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Staging and Follow-up of Anal Cancer

Variant: 1   Adult. Newly diagnosed squamous cell anal cancer. Locoregional assessment at initial staging.
Procedure Appropriateness Category Relative Radiation Level
MRI pelvis without and with IV contrast Usually Appropriate O
FDG-PET/CT skull base to mid-thigh Usually Appropriate ☢☢☢☢
MRI pelvis without IV contrast May Be Appropriate O
CT pelvis with IV contrast May Be Appropriate ☢☢☢
FDG-PET/MRI whole body May Be Appropriate ☢☢☢
US pelvis transrectal Usually Not Appropriate O
CT pelvis without IV contrast Usually Not Appropriate ☢☢☢
CT pelvis without and with IV contrast Usually Not Appropriate ☢☢☢☢

Variant: 2   Adult. Squamous cell anal cancer. Assessment for metastatic disease at initial staging or surveillance.
Procedure Appropriateness Category Relative Radiation Level
CT abdomen and pelvis with IV contrast Usually Appropriate ☢☢☢
CT chest with IV contrast Usually Appropriate ☢☢☢
CT chest without IV contrast Usually Appropriate ☢☢☢
FDG-PET/CT skull base to mid-thigh Usually Appropriate ☢☢☢☢
MRI abdomen and pelvis without and with IV contrast May Be Appropriate O
CT abdomen and pelvis without IV contrast May Be Appropriate ☢☢☢
MRI abdomen and pelvis without IV contrast Usually Not Appropriate O
CT chest without and with IV contrast Usually Not Appropriate ☢☢☢
FDG-PET/MRI whole body Usually Not Appropriate ☢☢☢
CT abdomen and pelvis without and with IV contrast Usually Not Appropriate ☢☢☢☢

Variant: 3   Adult. Squamous cell anal cancer. Posttreatment locoregional assessment.
Procedure Appropriateness Category Relative Radiation Level
MRI pelvis without and with IV contrast Usually Appropriate O
FDG-PET/CT skull base to mid-thigh Usually Appropriate ☢☢☢☢
MRI pelvis without IV contrast May Be Appropriate O
CT pelvis with IV contrast May Be Appropriate ☢☢☢
FDG-PET/MRI whole body May Be Appropriate ☢☢☢
US pelvis transrectal Usually Not Appropriate O
CT pelvis without IV contrast Usually Not Appropriate ☢☢☢
CT pelvis without and with IV contrast Usually Not Appropriate ☢☢☢☢

Panel Members
Natally Horvat, a; Peter S. Liu, MDb; Kathryn J. Fowler, MDc; James H. Birkholz, MDd; Brooks D. Cash, MDe; Bari Dane, MDf; Cathy Eng, MDg; Avinash R. Kambadakone, MDh; Elena K. Korngold, MDi; Jason A. Pietryga, MDj; Tamer Refaat, MD, PhD, MSk; Cynthia S. Santillan, MDl; Devaki Shilpa Surasi, MDm; Sarah Woolsey, MD, MPHn; David H. Kim, MDo.
Summary of Literature Review
Introduction/Background
Discussion of Procedures by Variant
Variant 1: Adult. Newly diagnosed squamous cell anal cancer. Locoregional assessment at initial staging.
Variant 1: Adult. Newly diagnosed squamous cell anal cancer. Locoregional assessment at initial staging.
A. CT pelvis with IV contrast
Variant 1: Adult. Newly diagnosed squamous cell anal cancer. Locoregional assessment at initial staging.
B. CT pelvis without and with IV contrast
Variant 1: Adult. Newly diagnosed squamous cell anal cancer. Locoregional assessment at initial staging.
C. CT pelvis without IV contrast
Variant 1: Adult. Newly diagnosed squamous cell anal cancer. Locoregional assessment at initial staging.
D. FDG-PET/CT skull base to mid-thigh
Variant 1: Adult. Newly diagnosed squamous cell anal cancer. Locoregional assessment at initial staging.
E. FDG-PET/MRI whole body
Variant 1: Adult. Newly diagnosed squamous cell anal cancer. Locoregional assessment at initial staging.
F. MRI pelvis without and with IV contrast
Variant 1: Adult. Newly diagnosed squamous cell anal cancer. Locoregional assessment at initial staging.
G. MRI pelvis without IV contrast
Variant 1: Adult. Newly diagnosed squamous cell anal cancer. Locoregional assessment at initial staging.
H. US pelvis transrectal
Variant 2: Adult. Squamous cell anal cancer. Assessment for metastatic disease at initial staging or surveillance.
Variant 2: Adult. Squamous cell anal cancer. Assessment for metastatic disease at initial staging or surveillance.
A. CT abdomen and pelvis with IV contrast
Variant 2: Adult. Squamous cell anal cancer. Assessment for metastatic disease at initial staging or surveillance.
B. CT abdomen and pelvis without and with IV contrast
Variant 2: Adult. Squamous cell anal cancer. Assessment for metastatic disease at initial staging or surveillance.
C. CT abdomen and pelvis without IV contrast
Variant 2: Adult. Squamous cell anal cancer. Assessment for metastatic disease at initial staging or surveillance.
D. CT chest with IV contrast
Variant 2: Adult. Squamous cell anal cancer. Assessment for metastatic disease at initial staging or surveillance.
E. CT chest without and with IV contrast
Variant 2: Adult. Squamous cell anal cancer. Assessment for metastatic disease at initial staging or surveillance.
F. CT chest without IV contrast
Variant 2: Adult. Squamous cell anal cancer. Assessment for metastatic disease at initial staging or surveillance.
G. FDG-PET/CT skull base to mid-thigh
Variant 2: Adult. Squamous cell anal cancer. Assessment for metastatic disease at initial staging or surveillance.
H. FDG-PET/MRI whole body
Variant 2: Adult. Squamous cell anal cancer. Assessment for metastatic disease at initial staging or surveillance.
I. MRI abdomen and pelvis without and with IV contrast
Variant 2: Adult. Squamous cell anal cancer. Assessment for metastatic disease at initial staging or surveillance.
J. MRI abdomen and pelvis without IV contrast
Variant 3: Adult. Squamous cell anal cancer. Posttreatment locoregional assessment.
Variant 3: Adult. Squamous cell anal cancer. Posttreatment locoregional assessment.
A. CT pelvis with IV contrast
Variant 3: Adult. Squamous cell anal cancer. Posttreatment locoregional assessment.
B. CT pelvis without and with IV contrast
Variant 3: Adult. Squamous cell anal cancer. Posttreatment locoregional assessment.
C. CT pelvis without IV contrast
Variant 3: Adult. Squamous cell anal cancer. Posttreatment locoregional assessment.
D. FDG-PET/CT skull base to mid-thigh
Variant 3: Adult. Squamous cell anal cancer. Posttreatment locoregional assessment.
E. FDG-PET/MRI whole body
Variant 3: Adult. Squamous cell anal cancer. Posttreatment locoregional assessment.
F. MRI pelvis without and with IV contrast
Variant 3: Adult. Squamous cell anal cancer. Posttreatment locoregional assessment.
G. MRI pelvis without IV contrast
Variant 3: Adult. Squamous cell anal cancer. Posttreatment locoregional assessment.
H. US pelvis transrectal
Summary of Highlights
Supporting Documents

The evidence table, literature search, and appendix for this topic are available at https://acsearch.acr.org/list. The appendix includes the strength of evidence assessment and the final rating round tabulations for each recommendation.

For additional information on the Appropriateness Criteria methodology and other supporting documents, please go to the ACR website at https://www.acr.org/Clinical-Resources/Clinical-Tools-and-Reference/Appropriateness-Criteria.

Gender Equality and Inclusivity Clause
The ACR acknowledges the limitations in applying inclusive language when citing research studies that predates the use of the current understanding of language inclusive of diversity in sex, intersex, gender, and gender-diverse people. The data variables regarding sex and gender used in the cited literature will not be changed. However, this guideline will use the terminology and definitions as proposed by the National Institutes of Health.
Appropriateness Category Names and Definitions

Appropriateness Category Name

Appropriateness Rating

Appropriateness Category Definition

Usually Appropriate

7, 8, or 9

The imaging procedure or treatment is indicated in the specified clinical scenarios at a favorable risk-benefit ratio for patients.

May Be Appropriate

4, 5, or 6

The imaging procedure or treatment may be indicated in the specified clinical scenarios as an alternative to imaging procedures or treatments with a more favorable risk-benefit ratio, or the risk-benefit ratio for patients is equivocal.

May Be Appropriate (Disagreement)

5

The individual ratings are too dispersed from the panel median. The different label provides transparency regarding the panel’s recommendation. “May be appropriate” is the rating category and a rating of 5 is assigned.

Usually Not Appropriate

1, 2, or 3

The imaging procedure or treatment is unlikely to be indicated in the specified clinical scenarios, or the risk-benefit ratio for patients is likely to be unfavorable.
Relative Radiation Level Information

Potential adverse health effects associated with radiation exposure are an important factor to consider when selecting the appropriate imaging procedure. Because there is a wide range of radiation exposures associated with different diagnostic procedures, a relative radiation level (RRL) indication has been included for each imaging examination. The RRLs are based on effective dose, which is a radiation dose quantity that is used to estimate population total radiation risk associated with an imaging procedure. Patients in the pediatric age group are at inherently higher risk from exposure, because of both organ sensitivity and longer life expectancy (relevant to the long latency that appears to accompany radiation exposure). For these reasons, the RRL dose estimate ranges for pediatric examinations are lower as compared with those specified for adults (see Table below). Additional information regarding radiation dose assessment for imaging examinations can be found in the ACR Appropriateness Criteria® Radiation Dose Assessment Introduction document.

Relative Radiation Level Designations

Relative Radiation Level*

Adult Effective Dose Estimate Range

Pediatric Effective Dose Estimate Range

O

0 mSv

 0 mSv

☢

<0.1 mSv

<0.03 mSv

☢☢

0.1-1 mSv

0.03-0.3 mSv

☢☢☢

1-10 mSv

0.3-3 mSv

☢☢☢☢

10-30 mSv

3-10 mSv

☢☢☢☢☢

30-100 mSv

10-30 mSv

*RRL assignments for some of the examinations cannot be made, because the actual patient doses in these procedures vary as a function of a number of factors (e.g., region of the body exposed to ionizing radiation, the imaging guidance that is used). The RRLs for these examinations are designated as “Varies.”
References
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28. Susko MS, Lazar AA, Wang CJ, et al. Use of advanced PET-volume metrics predicts risk of local recurrence and overall survival in anal cancer. PLoS ONE. 16(2):e0246535, 2021.
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Disclaimer
The ACR Committee on Appropriateness Criteria and its expert panels have developed criteria for determining appropriate imaging examinations for diagnosis and treatment of specified medical condition(s). These criteria are intended to guide radiologists, radiation oncologists and referring physicians in making decisions regarding radiologic imaging and treatment. Generally, the complexity and severity of a patient’s clinical condition should dictate the selection of appropriate imaging procedures or treatments. Only those examinations generally used for evaluation of the patient’s condition are ranked.  Other imaging studies necessary to evaluate other co-existent diseases or other medical consequences of this condition are not considered in this document.  The availability of equipment or personnel may influence the selection of appropriate imaging procedures or treatments. Imaging techniques classified as investigational by the FDA have not been considered in developing these criteria; however, study of new equipment and applications should be encouraged.  The ultimate decision regarding the appropriateness of any specific radiologic examination or treatment must be made by the referring physician and radiologist in light of all the circumstances presented in an individual examination