Management of Concomitant Abdominal Aortic Aneurysm and Intra-abdominal, Retroperitoneal Malignancy

Discussion

As the number of older inhabitants within the population increases, so does the incidence of AAA and IRM. Many etiopathogenic factors are common to both groups of patients. These include age above 65 years, male gender, smoking, high cholesterol level and genetic factors. Most often AAA occurs jointly with colorectal (0.5-4.9%) carcinoma, renal carcinoma (1.3-4.2%), stomach (2-3.8%) carcinoma and hepatocellular carcinoma (0.4-0.8%) (3, 4). The coincidence of both diseases represents a treatment challenge for the surgeon who has to decide on a one-stage or two-stage procedure, an open AAA resection or EVAR, and on dealing with IRM through an open or laparoscopic (robotic) operation. For IRM the type of tumour and perioperative oncological treatment are taken into the treatment consideration.

Those who favour a one-stage procedure solution (5-7) see the benefit of this procedure in the early resolution of both nosological units without the undue delay of a two-stage procedure. There is, thus, no danger of an AAA rupture if the IRM is dealt with first during a two-stage procedure. It is stated that 6-10 % of AAA rupture during the first three weeks after another intra-abdominal operation (in particular if there are complications) as a result of the start of collageno- and elastolysis in the case of activation of metalloproteinase, inflammatory cytokines, deterioration in nutrition of patients in post-operative period and when adjuvant chemotherapy is started. Most often it involves an AAA with a diameter greater than 60 mm (8). In contrast with this, if the IRM is dealt with in the second stage, and complications arise after the first AAA operation, the interval between operations may be extended incommensurately and there may occur progress with possible generalisation of IRM. These are primarily tumours in higher TNM stage (9). Further possible advantages of an one-stage procedure include resolution of both diseases during a single operation, under general anaesthesia only once.

Those who oppose one-stage procedures (10, 11) are concerned with the risk of infection of the vascular prosthesis, in particular during the resection of colorectal tumours concurrently with open AAA resection due to infectious content in the large intestine. This complication is more at the theoretical level, because current perioperative procedures (preparation of bowel, antibiotic prophylaxis) combined with adequate surgical and anaesthesiological techniques preclude these complications in practice (12, 13). They also state that one-stage procedures are more time consuming, with higher operation stress for the patient and weakened immunity, which plays a role in the long-term results of tumour treatment. So, one-stage procedures are burdened by a higher incidence of post-operative complications.

Both schools of thought concur in the indication for acute (urgent) operations for symptomatic diseases with AAA (symptomatology, rupture), or with IRM (bowel obstruction, bleeding, perforation), where the symptomatic disease is dealt with first, and then the secondary disease after the patient has healed (14).

From the aspect of operational technique for AAA or IRM, open, endovascular and mini-invasive procedures (laparoscopy, robotic surgery) are possible. An undoubted advantage of EVAR given good anatomical conditions of AAA is the minimally invasive nature of the procedure, less surgical stress, lower number of complications (especially cardiac, pulmonary and renal), possibility of performing intervention under analgesia-sedation, significant reduction in need for blood replacement, faster convalescence and shorter hospitalization period. Another advantage of EVAR during a one-stage procedure is minimisation of infection of the endograft compared to open AAA resection. In two-stage procedures it is usually possible to deal with IRM in a short 2-5 day interval after EVAR, and there is no danger of needless delay in oncological treatment. One unambiguous advantage is the use of EVAR during one stage with an IRM operation, because in most cases it represents a low operational burden for the patient. The advantage of EVAR is its use where an open resection would be very complicated, as is the case in patients with a “hostile abdomen” (15, 16).

One certain problem is the higher incidence of reinterventions for EVAR (up to 13%), primarily as a result of thrombosis, leaks and migration of endovascular prosthesis (17, 18). Thrombogenicity is a paraneoplastic manifestation and one of the complications of oncological treatment, and the lithotomy position of the patient during operations on the pelvis is a risk factor for endograft thrombosis. The incidence of abdominal angina after EVAR ranges in general from 1.5 to 3%. For patients with a tumour on the left side of the colon and rectum, during an EVAR it is important to preserve the patency of at least one internal iliac artery during exclusion of the inferior mesenteric artery for preservation of collateral circulation for this part of the intestine, which is essential for resections and the vitality of anastomoses in this area (19, 20). If for various reasons this is not possible, it is better to choose an open operation, primarily for AAA with aneurysms in the iliac arteries with implantation of inferior mesenteric artery to preserve the vitality of bowel anastomosis in this area. This procedure can also be recommended for patients following a prior resection of colorectal cancer on the left colon and rectum with patent inferior mesenteric artery (21).

Some studies also warn of possible worse incorporation of EVAR for patients with adjuvant oncological treatment which leads to reduced synthesis of collagen, elastin and function of smooth muscle tunica media, increased activity of metalloproteinase, release of inflammatory cytokines and inhibition of DNA synthesis (22-24). The problem of oncological treatment combined with an AAA operation arises primarily for more advanced tumours of the rectum with a need for neoadjuvant chemoradiotherapy. So, for these patients it is a good idea to use an AAA solution through EVAR during the first stage. It is also better to perform surgery associated with an operation on a rectal carcinoma in two stages, with surgery for AAA in the first stage as a result of possible infection complications given an insufficiency of anastomosis or wound infection, which could significantly delay dealing with the AAA operation (25, 26).

An open AAA resection with replacement using bifurcated or tubular graft is possible in both procedures, i.e., during one-stage or two-stage procedures (27). This surgery also displays minimal mortality and morbidity in the case of elective operations in large centres, even in patients who are anatomically unsuitable for EVAR. At our facility we use infection-resistant vascular prostheses in these cases. However, the post-operative convalescence of patients, and thus also hospitalization, is longer, and there is a much more frequent need for post-operative monitoring of patients at the intensive care unit. If we select the two-stage surgery, we have to assume an approximately two-week interval between operations necessary for the convalescence of the patient.

One-stage open procedure can be used well for patients with renal carcinoma and patients with tumours of the small and large intestine (in particular on the ascending and transverse colon) and liver (28). For bowel surgery it is recommended that the AAA resection first be performed, and then after coverage of the vascular prosthesis with AAA wall, rear sheet of retroperitoneum (sometimes even omentum) and draping with anti-septic drapes, perform bowel resection with minimisation of possible infection of vascular reconstruction. Prophylactic administration of antibiotics is a matter of course. In the group of our patients we observed no infections of the vascular prosthesis when this approach was applied. It is advantageous to use retroperitoneal access for AAA resections (29) in two-stage procedures. It is advantageous as a secondary operation in the case of preceding laparotomies, where we avoid intra-abdominal adhesions, or in the first stage, where we thus leave the abdominal cavity free for subsequent open or minimally invasive surgery for IRM.

There is a general increase in the use of minimally invasive laparoscopic approaches in surgery on the gastrointestinal tract and in urology for operations on renal carcinomas, and they can be used well primarily for two-stage surgery, where they are the first operation, and with regard to the rapid convalescence of the patient it is possible to perform AAA resection or EVAR after a short interval of approximately one week. One highly advantageous procedure is a one-stage procedure using both minimally invasive techniques - EVAR with laparoscopic (or robotic) IRM operation (30), which can be performed primarily for anatomically suitable AAA for EVAR and simple laparoscopic interventions.

In addition to the aforementioned, it is necessary to mention the adequacy of using EVAR and open AAA resection in combined operations from the aspect of life expectancy and the economic aspects of operations. Should it involve a patient of high biological age with generalized malignancy and short life prognosis, there is no indication to burden the patient with any operations for AAA or IRM unless absolutely essential. In the case of advanced colorectal carcinomas with bowel obstruction, we choose to insert a bowel stent or perform a palliative operation on the bowel without dealing with AAA. From the aspect of treatment strategy, the multidisciplinary team decision and wishes of the patient have a fundamental role.

We are aware of the many limitations of this study. It is a retrospective, non-randomised study with limited number of patients. However, in recent literature dealing with the same matter there are also small, heterogeneous retrospective cohorts, often based on case series, with absent perioperative data. In terms of selection of patients our work is also of a heterogeneous nature, primarily from the aspect of malignant diseases, although this was unavoidable given the low level of representation of individual tumours. Moreover, as a result of the limitation of the patient cohort it is not possible to comment on the advantages or disadvantages of a given operation technique (open or minimally invasive). In our overall cohort of patients with AAA there is an evident very low proportion of EVAR compared with open operations, which is given by the greater preference for open operations in general at our Department, primarily in the first years of the twenty-year period under examination. We still believe that open AAA resection is better in the cases of concomitant IRM for its evaluation and choice of optimal onco-surgical procedure. But over the past decade there has been a gradual increase in the proportion of EVAR at the expense of open AAA resections in patients with AAA only. We did not evaluate the reason for worse long-term results in patients with combined procedures compared to operations for AAA only. They are most likely due to a shorter life expectancy in patients with intra- or retroperitoneal malignancy. However, a larger group of patients with combined procedures and a more targeted analysis of the deaths of both monitored groups of patients would be necessary for a precise specification of the causes.