Multidisciplinary Management of Early Rectal Cancer

*Sean Ramcharan, Vanessa Cubas, Cortland Linder, Thomas Evans, Julia Merchant and Rakesh Sinha*

### **Abstract**

The incidence of colorectal cancers detected at an early stage, that is stage T2 or less, has increased over the last decade, driven primarily by better access to screening and diagnostic pathways. Consequently, timely treatment leads to better outcomes. Early stage rectal cancers (ERC), by virtue of their location, allows for alternative treatment strategies towards organ (rectum) preservation. Local excision techniques have evolved and improved with advances in radiological assessment and minimally invasive surgery. However, decisions on treatment to mitigate local recurrence remain a challenge. This chapter explores the current understanding of the management of ERC and offers insights to the multidisciplinary team to aid treatment strategies.

**Keywords:** rectal cancer, minimally invasive, multidisciplinary, transanal surgery, TAMIS, TEMS, TEO, radiotherapy, brachytherapy, surveillance, chemotherapy, chemoradiotherapy, intense surveillance

### **1. Introduction**

Since the introduction of bowel cancer screening programs (BCSP) worldwide, the incidence of colorectal cancers (CRC) detected at an early stage, that is T2 or less (TNM Tumour, Node, Metastasis classification) has increased. In fact, 30% of all screendetected or asymptomatic CRCs are classed as early disease (stage I–II) versus 10% diagnosed at investigation for lower gastrointestinal (LGI) symptoms. Regardless of the diagnostic pathway, the obvious benefit is that early detection leads to timely treatment and better outcomes. This is certainly evident from the improvement in disease-free survival (DFS) and overall survival (OS) outcomes over the last 20 years [1–3].

Early rectal cancers (ERC) are no exception. Fortunately, their location allows for alternative treatment strategies towards organ preservation. Conceptually, local excision began in the 1980s with transanal endoscopic microsurgery (TEMS) and subsequent technological advances in radiological assessment and minimally invasive surgery (MIS) made rectum preservation more feasible.

Overall, the number of patients over 60 years of age with CRC has plateaued. However, the incidence in the younger population (20–39 years) has steadily increased over the last decade, often with advanced disease. This may suggest a change in the biology of CRC amongst this sub-group, the impact of screening for a family history of CRC and better access to diagnostic pathways. Other factors include 'self-diagnosis' of concerning symptoms through internet search engines, cancer awareness campaigns and social media platforms [1].

Increasing public awareness has led to more patients of all ages seeking assessment of lower gastrointestinal (LGI) symptoms sooner and therefore it is likely the incidence of ERCs will continue to rise. Similarly, the incidence detected at BCSPs will improve with the inclusion of patients from 45 years of age (currently 55–60 years), as advocated by some public health policymakers in the US, in the context of the impact of survival benefits to the wider social and healthcare economy [1].

In primary care there has been more uptake of highly sensitive screening tools, such as faecal immunochemical test (FIT), for symptomatic assessment and to better manage the increasing burden of fast-track pathways. Recently, those pathways were challenged by the SARS-COV2 pandemic as more patients with LGI concerns came forward once the restrictions that limited access to primary care and diagnostic pathways were lifted. FIT became a useful tool to screen those needing urgent assessment, though its impact on investigation and treatment delays are yet to be described [2, 3].

The impact of FIT may also include earlier stage diagnosis. As a quantitative screening tool with sensitivities and specificities above 90%, the higher the faecal occult blood level (2–100 μg Hb/g of faeces) the more likely the presence of significant serrated polyps, high risk adenomas or early CRC [3].
