DOG1 overexpression is associated with mismatch repair deficiency and BRAF mutations but unrelated to cancer progression in colorectal cancer

INTRODUCTION

The transmembrane channel protein DOG1 (Discovered on GIST1) is normally expressed in the gastrointestinal interstitial cells of Cajal and also in gastrointestinal stroma tumors arising from these cells. However, there is also evidence for a relevant role of DOG1 expression in colorectal cancers. This study was undertaken to search for associations between DOG1 expression and colon cancer phenotype and key molecular alterations.

METHODS

A tissue microarray containing samples from more than 1,800 colorectal cancer patients was analyzed by immunohistochemistry.

RESULTS

DOG1 immunostaining was detected in 503 (30.2%) of 1,666 analyzable colorectal cancers and considered weak in 360 (21.6%), moderate in 78 (4.7%), and strong in 65 (3.9%). Strong DOG1 immunostaining was associated with advanced pT stage (p=0.0367) and nodal metastases (p=0.0145) but these associations were not retained in subgroups of 1,135 mismatch repair proficient and 86 mismatch repair deficient tumors. DOG1 positivity was significantly linked to several molecular tumor features including mismatch repair deficiency (p=0.0034), BRAF mutations (p<0.0001), nuclear p53 accumulation (p=0.0157), and PD-L1 expression (p=0.0199) but unrelated to KRAS mutations and the density of tumor infiltrating CD8 positive lymphocytes.

CONCLUSION

Elevated DOG1 expression is frequent in colorectal cancer and significantly linked to important molecular alterations. However, DOG1 overexpression is largely unrelated to histopathological parameters of cancer aggressiveness and may thus not serve as a prognostic parameter for this tumor entity.

Mucin 5AC expression is common but unrelated to tumor progression in pancreatic adenocarcinoma

Introduction: Mucin 5AC (MUC5AC) belongs to the family of secreted gel-forming mucins. It is physiologically expressed in some normal mucin producing epithelial cells but also in pancreatic, ovarian, and colon cancer cells. The role of MUC5AC expression in cancer is not fully understood. This study was designed to explore the role of MUC5AC for pancreatic cancer progression, its association to microsatellite instability, and its diagnostic utility. Methods: Mucin 5AC expression was studied immunohistochemically in a tissue microarray (TMA) from 532 pancreatic cancers, 61 cancers of the ampulla Vateri, six acinar cell carcinomas and 12 large sections of pancreatitis. Results: Mucin 5AC staining was interpretable in 476 of 599 (79%) arrayed cancers. Staining was completely absent in normal pancreas and pancreatitis, but frequent in pancreatic cancer. Membranous and cytoplasmic MUC5AC expression was most common in pancreatic adenocarcinomas (71% of 423), followed by carcinomas of the ampulla Vateri (43% of 47), and absent in six acinar cell carcinomas. Mucin 5AC expression was unrelated to tumor phenotype (tumor stage, tumor grade, lymph node, and distant metastasis), and microsatellite instability in ductal adenocarcinomas and carcinomas of the ampulla Vateri. Conclusion: Our study indicates that MUC5AC is an excellent biomarker for pancreatic cancer diagnosis, especially to support the sometimes-difficult diagnosis on small biopsies. Mucin 5AC expression is unrelated to pancreatic cancer aggressiveness.

Central perforated VRAM flap and neurostimulated levator augmentation for functional and aesthetical reconstruction after abdominoperineal excision in cancer

BACKGROUND

Preservation of quality of life regarding fecal continence after abdominoperineal excision (APE) in cancer is challenging. Simultaneous soft tissue coverage and restoration of continence mechanism can be provided through an interdisciplinary collaboration of colorectal and plastic reconstructive surgery.

OBJECTIVE

Evaluation of surgical procedure and outcome combining soft tissue reconstruction using a central perforated vertical rectus abdominis myocutaneous flap (VRAM), implementing a perineostoma and restoring anorectal angle augmenting the levator ani by neurostimulated graciloplasty.

METHODS

14 Patients underwent APE due to cancer. In all patients coverage was achieved by pedicled VRAM and simultaneous pull-through descendostomy (perineostoma). 10 of those patients received a levator augmentation additionally. Postoperative complications, functional measures of continence as well as quality of life were obtained.

RESULTS

Perineal minor complication rate was 43% without need of surgical intervention. All but one VRAM survived. Continence measures and disease specific life quality showed a good preservation of continence in most patients.

CONCLUSION

The results present a complex therapy option accomplished by a collaboration of two highly specialized partners (visceral and plastic surgery) after total loss of the sphincter function and consecutive fecal insufficiency after APE.

High density of cytotoxic T-lymphocytes is linked to tumoral PD-L1 expression regardless of the mismatch repair status in colorectal cancer

BACKGROUND

Immune checkpoint-inhibitors targeting the PD-1/PD-L1 system are FDA approved in microsatellite instable (MSI) or mismatch repair deficient (dMMR) colorectal cancer (CRC). PD-L1 expression is tightly linked to features connected to immune checkpoint inhibitor response, but studies on large subsets of cancers analyzing the correlation between different status of MSI/dMMR, tumor infiltrating lymphocytes and PD-L1 expression are still lacking.

METHODS

More than 1800 CRC were analyzed for PD-L1 by immunohistochemistry in a tissue microarray format. Data were compared to MMR, the number of intratumoral CD8⁺ cytotoxic T-cells, and adverse clinico-pathological parameters. Different cutoff levels for defining PD-L1 positivity in tumor cells (1%, 5%, 10%, and 50%) yielded comparable results.

RESULTS

At a cutoff level of 5%, PD-L1 positivity was seen in 5.1% of tumors. PD-L1 was more often positive in dMMR (18.6%) than in MMR proficient (pMMR) cancers (4.1%; p < 0.0001). The number of intratumoral CD8⁺ lymphocytes was strikingly higher in PD-L1 positive (939.5 ± 118.2) than in PD-L1 negative cancers (310.5 ± 24.8). A higher number of intratumoral CD8⁺ lymphocytes was found in dMMR CRC (PD-L1 positive: 1999.7 ± 322.0; PD-L1 negative: 398.6 ± 128.0; p < 0.0001) compared to pMMR CRC (PD-L1 positive: 793.2 ± 124.8; PD-L1 negative: 297.2 ± 24.2; p < 0.0001). In dMMR and pMMR CRC, PD-L1 expression in tumor cells was unrelated to tumor stage, lymph node status or lymphatic/venous invasion. PD-L1 positivity in tumor associated immune cells was seen in 47.5% of cases and was significantly linked to high numbers of tumor infiltrating CD8⁺, low tumor stage, and absence of lymph node metastasis and lymphatic/venous invasion (p < 0.0001 each).

CONCLUSION

The data support the previously suggested fact that PD-L1 expression in tumor cells is driven by extensive cytotoxic T-cell infiltration in highly immunogenic dMMR and pMMR CRC. Frequent and intense PD-L1 expression in tumor cells of dMMR CRC may contribute to the high response rates of dMMR CRC to immune checkpoint-inhibitors.

Obstructed defaecation syndrome: European consensus guidelines on the surgical management

Management of obstructed defaecation is challenging and remains controversial. No international guidelines have been published.

Elevated MUC5AC expression is associated with mismatch repair deficiency and proximal tumor location but not with cancer progression in colon cancer

Mucin 5AC (MUC5AC) is a secreted gel-forming mucin expressed by several epithelia. In the colon, MUC5AC is expressed in scattered normal epithelial cells but can be abundant in colorectal cancers. To clarify the relationship of MUC5AC expression with parameters of tumor aggressiveness and mismatch repair deficiency (dMMR) in colorectal cancer, a tissue microarray containing 1812 colorectal cancers was analyzed by immunohistochemistry. MUC5AC expression was found in 261 (15.7%) of 1,667 analyzable colorectal cancers. MUC5AC expression strongly depended on the tumor location and gradually decreased from proximal (27.4% of cecum cancers) to distal (10.6% of rectal cancers; p < 0.0001). MUC5AC expression was also strongly linked to dMMR. dMMR was found in 21.3% of 169 cancers with MUC5AC positivity but in only 4.6% of 1051 cancers without detectable MUC5AC expression (p < 0.0001). A multivariate analysis showed that dMMR status and tumor localization predicted MUC5AC expression independently (p < 0.0001 each). MUC5AC expression was unrelated to pT and pN status. This also applied to the subgroups of 1136 proficient MMR (pMMR) and of 84 dMMR cancers. The results of our study show a strong association of MUC5AC expression with proximal and dMMR colorectal cancers. However, MUC5AC expression is unrelated to colon cancer aggressiveness.

MMR Deficiency is Homogeneous in Pancreatic Carcinoma and Associated with High Density of Cd8-Positive Lymphocytes

BACKGROUND

Microsatellite instability (MSI) has emerged as a predictive biomarker for immune checkpoint inhibitor therapy. Cancer heterogeneity represents a potential obstacle for the analysis of predicitive biomarkers. MSI has been reported in pancreatic cancer, but data on the possible extent of intratumoral heterogeneity are lacking.

METHODS

To study MSI heterogeneity in pancreatic cancer, a tissue microarray (TMA) comprising 597 tumors was screened by immunohistochemistry with antibodies for the mismatch repair (MMR) proteins MLH1, PMS2, MSH2, and MSH6.

RESULTS

In six suspicious cases, large section immunohistochemistry and microsatellite analysis (Bethesda panel) resulted in the identification of 4 (0.8%) validated MSI cases out of 480 interpretable pancreatic ductal adenocarcinomas. MSI was absent in 55 adenocarcinomas of the ampulla of Vater and 7 acinar cell carcinomas. MMR deficiency always involved MSH6 loss, in three cases with additional loss of MSH2 expression. Three cancers were MSI-high and one case with isolated MSH6 loss was MSS in PCR analysis. The analysis of 44 cancer-containing tumor blocks revealed that the loss of MMR protein expression was always homogeneous in affected tumors. Automated digital image analysis of CD8 immunostaining demonstrated markedly higher CD8 + tumor infiltrating lymphocytes in tumors with (mean = 685, median = 626) than without (mean = 227; median = 124) MMR deficiency (p < 0.0001), suggesting a role of MSI for immune response.

CONCLUSIONS

Our data suggest that MSI occurs early in a small subset of ductal adenocarcinomas of the pancreas and that immunohistochemical MMR analysis on limited biopsy or cytology material may be sufficient to estimate MMR status of the entire cancer mass.

Anorectal angle at rest predicting successful sacral nerve stimulation in idiopathic fecal incontinence-a cohort analysis

PURPOSE

Sacral nerve stimulation is an effective treatment for patients suffering from fecal incontinence. However, less is known about predictors of success before stimulation. The purpose of this study was to identify predictors of successful sacral nerve stimulation in patients with idiopathic fecal incontinence.

METHODS

Consecutive female patients, receiving peripheral nerve evaluation and sacral nerve stimulation between September 2008 and October 2014, suffering from idiopathic fecal incontinence were included in this study. Preoperative patient's characteristics, anal manometry, and defecography results were collected prospectively and investigated by retrospective analysis. Main outcome measures were independent predictors of treatment success after sacral nerve stimulation.

RESULTS

From, all in all, 54 patients suffering from idiopathic fecal incontinence receiving peripheral nerve evaluation, favorable outcome was achieved in 23 of 30 patients after sacral nerve stimulation (per protocol 76.7%; intention to treat 42.6%). From all analyzed characteristics, wide anorectal angle at rest in preoperative defecography was the only independent predictor of favorable outcome in multivariate analysis (favorable 134.1 ± 13.9° versus unfavorable 118.6 ± 17.1°).

CONCLUSIONS

Anorectal angle at rest in preoperative defecography might present a predictor of outcome after sacral nerve stimulation in patients with idiopathic fecal incontinence.

[Transtar™ operation for rectocele and obstructed defecation syndrome]

The Contour® Transtar™ operation represents a further methodological development of conventional transanal stapled rectal resection (STARR) for the treatment of obstructed defecation syndrome (ODS) and/or full thickness rectal prolapse. In contrast to the conventional STARR technique a specially designed single curved stapler is used with which the rectal wall is incised in a circular fashion and anastomosed. This results in a monoblock resection with almost unlimited extent of resection. In multicenter studies the procedure has generally been shown to be effective for treatment of ODS with intussusception and rectocele. In comparison to conventional STARR the resected tissue samples are larger and the functional effectiveness is comparable. Furthermore, data from prospective randomized trials revealed higher effectiveness in long-term follow-up. With reference to full thickness rectal prolapse, feasibility studies have been performed which showed low morbidity but long-term follow-up studies suggest a high recurrence rate of >40 %.

Neurostimulated levator augmentation--a new approach in restoring continence

PURPOSE

Restoration of continence remains a major challenge in patients after abdominoperineal rectal excision (APE) or with end-stage fecal incontinence. A new surgical technique, the neurostimulated levator augmentation, was introduced for pelvic floor augmentation using dynamic graciloplasty in order to restore anorectal angulation. The aim of this study was to assess feasibility and efficiency.

METHODS

From November 2009 to March 2014, n = 17 patients underwent neurostimulated levator augmentation (n = 10 after APE, n = 5 intractable idiopathic fecal incontinence, n = 2 traumatic anal amputation). Gracilis muscle was transposed through the obturator foramen into the pelvic cavity, positioned in a U-shaped sling behind the rectum, fixed to the contralateral os pubis to restore anorectal angulation, and then conditioned by neurostimulation. Questionnaires analyzing function and quality of life were administered.

RESULTS

For neurostimulated levator augmentation, four patients suffered from complications that needed operative intervention (n = 3 wound infection, n = 1 colon perforation); three pharmacological treatment and two complications needed no further invasive intervention. One patient died due to causes unrelated to the operation, and no complication required intensive care management. Fecal incontinence in patients with idiopathic incontinence improved significantly after surgery as well as incontinence episodes, urgency, and disease-specific quality of life through all dimensions. Generic quality of life was significantly better after surgery in all patients. After median follow-up of 17 months (2-45), all but one patient would undergo the procedure again.

CONCLUSIONS

Neurostimulated levator augmentation was feasible in all patients with acceptable morbidity. It may represent a new therapeutic option in selected patients with intractable fecal incontinence.

Multimodal therapy in treatment of rectal cancer is associated with improved survival and reduced local recurrence - a retrospective analysis over two decades

Background

The management of rectal cancer (RC) has substantially changed over the last decades with the implementation of neoadjuvant chemoradiotherapy, adjuvant therapy and improved surgery such as total mesorectal excision (TME). It remains unclear in which way these approaches overall influenced the rate of local recurrence and overall survival.

Methods

Clinical, histological and survival data of 658 out of 662 consecutive patients with RC were analyzed for treatment and prognostic factors from a prospectively expanded single-institutional database. Findings were then stratified according to time of diagnosis in patient groups treated between 1993 and 2001 and 2002 and 2010.

Results

The study population included 658 consecutive patients with rectal cancer between 1993 and 2010. Follow up data was available for 99.6% of all 662 treated patients. During the time period between 2002 and 2010 significantly more patients underwent neoadjuvant chemoradiotherapy (17.6% vs. 60%) and adjuvant chemotherapy (37.9% vs. 58.4%). Also, the rate of reported TME during surgery increased. The rate of local or distant metastasis decreased over time, and tumor related 5-year survival increased significantly with from 60% to 79%.

Conclusion

In our study population, the implementation of treatment changes over the last decade improved the patient’s outcome significantly. Improvements were most evident for UICC stage III rectal cancer.

Recurrence after perineal rectosigmoidectomy: when and why?

AIM

Reported recurrence rates after perineal rectosigmoidectomy (Altemeier's procedure) in patients with full-thickness rectal prolapse vary from 0% to 60%. The object of this study was to analyse risk factors for recurrence after this procedure.

METHOD

From May 2004 to December 2012, 63 consecutive patients suffering from full-thickness rectal prolapse undergoing perineal rectosigmoidectomy were included. Of these 46 were female and the median age of the whole group was 79 (30-90) years. The median follow-up was 53 (3-99) months. Patient characteristics and operative parameters were compared between patients with and without recurrence.

RESULTS

One patient died and another patient needed re-operation. Eight full-thickness recurrences occurred in eight patients after a median of 18 (6-48) months. Stapled compared with handsewn anastomosis (hazard ratio 7.96, 95% confidence interval 1.90-33.47; P = 0.001) and shorter specimen length (hazard ratio 4.06, 95% confidence interval 0.97-16.99; P = 0.03) increased the risk of recurrence in Cox regression analysis.

CONCLUSION

The operative technique including stapled anastomosis and length of the resected specimen seems to be associated with a high recurrence rate after perineal rectosigmoidectomy.

[Transanal procedure for functional bowel diseases]

The transanal operative procedure for the treatment of obstructive defecation syndrome (ODS) can be secondarily applied in cases of failure or ineffectiveness of conservative treatment. Clinically established transanal procedures are rectocele resection (RR), mucosectomy for internal rectal prolapse according to the Rehn-Delorme procedure (MR) and stapled transanal rectal resection (STARR Contour Transtar). Only few studies have indicated the value of RR and MR in the treatment of obstructive diseases and in general study quality and evidence level are low. There might be an indication in rectocele-associated symptoms, such as incomplete evacuation, straining and digitation. In contrast the STARR procedure has been well characterized by a large number of high quality studies providing an elevated evidence level for the treatment of ODS. Functional results are available with a follow-up of 1 year up to 68 months postoperatively. Response rates of up to 90% were reported whereas recurrence rates were given as a maximum of 18% at 68 months follow-up. In summary the STARR procedure provides good functional results for conservative refractory outlet obstruction with minor morbidity and outcome seems to remain stable in the long-term follow-up.

Perineal rectosigmoidectomy: quality of life

AIM

For any surgical treatment of full-thickness rectal prolapse, little attention has been given to quality of life (QoL). This study prospectively evaluated continence, constipation and QoL after perineal rectosigmoidectomy for full-thickness rectal prolapse in young and elderly patients in the long term.

METHOD

From May 2003 to May 2010, consecutive patients suffering from full-thickness rectal prolapse and treated with perineal rectosigmoidectomy were prospectively studied. A standardized questionnaire, including the Cleveland Clinic Constipation Score (CCCS), the Cleveland Clinic Incontinence Score (CCIS) and generic [EuroQol five-dimension (EQ-5D)] and constipation-specific [Patient Assessment of Constipation-Quality of Life (PAC-QOL)] QoL scores, was administered pre- and postoperatively. The Wilcoxon test (for EQ-5D data) and two-sample Student's t-test [for EuroQol visual analogue scale (EQ-VAS), CCCS, CCIS and PAC-QOL data) were used for statistical analyses.

RESULTS

Fifty-three patients (47 women), 72.7 (range 30-89) years of age, underwent perineal rectosigmoidectomy. One patient died and one patient needed reoperation. Five full-thickness recurrences occurred. Thirty-seven patients completed the follow-up questionnaire at a median of 49 (range, 6-89) months. Postoperative incontinence and constipation improved significantly (CCIS from 13 ± 7.28 to 8.7 ± 6.96 and CCCS from 8.32 ± 6.96 to 3.49 ± 4.17). Furthermore, QoL, in terms of mobility, usual activity, pain/discomfort and anxiety/depression and subjective state of health, were significantly better at follow-up (P < 0.001). All dimensions of constipation-related QoL improved (P < 0.001). The results did not differ significantly between patients under or over 69 years of age.

CONCLUSION

Patients' experience improved general and constipation-related QoL after perineal rectosigmoidectomy, and this was independent of age.

Impact of peritoneal carcinomatosis in the disease history of colorectal cancer management: a longitudinal experience of 2406 patients over two decades

Background:

Recent therapeutic developments demand for an update of information on natural history, risk factors and prognosis of peritoneal carcinomatosis (PC) of colorectal origin. Therefore, prospective registry data should provide information about incidence, predictors and outcome.

Methods:

From a prospectively expanded single-institutional database with 2406 consecutive patients with colorectal cancer (CRC), clinical, histological and survival data were analysed for independent risk factors and prognosis. Findings were then stratified to the era of treatment without chemotherapy, 5-Fluorouracil-only and contemporary systemic chemotherapy, respectively.

Results:

Overall, 256 (10.6%) patients were diagnosed with PC thereof 141 (5.85%) with metachronous PC. Independent risk factors for the development of metachronous PC were age <62 years, N2-status, T4-status, location of the primary in the left colon or appendix. In the era of contemporary systemic chemotherapy, prognosis for PC improved only not-significantly (median survival of 17.9 months vs 7.03 months, P=0.054).

Conclusion:

Despite improvement in the overall outcome with prolonged median survival for the complete patient cohort with CRC, those patients with PC have not experienced the same benefit. In the era of contemporary systemic chemotherapy, progress in treatment resulted in only limited survival benefit. Thus, continuous efforts for further therapeutic advancements should be undertaken in these patients diagnosed with PC.

Complete pathological remission of locally advanced, unresectable pancreatic cancer (LAPC) after intensified neoadjuvant chemotherapy

BACKGROUND

Unresectable locally advanced pancreatic cancer (LAPC) has an extremely poor prognosis. Results of neoadjuvant (radio-)chemotherapy approaches aiming at achieving resectability are currently not satisfactory.

CASE REPORT

We report the case of a 67-year-old woman with histologically confirmed pancreas carcinoma that was not resectable on first surgical exploration who achieved a well-documented complete pathological remission (pCR). The carcinoma became resectable after consecutive neoadjuvant treatment with nanoparticle albumin-bound (nab)-paclitaxel/gemcitabine and FOLFIRINOX chemotherapy regimens.

CONCLUSION

This is the first reported LAPC case in which neoadjuvant chemotherapy alone has been shown to lead to demonstrated pCR. CA19-9 levels, but not imaging criteria, were useful for response prediction and timing of the Whipple's procedure. The findings in this case suggest possible conceptual changes in the treatment approach for LAPC, and indicate that the new effective chemotherapy regimens should be integrated into clinical trials for LAPC.

[Impact of endoscopy and endosonography on local staging of rectal carcinoma]

For rectal carcinoma the decision between primary resection, neoadjuvant therapy and local excision depends on an accurate local staging. Local staging includes digital examination, rigid rectoscopy and endorectal ultrasound (EUS). The rectal digitation allows clinical staging according to the mobility of the tumor in relation to the rectal mucosa or the rectal wall. The rigid rectoscopy determines the aboral distance of the tumor from the dentate line or the anal verge. The endorectal ultrasound determines the pre-therapeutic UICC stage on the basis of evaluating the pretherapeutic T and N categories. Results of EUS should be discussed on the background of neoadjuvant therapy including response evaluation and in comparison with the results of magnetic resonance imaging. In addition, there is only little information available concerning evaluation of the circumferential resection margin by EUS. Technical improvements, such as the 3D-EUS, might be appropriate in the future to provide enhancement of EUS staging of rectal tumors.

[Stapled transanal resection for the treatment of obstructed defaecation syndrome]

Stapled transanal rectal resection (STARR) has become a well-evaluated surgical procedure for the treatment of outlet obstruction in the context of conservative refractory obstructed defaecation syndrome (ODS). The diagnosis of ODS needs to be objectified which can be best ensured by clinical scoring systems. Besides a general coloproctological examination, dynamic defecography represents the most important diagnostic procedure. Pelvic floor dyssynergia and slow transit constipation should always be taken into account for the differential diagnosis and for which the STARR procedure is generally contraindicated. Surgery is performed via a transanal approach using a full thickness rectal resection of either the ventral or dorsal proportion of the rectal wall in the PPH01 conventional procedure or circumferentially by monoblock resection in the contour transtar® procedure. Morbidity is best characterised by data of the European STARR registry which contains a total number of n = 2,838 consecutive patients. The overall morbidity rate was 36 % whereby urgency (20 %) and bleeding (5 %) were the most frequent complications. More favourable data have been published in single centre studies. Functional results are available with a follow-up of 1 year up to 68 months postoperatively. Response rates of up to 90 % were reported whereas recurrence rates were given with a maximum of 18 % at 68 months follow-up. In summary, the STARR procedure provides good functional results in conservative refractory outlet obstruction with minor morbidity and the outcome seems to remain stable in the long-term follow-up.

Stapled transanal rectal resection and sacral nerve stimulation - impact on faecal incontinence and quality of life

AIM

The aim of the study was to assess the impact of stapled transanal rectal resection (STARR) on pre-existing faecal incontinence and quality of life in patients suffering from obstructive defaecation syndrome (ODS) and to evaluate the efficiency of sequential sacral nerve stimulation (SNS) for improvement of persistent incontinence after STARR.

METHOD

Thirty-one patients with ODS and major faecal incontinence prior to STARR were prospectively enrolled. The outcome was measured using the Cleveland Clinic Constipation and Incontinence score (CCS, CCIS), Faecal Incontinence Qualities-of-Life Index (FIQL), Patient Assessment of Constipation Quality-of-Life (PAC-QOL) and EuroQol visual analogue scale (EQ-VAS).

RESULTS

The overall levels of constipation (CCS from 13.1 ± 3.8 to 6.2 ± 5.4; P < 0.001) and incontinence (CCIS from 12.6 ± 3.2 to 9.4 ± 5.1; P = 0.005) were significantly improved after STARR; concordantly, the global and specific quality of life were significantly improved. Following postoperative constipation and incontinence, three different groups of patients were differentially referred to SNS. In group I (n = 16, 52%), both constipation (CCS from 12.6 ± 4.0 to 3.6 ± 1.9; P < 0.001) and incontinence (CCSI from 12.43 ± 3.2 to 5.1 ± 1.9; P < 0.001) were improved. In group II (n = 8, 25%), only constipation was improved (CCS from 12.3 ± 2.3 to 3.3 ± 2.2; P < 0.001), while incontinence persisted (CCIS from 12.8 ± 2.9 to 13.1 ± 3.1; P > 0.05). In group III (n = 7, 23%) there was no improvement at all. Sacral nerve stimulation was successfully carried out in six (85%) of seven patients in group II (post-SNS CCSI 6.1 ± 1.7; P = 0.01) but failed in five of five patients in group III.

CONCLUSION

Stapled transanal rectal resection improves quality of life in ODS patients with both severe constipation and faecal incontinence. Sacral nerve stimulation may efficiently improve persisting incontinence after STARR in selected patients.

Predictive factors for postoperative constipation and continence after stapled transanal rectal resection

BACKGROUND

Although stapled transanal rectal resection (STARR) has become an important surgical option in the treatment of obstructive defaecation syndrome, objective data about parameters that predict its success or failure are not yet available.

METHODS

Medical history, clinical and radiomorphological data were obtained prospectively from a multi-institutional STARR registry. Predictive factors for postoperative constipation (Cleveland Clinic Constipation Score, CCS) and incontinence (Cleveland Clinic Incontinence Score, CCIS) were identified using univariable and multivariable analysis.

RESULTS

Data were obtained for 181 of 201 patients in the STARR registry, with completed median follow-up of 19·4 (range 12-41) months. Although the CCS decreased significantly overall (from mean(s.d.) 16·3(4·9) to 6·7(4·1); P < 0·001), 31 patients (17·1 per cent) complained about persisting constipation. CCIS levels remained unchanged overall, but 16 patients (8·8 per cent) had new-onset faecal incontinence. Multivariable analysis revealed that rectocele (β = -0·302, P < 0·001) and intussusception (β = -0·392, P < 0·001) were independent predictors of low CCS levels, and intussusception (β = -0·216, P = 0·001) and enterocele (β = -0·171, P = 0·012) were independent predictors of low CCIS levels. In contrast, small rectal diameter (β = -0·293, P < 0·001), low squeeze pressure (β = -0·188, P = 0·005) and increased pelvic floor descent at rest (β = 0·264, P < 0·001) predicted high CCIS levels.

CONCLUSION

Factors for a favourable outcome after STARR included rectocele, intussusception and enterocele, whereas small rectal diameter, low sphincter pressure and increased pelvic floor descent were unfavourable. These findings should be integrated into the therapy algorithm for STARR.

Enterocele is not a contraindication to stapled transanal surgery for outlet obstruction: an analysis of 170 patients

AIM

Enterocele is common among patients suffering from obstructive defecation syndrome (ODS), but it is often considered a contraindication for stapled transanal surgery. The functional results and complication rates were compared in patients with or without enterocele who were treated with stapled transanal rectal resection (STARR) for ODS.

METHOD

Patients presenting with ODS were evaluated using standardized clinical and radiological investigations. A total of 170 patients were treated with either PPH01-STARR or Contour Transtar® and were followed up for a median of 18 months.

RESULTS

On preoperative defecography, 55 (32%) of 170 patients were found to have an enterocele. The preoperative Cleveland Clinic Constipation Scores (CCCS) in patients with and without enterocele were (mean ± standard deviation) 15.9 ± 5.4 and 15.4 ± 5.2, respectively. At 18 months postoperatively the CCCS were 8.5 ± 2.7 and 8.1 ± 2.6 (P < 0.001), respectively, in patients with and without enterocele. Morbidity was 7.3% (n = 4) in patients with enterocele (anal pain, n = 1; minor bleeding, n = 2; and acute urinary retention, n = 1) and 7.0% (n = 8) in patients without enterocele (anal pain, n = 3; minor bleeding, n = 3; acute urinary retention, n = 1; and staple line dehiscence, n = 1). There were no cases of pelvic sepsis, small bowel injury or postoperative ileus. No patient needed surgical re-operation.

CONCLUSION

There was no difference in functional outcome and postoperative complications in patients with and without enterocele undergoing STARR for ODS.

What happens in stapled transanal rectum resection?

INTRODUCTION

Stapled transanal rectum resection is becoming increasingly popular as a surgical option for the treatment of obstructive defecation syndrome. However, details about the anatomical changes produced by stapled transanal rectum resection and its correlation with success or failure is poorly understood. The aim of this study was to correlate the defecographical and clinical patterns in patients treated with stapled transanal rectum resection.

PATIENTS AND METHODS

Based on a multi-institutional stapled transanal rectum resection registry composed of a total of 182 patients, correlation analysis of clinical and radiological parameters was prospectively obtained from 51 patients with a completed 12-month follow-up.

RESULTS

Postoperative defecography shows significant changes in the following parameters: intussusception (89%-19%; P < .0001), enterocele (38%-18%; P = .038), rectocele (mean ± SD: 27.1 ± 7.4 mm to 16.5 ± 9.7 mm; P < .0001), rectal lumen (mean ± SD: 46 ± 11.4 mm to 35 ± 9.9 mm; P < .0001), anorectal angle (mean ± SD: 146.4 ± 10.6° to 132.4 ± 11.1°; P = .002), pelvic floor descent (mean ± SD: 59 ± 18 mm to 47 ± 1.3 mm; P = .0001), and, as a dynamic parameter, dynamic pelvic floor descent (mean ± SD: 30 ± 0.8 mm to 17 ± 0.4 mm; P < .0001). Of these parameters, reduction of intussusception (r = 0.433, 95% CI 0.15-0.61; P = .003), rectocele (r = 0.507, 95% CI 0.26-0.67; P = .001), and dynamic pelvic floor descent (r = 0.427, 95% CI 0.31-0.64; P = .001) correlated with a significant improvement in constipation. Reduction of intussusception positively affected postoperative continence (r = 0.524, 95% CI 0.29-0.70; P = .001), whereas reduced rectal lumen size correlated with incontinence and fecal urgency (r = -0.557, 95% CI -0.69 to -0.28; P = .001).

CONCLUSIONS

Improved constipation after stapled transanal rectum resection is associated with improvement of intussusception, rectocele, and dynamic pelvic floor descent. Postoperative continence is determined by 2 parameters, reduction of intussusception and rectal lumen size, which have opposing effects. Reduction of rectal lumen size may be responsible for new-onset fecal urgency, which is occasionally seen after stapled transanal rectum resection.

Comparative study of Contour Transtar and STARR procedure for the treatment of obstructed defecation syndrome (ODS)--feasibility, morbidity and early functional results

AIM

Stapled transanal rectal resection (STARR) is a promising new treatment for obstructed defecation syndrome (ODS). It may be performed using either a double-stapling technique (PPH-STARR) or with the new Contour Transtar (CT) device. The aim of this study was to evaluate the two techniques with respect to morbidity and functional outcomes.

METHOD

Patients presenting with ODS were evaluated using standardized clinical and radiological investigations and prospectively entered into a database. A total of 150 Patients were treated with either PPH-STARR (n = 68) or CT (n = 82) and further evaluated at 12 month postoperatively.

RESULTS

The mean size of the resected specimen was 27 cm(2) (SD +/-4.86 cm(2)) in the PPH-STARR group and 46 cm(2) (SD +/-10.6 cm(2)) in the CT group [P < 0.001]. Morbidity was 7.3% (n = 5) in the PPH-STARR group and 7.5% (n = 6) in the CT group. The most common complication was minor postoperative bleeding in both groups (PPH-STARR: n = 2, 2.9%; CT: n = 2, 2.4%) Overall there were no septic complications and no surgical re-interventions. There was a tendency for more postoperative pain following CT (n = 3, 3.6%) as compared with PPH-STARR (n = 1, 1.4%). Constipation Scores (CCS) were 15.50 +/- 5.71 in the PPH-STARR group and 15.70 +/- 5.84 in the CT group preoperatively and decreased significantly to 8.25 (SD +/-1.45) and 8.01 (SD +/-2.31) 12-months after surgery. Values did not differ significantly between the two groups.

CONCLUSIONS

Contour Transtar is as safe and effective as PPH-STARR and provides a true circumferential resection of rectal intussusception. This may benefit selected patients and result in improved long-term durability of the technique.

Outcome after resection of one hundred gastrointestinal stromal tumors

AIMS

To evaluate the outcome after surgical resection in patients with gastrointestinal stromal tumors and to determine the factors influencing local tumor recurrence or distant metastatic disease after locally complete tumor resection (R0).

METHODS

Outcomes of 100 patients with primary gastrointestinal stromal tumors (GIST) surgically managed between 1997 and 2006 at a single institution were reviewed. Univariate and bivariate analyses were used to determine factors affecting recurrence-free and tumor-free survival.

RESULTS

All patients (n = 100) had c-kit-positive GIST. There were 17% (n = 17) very low risk, 41% (n = 41) low risk, 19% (n = 19) intermediate risk and 23% (n = 23) high risk GIST originating from the stomach, small bowel, colon and rectum. The median patient age was 68 years (range 39-92). Seventy-three percent of the patients had symptomatic local disease. Most (94%; n = 94) of them underwent R0 resections of their primary tumor. R0 resection was significantly associated with a lower tumor-related mortality rate (p = 0.0001). The patients with recurrence/metastases had significantly larger tumors (p = 0.0017) and a mitotic index higher than 5/50 HPF (p = 0.0001). Seven of 20 patients from the high-risk group and 2 of 7 patients with metastatic disease developed local recurrence or further metastatatic tumor spread following R0 resection.

CONCLUSION

Surgical removal continues to be the mainstay of GIST treatment. R0 resection, tumor size and mitotic index are significant prognostic factors. Overall, more than 30% of the patients with high-risk GIST develop local recurrences and distant metastases despite R0 resection. Additional molecular pathological markers are needed to yield a more accurate tumor profile and to thus achieve a better predictability of the biological behavior of GIST.

Quality of life after transperineal rectosigmoidectomy

Background

This study evaluated continence, constipation and quality of life before and after perineal rectosigmoidectomy for full-thickness rectal prolapse.

Methods

Consecutive patients with full-thickness rectal prolapse undergoing perineal rectosigmoid- ectomy (Altemeier's procedure) between May 2004 and June 2008 were studied. A standardized questionnaire, including the Cleveland Clinic Constipation Score (CCCS), Cleveland Clinic Incontinence Score (CCIS) and quality of life scores (EuroQol—Five Dimensions, EuroQol—Visual Analogue Scale and Patient Assessment of Constipation—Quality of Life (PAC-QOL)), was administered before and after operation.

Results

Thirty-eight patients (32 women) of mean(s.d.) age 75(13) years underwent rectosigmoid- ectomy. Seven patients developed postoperative complications and one died. There was one recurrence 5 months after surgery. Twenty-nine patients completed the follow-up questionnaire and were reviewed after a median of 24 (range 6–48) months. Constipation and incontinence were significantly improved after surgery (mean CCCS from 10·21 to 3·58 and CCIS from 14·17 to 11·42; P &lt; 0·001). Quality of life, in terms of mobility, usual activities, pain/discomfort and anxiety/depression, were significantly better at follow-up (P &lt; 0·001), as was subjective health status (P &lt; 0·001). The PAC-QOL score improved significantly in all dimensions (P &lt; 0·001).

Conclusion

Transperineal rectosigmoidectomy improves general and constipation-related quality of life with good functional results.

Curative in situ ablation of colorectal liver metastases-experimental and clinical implementation

INTRODUCTION

In situ ablation of colorectal liver metastases is frequently assessed for palliative treatment only. The establishment of clinically relevant lesion size and a lack of long-term survival data were regarded as main limitations to using them with curative intention. In contrast to surgical liver resection, whose oncological findings seem to have remained unchanged over the years, the in situ ablation methods have considerably changed technically and clinically in the last few years.

OBJECTIVE

The aim of the paper was to point out experimental and clinical data underlining the impact of in situ ablation for potentially curative treatment of colorectal liver metastases.

DISCUSSION

On the basis of experimental data, the aim of complete local tumor control (R0 ablation) can only be obtained if additional energy is applied after reaching the tumor-adapted maximal coagulation volume. Analogous to the oncological safety margin in surgical resection, we defined this decisive energy difference as the "energy safety margin" for in situ ablation. The energy safety margin is the energy that must be additionally applied after reaching the plateau in the energy/volume curve to achieve complete tumor coagulation. In addition to that, in situ ablation should be combined with temporary interruption of hepatic perfusion whenever possible to prevent intralesional recurrences. In this way, the thermoprotective mechanism of hepatic perfusion can be effectively eliminated. With restrictions, the survival data after ablation in specialized centers is comparable to surgical resection with concomitantly lower morbidity and mortality. Based on recent findings and with the corresponding expertise in the field of ablation and state-of-the-art equipment, ablation is, thus, an alternative to surgical resection. The combined application of surgical resection and ablation is also a suitable method for increasing the R0 rate and thus helps improve the prognosis of treated patients. In summary, it can be said that in situ ablation is a useful expansion of the therapeutic spectrum of liver metastases and can be applied as an alternative to or in combination with surgical resection.

Laser-induced thermotherapy (LITT) elevates mRNA expression of connective tissue growth factor (CTGF) associated with reduced tumor growth of liver metastases compared to hepatic resection

BACKGROUND AND OBJECTIVES

Proliferation and synthesis of hepatocellular tissue after tissue damage are promoted by specific growth factors such as hepatic tissue growth factor (HGF) and connective growth factor (CTGF). Laser-induced thermotherapy (LITT) for the treatment of liver metastases is deemed to be a parenchyma-saving procedure compared to hepatic resection. The aim of this study was to compare the impact of LITT and hepatic resection on intrahepatic residual tumor tissue and expression levels of mRNA HGF/CTGF within liver and tumor tissue.

STUDY DESIGN/MATERIALS AND METHODS

Two independent adenocarcinomas (CC531) were implanted into 75 WAG rats, one in the right (untreated tumor) and one in the left liver lobe (treated tumor). The left lobe tumor was treated either by LITT or partial hepatectomy. The control tumor was submitted to in-situ hybridization of HGF and CTGF 24-96 hours and 14 days after intervention.

RESULTS

Volumes of the untreated tumors prior to intervention were 38+/-8 mm(3) in group I (laser), 39 +/- 7 mm(3) in group II (resection), and 42 +/- 12 mm(3) in group III (control) and did not differ significantly (P > 0.05). Fourteen days after the intervention the mean tumor+/-SEM volume of untreated tumor in group I (laser) [223 +/- 36] was smaller than in group II (resection) [1233.28 +/- 181.52; P < 0.001], and in group III (control) [978.92 +/- 87.57; P < 0.003]. Forty-eight hours after the intervention intrahepatic mRNA expression level of HGF in group II (resection) was almost twofold higher than in group I (laser) [7.2 +/- 1.0 c/mf vs. 3.9 +/- 0.4 c/mf; P<0.01]. Fourteen days after the intervention intrahepatic mRNA expression level of CTGF in group I (laser) was higher than in group II (resection) [13.89 +/- 0.77 c/mf vs. 9.09 +/- 0.78 c/mf; P < 0.003].

CONCLUSIONS

LITT leads to a decrease of residual tumor growth in comparison to hepatic resection. Accelerated tumor growth after hepatic resection is associated with higher mRNA level of HGF and reduced tumor growth after LITT with higher mRNA level of CTGF. The increased CTGF-mediated regulation of ECM may cause reduced residual tumor growth after LITT.

Improving laser-induced thermotherapy of liver metastases--effects of arterial microembolization and complete blood flow occlusion

INTRODUCTION

A prerequisite for an oncologically curative application of laser-induced thermotherapy (LITT) of liver metastases is complete tumor destruction. This increased effectiveness was achieved experimentally by combining LITT with interrupted hepatic perfusion. The aim of this study was to evaluate whether an interventional selective arterial microembolization might be as effective as complete blood flow occlusion using an open Pringle's maneuver.

PATIENTS AND METHODS

We included patients with unresectable colorectal liver metastases. LITT was performed without interrupted hepatic perfusion (control group) compared to LITT in combination with interrupted perfusion either by embolization of intraarterial degradable starch microspheres (DSM) (percutaneous access) or by complete hepatic inflow occlusion (Pringle's maneuver; open access). Online monitoring was performed using intraoperative ultrasound or MRI. Volumetric techniques were used to assess metastases and postinterventional lesions.

RESULTS

Fifty-six patients with 104 metastases (control group (25), DSM (37), and Pringle (42)) were treated. The preinterventional tumor volumes were significantly smaller than the postinterventional lesion volumes (control group: 9.8 vs. 25.3 cm3; DSM: 9.5 vs. 65.4 cm3; Pringle: 12.9 vs. 76.5 cm3). The morbidity rate was 21.4% without treatment-related mortalities. After 6 months follow-up, tumor recurrence was diagnosed in 6 patients (control group (4), LITT with DSM (1), and Pringle (1)).

CONCLUSIONS

Combining LITT with blood flow occlusion leads to a significant increase in lesion size. The application of DSM offers a safe and effective alternative to the open access with Pringle's maneuver. Compared to LITT-monotherapy, this modality achieves significantly larger thermal lesions with the need of fewer applications.

Bericht über den Workshop „Workflow Rektumkarzinom II” am 10. / 11.11.2006 in Burghausen

The task force "workflow rectal cancer II" defined operative techniques in lower rectal cancer, especially the total mesorectal excision and an improved technique of abdominalperineal resection. New aspects for treatment of rectal cancer with primary distant metastases are described. Due to newer publications a concept of bidirectional procedure with surgery and radiochemotherapy is recommended, where the operation must not be inevitably the first step. In anastomoses below 6 cm of the anocutaneous verge a reservoir should be performed on principle due to better functional results. The colon-j-pouch with a maximal loop length of 6 cm is best investigated under these conditions, the other procedures should be further evaluated.

Qualitätsindikatoren bei Diagnostik und Therapie des Rektumkarzinoms

Diagnostic and treatment of rectal cancer need a continuous quality assessment. Indicators of quality were compiled as indicator profile for a summarizing evaluation. The indicators selected should potentially show an appreciable variation of the quality target and in addition should be decisive for the outcome. For the evaluation of the clinical diagnostic the frequency of the determination of the pretherapeutic T, N and M categories and the proportion of pT 1-tumors were chosen, for the pathological diagnostic the number of histologically examined lymph nodes and the proportion of lymphnode positive patients. Process quality of treatment was defined by the following indicators: proportion of tumor excision, of definite therapy by local tumor removal, of neo-adjuvant long-term radiochemotherapy, of adjuvant treatment in patients not selected for neoadjuvant therapy, of total / partial mesorectal excision, of abdomino-perineal resection, postoperative mortality, frequency of clinically apparent anastomotic leakage, and of neurogenic bladder dysfunction at hospital discharge. The indicators for the quality of the performance of treatment were differentiated between surrogate indicators that can be determined immediately after accomplishment of primary surgical therapy giving strong clues for the further course of disease at an early date, and definite indicators. Important surrogate indicators comprise the occurrence of intraoperative local tumor cell dissemination, R 1 / 2-resection, pathohistologically CRM-positive tumor resection, and the quality of mesorectal excision (proportion of incomplete mesorectal excision). The definite indicators include the 5-year local recurrence rate and the 5-year overall survival rate. The corresponding quantifying parameters for the individual indicators are specified in this paper with precise figures.

Colorectal tumors and hepatic metastases differ in their optical properties—relevance for dosimetry in laser-induced interstitial thermotherapy

BACKGROUND AND OBJECTIVES

The therapeutic application of laser light is a promising alternative to surgical resection of colorectal liver metastases. The extent of tumor destruction achieved by this strategy depends primarily on light distribution in the target tissue. Knowledge about optical properties is necessary to predict light distribution in the tissue for careful irradiation planning. The aim of this study was to compare the optical behavior of healthy colon tissue with that of colorectal carcinomas and their hepatic metastases in the native and coagulated state in order to test the effect of malignant degeneration, metastasis, and thermal coagulation on optical parameters.

MATERIALS AND METHODS

Ninety tissue samples were taken from patients with a colorectal carcinoma and concomitant liver metastases: healthy colon tissue (n = 30); colon carcinoma (n = 30); liver metastases (n = 30). Optical properties were measured according to the single integrating sphere principle in the native state and after thermal coagulation in the wavelength range of 800-1,100 nm and analyzed by inverse Monte Carlo simulation.

RESULTS

The highest optical penetration depth for all tissue types was obtained at the end of the spectral range investigated. The highest penetration depths of 4.13 mm (healthy colon), 7.47 mm (colon carcinoma tissue), and 4.08 (liver metastases) were at 1,060 nm, although the values decreased significantly after thermal coagulation. Comparing healthy colon-to-colon carcinoma always revealed a significantly lower absorption and scattering coefficient in the tumor tissue. This resulted in a higher optical penetration depth of the laser light in the colon carcinoma tissue (P < 0.05). A direct comparison disclosed no agreement between the optical properties of the primary tumor and the liver metastases. In the native state, colon carcinoma tissue had a lower scattering coefficient (P < 0.05), higher anisotropy factor, and optical penetration depth than liver metastases (P < 0.05). The absorption coefficient did not differ significantly. The differences in the native state were equalized by tissue coagulation.

CONCLUSIONS

Colon carcinoma tissue has a higher optical penetration depth than healthy colon tissue, which speaks in favor of tumor selectivity for interstitial laser application, since large treatment volumes can be obtained in the tumor. The lack of agreement between primary tumors and their concomitant liver metastases indicates a modification of optical behavior through metastasis. Thermal coagulation of tissue leads to changes in the optical properties, which are clearly less pronounced in carcinoma tissue. The data obtained in this study clearly show that an individual irradiation schedule is necessary for effective and safe dosimetry in laser-induced thermotherapy (LITT).

In-vivo evaluation of a novel bipolar radiofrequency device for interstitial thermotherapy of liver tumors during normal and interrupted hepatic perfusion

BACKGROUND

Only monopolar systems have thus far been available for radiofrequency ablation of liver tumors, whose application is restricted because of the incalculable energy flow, reduction of electrical tissue conduction, and limited lesion size. The aim of this study was to evaluate a novel internally cooled bipolar radiofrequency application device under in vivo conditions and to compare the effect of this system on lesion size when combined with hepatic arterial microembolization or complete hepatic blood flow occlusion.

MATERIALS AND METHODS

In a porcine liver model, RFA (60 W, 12 min) was performed with either normal (n = 12), partially interrupted (arterial microembolization via a hepatic artery catheter n = 12) or completely interrupted hepatic perfusion (Pringle's maneuver, n = 12). RFA parameters (impedance, power output, temperature, applied energy) were determined continuously during therapy. RFA lesions were macroscopically assessed after liver dissection.

RESULTS

Bipolar RFA induced clinical relevant ellipsoid thermal lesions without complications. Hepatic inflow occlusion led to a 4.3-fold increase in lesion volume after arterial microembolization and a 5.8-fold increase after complete interruption (7.4 cm(3)versus 31.9 cm(3)versus 42.6 cm(3), P < 0.01).

CONCLUSIONS

The novel bipolar RFA device is a safe and effective alternative to monopolar RFA-systems. Interrupting hepatic perfusion significantly increases lesion volumes in bipolar RFA. This beneficial effect can also be achieved in the percutaneous application mode by RFA combined with arterial microembolization via a hepatic artery catheter.

[Nonoperative ablation for liver metastases. Possibilities and limitations as a curative treatment]

Under the term "nonoperative ablation" are grouped a number of heterogeneous approaches for the treatment of liver metastases, including laser-induced thermotherapy (LITT), radio-frequency therapy (RF), and cryotherapy. In general these procedures had been intended only for palliative purposes. The establishment of clinically relevant lesion size and a lack of long-term survival data were regarded as main limitations to using them with curative intention. During the last years however, new application systems have demonstrated remarkable results in RF and LITT, and some clinical studies have shown long-term survival in selected patients comparable to that for hepatic resection. We review possibilities and limitations of nonoperative ablation procedures with curative intent, highlighting the histopathological bases of thermal ablation techniques and clinical aspects such as R0 ablation and long-term survival.

Enhancement of the immune response to residual intrahepatic tumor tissue by laser-induced thermotherapy (LITT) compared to hepatic resection

BACKGROUND AND OBJECTIVES

In contrast to hepatic resection, thermally destroyed autologous tumor cells remain in situ after laser-induced thermotherapy (LITT). The aim of the study was to evaluate the effect of LITT and hepatic resection on the immune response to residual intrahepatic tumor tissue and the growth of untreated liver metastases.

STUDY DESIGN/MATERIALS AND METHODS

Two independent adenocarcinomas (CC531) were implanted into 60 WAG rats, one in the right (control tumor) and one in the left liver lobe (treated tumor). The left lobe tumor was treated either by LITT or partial hepatectomy. The control tumor was submitted to further investigation 24 hours, 96 hours, 7 days, and 10 days after treatment.

RESULTS

Ten days after treatment, control tumor volumes were 296+/-46 mm_ after LITT and 1,181+/-192 mm_, 1,387+/-200 mm_ after hepatic resection and no treatment, respectively (P<0.001). Peritoneal tumor spread was detected in 4/20 cases after LITT and in 17/20 cases after hepatic resection. Expression of CD8, B7-2 (CD86), and to lesser extent MHCII, LFA1 (CD11a), and ICAM1 (CD54), was significantly enhanced at the invasion front of control tumors after LITT compared to hepatic resection.

CONCLUSIONS

Our results suggest that LITT increases the immune response against untreated intrahepatic tumor tissue, which can lead to reduced tumor growth.

Effectivity of laser-induced thermotherapy: In vivo comparison of arterial microembolization and complete hepatic inflow occlusion

BACKGROUND AND OBJECTIVES

Laser-induced thermotherapy (LITT) is a promising method for local treatment of liver metastases. The aim of this study was to compare the effect of LITT on lesion size when combined with hepatic arterial microembolization or complete hepatic blood flow occlusion.

STUDY DESIGN/MATERIALS AND METHODS

In a porcine liver model, LITT (30 W 15 minutes) was performed with either normal (n = 12), partially interrupted (arterial microembolization via a hepatic artery catheter n = 12) or completely interrupted hepatic perfusion (Pringle's maneuver, n = 12). LITT lesions were macro- and microscopically assessed after liver dissection.

RESULTS

Hepatic inflow occlusion led to a fourfold increase in lesion volume after arterial microembolization and a ninefold increase after complete interruption (6.3. cm3 vs. 27.1 cm3 vs. 58.8 cm3, P < 0.01).

CONCLUSIONS

Interrupting hepatic perfusion significantly increases lesion volumes in LITT. This beneficial effect can also be achieved in the percutaneous application mode by LITT combined with arterial microembolization via a hepatic artery catheter.

In situ ablation of experimental liver metastases delays and reduces residual intrahepatic tumour growth and peritoneal tumour spread compared with hepatic resection

Background

The aim of this study was to evaluate the influence of in situ ablation and hepatic resection of experimental liver metastases on residual intrahepatic tumour growth and macroscopic peritoneal tumour spread.

Methods

Two colonic carcinomas (CC 531) were implanted into 90 WAG rat livers, one in the right liver lobe (untreated tumour) and one in the left liver lobe (treated tumour) of each rat. The animals were randomized into two test groups and a sham-operated control group. Animals in group 1 received in situ ablation (laser-induced thermotherapy) of the treated tumour. Rats in group 2 were submitted to partial hepatectomy. Untreated tumour volumes were calculated and the incidence of macroscopic peritoneal spread was determined at different times.

Results

After 21 days median (95 per cent confidence interval) volumes of untreated tumours were 507 (282) mm3 in group 1, 2096 (994) mm3 in group 2 and 1896 (755) mm3 in group 3. Compared with values obtained before treatment, growth of the untreated tumours had increased significantly after 4 days in group 2, after 7 days in group 3 and after 10 days in group 1. Macroscopic peritoneal tumour spread was detected in six of 30 animals in group 1 (laser), in 20 of 30 in group 2, and in 24 of 30 in group 3.

Conclusion

Compared with hepatic resection, in situ ablation of experimental liver metastases delays and reduces residual intrahepatic tumour growth and macroscopic peritoneal tumour spread.

Laser induced thermotherapy (LITT) of experimental liver metastasis-detection of residual tumors using Gd-DTPA enhanced MRI

BACKGROUND AND OBJECTIVE

The aim of this study was to evaluate the accuracy of Gd-DTPA MRI in the detection of recurrent tumor after laserinduced thermotherapy (LITT) of experimental liver metastases.

STUDY DESIGN/MATERIALS AND METHODS

LITT was performed at different energy levels in VX-2 tumor-bearing rabbits (n = 80). MRI and histology were placed at 0, 24, 96 hours, and 14 days. Signal intensities were calculated of the transition between thermally damaged and undamaged tissue (transition zone = TZ) and of the surrounding tissue (reference zone = RZ).

RESULTS

Tumor recurrence was seen in 47 animals. At 24 hours sensitivity, specificity and accuracy was 92, 100, and 95% in TZ and 23, 100, and 50% in RZ. At 14 days sensitivity, specificity and accuracy was 100, 11, and 60% in TZ and 100, 89, and 95% in RZ.

CONCLUSIONS

Recurrence is best excluded in TZ at 24 hour and in RZ at 14 day with an accuracy up to 95%.

Laser-induced thermotherapy: intra- and extralesionary recurrence after incomplete destruction of experimental liver metastasis

PURPOSE

The aim of this study was to determine the energy (J/mm3 tumor volume) and temperature required for a complete laser-induced thermotherapy (LITT) of experimental liver tumors, and to find out causes and areas of local recurrence followed by incomplete treatment.

METHODS

In VX-2 tumor-bearing rabbits LITT was performed using neodymium:yttrium-aluminum-garnet (Nd:YAG) laser (1064 nm) with a diffuser-tip applicator and a temperature feedback system. The animals were randomized into four groups (n = 20) that differed in the target temperature at the tumor border as follows: 45 degrees C, 50 degrees C, 55 degrees C and 60 degrees C. The target temperature was held for 10 min constant. Histologic examination (hematoxylin and eosin [H and E], nicotinamide adenine dinucleotide phosphate [NADPH]-dehydrogenase) was performed at 0 h, 24 h, 96 h, and 14 days after LITT.

RESULTS

The pretreatment tumor volume of 2191 +/- 61 mm3 was the same for all groups (p > 0.05). Energy up to target temperature and total energy required, lesion size, and the rate of incomplete tumor ablation (recurrences) are listed below (ap < 0.05, Kruskal-Wallis test). Histologically, two forms of local recurrences could be differentiated intralesionary and extralesionary.

CONCLUSIONS

To achieve complete in situ ablation under the given conditions, it is necessary to apply laser energy of 3 J/mm3 tumor volume. A minimum temperature of 60 degrees C on the tumor border presumed an application of 10 min. Recurrence was found outside the coagulation zone (extralesionary) and in high vascularized areas within the coagulation zone (intralesionary).