Innovations and developments in surgical coloproctology

Abstract

The field of coloproctology covers the treatment of both benign and cancerous disease of the colon, rectum and anus. Significant recent developments in the surgical treatment of colorectal cancer include the development of minimally invasive techniques for colorectal resections and the use of stenting for obstructed patients. The introduction of widespread screening aims to diagnose the disease at an earlier stage. Developments in chemotherapy and radiotherapy have also complimented surgical advances towards this disease. There have also been changes in the treatment of benign disease such as diverticular disease, haemorrhoids and anal fissures with a trend towards less invasive surgical techniques.

Introduction

The field of coloproctology covers the treatment of both benign and cancerous disease of the colon, rectum and anus. Both areas have seen significant recent developments. Many of these are the result of the incorporation of new technologies into surgical practice. This review will look at surgical developments in this field and place them in the context of established practice.

Methods

Decisions were made between the authors about the scope and extent of the article. A search was conducted using Medline and PubMed to retrieve current and appropriate papers and chapters to gather evidence for the review.

Developments in the treatment of colorectal cancer

Bowel cancer remains the third most common cancer in the UK.¹ There have been significant developments in all aspects of the management of colorectal cancer (CRC), from earlier detection by screening programmes, through new techniques of surgery for early disease, to the treatment of advanced disease.

Screening

In the UK, the National Health Service (NHS) Bowel Cancer Screening Programme seeks to try and detect the disease at an earlier stage (www.cancerscreening.nhs.uk/bowel/).. Current practice in England and Wales is to offer subjects in their 60s stool testing for occult blood every two years. This follows pilot studies both in the UK and Europe that showed a reduction in mortality where there was uptake of the test. Worldwide most screening programmes use faecal occult blood although some countries offer flexible sigmoidoscopy. Variation also exists in the frequency of testing; interval cancers have been seen in all programmes. If a screening test is positive, colonoscopy may be offered. Most CRCs develop from adenomas, which can be removed at colonoscopy, making this disease ideal for prevention by screening.

Early disease

Colonoscopy is now used to excise an increasing range of polyps in the colon. Some of these are early cancers that may be cured by colonoscopic excision alone. Histological staging systems that look at depth of invasion, such as Haggitt and Kikuchi, help to guide whether further treatment is necessary. Newer endoscopic techniques such as submucosal resection for broad-based polyps may be used for more extensive lesions in the colon.

In the rectum, lesions that are unsuitable for colonoscopic excision may be removed by trans-anal endoscopic microsurgery (TEM). Using a specially designed operating proctoscope with its own instruments and microscope, the lesion is removed without the need for an abdominal approach. This technique is mainly used for the removal of adenomas, particularly those beyond the reach of traditional trans-anal excision. TEM has also been used for the treatment of early cancers that crucially have a low risk of involving lymph nodes.² As it is a local procedure, TEM has a much lower morbidity than conventional surgery involving a rectal resection, but local recurrence for more advanced tumours is a concern. The risks of local recurrence and lymph node metastases are such that total mesorectal excision (TME) remains the gold standard.²

The multidisciplinary team

All cancer cases should be discussed at a multidisciplinary team meeting to explore possible treatments and standardise care. Cancer networks across specialties and organizations also aim to improve patient outcomes and experience. Centralized care exists for certain cancers to ensure referral to centres with a specialist interest, for instance in squamous cell carcinoma of the anus.

Laparoscopic colorectal resection

Surgical resection of colorectal tumours including their vascular pedicle and lymphatic drainage remains the optimum treatment of most cancers. This also allows accurate staging for postoperative adjuvant treatments. Minimally invasive options for abdominal surgery have increased dramatically in the past 20 years. The National Institute of Health and Clinical Excellence (NICE) has recently recommended that laparoscopic colorectal resection for cancer should be offered as an alternative to open surgery.³ The most common surgical option in the UK is laparoscopic mobilization of the bowel and division of the vascular pedicle. The specimen is then extracted through a small incision, for division and removal prior to anastomosis. Improvements in visual image display, laparoscopic stapling devices and instruments to coagulate and divide tissue (commonly using either electrical or ultrasonic energy) have helped surgeons perform this procedure more safely and efficiently.

Meta-analyses have illustrated the short-term benefits of laparoscopic surgery including better pain control and cosmesis, with fewer cardiorespiratory complications and the earlier return of gastro-intestinal function.⁴ These gains are usually achieved at the expense of longer operating times. There is a learning curve, demonstrated by reduced conversion rates to open surgery, with increasing surgical experience. A converted procedure is generally defined as an inability to complete mobilization and vascular division laparoscopically. This is more common in patients with a high body mass index, previous surgery and advanced tumours. Some studies have shown conversion from laparoscopic to open operation is associated with worse overall survival. Longer-term follow-up of randomized studies of laparoscopic and open resections, including the MRC CLASICC study, have shown equivalent disease-free and overall survival between the two techniques with similar oncological outcomes including lymph node yield.⁵ One single institution study⁶ has even suggested a survival advantage for individuals with stage III disease undergoing laparoscopic compared to open procedures, but this work has yet to be replicated.

Single incision laparoscopic surgery and natural orifice transluminal endoscopic surgery

The changes seen in approach and outcomes following the introduction of laparoscopic surgery have led surgical innovators to search for new technologies to minimize the surgical insult to patients. Single incision laparoscopic surgery (SILS) uses one large port containing several instrument channels and can be applied to most laparoscopic procedures.⁷ The challenge has been to create ports and instruments that have enough flexibility to overcome the loss of triangulation that results from SILS. Natural orifice transluminal endoscopic surgery (NOTES) is a further development, but this requires a breach in viscera such as the vagina or the stomach to access the operating field. Although it is technically feasible, it has not yet become established in clinical practice.

Rectal cancer

The anatomy of the rectum as a pelvic organ surrounded by a mesorectal envelope of fatty tissue containing lymph nodes means it is considered separately from colonic tumours. Surgery for rectal cancers should now include complete excision of this fatty tissue around the tumour. TME, first described by Heald et al.,⁸ has resulted in significantly lower rates of local recurrence and is now accepted practice for mid and lower rectal tumours. Laparoscopic approaches allow visualization of the pelvis with magnification and often better retraction. Laparoscopic TME has short-term advantages in terms of pain and return to diet⁹ and in the studies of laparoscopic versus open surgery in patients with rectal cancer there was no difference in oncological outcome.¹⁰

An abdomino-perineal excision of the rectum (APER) involves excision of the anal canal as well as the rectum with a permanent end colostomy. This remains the standard operation for tumours of the lower third of the rectum. However, many tumours that would previously have been removed by APER are now removed by low anterior resection with anastomosis. Distal intramural spread of rectal cancer is unusual except in advanced tumours whose treatment is palliative rather than curative;¹¹ therefore, large distal resection margins are now considered unnecessary. Higher local recurrence rates have been found following APERs compared to anterior resections. This has led some surgeons to practice an even wider excision of the rectum called the extralevator approach to APER. Usually performed in the prone position, the levator ani is divided as laterally as possible to avoid the ‘waisting’ of the specimen seen at the level of puborectalis.¹² The results for local recurrence and survival are awaited. The defect left by this wide excision may be filled by a myocutaneous flap, either from the abdominal wall (rectus abdominis flap) or a local inferior gluteal artery flap. Alternatively, a wide range of meshes have been used to prevent perineal herniation.

The importance of a circumferential resection margin clear of cancer has led to the use of preoperative radiotherapy and chemotherapy for rectal cancers. Improved imaging techniques using magnetic resonance imaging (MRI) and endoanal ultrasound have facilitated this. Short-course radiotherapy lasting one week only is given for some resectable cancers to sterilize the operative field. In the original studies from Sweden, surgery was performed one week following the end of radiotherapy and showed reduced rates of local recurrence.¹³ More advanced tumours and those of the lower rectum are considered for chemoradiotherapy over five or six weeks.¹⁴ This treatment often results in regression of the primary tumour (down-staging) and this may make surgery technically easier. The treatment results in less local recurrence although there is no convincing evidence of prolongation of survival.¹⁵ Complete regression of the tumour is occasionally seen (see below).

Robotic surgery

The importance of the plane of surgery in reducing local recurrence and protecting pelvic nerves has led some surgeons to perform laparoscopic colorectal surgery with robotic assistance. There are simple robots with single arms that act as holders for the laparoscope (EndoAssist, Vicky) and more sophisticated devices with multiple arms which hold laparoscopic instruments and which are controlled by the surgeon from a remote console within the operating theatre (DaVinci). While robotic colectomies can be performed, the greatest benefit is likely to be in robotic TME for rectal cancer. Proponents suggest that the robotic instruments, which have more degrees of movement than the human hand, can provide superior dexterity. Retraction may be better, which may have particular advantages in the obese patient. All these benefits must be offset against the significant costs for both the apparatus and its disposable instruments.¹⁶

Avoiding a rectal excision?

A number of patients, 10–30% in some series, undergoing preoperative chemoradiotherapy for rectal cancer will have a complete pathological response.¹⁷ A number of other patients will have sufficient response to consider local excision (e.g. TEM) rather than a rectal resection with its associated risks.¹⁸ Unfortunately, non-invasive staging methods still struggle to differentiate fibrosis from residual tumour. Several series have been published of patients undergoing close observation following a complete clinical response after chemoradiotherapy. Salvage surgery was performed when recurrent tumour was identified during surveillance. Overall survival appears to be equivalent to those that underwent initial resection and were found to have had a complete pathological response.¹⁷ These are the early results that need to be confirmed.

Emergency surgery

Some 20% of patients with CRC present as an emergency, usually with intestinal obstruction. Such patients have a higher morbidity and mortality than elective patients, and the recent 30-day mortality figures put the figure at 14.9% for emergency resections compared with 5.8% for elective cases.¹⁹ Surgical options depend on the site of the tumour. Resection and primary anastomosis is usually undertaken for right-sided tumours but is now becoming more popular for left-sided tumours as well. In the past, patients with a left sided tumour may have undergone a three-stage procedure of defunctioning colostomy, resection with anastomosis followed by stoma closure. Recent studies have suggested that non-perforated left-sided tumours can be treated with similar levels of morbidity and mortality by subtotal colectomy or segmental resection and primary anastomosis.²⁰

Self-expanding metal stents (SEMS) can provide a ‘bridge to surgery’. The stent relieves the obstruction, allowing the patient's physiology to be optimized with the aim of performing an elective procedure at a later date with the associated reduction in morbidity and mortality. A recent meta-analysis has suggested technical and clinical success rates of around 70%, which is lower than suggested by previous retrospective studies.²¹ However, the use of SEMS as a bridge to surgery led to higher successful primary anastomosis rates and lower stoma rates than emergency surgery. Stent migration and re-obstruction are seen in about 10% of cases.²¹ CReST – a multicentre randomized study of the role of stenting in the acute management of obstructing CRC is now recruiting. SEMS should also be considered in the obstructed patient with metastatic disease, either as a palliative procedure or to allow chemotherapy prior to surgery.

Enhanced recovery programme

Most units providing colorectal resections now subscribe to an enhanced recovery process. This programme is a multidisciplinary approach designed to minimize the perioperative stress response and to speed up a patient's return to normality. Patients are encouraged to drink carbohydrate drinks up to 2 h preoperatively and early postoperative mobilization and tube removal is encouraged. Bowel preparation is often avoided, as it causes significant fluid shifts.²² Perioperatively, excessive fluid infusions are avoided, in some studies replaced by limited boluses guided by trans-oesophageal Doppler measurements of cardiac output. A systematic review has suggested a reduction in morbidity and reduced length of stay and no increase in re-admission or mortality.²³

Developments in the treatment of benign disease

Diverticular disease

Diverticulosis is common in UK, although mostly asymptomatic. Surgery remains an option for the complications of diverticular disease. Perforated diverticular disease with faecal contamination is usually treated by resection, commonly a Hartmann's procedure. Localized perforation may be treated by antibiotics and radiological drainage or, for more widespread infection without faecal peritionitis, some centres advocate laparoscopic washout and drainage without resection.²⁴ Complicated diverticular disease with fistulas or symptomatic colonic stenosis is best treated by resection and, if appropriate, anastomosis of soft compliant bowel onto the rectum.²⁵ Decisions over surgery for recurrent attacks of diverticulitis should be made on an individual basis. Studies following patients treated non-operatively for their first attack of diverticulitis suggest that the majority will not suffer a further complication, and expectant treatment is possible.²⁵

Benign anorectal disorders

There is a trend to establishing lesser invasive surgical treatments for troublesome anorectal conditions. These often fit into a treatment ‘ladder’. A good example of this is the treatment of anal fissure. Most chronic fissures are associated with high resting anal pressures and treatments are aimed at reducing sphincter tone to stimulate healing. Conservative treatments include stool softeners and topical ointments such as glyceryl trinitrate and calcium channel blockers (e.g. diltiazem). These are successful in approximately 50% of patients. For those patients who fail this initial non-invasive treatment, a next step can be injection with botulinum toxin. This causes partial sphincter paralysis, reducing sphincter tone, and may be combined with fissurectomy to remove granulation tissue from chronic fissures. Healing rates of between 44 and 100% have been reported.²⁶ Persistent fissures may heal with the established treatment of partial internal sphincterotomy, but caution is required as this may lead to a reduction in continence, particularly in women with occult obstetric injury. Anal advancement flaps have also been used successfully for resistant fissures.

The treatment of haemorrhoids may follow a similar concept of the ‘escalating ladder’. Haemorrhoids cause a variety of symptoms from pain and bleeding to prolapse and disturbed continence. While many symptoms will respond to dietary and toileting advice, outpatient banding or injection with sclerosants may be considered. Treatment of more significant haemorrhoids previously only involved excisional haemorrhoidectomy, a procedure that is often associated with significant postoperative pain. Newer treatments including stapled haemorrhoidopexy and Doppler-guided haemorrhoid artery ligation (DGHAL) aim to be less invasive. The aim of stapled haemorrhoidopexy is to excise a ring of mucosa in the distal rectum and lift the haemorrhoidal cushions into a more correct anatomical position, reducing blood flow and leading to scarring.²⁷ DGHAL uses a Doppler probe to locate the terminal branches of the haemorrhoidal artery, then a suture is used to ligate these at multiple locations. Symptom resolution has been reported in around 85% of patients,²⁸ and the procedure seems to be less painful than traditional haemorrhoidectomy.

Previously, many treatments for benign anorectal disease were based on symptoms alone. It is now increasingly common to utilize imaging such as fluoroscopic or MRI defaecating proctograms, endoanal ultrasound and ano-rectal physiology such as manometry. These investigations identify anatomical abnormalities such as sphincter defects, prolapse and enteroceles which may contribute to disturbed continence or obstructive defaecation. Correction of complex pelvic floor problems is beyond the scope of this article but usually starts with simple dietary and conservative measures before considering corrective surgery.

Clinical assessment of complex problems such as anal fistula can be aided by investigations such as MRI and endoanal ultrasound. Initial management of this troublesome condition should still involve drainage of sepsis by laying open the fistula or seton drainage. Eventual cure may involve staged fistulotomy or newer techniques such as anal advancement flaps. Developments such as fibrin plugs and glue have still to prove their efficacy in improving healing rates.²⁹

Conclusion

This review has focused on trends and developments in surgery for CRC and benign conditions in coloproctology. Many of the developments centre on reducing the surgical insult, finding minimally invasive versions of tried and tested operations and new alternatives that increase the options available to patients. These developments in surgery need to be seen in the context of advances in other fields such as genetics, imaging, oncology and endoscopy that complement surgical advances. The importance of multidisciplinary teams in the face of these options is clear.

DECLARATIONS

Competing interests

None declared

Funding

None declared

Ethical approval

Not applicable

Guarantor

JMG

Contributorship

JG and JR determined the extent of the article, researched and contributed to the paper. JR complied the first draft

Acknowledgements

The authors are grateful to D McGrath, for comments on a draft of this paper

Reviewer

Arin Saha