic inflammatory bowel disease. • An established association exists with human papillomavirus (HPV) infection and premalignant intra-epithelial dysplasia. • Phased-array MRI is recommended as the preferred imaging modality for regional staging. • Imaging allows detection of infectious complications, planning of radiotherapy or salvage surgery. • Follow-up MRI allows reliable assessment of therapeutic response after chemo-radiotherapy.

Imaging of anal carcinoma

OBJECTIVE

The purpose of this article is to review the role of imaging in the management of patients with anal cancer. The relevant anatomy, imaging techniques, and interpretation of images of patients before and after therapy will be discussed.

CONCLUSION

Anal carcinomas are uncommon but increasing in frequency. Radiologists must recognize typical patterns of disease at initial evaluation, posttherapy appearances, and when to suspect residual or recurrent disease to guide clinicians and achieve optimal patient outcome.

Epidermoid cancer of the anal canal

Anal canal cancer is a rare cancer with incidence that continues to rise. This has been in large part due to increased prevalence of immunosuppressed conditions such as organ transplantation and human immunodeficiency virus along with transmission of the human papillomavirus. Identification of high-risk groups and close monitoring of these groups can help to detect earlier stages of cancer. Chemoradiation therapy remains the mainstay of treatment with excellent outcomes. Surgery for anal canal carcinoma remains as a salvage technique for failed chemoradiation or recurrent disease.

Diffusion tensor imaging of the anal canal at 3 tesla: feasibility and reproducibility of anisotropy measures

PURPOSE

To assess the feasibility and reproducibility of 3-tesla diffusion tensor imaging (DTI) of the anal canal.

MATERIALS AND METHODS

DTI was performed in 25 men with no clinical history of anal canal disease undergoing MRI for prostate cancer. Analysis of fractional anisotropy (FA), relative anisotropy (RA), and apparent diffusion coefficient (ADC) were determined for the epithelial/subepithelial layer, internal sphincter, external sphincter, and puborectalis. The directionality of diffusion was recorded from color-coded tractography maps. Obturator internus and gluteus maximus served as reference muscles. Mean (SD) of values for FA, RA, and ADC were compared using analysis of variance. Intra and inter-rater agreement and test reproducibility (n = 5) was assessed by Bland-Altman statistics.

RESULTS

Mean (SD) for the epithelial/subepithelial layer, internal, external sphincter, and puborectalis were as follows: FA: 0.283 (0.099); 0.337 (0.049); 0.415 (0.072); and 0.407 (0.062), respectively. RA: 0.241 (0.094); 0.292 (0.050); 0.371 (0.083); 0.361 (0.067), respectively; and ADC: 1.49 (0.23); 1.59 (0.19); 1.51 (0.28); and 1.54 (0.29) × 10(-3) mm(2) /s, respectively. Good overall intra and inter-rater agreement and test-retest reproducibility was noted (coefficient of variation of 4.8-19.4% and 5.9-12.9%, respectively).

CONCLUSION

Anisotropy is evident in the anal canal with good inter-rater agreement and test reproducibility.

SEOM clinical guidelines for the treatment of anal cancer

Anal carcinoma is an uncommon disorder accounting for less than 2% of large bowel malignancies and 1-6% of anorectal tumours. Its incidence ranges between 0.5 and 1% per 100,000. Local staging should be done with MR imaging using an external pelvic phased-array coil. Treatment strategy should be optimally discussed in a multidisciplinary team. HIV-positive patients seem to achieve similar response rate and overall survival to HIV-negative patients but with increased toxicity and higher local recurrences. Combined modality treatment with irradiation and chemotherapy has resulted in complete response over 90% and local control over 85%. This guide gives recommendations for diagnosis, staging and treatment.

Imaging of unusual perineal masses

OBJECTIVE

The purpose of this article is to describe the radiologic features of unusual tumors that occur in the perineum.

CONCLUSION

The perineal space is often overlooked because of the infrequency of abnormalities. Accurate image interpretation and visualization of extent of pathology is important for proper management. Trauma and infectious diseases occur in the acute setting, whereas tumors are common in the chronic setting. Cross-sectional imaging plays a crucial role in depicting perineal anatomy and evaluating the extent of disease.

Anal carcinomas: the role of endoanal ultrasound and magnetic resonance imaging in staging, response evaluation and follow-up

Anal carcinoma is an important but rare condition, managed in specialist centres. Both endoanal ultrasound and magnetic resonance imaging (MRI) can be used in the locoregional staging and follow-up of patients with anal cancer, and both may assist in treatment planning and prognosis. Recent guidelines published by the European Society for Medical Oncology have recommended MRI as the technique of choice for assessment of locoregional disease. This paper describes the techniques for both endoanal ultrasound and MRI, and compares the relative merits and disadvantages of each in the local assessment of anal carcinoma.

Magnetic resonance imaging of anorectal neoplasms

Among imaging techniques, magnetic resonance imaging (MRI) has evolved as the most robust technique for the detection, characterization, and staging of anorectal cancers. With its superior contrast resolution, multiplanar imaging capability, and nil radiation risk, it has become the standard preoperative imaging tool in rectal tumors. In this article we aim to outline the various types of anorectal cancers, highlight the complex anatomy of this region, and discuss the immensely useful role of MRI in the management of anorectal cancers. Existing limitations and future applications in this area will also be discussed. Because rectal adenocarcinomas constitute the majority of tumors in this region, we will be discussing the input of MRI in the management of this condition in greater detail. This will be followed by an overview of MRI in anal carcinoma and other less common anorectal neoplasms.