Surgical approach to a malignant appendix

At this year’s ESCP annual conference in Berlin which takes place in September, consultant surgeon Brendan Moran will lead a session looking at how to deal with a malignant appendix.

‘Colorectal surgeons will occasionally encounter an appendix tumour during surgery. Finding such tumours is even more likely when performing emergency surgery. These tumours could be incidental or they could co-exist with other pathologies. For instance, what had been thought of as a routine appendectomy for appendicitis may turn out to be complicated by the pathological report of a malignant tumour in the appendectomy specimen.

The norm is to refer these cases to a colorectal surgeon and a colorectal multidisciplinary team. Additionally, colorectal surgeons may be called by a gynaecologist or upper GI surgeon when they encounter an abnormal appendix while performing their own laparoscopy or laparotomies.

All colorectal surgeons need some knowledge on appendix tumours and how to access appropriate information, optimise decision making and be aware of the best management strategies, including referral to a specialist centre.

Importance of pathology 

It is important it is to have a detailed pathology report, including a second or third opinion by appropriately experienced pathologists preferably with an interest in appendix tumours. For instance, a perforated tumour of the appendix may be inaccurately reported as a pT4 adenocarcinoma when in fact it is a low grade mucinous tumour of the appendix. In these instances, the latter would require a follow-up instead of a true pT4 adenocarcinoma of the appendix.

We also need to take careful note of operative findings such as any evidence of spread or residual disease after completion of the appendectomy. Ultimately, optimal treatment depends on the pathology and findings.

For example, take the commonest appendix tumour, a carcinoid. A right hemicolectomy is the recommended approach depending on the size of the tumour (greater than two centimetres being a cut-off determining higher risk of nodal involvement) or an involved margin or invasion of the mesentery. Compare this to  a perforated mucinous tumour where pathological classification into low grade or high grade is important. High grade requires a right hemicolectomy, which is best combined with what is now termed cytoreductive surgery. This involves peritonectomy of diseased peritoneum, removal of the omentum and careful inspection of the ovaries with oophorectomy in post-menopausal women as well as hyperthermic intraperitoneal chemotherapy (HIPEC).

A number of patients present insidiously with the condition of pseudomyxoma peritonei (PMP), also known as ‘jelly belly’ characterised by mucinous ascites with diffuse involvement of the whole peritoneal cavity.

Using these different pathological classifications, the strategies for treatment result in the best outcomes with fewer interventions for the patient which are also cost effective.

Combination treatments for results 

Optimal treatment is a combination of surgery and chemotherapy to treat appendicular tumours with peritoneal spread. The evidence is very clear and indicates the most effective way to treat a patient is through cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). This treatment is offered widely as the majority of countries across the world have well established active peritoneal malignancy programmes or are actively developing these programmes.

An emerging area of research is in the use of agents to dissolve the mucin and mucin producing cells, which cause these tumours. This is to reduce the requirement for major surgery or to allow surgery to proceed. The best outcomes result in complete tumour removal and are combined with HIPEC. This is feasible between 70 – 80 per cent of patients treated in experienced units. We hope that the ongoing research into these topics will increase these numbers. Better yet, we hope that research will develop new and more sophisticated strategies to treat these increasingly common tumours.

In my unit we are working with transplant units to evaluate multivisceral small bowel and abdominal transplant for highly selected cases with low grade tumours. We also run a pilot programme researching a long natural history of intestinal and abdominal wall failure by fistulation.

Most surgeons will have encountered a case or cases of a malignant tumour during their career. This is largely due to the fact that an appendix tumour may be found incidentally at any laparotomy or laparoscopy or in an appendectomy specimen.

This topic is therefore relevant to all colorectal surgeons who participate in an emergency on-call rota or who perform laparoscopies or laparotomies.’