Dielectric characterization of healthy and malignant colon tissues in the 0.5-18 GHz frequency band

Several reports over the last few decades have shown that the dielectric properties of healthy and malignant tissues of the same body organ usually show different values. However, no intensive dielectric studies of human colon tissue have been performed, despite colon cancer's being one of the most common types of cancer in the world. In order to provide information regarding this matter, a dielectric characterization of healthy and malignant colon tissues is presented. Measurements are performed on ex vivo surgery samples obtained from 20 patients, using an open-ended coaxial probe in the 0.5-18 GHz frequency band. Results show that the dielectric constant of colon cancerous tissue is 8.8% higher than that of healthy tissues (p  =  0.002). Besides, conductivity is about 10.6% higher, but in this case measurements do not have statistical significance (p  =  0.038). Performing an analysis per patient, the differences in dielectric constant between healthy and malignant tissues appear systematically. Particularized results for specific frequencies (500 MHz, 900 MHz, 2.45 GHz, 5 GHz, 8.5 GHz and 15 GHz) are also reported. The findings have potential application in early-stage cancer detection and diagnosis, and can be useful in developing new tools for hyperthermia treatments as well as creating electromagnetic models of healthy and cancerous tissues.

Colonic prolapse after intersphincteric resection for very low rectal cancer: a report of 12 cases

BACKGROUND

There are no published data concerning management of patients with exteriorized colonic prolapse (CP) after intersphincteric rectal resection (ISR) and side-to-end coloanal manual anastomosis (CAA) for very low rectal cancer. The aim of the present study was to report our experience in 12 consecutive cases of CP following ISR with CAA.

METHODS

From 2006 to 2014, all patients with very low rectal cancer who developed CP after ISR and CAA were reviewed. Demographic and surgical data, prolapse symptoms and treatment were recorded. Postoperative morbidity, functional outcomes and results after prolapse surgery were recorded.

RESULTS

Twelve out of 143 patients (8 %) who underwent ISR with side-to-end CAA for low rectal cancer presented CP: 7/107 ISR (7 %) with partial resection of the internal anal sphincter (IAS) and 5/36 ISR (14 %) with subtotal or total resection of the IAS (NS). CP was diagnosed after a median of 6 months (range 2-72 months) after ISR. All patients with CP suffered from pain and fecal incontinence. Median Wexner fecal incontinence score before surgery was 16.5 (range 12-20). Three patients refused reoperation. Nine patients underwent transanal surgery with prolapse resection (including colonic stump and side-to-end anastomosis) and new end-to-end CAA (with posterior myorraphy in 4 cases). After a median follow-up of 30 months (range 8-87 months), 3/9 patients (33 %) had CP recurrence: One with very poor function was treated by abdominoperineal resection and definitive stoma. The 2 others were successfully reoperated on transanally. Median Wexner fecal incontinence score after CP surgery was 9 (range 0-20). No CP recurrence was noted for the 6 other patients, and function improved in all cases. Thus, at the end of follow-up, 8/9 patients (89 %) had no recurrence after surgery.

CONCLUSIONS

We believe surgery must be attempted in these patients who develop CP after ISR with CAA for very low rectal cancer in order to improve function and symptoms. A transanal approach with CP resection and new end-to-end anastomosis appeared to be safe and effective. Larger studies are needed to confirm our results.

Anastomotic leakage after colon cancer resection: does the individual surgeon matter?

AIM

Anastomotic leakage is one of the most feared complications after colonic resection. Many risk factors for anastomotic leakage have been reported, but the impact of an individual surgeon as a risk factor has scarcely been reported. The aim of this study was to assess if the individual surgeon is an independent risk factor for anastomotic leakage in colonic cancer surgery.

METHOD

This was a retrospective analysis of prospectively collected data from patients who underwent elective resection for colon cancer with anastomosis at a specialized colorectal unit from January 1993 to December 2010. Anastomotic leaks were diagnosed according to standardized criteria. Patient and tumour characteristics, surgical procedure and operating surgeons were analysed. A logistic regression model was used to discriminate statistical variation and identify risk factors for anastomotic leakage.

RESULTS

A total of 1045 patients underwent elective colon cancer resection with primary anastomosis. Anastomotic leakage occurred in 6.4% of patients. Ileocolic anastomosis had an anastomotic leakage rate of 7.2%, colo-colonic/colorectal anastomosis 5.2% and ileorectal anastomosis 12.7%, with intersurgeon variability. The independent risk factors associated with anastomotic leakage were the use of perioperative blood transfusion (OR 2.83, CI 1.59-5.06, P < 0.0001) and the individual surgeon performing the procedure (OR up to 8.44, P < 0.0001).

CONCLUSION

In addition to perioperative blood transfusion, the individual surgeon was identified as an important risk factor for anastomotic leakage. Efforts should be made to reduce performance variability amongst surgeons.

Is biological mesh interposition a valid option for complex or recurrent rectovaginal fistula?

AIM

Many surgical techniques are available for the treatment of rectovaginal fistula (RVF). There is hitherto little information on its treatment by biological mesh interposition. The aim of the present study was to analyse our results of RVF treatment using biological mesh interposition.

METHOD

Patients with RVF undergoing biological mesh interposition were identified. Success was defined by the absence of a diverting stoma and/or any vaginal discharge of faeces, flatus or mucous discharge.

RESULTS

Ten women [median age 39 (24.5-65) years] were included. Nine (90%) had recurrent RVF, and the median number of previous attempts at closure was 2.5 (0-8). The main cause of RVF was Crohn's disease (40%). All patients had faecal diversion. No intra-operative complications occurred from mesh interposition. Seven (70%) patients developed postoperative morbidity which was major (Dindo III) in two (20%). The primary success rate was 20% (2/10) but final success rate was achieved in 70% after reoperation with other procedures at 11.1 (2.7-13.1) months of follow-up.

CONCLUSION

The study has shown disappointing results with biological mesh interposition for RVF with a healing rate lower than achieved by gracilis muscle interposition.

Rectal cancer threatening or affecting the prostatic plane: is partial prostatectomy oncologically adequate? Results of a multicentre retrospective study

AIM

The management of rectal cancer threatening or affecting the prostatic plane is still under debate. The role of preoperative chemo radiotherapy and the extent of prostatectomy seem to be key points in the treatment of these tumours. The aim of the present study was to evaluate the pathological circumferential margin status and the local recurrence rate following different therapeutic options.

METHOD

A multicentre, retrospective study was conducted of patients with rectal cancer threatening or affecting the prostatic plane, but not the bladder, judged by magnetic resonance imaging (MRI). The use of preoperative chemoradiotherapy and the type of urologic resection were correlated with the status of the pathological circumferential resection margin (CRM) and local recurrence.

RESULTS

A consecutive series of 126 men with rectal cancer threatening (44) or affecting (82) the prostatic plane on preoperative staging and operated with local curative intent between 1998 and 2010 was analysed. In patients who did not have chemoradiotherapy but had a preoperative threatened anterior margin the CRM-positive rate was 25.0%. In patients who did not have preoperative chemoradiotherapy but did have an affected margin, the CRM-positive rate was 41.7%. When preoperative radiotherapy was given, the respective CRM infiltration rates were 7.1 and 20.7%. In patients having preoperative chemoradiotherapy followed by prostatic resection the rate of CRM positivity was 2.4%. Partial prostatectomy after preoperative chemoradiotherapy resulted in a free anterior CRM in all cases, but intra-operative urethral damage occurred in 36.4% of patients who underwent partial prostatectomy, resulting in a postoperative urinary fistula in 18.2% of patients.

CONCLUSION

Preoperative chemoradiation is mandatory in male patients with a threatened or affected anterior circumferential margin on preoperative MRI. In patients with preoperative prostatic infiltration, prostatic resection is necessary. In this group of patients partial prostatectomy seems to be oncologically safe.

Management of cryptoglandular supralevator abscesses in the magnetic resonance imaging era: a case series

AIM

The aim of this study is to describe the diagnostic performance of magnetic resonance imaging in the management of supralevator abscess, regarding its origin, location, drainage route, subsequent treatment of the fistula, and long-term results.

METHODS

A retrospective case series including thirteen consecutive patients with cryptoglandular supralevator abscess treated between 2001 and 2011 at a colorectal unit of a tertiary referral center. A magnetic resonance imaging was performed in all patients before surgical drainage, and its usefulness in assessing supralevator abscess origin was analyzed. Short- and long-term results after drainage were also evaluated.

RESULTS

The final diagnosis of supralevator abscess and the location described in the magnetic resonance were confirmed intraoperatively in all patients. An ischiorectal origin was identified in nine patients, and perineal translevator drainage was performed placing a mushroom catheter through the ischiorectal or the postanal space. Four patients underwent secondary treatment of anal fistula: two rectal advancement flap and two non-cutting seton. In the other four patients, an intersphincteric origin was identified and transanal surgical drainage was performed placing a long-term mushroom catheter. Several weeks later, transanal unroofing of the residual cavity was performed and the fistula lay open to the anorectal lumen. In the long-term follow-up (median 61 months), only patients with supralevator abscess of ischiorectal origin in whom fistula was not subsequently treated presented a recurrence of the anal sepsis.

CONCLUSIONS

Magnetic resonance imaging seems essential to clarify the location of supralevator abscess, its origin, and choice of the right drainage route. Subsequent treatment of the fistula is necessary to avoid recurrence.

The use of an endostapler in the treatment of supralevator abscess of intersphincteric origin

AIM

This technical note describes the use of an endostapler for the definitive treatment of supralevator abscess upward from an intersphincteric origin.

METHOD

A two-stage treatment was performed. First an endoanal drainage was performed by inserting a mushroom catheter in the supralevator abscess cavity. In the second stage transanal unroofing of the fistula was performed with an endostapler.

RESULTS

Since 2011, three patients have been treated in this way. After 2 years of follow up, none of the patients had recurrence of the abscess or been referred for anal incontinence.

CONCLUSION

The use of an endostapler in the treatment of supralevator abscess of intersphincteric origin may be an alternative to decrease the risk of recurrence and incontinence.

Prospective evaluation of intraoperative peripheral nerve injury in colorectal surgery

AIM

Intraoperative peripheral nerve injury can have permanent neurological consequences. Its incidence is not known and varies according to the location and the surgical specialty. This study was a prospective analysis of intraoperative peripheral nerve injury as a complication of abdominal colorectal surgery.

METHOD

All patients who underwent major colorectal abdominal surgery in our Colorectal Unit between 1996 and 2009 were analyzed. Data on nerve injury were prospectively collected.

RESULTS

There were 2304 patients, of whom eight (0.3%) experienced intraoperative peripheral nerve injury. This occurred in 5/2211 (0.2%) open procedures and in 3/93 (3%) laparoscopic procedures. There was no association between intraoperative peripheral nerve injury and age, gender, body mass index, surgeon, operation time, American Society of Anesthesiology (ASA) score and urgent surgery. The use of Allen-type stirrups and a vacuum bag (in laparoscopic surgery) seemed to be protective for nerve injury in the lower and upper limbs respectively.

CONCLUSION

Adequate positioning and the use of pressure-free positioning devices may prevent intraoperative peripheral nerve injury, particularly during laparoscopy.

Long-term outcomes after laparoscopic colectomy

AIM: To evaluate long-term outcomes in a large series of patients who randomly received laparoscopic or open colorectal resection.

METHODS: From February 2000 to December 2004, six hundred sixty-two patients with colorectal disease were randomly assigned to laparoscopic (LPS, n = 330) or open (n = 332) colorectal resection. All patients were analyzed on an intention-to-treat basis. Long-term follow-up was carried out every 6 mo by office visits. In 526 cancer patients five-year overall and disease-free survival were evaluated. Median oncologic follow-up was 96 mo.

RESULTS: Eight (4.2%) LPS group patients needed conversion to open surgery. Overall long-term morbidity rate was 7.6% (25/330) in the LPS vs 11.1% (37/332) in the open group (P = 0.17). In cancer patients, five-year overall survival was 68.6% in the LPS group and 64.0% in the Open group (P = 0.27). Excluding stage IV patients, five-year local and distant recurrence rates were 32.5% in the LPS group and 36.8% in the Open group (P = 0.36). Further, no difference in recurrence rate was found when patients were stratified according to cancer stage.

CONCLUSION: LPS colorectal resection was associated with a slightly lower incidence of long-term complications than open surgery. No difference between groups was found in overall and disease-free survival rates.

The role of the pathologist in rectal cancer diagnosis and staging and surgical quality assessment

Since the introduction of the total mesorectal excision by Heald, many changes in the therapeutic management of rectal cancer have been incorporated. The multidisciplinary approach to colorectal cancer, integrated in a team of different specialists, ensures individualised treatment for each patient with rectal cancer. Therefore the role of the pathologist has acquired an important relevance, not only in diagnosing but also managing and evaluating the surgical specimen. The knowledge of preoperative staging, distance between tumour and anal verge or in patients subjected to a neoadjuvant treatment is necessary for the pathologist to make a detailed, accurate and good-quality report. Parameters such as the macroscopic quality of the mesorectum, the status of the circumferential resection margin and the lymph node harvest are considered basic criteria recommended by the current guidelines for the multidisciplinary team audit.

Randomized clinical trial of laparoscopic versus open left colonic resection

BACKGROUND

The main aim of this study was to compare short-term results and long-term outcomes of patients undergoing laparoscopic versus open left colonic resection.

METHODS

Between February 2000 and December 2004, all adult patients undergoing elective left colonic resection were assessed for eligibility to the study. The protocol for postoperative care was the same in both groups. Cost-benefit analysis was based on hospital costs. Quality of life, long-term morbidity and 5-year survival were also evaluated.

RESULTS

Some 268 patients undergoing left colonic resection were assigned randomly to the laparoscopic (n = 134) or open (n = 134) approach. The short-term morbidity rate was 20.1 per cent in the open group and 11.9 per cent in the laparoscopic group (P = 0.094). Hospital stay was longer in the open group (8.7 versus 7.0 days for the laparoscopic approach; P = 0.002). Cost-benefit analysis showed an additional cost of euro66 per patient randomly allocated to the laparoscopic group. Quality of life was significantly improved in the laparoscopic group 6 months after surgery, but no difference was found subsequently. The long-term morbidity rate was 11.9 per cent in the open group and 7.5 per cent in the laparoscopic group (P = 0.413). The 5-year survival rate of patients with cancer was 66 and 72 per cent for open and laparoscopic groups respectively (P = 0.321).

CONCLUSION

Laparoscopic left colonic resection resulted in an earlier recovery after surgery. As cost-benefit analysis and long-term follow-up showed similar results, the laparoscopic approach should be preferred to open surgery.

Benefits of laparoscopic colorectal resection are more pronounced in elderly patients

PURPOSE

The purpose of this study was to evaluate the impact of laparoscopic colorectal resection on short-term postoperative outcome in elderly patients.

METHODS

A series of 535 patients with colorectal disease who had been randomly assigned to laparoscopic (n=268) or open (n=267) resection was analyzed. A total of 201 patients (37.6 percent) were elderly (aged 70 years or older) and 334 patients (62.4 percent) were younger than aged 70 years. Follow-up for postoperative morbidity was performed for 30 days after hospital discharge.

RESULTS

Elderly patients had a higher American Society of Anesthesiologists score compared with younger patients in both the laparoscopic and open groups (P=0.0001). In the open group, elderly patients had higher morbidity rate (37.5 vs. 23.9 percent; P=0.02) and longer length of hospital stay (13 vs. 10.6; P=0.007) compared with younger patients. In the laparoscopic group, morbidity rate (20.2 vs. 15.1 percent) and length of hospital stay (9.5 vs. 9.1) were similar in elderly and younger patients. In elderly patients, the laparoscopy-reduced morbidity rate (20.2 vs. 37.5 percent; P=0.01) and length of hospital stay (9.5 vs. 13; P=0.001) compared to the open approach. In younger patients, the advantages of the laparoscopic approach on morbidity rate (15.1 vs. 23.9 percent; P=0.06) and length of stay (9.1 vs. 10.6; P=0.004) were less pronounced.

CONCLUSIONS

Laparoscopy improved short-term postoperative outcome more in elderly than in younger patients. Advanced age was associated with higher morbidity and longer length of stay only in patients who underwent open colorectal surgery.

Serological immunoreactivity against colon cancer proteome varies upon disease progression

Sera from colon carcinoma patients were used to identify tumor-associated antigens (TAAs) by screening tumor proteome resolved by 2D electrophoresis. A panel of six TAAs eliciting a serological immune response in colorectal cancer was identified, showing a modification in antigen recognition by B cells in patients as a function of colon cancer progression. The expression of these proteins was either confined or increased in tumor as compared to normal mucosa.

Laparoscopic resection in rectal cancer patients: outcome and cost-benefit analysis

PURPOSE

This study was designed to evaluate the impact of laparoscopic rectal resection on short-term postoperative morbidity and costs.

METHODS

A total of 168 patients with rectal cancer were randomly assigned to laparoscopic (n = 83) or open (n = 85) resection. Outcome parameters were: postoperative morbidity, length of hospital stay, quality of life, long-term survival, and local recurrences. The mean follow-up period was 53.6 months. Cost-benefit analysis was based on hospital costs.

RESULTS

Operative time was 53 minutes longer in the laparoscopic group (P < 0.0001). Postoperative morbidity rate was 28.9 percent in the laparoscopic vs. 40 percent in the open group (P = 0.18). The mean length of hospital stay was 10 (4.9) days in the laparoscopic group and 13.6 (10) days in the open group (P = 0.004). Local recurrence rate and five-year survival were similar in both groups; however, the limited number of patients does not allow firm conclusions. Quality of life was better in the laparoscopic group only in the first year after surgery (P < 0.0001). The additional charge in the laparoscopic group was $1,748 per patient randomized ($1,194 the result of surgical instruments and $554 the result of longer operative time). The saving in the laparoscopic group was $1,396 per patient randomized ($647 the result of shorter length of hospital stay and $749 the result of the lower cost of postoperative complications). The net balance resulted in $351 extra cost per patient randomly allocated to the laparoscopic group.

CONCLUSIONS

Short-term postoperative morbidity was similar in the two groups. Laparoscopic resection reduced length of hospital stay, improved first-year quality of life, and slightly increased hospital costs.

[Laparoscopic-assisted versus open surgery for colorectal cancer: postoperative morbidity in a single center randomized trial]

AIM

The primary objective of the study was to compare the effect of laparoscopic-assisted (LPS) versus open surgery (LPT) for colorectal cancer on postoperative morbidity. The secondary objectives were to evaluate immune response and intestinal wall oxygen perfusion.

METHODS

A total of 610 patients with colorectal cancer were randomly assigned to receive colon resection by either LPS (n=306) or LPT (n=304). Four surgical staff members not involved in the study recorded postoperative complications up to 30 days after the operation. Immune response was evaluated by measuring lymphocytic proliferation after challenge with Candida albicans and phytohemoagglutinin before, at 3 and 15 days after the operation. Intestinal wall oxygen perfusion was continuously monitored using a probe.

RESULTS

The conversion rate was 4.6% in the LPS group. Morbidity was 18.6% in the LPS group and 34.5% in the LPT group (P<0.0005). Infections developed in 9.1% of LPS-treated patients and in 20.2% of LPT-treated patients (P<0.0005). The mean length of stay was 9.7+/-2.6 days in the LPS group and 12.2+/-4.2 days in the LPT group (P<0.0001). In both groups lymphocytic proliferation was low at 3 days postoperative but returned to normal range at 15 days only in the LPS group. Interoperative intestinal oxygen perfusion values were higher in the LPS group.

CONCLUSIONS

Laparoscopic colorectal surgery reduced both postoperative morbidity and length of stay. Lymphocytic proliferation and intestinal wall oxygen perfusion were higher in patients who underwent laparoscopic-assisted surgery.

Laparoscopic versus open colorectal surgery: cost-benefit analysis in a single-center randomized trial

SUMMARY BACKGROUND DATA

Studies comparing the costs of colorectal resection by laparoscopic (LPS) and open approaches are small sized or not randomized. The main purpose of this study is to compare the hospital costs of LPS and open colorectal surgery in a large series of randomized patients.

METHODS

A total of 517 patients with colorectal disease were randomly assigned to LPS (n = 258) or open (n = 259) resection. The following costs were calculated: surgical instruments, operative room (OR) occupation, routine care, postoperative morbidity, and length of hospital stay (LOS). Follow-up for postoperative morbidity was carried out for 30 days after hospital discharge.

RESULTS

Operative time was 37 minutes longer in the LPS group. Overall morbidity rate was 18.2% (47 of 258) in the LPS versus 34.7% (90 of 259) in the open group (P = 0.0005). The mean LOS was 9.9 (2.6) days in the LPS group and 12.4 (3.9) days in the open group (P < 0.0001). The additional OR charge in the LPS group was 1171 per patient randomized (864 due to surgical instruments and 307 due to longer time). The saving in the LPS group was 1046 per patient randomized (401 due to shorter LOS and 645 due to the lower cost of postoperative complications). The net balance resulted in 125 extra cost per patient allocated to the LPS group.

CONCLUSIONS

The present cost-benefit analysis showed a slight additional cost in the LPS group. The better postoperative short-term outcome in patients receiving LPS had a key role to nearly balance the operative room charges due to laparoscopy.