| 1. |
- Holmgren, Klas, 1989-
(författare)
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Permanent stoma after anterior resection for rectal cancer : prevalence and mechanisms
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- While sphincter-saving surgery constitutes standard treatment for rectal cancer, anterior resection still harbours a significant risk of a permanent stoma in the long run. Although anastomotic leakage plays a major role in this surgical dilemma, the exact mechanisms are not known, while surveys indicate a stoma-free outcome is essential for a majority of patients. To address this issue, the overall aim of the present thesis was to investigate the permanent stoma prevalence in patients undergoing anterior resection for rectal cancer in Sweden, and to identify plausible mechanisms that impede prospects of a stoma-free outcome.In a population-based cohort, chart review of patients who had anterior resection for rectal cancer in the Northern healthcare region in Sweden between 2007 and 2013 showed that 75 out of 316 (24%) patients ended up with a permanent stoma. Of 274 patients (87%) primarily defunctioned with a stoma, 229 underwent stoma closure, 21 (9%) of whom suffered major complications that required return to theatre or worse. A permanent stoma was shown to be more common among patients with anastomotic leakage and an advanced tumour stage.A registry-based method to estimate nationwide stoma outcome after anterior resection for rectal cancer was developed, using data from the Swedish Colorectal Cancer Registry and the National Patient Registry. With a chart-reviewed cohort as reference, stoma outcome was assessed with a positive predictive value of 85.1%, and a negative predictive value of 100.0%. In patients operated in Sweden between 2007 and 2013, the registry-based method determined that 942 out of 4768 (19.8%) had a permanent stoma, while stoma rates varied substantially between different healthcare regions.In a 1:1 matched case-control study of 82 patients who had curative resection for non-disseminated colorectal cancer, a subgroup analysis of 34 patients with rectal cancer displayed biomarker aberrations in serum measured preoperatively in those with anastomotic leakage. Compared to complication-free controls, 15 proteins related to inflammation were elevated, of which two (C-X-C motif chemokine 6, and C-C motif chemokine 11) remained significant after adjustment for multiple testing.Based on a cohort of 4529 patients who had anterior resection, tumour height served as a proxy to determine the extent of mesorectal excision, while long-term stoma outcome was classified using a previously validated registry-based method. Defunctioning stomas significantly decreased chances of a stoma-free outcome, especially in patients undergoing partial mesorectal excision; for these patients, faecal diversion was also least beneficial in terms of reducing anastomotic leakage.In conclusion, every fifth patient undergoing anterior resection for rectal cancer in Sweden eventually ends up with a permanent stoma. Although construction of a defunctioning stoma decreases the risk of symptomatic anastomotic leakage, subsequent takedown surgery carries a substantial risk of major complications, while chances of a long-term stoma-free outcome become significantly reduced. To facilitate selective use of faecal diversion, novel markers to identify high-risk anastomoses prior to surgery have been identified, but require validation in larger prospective settings. Anterior resection without a defunctioning stoma should be considered in appropriately informed patients for whom a stoma-free outcome is of importance. In particular, this holds true for patients eligible for partial mesorectal excision, where anastomotic dehiscence is less frequent and the advantageous effects of a defunctioning stoma are limited.
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| 2. |
- Kverneng Hultberg, Daniel, 1990-
(författare)
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Surgery for rectal cancer : the impact of perioperative factors
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Rectal cancer is one of the most common and deadly cancer forms worldwide. A large proportion of rectal cancer patients are surgically treated with curative intention, with anterior resection being the most frequently used method today. During surgery, the inferior mesenteric artery is either ligated proximal (high tie) or distal to the left colic artery (low tie). It is not known whether the tie level affects the oncologic nor the functional outcome. Postoperatively, about one in ten patients develop an anastomotic leakage. It is unclear whether treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) affects the risk of leakage, or whether having a leakage influences the functional outcome. The general aims of this dissertation were to increase the knowledge of intra- and postoperative treatment for rectal cancer, with the goal of improving the oncologic and functional outcomes, as well as reducing postoperative complications. National registers, predominantly the Swedish Colorectal Cancer Registry, were used in all of the dissertation’s four retrospective cohort studies to identify and retrieve information regarding patients. Various statistical methods have been used in all studies with the aim of eliminating bias, including confounding.In Study I, high tie slightly increased the total number of harvested lymph nodes in the included 8287 patients, as compared with low tie, while the primary outcome cancer-specific survival, as well as secondary oncologic outcomes, were not affected. This indicates that the oncologic outcome does not have to be considered when the surgeon determines the level of tie.In Study II, investigating the effect of tie level on the functional outcome, the outcome was any defecatory or urogenital symptoms two years after anterior resection, assessed with a mailed questionnaire. With a response rate of 86%, 805 patients were included. High tie did not, except for increasing the need of defecation at night, influence the risk of major dysfunction. Again, this would facilitate the choice of tie level.Study III used the same outcome, and in part the same study population, as Study II, but instead with the exposure anastomotic leakage. With a response rate of 82%, 1180 patients were included. We found that anastomotic leakage increased the risk of reduced sexual activity and increased the use of aid products for fecal incontinence after anterior resection, while the risk of urinary incontinence was unexpectedly decreased. Other outcomes were not clearly affected. In Study IV, in addition to the register, information was gathered from patient records. In the included 1495 patients who had undergone anterior resection, postoperative NSAID treatment was not found to increase the risk of symptomatic anastomotic leakage. There were no differences between non-selective and COX-2 selective NSAIDs. This study does not support that NSAID treatment increases the risk of anastomotic leakage after such surgery.
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| 3. |
- Boström, Petrus, 1981-
(författare)
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Rectal cancer : the influence of surgical technique on morbidity, mortality and survival
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Surgery is still the most common treatment for rectal cancer, being the most effective and cost-efficient modality. However, it is not without risk, nor without controversies. This dissertation is an evaluation of the pros and cons of high versus low ligation, whether anastomotic leakage is still prevalent after surgery and associated with increased mortality, and if the risk of leakage could be predicted by early postoperative pain.Study I relied upon case records and registry data to evaluate the causal effect of high ligation on the risk of anastomotic leakage after anterior resection in 722 patients with increased cardiovascular risk. When controlling for confounders, no association was found overall. However, an increased risk for leakage after high ligation was noted for the few patients who suffered from both manifest cardiovascular disease and ASA III–IV (OR 3.66, 95% CI 1.04–12.85) and when performed in a low volume hospital (OR 3.89, 95% 1.58– 9.59). Study II estimated the risk of anastomotic leakage and death after anterior resection today. Among the 6,948 patients, 10.0% suffered from leakage, in whom mortality was 3.9% versus 1.5% for patients without a leak. However, this increased mortality was driven entirely by patients in need of reintervention, who exhibited a 7.5% 90-day mortality, resulting in a significantly increased risk (OR 5.57, 95% CI 3.29–9.44), when controlling for confounders, while conservatively treated leakage was not associated with mortality. Age acted as an effect modifier, as postoperative mortality after leakage was increased in the elderly.Study III returned to high versus low ligation as exposure, to evaluate the long-term oncological benefits of either ligation level, with cancer-specific survival as primary outcome. The final cohort of 8,287 patients who underwent abdominal surgery for rectal cancer, with curative intent, was followed for a minimum of 3.5 years. After propensity score matching, no significant differences were found between high and low ligation for any survival or recurrence analysis, nor in the unmatched cohort, when controlling for confounders. A statistically significant difference was found for lymph node harvest, which was slightly greater in high ligation (17.7 vs 16.7 lymph nodes). Finally, study IV estimated the independent predictive ability of postoperative pain, measured on the numerical rating scale (NRS), on the risk for anastomotic leakage after colorectal cancer surgery. It seems as if increased early pain is an independent predictor for leakage (OR 1.73, 95% CI 1.22– 2.46 for NRS 4–10), with increasing risk of leakage with increasing pain (OR 2.42 for NRS 8–10). In addition, increased pain was more strongly associated with more severe leakage.In summary, the level of ligation seems to be of importance only in a select group of high-risk patients, but offers no obvious oncological advantages. The high incidence and serious sequelae of anastomotic leakage makes it one of the most important clinical challenges in colorectal surgery, with especially detrimental effects in the elderly. A better understanding of the causal pathways behind leakage, and the overall harm and benefit of ligation level and diverting stomas, might allow a better selection of treatment for future patients.
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| 4. |
- Falk, Wiebke, 1978-
(författare)
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Epidural Analgesia for Colorectal Cancer Surgery : Experimental and Clinical studies
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Epidural analgesia (EA) with local anaesthetics and opioids is used for pain management after colorectal cancer (CRC) surgery. In recent years, a possible beneficial effect of EA on cancer recurrence and survival after surgery has been proposed. The aim of this thesis was to study the effects of EA on short- and long-term postoperative outcomes after CRC surgery with curative intent.Study I, an in vitro study, investigated the effects of two different local anaesthetics, lidocaine and ropivacaine, on cell viability and cell proliferation in colon cancer cell lines SW480 and SW620. Neither lidocaine nor ropivacaine reduced cell viability or proliferation at systemically, by epidural administration achievable concentrations.In study II, the effect of EA on the systemic level of different cytokines as a marker of inflammation was studied. Except for a reduced level of the anti-inflammatory cytokine IL-10, no other significant effects of EA on the systemic cytokine levels at two time points postoperatively could be shown, when compared to patients receiving intravenous morphine.Study III was an epidemiological study, examining the question if EA affects postoperative complications and mortality after surgery using data from the Swedish Colorectal Cancer Registry and the Swedish Perioperative Registry. No association between EA and a reduction in postoperative complications or mortality could be established.Study IV, a randomised, controlled trial, the effects of EA on diseasefree survival (DFS), postoperative complications and pain after surgery were compared to patient-controlled intravenous analgesia with morphine. Apart from superior pain relief during the first postoperative day, no significant effects of EA on the occurrence of postoperative complications, length of hospital stay or DFS were found.
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| 5. |
- Floodeen, Hannah, 1981-
(författare)
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Defunctioning stoma in low anterior resection of the rectum for cancer : Aspects of stoma reversal, anastomotic leakage, anorectal function, and cost-effectiveness
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Rectal cancer is a common malignancy treated with surgical resection and curative intent in the majority of cases. One treatment option is low anterior resection (LAR) with preserved bowel continuity, often involving the formation of a temporary defunctioning stoma (DS).The general aim of this thesis was to improve understanding of the role of DS in rectal cancer surgery with regard to timing of stoma reversal and development of anastomotic leakage (AL), impact on long-term anorectal function (AF), as well as aspects of cost-effectiveness.Study I addressed the timing of stoma reversal following LAR. We found that 19% of reversed patients were reversed within 4 months of LAR, while 81% of reversals were delayed. In 58% of delayed reversals the delay was due to low priority on surgical waiting lists.Studies II-IV were based on 234 patients randomized to receive a DS or no DS following LAR. Study II compared patients with AL following LAR diagnosed during the initial hospital stay (early leakage, EL) with patients diagnosed after hospital discharge (late leakage, LL). LL was more common in females, and originated more frequently from the transverse stapler line. EL was more common in males, and originated more frequently from the circular stapler line. Study III assessed AF 5 years after LAR with regard to whether patients initially had a DS or no DS. We found no difference in AF between the two randomized groups. When comparing with a 1-year follow-up in the same patient cohort, there were no further changes in AF over time. Study III assessed necessary healthcare resources and cost within 5 years of LAR, depending on whether patients initially had a DS or no DS. The overall cost analysis revealed a higher cost for patients randomized to DS, regardless of the cost-savings associated with a reduced frequency of anastomotic leakage.
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| 6. |
- Grahn, Oskar, 1985-
(författare)
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Modulating the inflammatory response after colorectal cancer surgery : friend or foe?
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Colorectal cancer was the second most deadly and third most common cancer globally in 2020. In Sweden, more than 5,000 new colonic cancer cases and more than 2,000 rectalcancer cases were reported in 2021, making colorectal cancer the third most common in Sweden (excluding skin malignancies).Anastomotic leakage after colorectal cancer surgery is a feared complication that confers substantial morbidity, including a higher risk of permanent stoma and cardiovascular morbidity, but can also impart an increased risk of recurrence and mortality; the reason why leakage might cause this is not established. Perioperative inflammation including upregulation of cyclooxygenase-enzymes, which is further increased by anastomotic leakage, can possibly modulate both anastomotic healing as well as impact minimal residual disease. Non-steroidal anti-inflammatory drugs (NSAIDs) act by inhibiting COX-enzymes and can be part of a postoperative multimodal analgesia protocol. However, their postoperative use has been debated, with fears of NSAIDs possibly increasing anastomotic leakage rates.Study I was a retrospective cohort study on 1,341 patients who had undergone anterior resection for rectal cancer. Exposure was at least two days with NSAIDs during the first postoperative week, and the primary outcome was recurrence-free survival. A Cox regression model could not demonstrate a significant association with a hazard ratio (HR) of 1.02 (95% confidence interval (CI): 0.79–1.33) and neither did a propensity score-matched analysis. An instrumental variable analysis displayed a tentative improvement in recurrence-free survival in the NSAID-exposed (HR 0.61; 95% CI 0.38–0.99), but the core assumptions to perform such an analysis were not fully satisfied.Study II was a protocol-based retrospective cohort study with a total of 6,945 patients resected for colorectal cancer with a primary anastomosis formed. NSAID-exposure was determined by each individual hospital’s postoperative analgesia protocol, while patient data and outcomes were retrieved from the Swedish colorectal cancer registry. Some 3,996 (58%) patients were treated at a hospital with NSAIDs included in their postoperative analgesia protocol. No significant association with recurrence-free survival was seen (HR 0.97, 95% CI0.87–1.09). However, a reduction in cancer recurrence was demonstrated (HR 0.83, 95% CI0.72‒0.95), with an increased risk reduction for locoregional (HR 0.68, 95% CI 0.48–0.97) in comparison to distant recurrence (HR 0.85, 95% CI 0.74–0.98). Anastomotic leakage was less frequent as well, mainly because of a reduction in the group with colorectal or ileorectal anastomoses (HR 0.47, 95% CI 0.33–0.68).In Study III, the aim was to explore proteomic and biological pathway alterations in patients with peritoneal infection. This was a 1:1 matched cohort study on patients resected for colorectal cancer with a primary anastomosis formed, including 32 cases who suffered a postoperative peritoneal infection matched with 32 controls with a complication-free postoperative stay. Serum samples were retrieved from their first postoperative visit and at one year postoperatively. Out of a total of 270 proteins tested, 77 were differentially expressed at the first postoperative visit at a median sampling time of 41 days after surgery. Many of the top hub proteins are known actors in colorectal cancer progression, including survival and invasiveness, potentially enhancing minimal residual disease. Over-represented pathways were related to cardiomyopathy, cell-adhesion, extracellular matrix, phosphatidylinositol-3-kinase/Akt (PI3K-Akt) and transforming growth factor beta (TGF-Beta) signalling.In Study IV, the aim was to evaluate the frequency of a known polymorphism of the COX-2 gene promotor -765G>C in a Swedish cohort of colorectal cancer patients, and whether a previously reported association between this gene variant with an increase in anastomotic leakage could be reproduced. This was a 1:1 matched case-control study on a total of 94 patients who were resected for colorectal cancer with a subsequent primary anastomosis, with cases suffering a peritoneal infection. Preoperative blood and serum samples were genotyped and analysed using pre-defined protein panels. Of the 94 patients in total, one in each group were homozygous for the minor allele C/C, and ten cases and 14 controls were heterozygous with G/C and the rest were homozygous for the major allele. Thus, there were fewer individuals with the minor allele in the case group, with a non-significant odds ratio of 0.71(p=0.413), ultimately not replicating the finding of the previous study. The protein quantitative trait loci analysis rendered no associations of interest.In conclusion, no statistically significant effects on recurrence-free survival from postoperative NSAIDs in patients resected for colorectal cancer could be demonstrated in study I, whereas significant associations between NSAID use and reduction in frequency of anastomotic leaks as well as cancer recurrence could be shown in study II. In study III, numerous proteins were differentially expressed in patients suffering a postoperative peritoneal infection, even after more than a month’s duration, potentially stimulating minimal residual disease. The over-representation analysis found pathways related to cardiomyopathy, which could help explain the increase in cardiovascular morbidity in patients suffering anastomotic leakage. Study IV could not reproduce the potentially marked increase in anastomotic leak frequency in carriers of the COX-2 gene promotor -765G>C polymorphism in a Swedish sample. Whether to include NSAIDs or not in postoperative multimodal analgesia is a question still not answered, and it may depend on the genotype, the patient’s preoperative inflammatory state, tumour location, the specific NSAID used, and whether a leak has already occurred. NSAIDs might have effects on both morbidity including cardiovascular and anastomotic leakage as well as minimal residual disease including recurrence and mortality. This thesis suggests potential protective effects regarding both anastomotic leakage as well as cancer recurrence, but it seems to depend on at least some of the aforementioned factors. The proteomic landscape regarding postoperative peritoneal infection has been investigated, and where it has also been demonstrated that the duration of said alterations can be greater than was earlier suspected. Finally, even if a replication attempt was not successful considering the relation between a COX-2 gene promotor polymorphism and anastomotic leakage, it could be worthwhile to attempt further replication studies.
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