# A Systematic Review Defining Early Anal Squamous Cell Carcinoma and Identifying Treatment

## TL;DR

This review clarifies the definition of early anal cancer and highlights the lack of consensus on its best treatment.

## Contribution

It systematically defines early anal cancer as T1-2N0M0 and identifies current treatment options.

## Key findings

- Early anal cancer is most commonly defined as T1-2N0M0 or Superficially Invasive Squamous Cell Carcinoma.
- Treatment options include chemoradiation, radiation only, and local excision ± adjuvant therapy.
- The quality of existing research is low, and randomized controlled trials are needed to determine optimal treatment.

## Abstract

The prevalence of squamous cell carcinoma is increasing with the earlier detection of anal cancer, due in part to high-resolution anoscopy. Early anal cancer is poorly defined. The aim of this systematic review is to clarify the definition of early anal cancer and to identify the management of early anal cancer. The MEDLINE, EMBASE, and Cochrane databases were queried, and 15 articles met the inclusion criteria. The current treatments for early anal cancer include chemoradiation, radiation only, and local excision ± adjuvant therapy. The most common early anal cancer definition was T1-2N0M0. Overall, given that the studies vary in their primary outcomes and their conclusions, no meta-analysis was performed. The quality of existing research is considered low, and further high-quality studies are needed to identify the best treatment modality for early anal cancer.

Background: Anal cancer screening has allowed for the diagnosis of early-stage anal cancers; however, guidelines for the treatment of early anal cancers remain mixed given the scarcity of clinical trials and data. Management ranges from chemoradiation therapy to local surgical excision. Methods: This paper’s objective is to clarify the definition of early anal cancer and its management. Approval for this systematic review was obtained through PROSPERO [CRD42022304327]. Three independent reviewers screened the studies and performed data analysis, with conflicts resolved by a fourth reviewer. All information is presented according to the Preferred Reporting Item for Systematic Reviews and Meta-Analysis (PRISMA). The Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) criteria were used to assess the certainty of the evidence. Results: The MEDLINE, EMBASE and Cochrane databases were queried with 628 articles screened. A total of 15 articles were selected for inclusion. Early anal cancer was most often defined as T1-2N0M0 anal cancer but also included Superficially Invasive Squamous Cell Carcinoma (SISCCA). There were various treatments assessed for outcomes including local excision, chemoradiation, and radiation. The studies reported overall survival, cancer-specific survival, recurrence-free survival, and/or colostomy-free survival, leading to significant heterogeneity amongst the studies. No meta-analysis was possible. Conclusions: Poor-quality studies exist for the evaluation of the most effective treatment modality for early anal cancer. Surgical excision alone with adequate margins has equivocal results, but data is poor. Chemoradiation is successful but may be overtreatment. Randomized controlled studies are needed, as screening will result in earlier anal cancer diagnoses.