Impact of Conversion to Open Surgery on Early Postoperative Morbidity After Laparoscopic Resection for Rectal Adenocarcinoma: A Retrospective Study

Abstract

Background:

The impact of conversion to open surgery after a laparoscopic resection for rectal adenocarcinoma on postoperative morbidity is still unclear. Most previous studies included colon and rectal carcinomas and produced conflicting results. The aim of this study was to investigate the impact of conversion to open surgery on early postoperative morbidity in patients who underwent a laparoscopic resection for rectal adenocarcinoma.

Methods:

This was a retrospective bicentric study. It included all consecutive patients who underwent a laparoscopic resection for nonmetastatic rectal adenocarcinoma between January 2005 and December 2013. The impact of conversion to open surgery on 30-day postoperative morbidity was analyzed by univariate and multivariate analyses. Risk factors for conversion were also investigated by univariate and multivariate analyses.

Results:

One hundred thirty-one patients were included. The conversion rate was 26.7%. The global 30-day morbidity rate was 31.3% (41 patients). The conversion to open surgery was associated with higher rates of postoperative complications, anastomotic leaks, and reoperations. It was also an independent predictive factor to postoperative morbidity in the multivariate analysis (P = .01; odds ratio 2.86; 95% confidence interval [CI] 1.23–6.63), in addition to T4 tumors (P = .04; odds ratio 3.92; 95% CI 1.05–14.61). Risk factors for conversion in the multivariate analysis were T4 tumors (P = .006; odds ratio 6.09; 95% CI 1.66–22.32) and the height of the tumor (P = .025; odds ratio 2.7; 95% CI 1.13–6.43).

Conclusions:

This study showed that conversion to open surgery after laparoscopic proctectomy for rectal adenocarcinoma was associated with higher rates of early postoperative complications. It also showed that T4 tumors and the height of the tumor were independent factors associated with the conversion to open surgery. Reducing postoperative morbidity could be achieved by a better patient selection and a policy of early conversion.

Introduction

Despite the widespread use of laparoscopic surgery, its adoption for the surgical treatment of rectal adenocarcinoma has been slow.¹ Recently, randomized controlled trials comparing laparoscopic surgery to open surgery have shown similar results in terms of mobility, mortality, short- and long-term oncological outcomes.^2–5 However, two recent randomized trials have failed to establish the noninferiority of laparoscopy compared to open surgery, concerning the adequacy of cancer clearance.^6,7 Particularly, the rates of positive lateral margin were 12.1% and 7% in the laparoscopic groups, compared to 7.7% and 3% in the open groups, respectively.^6,7 Therefore, the debate about the advantages of laparoscopic surgery in the treatment of rectal adenocarcinoma is not closed yet.

Another aspect that contributed to delaying the adoption of laparoscopic rectal surgery is the technical difficulty and the challenging and complex learning curve involved.⁸ The reported conversion rates have been relatively high.⁹ The clinical consequences of the conversion to open surgery on the patients' outcomes are still unclear. Some authors have reported that the conversion to open surgery is associated with longer hospital stay, greater blood loss, more postoperative morbidity, and even inferior oncological results.^10,11 Other reports showed no impact of the conversion on patients' outcomes.¹² If the conversion to open surgery leads to worse clinical results, efforts should focus on reducing their rate, either by a better patient selection or by the improvement of the surgical technique.¹³

The aim of this study was to investigate the impact of conversion to open surgery on 30-day postoperative morbidity following laparoscopic resection for rectal adenocarcinoma.

Materials and Methods

This is a retrospective study performed in two units in North Africa: The Surgical Unit C (Ibn Sina University Hospital, Rabat in Morocco) and the Surgical Oncology Unit (Anticancer Hospital, Batna, Algeria). It included all consecutive patients who underwent a laparoscopic resection for rectal adenocarcinoma between January 2005 and December 2013. All surgeries were performed by two surgeons (A.H., M.A.).

Patients eligible for the laparoscopic approach were those with the following criteria: age more than 18 years old; rectal adenocarcinoma (located within 15 cm from the anal verge); ASA 1 or 2 (American score of Anesthesiologists), and body mass index less than 30 kg/m². Patients with the following criteria were excluded: histologic types other than adenocarcinoma, history of submesocolic surgery, and the presence of distant metastasis.

The preoperative workup included the following: rigid rectal endoscopy with biopsies, total colonoscopy, chest and abdominal computed tomography (CT scan), and carcinoembryonic antigen. For locoregional assessment of the tumor, pelvic CT scan, or/and endorectal ultrasonography or/and pelvic magnetic resonance imaging were used. Patients with tumors located within 10 cm from the anal verge, suspected T 3–4, and/or positive lymph node on workup underwent preoperative chemoradiotherapy (CRT) or short-course radiotherapy.

The delay between the end of neoadjuvant treatment and surgery was 6 to 8 weeks in the case of CRT and 7 to 10 days in the case of short-course radiotherapy. Laparoscopic surgery was performed with five trocars, following the principles described by Heald.¹⁴ In case of anterior resection, the specimen was extracted through a short suprapubic incision. Colorectal anastomoses were created using a mechanical circular stapler, and coloanal anastomoses were hand-sewn. In case of abdominoperineal resection (APR), the specimen was extracted through the perineal incision. The perineum was either closed, with the creation of abdominal colostomy, or reconstructed using the pseudocontinent perineal colostomy technique.¹⁵

We defined conversion as follows: midline laparotomy or enlargement of suprapubic incision for another reason than extracting the specimen. Causes for conversion were identified in the surgical reports as described by the surgeons. We defined early postoperative morbidity as any postoperative complications occurring in the 30 days following surgery, graded higher than grade II according to Dindo classification,¹⁶ in addition to wound infections. We adopted the definition proposed by the International Study Group of Rectal Cancer¹⁷ for anastomotic leakage: “Defect of the intestinal wall integrity at the colorectal or coloanal anastomotic site (including suture and staple lines of neorectal reservoirs) leading to a communication between the intra- and extra luminal compartments. A pelvic abscess close to the anastomosis is also considered as anastomotic leakage.”

The impact of the conversion to open surgery on postoperative morbidity was analyzed by univariate and multivariate analyses. The following variables were included in the analyses: age; gender; height of the tumor (0–7 cm versus 8–15 cm from the anal verge); neoadjuvant CRT; type of surgery (anterior resection or abdominoperineal resection; T stage; N stage); tumor differentiation (well differentiated versus others); and the surgeon's experience (the first 30 patients for each surgeon versus others).

Quantitative data are presented as median with quartiles or mean with standard deviation, as appropriate. Qualitative data are presented as numbers with percentages. Univariate analysis was calculated by the chi-square or Fisher test as appropriate. Multivariate analysis was performed using a logistic regression model (95% confidence interval). Results were considered significant when P was less than .05.

Results

The study included 131 patients. Table 1 summarizes the patients' characteristics. There were 64 men (48.9%) with a mean age of 54.9 years. The median distance of the tumor from the anal verge was 7 cm and 84 patients (64.2%) had tumors located in the lower and mid-rectum. Neoadjuvant treatment was performed in 52 patients (39.7%). Sphincter-preserving surgery was performed in 104 patients (79.4%), with coloanal anastomosis in 54 patients (41.2%) and a stapled colorectal anastomosis in 47 patients (35.9%). After APR, 5 patients had pseudo-continent perineal colostomy (PCPC) and the others had perineal closure and abdominal colostomy.

Table 1.

Patients' Characteristics

Variable	Results
Age^a (years)	54.9 (13.6)
Gender^b
Men	64 (48.9)
Women	67 (51.1)
Tumor location^c,d (cm)	7 (4–10)
Tumor location^b,c
Low	47 (35.9)
Mid	53 (40.5)
High	31 (23.7)
Neoadjuvant treatment^b
No	52 (39.7)
Short course	17 (13)
Radiochemotherapy	62 (47.3)
Surgical treatment^b
Abdominoperineal resection	27 (20.6)
Conservative surgery	104 (79.4)
Coloanal anastomosis	54 (41.2)
Colorectal anastomosis	47 (35.9)
Hartmann	3 (2.3)
Histologic differentiation^b
Well	85 (64.9)
Others	44 (33.6)
Missing	2 (1.5)
T stage^b
0	10 (7.6)
1	10 (7.6)
2	32 (24.4)
3	67 (51.1)
4	12 (9.2)
N stage^b
N0	96 (73.2)
N1	35 (26.7)

Age is expressed in mean and standard deviation.

Results are expressed in numbers and percentages.

Tumor location from the anal verge in cm.

Expressed in median and quartiles.

The median operating time was 275 (quartiles 225–356.25) minutes. The median number of lymph nodes analyzed was 12 (quartiles 7–15). The median distal and circumferential margins were 3 cm (quartiles 1.2–4) and 4 mm (quartiles 2–10), respectively. Fifteen patients (11.4%) had an incomplete oncologic resection (positive circumferential margin <1 mm or/and positive distal margin). There was no statistical difference between converted and nonconverted patients concerning the rate of incomplete oncologic resection (10.4% versus 14.3%, P = .54).

Conversion and risk factors for conversion

The conversion rate to open surgery was 26.7% (35 patients). The most common causes for conversion were bulky tumors (37.1%) and difficult rectal stapling (20%). Table 2 summarizes the results of the univariate and multivariate analyses for variables associated with conversion. Multivariate analysis showed that T4 tumors (P = .006; odds ratio 6.09; 95% confidence interval [CI] 1.66–22.32) and tumors located below 7 cm from the anal verge (P = .025; odds ratio 2.7; 95% CI 1.13–6.43) were independent factors for conversion.

Table 2.

Predictive Factors for Conversion to Open Surgery: Univariate and Multivariate Analysis

Variable	Univariate	Multivariate
Age (years)	P = .13
<60	18/81 (22.2)
>60	17/50 (34)
Gender	P = .96
Men	17/64 (26.6)
Women	18/67 (26.9)
Tumor location^a (cm)	P = .05	P = .025, OR 2.7
<7	12/63 (19)	95% CI 1.13–6.43
>7	23/68 (33.8)
Neoadjuvant treatment	P = .09
No	18/52 (34.6)
Yes	17/79 (21.5)
Surgical treatment	P = .91
Abdominoperineal resection	7/27 (25.9)
Conservative surgery	28/104 (26.9)
Histologic differentiation^b	P = .41
Well	25/85 (29.4)
Others	10/44 (22.7)
T stage^b	P = .01	P = .006, OR 6.09
T 0–3	28/119 (23.5)	95% CI 1.66–22.32
T 4	7/12 (58.3)
N stage^b	P = .29
N0	28/96 (29.2)
N1	7/35 (20)

Bold to highlight significative results in univariate and multivariate analysis.

Tumor distance from the anal verge.

At histologic examination of the surgical specimen.

CI, confidence interval; OR, odds ratio.

Morbidity

The global postoperative morbidity rate was 31.3% (41 patients). Table 3 summarizes the causes of morbidity. Three patients died in the postoperative period (2.3%). Eighteen patients needed a revision surgery (13.7%). The causes for reoperation are shown in Table 3.

Table 3.

Causes of Postoperative Morbidity

Morbidity	Number (%)
Overall	41 (31.3)
Anastomotic leak^a	21 (20.8)
Perineal sepsis^b	5 (18.5)
Wound infection	4 (3)
Urinary	9 (6.9)
Reoperation	18 (13.7)
Anastomotic leaks	12 (66.7)
Stoma complications^c	2 (11.1)
Peritonitis^d	2 (11.1)
Intestinal obstruction	1 (5.5)
Deep wound infection	1 (5.5)
Mortality^e	3 (2.3)

After colorectal or coloanal anastomosis.

After abdominoperineal resection.

Necrosis and perineal sepsis after pseudoperineal colostomy.

Secondary to bladder and intestinal opening.

30-day mortality.

Impact of conversion on morbidity

Converted patients had statistically higher rates of global morbidity (51.4% versus 24%, P = .003), anastomotic leaks (25.7% versus 9.4%, P = .016), and reoperations (36% versus 15.8%, P = .03). Table 4 shows the results of univariate and multivariate analyses of variables associated to morbidity. Multivariate analysis showed that the conversion to open surgery was an independent factor associated to postoperative morbidity (P = .01; odds ratio 2.86; 95% CI 1.23–6.63). The other independent factor associated to morbidity was T4 tumors (P = .04; odds ratio 3.92; 95% CI 1.05–14.61).

Table 4.

Predictive Factors for Postoperative Morbidity: Univariate and Multivariate Analysis

Variable	Univariate	Multivariate
Age (years)	P = .52
<60	27/81 (33.3)
>60	14/50 (28)
Gender	P = .26
Men	23/64 (35.9)
Women	18/67 (26.9)
Surgeons' experience^a	P = .07
First 60 cases	14/60 (23.3)
Others	27/71 (38)
Tumor location^b (cm)	P = .62
<7	21/63 (33.3)
>7	20/68 (29.4)
Neoadjuvant treatment	P = .38
No	14/52 (26.9)
Yes	27/79 (34.2)
Surgical treatment	P = .23
Abdominoperineal resection	11/27 (40.7)
Conservative surgery	30/104 (28.8)
Conversion to open surgery	P = .003	P = .01; OR 2.86
No	23/96 (24)	95% CI 1.23–6.63
Yes	18/35 (51.4)
Histologic differentiation^c	P = .9
Well	27/85 (31.8)
Others	14/44 (31.8)
T stage^c	P = .009	P = .04; OR 3.92
T 0–3	33/119 (27.7)	95% CI 1.05–14.61
T 4	8/12 (66.7)
N stage^c	P = .98
N0	30/96 (31.3)
N1	11/35 (31.4)

Bold to highlight significative results in univariate and multivariate analysis.

First 30 cases for each surgeon (30 first patients for surgeon 1 + 30 first patients for surgeon 2).

Tumor distance from the anal verge by endoscopy.

At histologic examination of the surgical specimen.

CI, confidence interval; OR, odds ratio.

Discussion

This study showed that conversion to open surgery after laparoscopic proctectomy for rectal adenocarcinoma was associated with higher rates of 30-day postoperative complications. It also showed that T4 tumors and the height of the tumor were independent factors associated with the conversion to open surgery.

Conversion to open surgery was necessary in 26.7% of patients. In randomized controlled trials, the rates vary from 7.9% to 34%.^3,5–7,9,18 The most common predictive factors for conversion in the literature are obesity, male gender, surgeon's experience, per operative complications, and locally advanced tumors.^10–12 In this study, T4 stage was an independent predictive factor for conversion. This fact was largely reported in the literature.^10,11 These locally advanced tumors are hard to expose in the pelvis by laparoscopy with an increased risk for disrupted tumors and inadequate surgical margins.¹¹ Most authors consider these advanced tumors not suitable for laparoscopic rectal surgery.^10–12 An accurate radiological preoperative work-up would allow identifying these patients preoperatively and orienting them to an open surgical resection. The other factor associated with conversion to open surgery was the height of the tumor. Conversion rates were higher for tumors located 7 cm above from the anal verge. These patients had partial or total mesorectal excisions with colorectal or coloanal anastomoses. These higher conversion rates could be explained by the technical difficulties when performing rectal transaction.^19,20 It is considered by many authors as one of the most difficult steps in laparoscopic rectal surgery, mainly because of challenging factors such as the narrow anatomical space in the pelvis and the inadequacy of available laparoscopic instruments and mechanical staplers.^19,21,22 Particularly, bulky tumors located above the peritoneal reflection do not allow an easy exposition of the rectum for transection, especially in the surgeons' early experience. However, many authors have shown that the impact of this factor on conversion rates could be improved with surgical experience.^21,23

The impact of conversion to open surgery on postoperative morbidity is still debated in the literature. Most of the previous studies included both colon and rectal cancers and had conflicting results. This study showed a significantly higher complication rate after conversion to open surgery. Agha et al. found the same results in their study including 300 patients. The conversion group had a significantly higher morbidity rate and blood transfusions.¹⁰ Similarly, Chan et al. reported a significantly higher complication rate in the conversion group, in their analysis of 470 cases of colorectal cancer (56.1% versus 16.7%, P = .001).²⁴ In a recent meta-analysis, Clancy et al. showed that conversion to open surgery was associated with higher rates of blood transfusions and a higher mortality risk,¹¹ but postoperative morbidity was not analyzed. This higher rate of complications after conversion to open surgery may be explained by longer operation times and higher blood loss, which could increase the stress response and reduce the patients' immunity response leading to a higher susceptibility to develop postoperative complications.²⁴ In fact, the largest study in the literature, including 1073 rectal adenocarcinomas, showed a twofold increase in morbidity rates in the conversion group (43.6% versus 21.1%, P < .001), particularly wound infections and anastomotic leaks.²⁵

On the contrary, Martínek et al. did not report significantly higher rates of postoperative complications in the conversion group, even though there was significantly more blood loss in converted patients.²⁶ In a study including 279 rectal adenocarcinomas, Rickert et al. reported no statistical difference in postoperative morbidity rates between converted and nonconverted patients. However, there were more wound infections and anastomotic leaks in the conversion group.¹³ In another Italian study including 173 patients with rectal cancer, morbidity rates were not higher in the conversion group.²⁷ Similarly, Allaix et al. did not find a statistical difference in the complication rates between conversion and no-conversion groups.¹² They hypothesized that their strategy of early conversion would allow avoiding complications due to a long and laborious dissection. Both surgeons in this study did not have an early conversion strategy, and conversion was decided in the case of inability to complete the procedure laparoscopically. This may explain the higher rate of morbidity in converted patients in this series. However, no study has accurately investigated the timing and conditions of conversion and their impact on patients' outcomes. Future studies on this subject should analyze the impact of factors such as the timing of conversion and its causes on the patients' outcomes. Overall, the contradictory results in the literature highlight the difficulty to evaluate the impact of conversion and suggest that worse short-term outcomes after conversion is a complex process and does not necessarily represent a direct cause/effect relationship based on this event alone.

Limitations of this study include its retrospective design and possible bias in designing and performing the analysis in two different centers. It was facilitated by similar protocols in perioperative and surgical care in both units. Finally, there were prospective databases specifically dedicated to rectal adenocarcinoma, ensuring a good quality of data collection.

In conclusion, this study showed that conversion to open surgery after laparoscopic proctectomy for rectal adenocarcinoma was associated with higher rates of postoperative complications. It also showed that T4 tumors and the height of the tumor were independent factors associated with the conversion to open surgery. Reducing postoperative morbidity could be achieved by a better patient selection (avoiding T4 tumors) and a policy of early conversion.

Footnotes

Disclosure Statement

No competing financial interests exist.

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