The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for Anal Squamous Cell Cancers (Revised 2018)

The American Society of Colon and Rectal Surgeons is dedicated to ensuring high-quality patient care by advancing the science, prevention, and management of disorders and diseases of the colon, rectum, and anus. The Clinical Practice Guidelines Committee is composed of society members who are chosen because they have demonstrated expertise in the specialty of colon and rectal surgery. This committee was created to lead international efforts in defining quality care for conditions related to the colon, rectum, and anus. This is accompanied by developing clinical practice guidelines based on the best available evidence. These guidelines are inclusive and not prescriptive. The purpose of this guideline is to provide information on which decisions can be made rather than to dictate a specific form of treatment. These guidelines are intended for use by all practitioners and healthcare workers, as well as by patients who desire information about the management of the conditions addressed by the topics covered in these guidelines. It should be recognized that these guidelines should not be deemed inclusive of all proper methods of care or exclusive of methods of care reasonably directed toward obtaining the same results. The ultimate judgment regarding the appropriateness of any specific management decision must be made by the treating physician in light of all of the circumstances present in the care of the patient in question. STATEMENT OF THE PROBLEM Squamous cell cancers of the anal canal and perianal region remain one of the least common malignancies arising from the alimentary tract. As of 2016, it is estimated that 8200 new cases of squamous cell cancers of the anus were diagnosed in the United States, with 1.7 times as many women as men affected.1 Within this same time period, ≈1100 patients were estimated to have died of anal cancer, with cancer deaths among women being 1.4 times the number observed among men. Although squamous cancers of the anus remain relatively rare GI malignancies, 2 factors have nonetheless focused greater attention toward this disease. The first is the observation that the frequency of squamous cancers of the anus has increased in the United States from the 1970s through the 2000s,2 with a notable increase in incidence among men, and, in particular, black men.3 In addition, given the inverse relationship between stage of disease and survival,4 studies using population-level data suggest that earlier detection may improve survival from anal cancer, which makes anal cancer an important and treatable public health concern. The second factor that has resulted in a paradigm shift in understanding the etiology of anal cancer is the discovery that the human papilloma virus (HPV), especially HPV serotypes 16 and 18,5 is the primary cause of squamous cancers of the anus,6,7 making anal cancer a sequela of a sexually transmitted disease. This aspect of anal carcinogenesis reinforces the concept that it is a potentially preventable disease and that if evidence-based screening and preventative measures were developed and consistently applied, decreases in cancer-related deaths would follow. The modifiable risk of death from anal cancer is further underscored by large studies that have documented that ≈50% of patients with anal cancer present with localized, node-negative disease, which is associated with high cure rates; one third of patients will present with node-positive disease, whereas only 10% to 15% will present with distant metastases.8 Thus, even without effective preventative measures, the majority of patients with anal cancer are potentially curable at the time of diagnosis and treatment. The multiple risk factors associated with developing squamous cancers of the anus are well documented and can be grouped into the 2 broad categories of HPV and immunosuppression, although is an between these categories as the risk factors number of a of sexually transmitted diseases of any a of and a of or factors related to a diagnosis of disorders as and and being the of a and are associated with developing anal The management of anal cancers a and the of with can in the and the clinical stage of anal cancers The anal as by is to in at the rectum, the into the anal which to squamous as it further into perianal at the anal to the and for to in a region of a from the of the to the squamous of the anal to as of the of in the this region is to HPV In addition, the of in the have associated with a number of of squamous cancers of the anus of and Although were efforts to between of anal cancer, all of these are grouped because multiple can the same and because the and survival of these are by and cancer the of the anus will not be by who are in as and a has anal canal cancer would be any that be with of the whereas a perianal the anal can be with of the and that is of the anal from the anal would be as a and would not be related to the GI tract. the to the anus and perianal The Squamous for all squamous with a This as or squamous and based on as of and in squamous cell anal whereas and The between and is as with whereas to be as disease should be this Clinical Practice the and will be although to may This guideline only the management of and squamous of the anus and perianal The will be to to squamous cell These guidelines were on the American Society of Colon and Rectal Surgeons Practice for Squamous in of and the of was through for with regarding of were to the on of were The were based on the anal cancer and anal squamous cancer as primary with anal anal and were based on for anal cancer cancer cancer cancer cancer anal and cancer and of the from the primary were in and were given in developing these guidelines. The of was using the of and of the and at increased risk for anal squamous should be by and that the risk is in men who have with men and women with a of of based on large to studies have risk factors for anal and and that the of in was The of was and the incidence of anal cancer was men. the of was the of was and the incidence of anal cancer was men. of women that can risk in a of women with with without demonstrated an increased of anal cancer risk and risk with a should be should be to of based on or are in in defining the disease and The in the for studies have that can be this is based in on that that for using a was and that and HPV the to to a with anal should be at with a and a of screening of based on of cancer with screening for has a of screening and of anal will lead to in anal cancer is a of and as of of to anal cancer are than observed for of if screening is with anal should have a to for any new or modifiable risk a in an screening all the cancers that developed were on It is not that screening will a cancer from is that cancers a screening are at an studies have from to and from to cancer even of patients for anal for that to and developed anal of of patients in have estimated the of cancer although all the risk estimated the of to cancer at cases of estimated the of at at a third estimated the to of at to and a estimated the incidence of at is among that an is the to is screening to and will the incidence of even if the to cancer be diagnosis of a cancer and a and to and and a of screening is with anal anal may be in as of a screening the and of the not use for of based on to a or from the anal canal to the can be for of Although the data for cancer screening and are well efforts to in anal cancer screening have not screening as the of a is screening a will be studies women with a of from studies that have anal and are in The and are because the is the of on the of anal to patients at risk for is and an between anal and of anal cancer has not The decision to anal should be a decision with the a about will be further of anal and for squamous may be as an to screening for anal of based on The of especially 16 and is associated with the majority of anal for the of HPV to the risk of The to this is the high of HPV in the available HPV HPV for and and based on anal or is a that HPV into the The Squamous guidelines the use of in with to an diagnosis and or an The use of or any of the in a screening is studies have anal with HPV as have multiple The screening with HPV and HPV only of would have The HPV and as well as and with for the detection of HPV and for the detection of especially in the may be as a screening for patients at high risk for cancer by with in the based on is a in the or in the using and as and to and not by or The can be if in the In addition, because it is to or HPV in may be than the has estimated to be screening of all of HPV and In a of was in with screening any HPV and any only 15% of the for a in this one third of that would have the clinical use for The of to the of or of cancer has in of patients with of a was in was in of patients at an of to of for a of was in of all and with the of at was in patients and in the period, patients developed cancer, with the of cancer at are of with of patients with management in 2 one by who patients with management and the by 2 who patients with cancer in of the patients and 2 of the management The was in the 2 and the for these and practice to In addition, patient patient and the risk of have to to data are Although with of can the incidence of cancer or it can consistently than and with are for the of or of based on and have of patients with who were with of with a of a of with and that of and a with Although a in the was for the the was not if and were to third and that the for was studies have of patients with or that to with a second of patients with only a in in of studies have the use of of from patients demonstrated that of or to on although in of the of men on a of to or has in and The 16 patients with and a of of although 2 of at the of the of patients with demonstrated that disease, with a observed in 15% of with or are for of based on is as the primary screening can be as for of patients with with that of on was a to management in that the was from patients who or and patients who were In light of these the in this are best as a with have from a and it is from the a of with with that of and of were from were high in the and one third of patients were to of in of patients with with that only at of was in a of with were high were common and patient in the developed cancer treatment. of patients for with a or in a of of patients a of or in the of and in with of was in of patients in the of the and of the for for HPV in men and women for primary is of with anal for of and cancer is not of based on high-quality The of and has created that the of will be from Although are data for use of the in the use of the in with anal is of and of the of the in that it all of the that of studies in patients with disease disease without clinical for the for or of attention a of who were to the HPV or who the a of and the of was by of patients with with or without the demonstrated that was associated with risk of of patients has and in and the are available at The number of with and at or at or was the who have for anal may be observed without HPV or of or disease should be of based on or Although it is that is a to cancer, remain studies that screening with and of or disease. of patients in an that of patients with to The to cancer is from immunosuppression, to and a of In the which is the of the of The or in in and Squamous will patients with and who have will be to or patients who are the the patient should have or treatment. with may or with may have or In the number and frequency of the is to the of the treating patients who are and are with of any although screening and preventative remain management with of or disease an or that screening and of are to the incidence of anal OF THE and should be risk and of disease. of based on patients present with a the anal canal or the perianal and are in of although of patients may be of anal may be because of which are to as in to of with anal cancers may present with related to anal and factors associated with anal HPV a of as sexually multiple a of and of the incidence of anal cancer is among men as well as among patients for a high of should be in these patients who present with factors as and may and and are important to at the time of should on and of the should be to the and to for the of of as the or the anal or with is to the of the to the anal and to The of can suggest the for or to and to In disease is to on although a should be to any of distant that may patients with a new diagnosis of anal should a and and an of if not should a and men should to or Although the of and has to with the of anal in the of anal is being and should be to and for disease. of based on should be or with Although anal cancer is not a risk factor for the of colon cancer, have demonstrated in of patients with anal should be to of the and with should be to for distant disease and the which may in the of clinical or can to the a of the may be if the patient has or of being the of for anal of the primary is because it and for and are at present the 2 for primary anal and is only to that with in the primary of anal with in primary and Although is to be to for this has not in the with that it is and may cause in patients with anal may be as an in the of anal although it not for clinical of based on for of the anal canal on of the primary and As clinical is important to proper The clinical is the American Committee on and which stage by This not into and perianal or the of a perianal or which are important factors that have not well in the of American Committee on and of anal not a of the has to distant that are not by or in to of in a in in of In addition, studies the and of in anal have that at the primary as well as with The of at the primary cancer as well as with and by The primary for all squamous cell cancers of the anal and for perianal squamous cell is of based on high-quality the by patients with squamous anal cancers with patients with these malignancies were with The associated with primary were with as high as and survival from to In addition, the of an this time was even with the of in and data to in an of patients with squamous cancers of the anus who were with of with and In In this same were patients who an of was clinical of and of these patients were of any of is the of care for the of all anal canal squamous cell cancers and for all perianal squamous cell cancers that are not to Although are in is are that should be for should be to a of which is to the primary cancer in of an time The should from the of to to the the anus and the the perianal to the anus. should efforts to to the because of the risk of the first is the of should be with the aspect of the to the aspect of the the from for patients with disease. In addition, for any than a cancer or for that are a of to to the primary and to the is In this the of would be to The and of for can from among is at on to and to with in form at on and an can be for at a of is the of is increased to at the of the treating is associated with of In the a of of patients with form of GI from to and The incidence of or was in this whereas the incidence of was This high incidence of has into as for to be regarding and health men and women of should be regarding and the of should be if they have a with screening for given the between HPV and HPV of the patients who are on at any should be regarding the use of to in the for These are and and should be in to quality of for of anal with with with of based on high-quality with squamous are and with the of as for squamous cancers of the a high of disease and of was documented with and were and this regarding a for in with The first large to the of in anal cancer was the United Committee on In this patients were to of in to to or to the same form of with the of and a time of of the patients a with of the to a in associated with the use of of were observed in at Although the risk of death in the was was in survival between the 2 at treatment. the was associated with a incidence of whereas related to with This was in as the for squamous cancers of the anal of this has that is associated with and anal deaths for patients with with patients with In addition, although was a increase in deaths to anal cancer the first this increased risk of at as survival at The the for and of and a the of as with for anal In this patients were to by a of on the same with and the of which was as a only on the first in the a of with in the with and with and survival As with the United Committee on were in survival at treatment. The of and in with as for the of squamous cancers of the anus. of based on high-quality has a in the form of with and and of studies and of associated with of the was by the and the to be from the same disease and cure this patients were to from to with for the same with and at as a 2 for cancer not to a between and survival the that was in whereas was in the for and Although with was the of the nonetheless the of in with the use of and Although the of with and was in the of anal cancer regarding lead to to with important clinical have or disease The which the clinical on anal cancer to patients with squamous cancers of the anus from a of the United were to of or with and with or without 2 of of and at and of patients were with a of were in and at with of was in survival between the and and were between and of of and with in or this that for squamous cancers of the anus should as and with second the of was by in the a patients were to and with to of or to with by with and of patients were with a time of was between the in of survival or and distant were between the was associated with the whereas the a incidence of This that the use of in of is not of this same was by in to the of on and In this and survival were in the with the with a toward survival and These the to in for anal squamous The for and of the of not as a for as a for In this patients with node-negative cancers in or with node-positive disease were to with a in in the of the period, with or The patients demonstrated a toward with of were between the with the of a incidence of in the with this were made because of and not being this that the of and is data regarding this form of are can be The use of has with results. The was a to the of of on through and through and on and as well as to the of a to a were to the 2 of and a 2 of and a and a or and a the patients a with a of to or was with and and and of patients with anal cancers with of with and patients with with and by was was between the 2 based on or although survival was in the the to suggest that has a in the management of anal this is high-quality data to the use of of a clinical for of based on of the incidence of is that the of for anal squamous cancers should be although the is a of in large because of and in the studies on this all of which and The data on have the of and studies or have in studies at as the of to the The number of studies dedicated to the are although of a number of stage and The was with and with of with or without with patients with The on the of and that for cancers a of to was of the only studies on this patients with stage to disease, although with a of only and with a of only was for patients who although was from these the was a clinical that only patients with at least squamous anal cancers who with and with of which a The patients were with patients in the who to of a of patients in the a at and 2 without an in to was although for in were The of with of is in the of the which to by using should be because they are associated with disease of based on The the of with and the use of with and in to to of these This a high of with survival in the and and with an survival of with of patients with The of this these in to high with the of and in because of the to provide in a time by a which was a common of this observation can be from the a of patients to as of This a of patients who not a which the number of patients of were in patients without a which was than in who a in The a which was associated with increased and survival and to should be if although they as as in of patients with anal making a and potentially modifiable factor associated with should to from the of of based on of is based on from in which patients clinical documented at and of from this that of patients who not a at a by with patients are reasonably with anal by the of although earlier to should be to the The at to of Clinical should rectal and of the of for disease are at to and is from the of and be from the guidelines of the and for or rectal and should be for of of based on the first and of to for in or is in patients with of with and of any or should be and should be in patients with to or The majority of and the time for are the first of of The with demonstrated of suggest that this may be to to be to to of the and for for patients with to or are are with to or the of on for in patients and of and a for the detection of or disease of and of with to in management in of The of with and to or to be to earlier with clinical of or is effective for or disease. of based on to of patients will have or disease primary of and disease and at and the to Although patients with disease who present of have to have data suggest that and disease not any in and patients with may have a is for or disease for with in to of and survival of to or and a whereas as well as to and to disease have associated with survival are in to has associated with of without have a of than with the with the in of the of with or who present with anal cancer as the first of immunosuppression, and who are not can be to the same as of based on As the management of has and as the of patients with has and studies that for patients for anal cancer have in of to the management of patients with anal of these earlier studies that patients be to patients was in by In this of patients with anal cancer with or patients with disease with an incidence of to has in the for with a a incidence of although with of these patients disease from patients of was in all with a of and patients of disease. The that the and survival were and the majority of the patients were to without in or this the concept that patients be to with the of to of patients with of demonstrated of in all of the with of and with and survival of and This a in for although this in was not associated with increased with to of the in the of the studies on this to was a of patient data from the for squamous cancers of the of were documented to be As with this in the of based on with observed survival of and among and on was not associated with in are data to on is associated with with present diagnosis of anal cancer may not and may this of patients with is at risk for and squamous which are can be with with of anal cancers are with of based on with node-negative the perianal are with that of can be without the which would the of a The data in of are from although the of these studies are consistently with survival of In addition, the associated with perianal squamous cancers that not the should be with because is a of and survival cancers are with of should be for patients with distant disease. and can be in of based on or of high with of patients with disease are The is a of a at a in of with disease at the time of diagnosis and with distant were with and survival was was was of any patients who have or an survival of with with has in patients with with a survival of in that patients with anal cancer with and a of with patient a the of and in patients with a of with 2 patients a to the factor has because of the high of in anal The use of in the of disease has by with was and it is in the without is a for the of an to of the of are clinical in this available at and