Swedish Cancer Registry Research Articles

The impact of high exposure to perfluoroalkyl substances and risk for hormone receptor-positive breast cancer – A Swedish cohort study

IntroductionPerfluoroalkyl substances (PFAS) are persisting chemicals with endocrine disruptive and carcinogenic properties. Previous studies involving cohorts with high PFAS exposure have not shown an increased risk of breast cancer. Research on PFAS and breast cancer according to hormone receptor status is limited. This study aims to investigate the association between PFAS exposure and hormone receptor-positive breast cancer. Materials and MethodsIn 2013, high levels of PFAS (sum of PFAS > 10,000 ng/L), dominated by perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS) were found in the drinking water from one of the two waterworks in Ronneby, Sweden. Breast cancer diagnoses and information of adjuvant endocrine therapy were retrieved from the Swedish Cancer Register and The Prescribed Drug Register 2006–2016 for a cohort of women residing in the municipality between 1985 and 2013 (n = 24,509). Individual exposure was assessed based on municipality waterworks distribution data linked to annual residential addresses. Cox proportional hazards models were used in the analysis. The highest achieved educational level was used as an indicator of socioeconomic position. Sensitivity and subgroup analysis were performed for prepubertal exposure and diagnosis before or after age 50 (assumed menopause). ResultsThere were 313 cases of malignant breast cancer among women ≤ 85 years between 2006 and 2016. Of these, 224 cases (72 %) were considered hormone receptor-positive based on the first prescription of adjuvant endocrine therapy, antiestrogens (40 %) or aromatase inhibitor (60 %). Among women ever living at a residential address with high PFAS exposure, the hazard ratio (HR) for breast cancer classified as hormone receptor-positive was 0.84; 95 % confidence interval (CI) 0.61, 1.14. Findings were similar before and after menopause. ConclusionHigh PFAS exposure from drinking water, dominated by PFOS and PFHxS, was not associated with an elevated risk of hormone receptor-positive breast cancer.

Educational outcomes school year nine in children treated for acute lymphoblastic leukemia: A nationwide registry-based study from Sweden.

Acute lymphoblastic leukemia (ALL) constitutes approximately 25% of pediatric cancers, and with contemporary protocols, the 5-year survival rate is over 90%. Despite improved survival, neurocognitive impairments from treatment raise concerns. This registry study aimed to explore the impact of ALL treatment on educational outcomes from school year nine in Swedish children. A population-based cohort of 503 children diagnosed with ALL from 1990 to 2010 was identified from the Swedish Childhood Cancer Registry and matched with five controls each. Assessed variables were delayed graduation, high school eligibility, total merit value, school grades in Swedish, English, mathematics, and physical education, and results in national tests. Analyses were performed between cases and controls and by sex, age at diagnosis, and risk group. Our results showed that, compared to controls, cases had higher odds for delayed graduation, poorer results in physical education, and higher rates of absence in national tests in English and mathematics. Children in the standard-risk group (treated with first-line chemotherapy only) exhibited similar results to matched controls whereas children in the high-risk group (treated with cranial irradiation, hematological stem cell transplantation, or/and for ALL relapse and thus likely received also radiotherapy) had lower total merit value compared to controls. We conclude that Swedish children diagnosed with ALL between the years 1990-2010 mainly exhibited comparable educational outcomes to controls, although children in the high-risk group had lower results. These findings highlight the importance of evaluating especially children with high-risk ALL in order to identify those requiring educational support and for designing targeted interventions.

Evaluation of data quality in the Swedish National Penile Cancer Register.

The National Penile Cancer Register (NPECR) in Sweden was initiated in year 2000 and currently contains more than 3,900 men diagnosed with penile cancer. The aim of this study was to evaluate data quality in the NPECR in terms of completeness, timeliness, comparability, and validity. Completeness was assessed by cross-linkage to the Swedish Cancer Register. Timeliness, defined as time from date of diagnosis to date of reporting in the NPECR, was calculated. Comparability was evaluated by reviewing and comparing coding routines in the NPECR with national and international guidelines. To assess validity, medical records of 375 men with a penile cancer diagnosis in the NPECR between 2017 and 2020 were reviewed and selected variables were re-abstracted and compared with previously registered data. Completeness was high (93%). Timeliness was in median 4.6 (Inter Quartile Range 2.6-8.8) months. Comparability was good with coding routines and the registration forms were in compliance with current guidelines. Overall, the validity was high. The majority of variables showed an exact agreement exceeding 90%. Data quality in the Swedish NPECR is generally high with respect to completeness, timeliness, comparability, and validity. Hence, the NPECR represents a reliable data source for monitoring the quality of penile cancer care and research. Data quality can be further improved by revision of reporting forms and manuals, training of reporting staff, and by organizational adjustments.

Survival in Thyroid Cancer in Sweden From 1999 To 2018.

Thyroid cancer (TC) is diagnosed in several histological types which differ in their clinical characteristics and survival. We aim to describe how they influence TC survival in Sweden. Cancer data were obtained from the Swedish cancer registry between years 1999 and 2018, and these were used to analyze relative survival. Relative survival for all TC improved when analyzed in 10-year periods, and female survival improved more than male survival. Female survival advantage appeared to be present also for specific histological types, although case numbers were low for rare types. Female 5-year relative survival for TC was 100% for follicular, 95.1% for oncocytic, 93.4% for papillary, 89.7% for medullary, and 6.1% for anaplastic cancer. Among the clinical TNM classes, only T4 and M1 stages were associated with decreased survival compared to T1-3 and M0. Anaplastic cancer presented most often at high T and M1 stages, in contrast to other TC. Curiously, the diagnostic age for anaplastic M1 patients was lower than that for M0 patients. Both anaplastic and medullary cancers did not show age-dependent increases in the probability of metastases, in contrast to the main histological types. This could indicate the presence of several types of anaplastic and medullary cancers. The poor survival for anaplastic TC is an extreme contrast to the excellent survival of differentiated TC. As less than 20% of anaplastic cancer patients survived one year, urgent diagnosis and initiation of treatment are important. Facilitated treatment pathways have been instituted in Denmark resulting in improved survival. Anaplastic cancer should be a target of a major research focus.

General Population Mortality Adjustment in Survival Extrapolation of Cancer Trials: Exploring Plausibility and Implications for Cost-Effectiveness Analyses in HER2-Positive Breast Cancer in Sweden.

In economic evaluations of novel therapies, assessing lifetime effects based on trial data often necessitates survival extrapolation, with the choice of model affecting outcomes. The aim of this study was to assess accuracy and variability between alternative approaches to survival extrapolation. Data on HER2-positive breast cancer patients from the Swedish National Breast Cancer Register were used to fit standard parametric distribution (SPD) models and excess hazard (EH) models adjusting the survival projections based on general population mortality (GPM). Models were fitted using 6-y data for stage I and II, 4-y data for stage III, and 2-y data for stage IV cancer reflecting an early data cutoff while maintaining sufficient events for comparison of model estimates with actual long-term outcomes. We compared model projections of 15-y survival and restricted mean survival time (RMST) to 15-y registry data and explored the variability between models in extrapolations of long-term survival. Among 11,224 patients compared with the observed registry 15-y RMST estimates across the disease stages, EH cure models provided the most accurate estimates in patients with stage I to III cancer, whereas EH models without cure most closely matched survival in patients with stage IV cancer, in which cure assumption was less plausible. The Akaike information criterion-averaged model projections varied as follows: -8.2% to +5.3% for SPD models, -4.9% to +5.2% for the EH model without a cure assumption, and -19.3% to -0.2% for the EH model with a cure assumption. EH models significantly reduced between-model variance in the predicted RMSTs over a 50-y time horizon compared with SPD models. EH models may be considered as alternatives to SPD models to produce more accurate and plausible survival extrapolation that accounts for general population mortality. Excess hazard (EH) methods have been suggested as an approach to incorporate background mortality rates in economic evaluation using survival extrapolation.We highlight that EH models with or without a cure assumption can produce more accurate survival projections and significantly reduce between-model variability in comparison with standard parametric distribution models across cancer stages.EH models may be a preferred modeling method to reduce model uncertainty in health economic modeling since models that would otherwise have produced implausible extrapolations are constrained by the EH framework.Reduced uncertainty in economic evaluations will enhance the application of evidence-based health care decision making.

Malignancies After Lung Transplantation.

Lung transplantation (LTx) is a well-known treatment for end-stage lung disease. This study aimed to report the incidence of cancer after LTx and long-term outcome among lung transplant recipients with a pretransplant diagnosis of cancer. Patients who underwent LTx between 1990-2016 were included in the study. Detection of cancer was obtained by cross-checking the study population with the Swedish Cancer Registry and the Cause-of-Death registry. A total of 614 patients were followed for a median of 5.1years. In all, 159 malignancies were diagnosed. The excess risk of cancer or standardized incidence ratio (SIR) following LTx was 5.6-fold compared to the general Swedish population. The most common malignancies were non-melanoma skin cancer (NMSC) (SIR 76.5 (95%CI 61.7-94.8); non-Hodgkin lymphoma (SIR 23.5, 95%CI 14.8-37.2); and lung cancer (SIR 8.89, 95%CI 5.67-13.9). There was no significant difference in overall survival between those with and without a history of cancer before LTx (p = 0.56). In total, 159 malignancies were identified after LTx, which was a 5.6-fold higher relative to the general population. A history of previous cancer yields similar survival in selected recipients, compared to those without cancer prior to LTx.

Malignancies After Heart Transplantation.

Heart transplant patients have an increased risk of developing cancer. Patients who underwent HTx between 1985 and 2017 were included. Detection of cancer was obtained by cross-checking the study population with the Swedish Cancer-Registry and the Cause-of-Death-Registry. A total of 664 patients were followed for a median of 7.7years. In all, 231 malignancies were diagnosed in 138 patients. Compared to the general population the excess risk of cancer following HTx was 6.2-fold calculated as the standardized incidence ratio (SIR) and 2.9-fold after exclusion of non-melanoma skin cancer (NMSC). The most common malignancies were NMSC, non-Hodgins lymphoma, and lung cancer. There was no significant difference in overall survival between those with and without a history of cancer before HTx (p = 0.53). During a median follow-up of 7.7years, 19% of HTx recipients developed cancer, 6.2-fold higher relative to the general population, and 2.9-fold higher when excluding NMSC. Risk factors for malignancies (excluding NMSC) included previous smoking, hypertension and prolonged ischemic time; and for NMSC, increasing age, seronegative CMV-donors, and azathioprine. A previous cancer in selected recipients results in similar survival compared to those without cancer prior to HTx.

Melanoma Incidence and Mortality Trends in Sweden.

Over the past decades, many global regions have experienced a steady increase in the incidence of cutaneous melanoma. However, more recently, a downward trend has been observed in the younger age groups in Australia and the US. Yet, in Europe, none of the countries have reported any significant decline in melanoma incidence for any age group. To assess melanoma incidence and mortality trends in Sweden, with a focus on individuals younger than the average age of melanoma onset. This cohort study used data on the national population from the Swedish Melanoma Registry and the Swedish Cancer Registry, which cover more than 99% of all primary invasive cutaneous melanomas diagnosed in the country. All patients diagnosed from 1990 to 2022 were included. Incidence and mortality rates per 100 000 inhabitants were calculated for each year and shown as average annual rates for every 5-year period from 1990 to 2022. Joinpoint regression models were used to evaluate statistical significance of temporal trends and points of change. There were 34 800 primary invasive cutaneous melanomas (19 582 [56.3%] in females and 15 218 [43.7%] in males) reported in 33 324 individuals younger than 60 years (median [IQR] age, 48 [36-58] years) from 1990 to 2022. A consistent rise in melanoma incidence was observed among those 50 to 59 years old. The age groups from 20 to 29 years, 30 to 39 years, and 40 to 49 years showed an incidence peak in 2013 to 2015 followed by stable or significantly declining rates until 2022. In patients younger than 20 years, melanoma incidence remained low with no significant trends. There was also a significant decline in melanoma mortality among 30- to 59-year-old individuals, but not in those 60 years and older. The findings of this cohort study showed a significant recent downward trend in both melanoma incidence and melanoma mortality in the age group 30 to 49 years in Sweden. The reasons for these declines are unclear but may include UV protection, public health campaigns, changing population demographics, and the introduction of effective melanoma treatment. None of these possibilities were evaluated; further study is needed.

Oncological outcome following Hartmann's procedure compared with anterior resection and abdominoperineal resection for rectal cancer-The type of procedure does not influence local recurrence or distant metastasis: A population-based study.

The type of surgical procedure used in rectal cancer treatment may affect cancer recurrence. The aim of this study was to determine whether the type of procedure influences oncological outcomes in rectal cancer surgery. We gathered data from the Swedish Colorectal Cancer Registry regarding patients with TNM Stage I-III rectal cancer who underwent R0/R1 surgery from 2013 to 2017. The outcomes after Hartmann's procedure (HP), anterior resection (AR) and abdominoperineal resection (APR) were compared, and a multivariable Cox regression analysis was performed. The primary outcome of the study was the local recurrence rate. The secondary outcomes were distant metastasis, disease-free survival and overall survival at 5 years as well as risk factors for local recurrence. A total of 4741 patients were included in the study: 614 underwent HP, 3075 underwent AR and 1052 underwent APR. Multivariable Cox regression revealed no difference in local recurrence, distant metastasis or disease-free survival. Overall survival was higher following AR (OR 0.62, CI 0.54-0.72). Risk factors for local recurrence were intraoperative bowel perforation (OR 2.41, CI 1.33-4.40), a pT4 tumour (OR 1.93, CI 1.11-3.4) and a positive circumferential resection margin (OR 5.62, CI 3.28-9.61). This nationwide study showed that the type of procedure did not affect the local recurrence rate or distant metastasis. In patients who are unfit for restorative surgery, HP is a viable alternative with oncological outcomes similar to those of APR.

The risk for rectal cancer recurrence and overall mortality is not increased in men previously diagnosed with prostate cancer: a report from the Swedish colorectal cancer registry

IntroductionLimited data exists on oncological outcomes following rectal cancer surgery in men who have previously been diagnosed with prostate cancer (PC). This study aimed to assess overall mortality and rectal cancer recurrence in men previously diagnosed with PC who underwent bowel resection.MethodsData from the Swedish Colorectal Cancer Registry identified men who had rectal cancer surgery between 2000 and 2016, and the National Prostate Cancer Registry was used to identify those with a prior PC diagnosis. Cox regression analysis with propensity score matching was employed for data analysis. The primary outcome was overall mortality. Secondary outcome was recurrence for rectal cancer.ResultsOut of 13,299 men undergoing bowel resection for rectal cancer between 2000 and 2016, 1130 had a history of PC. Overall mortality did not significantly differ between men with and without a prior PC diagnosis. Cox regression analyses with propensity score matching revealed that men with previously diagnosed low- or intermediate-risk (HR, 0.79; 95% CI, 0.70–0.90) and high-risk PC (HR, 0.85; 95% CI, 0.74–0.98) had lower overall mortality after rectal cancer surgery compared with men without a PC. There was no significant difference in rectal cancer recurrence between men with a previous low or intermediate-risk PC (HR, 0.92; 95% CI, 0.74–1.14) or high-risk PC (HR, 0.73; 95% CI, 0.52–1.01) compared with those without PC history.ConclusionMen undergoing rectal cancer surgery with a previous diagnosis of prostate cancer do not experience an increased risk of rectal cancer recurrence or overall mortality compared with men without a previous history of prostate cancer.

Timing and type of breast reconstruction in SweBRO 3: long-term outcomes.

Breast reconstruction after mastectomy helps women with breast cancer feel better about their bodies and lives. There is debate about the best time and type of reconstruction (immediate versus delayed, and using own tissue versus implants). Long-term studies are rare. This study looked at long-term results of different breast reconstruction methods and timings in Swedish women who had mastectomies in 2000, 2005 or 2010. It focused on how satisfied the women were with their surgeries and their quality of life. The study included 5853 women from the Swedish National Breast Cancer Registry who had mastectomies in 2000, 2005 or 2010. Of these, 2904 women answered the survey, and 895 had breast reconstruction. Satisfaction and quality of life were measured using two surveys: EORTC QLQ-BRECON23 and BREAST-Q. Of the women who answered the survey, 895 (31%) had breast reconstruction. Of these, 176 (20%) had immediate reconstruction, and 719 (80%) had delayed reconstruction; 58% had implant-based reconstructions, 31% had reconstructions using their own tissue, 2% had both types and 9% did not report the type of reconstruction. There were no major differences in satisfaction between immediate and delayed reconstruction. Women who used their own tissue were more satisfied with their results and breast appearance than those with implants. Autologous reconstruction leads to better satisfaction and outcomes than implants. The timing of reconstruction (immediate versus delayed) was less of an influence on quality of life.

Cancer incidence and mortality after a first-ever venous thrombosis: a cohort study in northern Sweden

BackgroundVenous thromboembolism (VTE) has a high mortality rate and can be the first manifestation of cancer. We investigated the incidence of cancer after first-ever VTE and the association between VTE and all-cause mortality.MethodsA Swedish cohort study that included 105,997 participants without previous cancer who underwent a health examination from 1985–2014 was conducted. Manually validated first-ever VTE events, incident cancer according to the Swedish cancer registry, and mortality were registered. Participants were followed until September 5, 2014.ResultsThe mean age at inclusion was 46.2 years, and 50.3% of participants were female. We identified 1303 persons in the cohort with a VTE and no previous cancer. Among these, 179 (13.7%) were diagnosed with cancer after the VTE event, resulting in a cancer incidence of 26.4 (95% CI 22.8–30.6) cases per 1000 person-years. The incidence was highest during the first 6 months after the VTE. In the study population, VTE was associated with an increased risk of cancer (HR 1.95 [95% CI 1.67–2.29] in a multivariable model). VTE was also associated with an increased risk of death (HR 6.30 [95% CI 5.82–6.81]) in a multivariable model). There was an interaction between sex and VTE in relation to both risk of cancer and mortality, with a stronger association in women.ConclusionsThe incidence of cancer is high after first-ever VTE, especially close to the VTE event. VTE seems to be a stronger risk marker in women than in men for both cancer and death.

Earnings and work loss after colon and rectal cancer: a Swedish nationwide matched cohort study

Colorectal cancer is common and prognosis is improving. The conditions of survivors of treatment, including financial consequences, are thus important. The aim of this study was to quantify loss of earnings and work loss in working-age patients with colon and rectal cancer relative to matched comparators. The study utilised data from the CRCBaSe database that is generated from the nationwide Swedish ColoRectal Cancer Register and includes data from several Swedish nationwide registers. The study period was 1995-2020 for rectal cancer patients and 2007-2020 for colon cancer patients. A retrospective population-based nationwide cohort study on earnings, disposable income, and work loss, in survivors of stage I-III colorectal cancer treatment was undertaken. Median regression was used to analyse earnings and disposable income, and logistic regression to analyse the probability of work loss. A cohort of 8863 colorectal cancer survivors diagnosed before 2017 and 52,514 comparators matched on birth year, legal sex, and county of residence, was analysed. There was a clear reduction in earnings between the calendar year prior to and the calendar year after diagnosis, from € 31,319 to € 23,924 for colon cancer patients and from € 32,636 to € 22,647 for rectal cancer patients, and earnings never fully recovered during the 5-year follow-up. Disposable income was practically unaltered. The probability of work loss increased in the calendar year of diagnosis, from 29.8% to 25.3% the previous year to 83.3% and 84.4% for colon and rectal cancer patients respectively, and never fully recovered. The probability of work loss was similar between colon and rectal cancer survivors, but was higher among patients with rectal cancer who had received neoadjuvant therapy. This study shows that despite an extensive welfare system providing maintained disposable income, there is a financial burden in the form of increased risk of work loss and a reduction in earnings among survivors of colorectal cancer. The study was supported by the Swedish Cancer Society, the Swedish Cancer and Allergy Foundation, and the Stockholm Cancer Society, and supported by grants provided by the Regional Agreement on Medical Training and Clinical Research (ALF) between the Stockholm County Council and Karolinska Institutet.

Survival improvements in esophageal and gastric cancers in the Nordic countries favor younger patients.

Esophageal cancer (EC) and gastric cancer (GC) are fatal cancers with a relatively late age of onset. Age is a negative risk factor for survival in many cancers and our aim was to analyze age-specific survival in EC and GC using the recently updated NORDCAN database. NORDCAN data originate from the Danish, Finnish, Norwegian, and Swedish nationwide cancer registries covering years 1972 through 2021 inviting for comparison of 50-year survival trends between the countries. Relative 1- and 5-year survival and 5/1-year conditional survival (i.e., survival in those who were alive in Year 1 to survive additional 4 years) were analyzed. Survival in EC showed large gains for patients below age 80 years, 5-year survival in Norwegian men reaching 30% and in women over 30% but for 80-89 year old survival remained at 10%. In contrast, hardly any gain was seen among the 80-89 year patients for 1-year survival and small gains in 5 year and 5/1-year survival. Survival gaps between age-groups increased over time. For GC there was also a clear age-related negative survival gradient but the survival gaps between the age groups did not widen over time; Norwegian male and female 5-year survival for 80-89 year old was about 20%. The age-specific survival difference in GC arose in Year 1 and did not essentially increase in 5-year survival. While there were differences in survival improvements between the countries, poor survival of the 80-89 year old patients was shared by all of them. To conclude, survival has improved steadily in younger GC and EC patients in most Nordic countries. While the 80-89 year old population accounts for nearly a quarter of all patients and their poor survival depressed overall survival, which can therefore be increased further by improving diagnostics, treatment and care of elderly EC and GC patients.

72321 - Validation of the reporting of local recurrence of rectal cancer in the Swedish ColoRectal Cancer Registry (SCRCR)

72321 - Validation of the reporting of local recurrence of rectal cancer in the Swedish ColoRectal Cancer Registry (SCRCR)

Cancer incidence in Swedish oil refinery workers exposed to benzene

BackgroundOil refinery workers are exposed to benzene, which is a well-known cause of leukaemia, but results on leukaemia in oil refinery workers have been mixed, and the data on workers’ exposure is limited. Oil refinery workers are also exposed to asbestos and several studies have shown increased risk of mesothelioma. AimThe objective was to investigate cancer incidence, especially leukaemia, at low to moderate exposure to benzene in an update of a previous study of employees at three Swedish oil refineries. MethodsCancer incidence was followed up in 2264 men (1548 refinery operators) employed at three oil refineries in Sweden for at least one year. Job types and employment times were collected from complete company files. A retrospective assessment of the benzene exposure was performed by occupational hygienists in collaboration with the refineries using historic measurements as well as detailed information on changes in the industrial hygiene and technological developments. Cases of cancer were retrieved by a linkage with the Swedish Cancer Register through 35–47 years of follow-up and standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated. ResultsIn total, 258 tumors had occurred versus 240 expected (SIR 1.07; 95% CI 0.95–1.21). There were 10 cases of leukaemia, all in refinery operators (SIR 2.4; 95% CI 1.18–4.51). There were three cases of pleural mesothelioma, two of which in refinery operators. The mean estimated cumulative benzene exposure for the cases of leukaemia was 7.9 ppm-years (median 4.9, range 0.1–31.1). DiscussionThe study suggests that low to moderate average cumulative benzene exposure increases the risk of leukaemia. Limitations include the modest number of cases and potential misclassification of exposure. ConclusionThe present study indicated an increased risk of leukaemia in male oil refinery workers with low to moderate exposure to benzene.

Total mesorectal excision quality in rectal cancer surgery affects local recurrence rate but not distant recurrence and survival: population-based cohort study.

The quality of the total mesorectal excision specimen in rectal cancer surgery is assessed with a three-tier grade (mesorectal, intramesorectal and muscularis propria). This study aimed to analyse the prognostic impact of the total mesorectal excision grade on survival, and to identify risk factors for intramesorectal and muscularis propria resection in a population-based setting. All patients in the Swedish Colorectal Cancer Registry with rectal cancer stage I-III ≤ 10 cm from the anal verge, diagnosed 2015-2019, undergoing total mesorectal excision were analysed. Clinical, surgical and pathological data were retrieved and analysed for the following primary outcomes: local and distant recurrence and overall and relative survival; secondary outcomes were risk factors for total mesorectal excision grading (intramesorectal or muscularis propria resection). Of note, postoperative death < 30 days or recurrence within 90 days were exclusion criteria for survival and recurrence analysis. Recurrence-free patients with less than 3 years follow-up, and patients lacking data regarding recurrence, were also excluded from recurrence analyses. Overall, of 7979 patients treated during the study interval, 1499 patients were eligible for recurrence, 2441 patients for survival and 2476 patients for risk-factor analyses, of which 75% were graded mesorectal, 17% intramesorectal and 8% muscularis propria. Median follow-up for survival was 42 (1-77) months. The worst total mesorectal excision grading (muscularis propria resection) was an independent risk factor for local recurrence in multivariable analysis (HR 2.73, 95% c.i. 1.07 to 7.0, P = 0.036). Total mesorectal excision grade had no impact on distant recurrence or survival. Female sex, tumour level <5 cm, abdominoperineal resection, minimally invasive surgery (laparoscopic and robotic), high blood loss, long duration of surgery and intraoperative perforation were independent risk factors for worse total mesorectal excision grading (intramesorectal and/or muscularis propria resection) in multivariable analyses. Muscularis propria resection increases the risk of local recurrence but does not seem to affect distant recurrence or survival.

ACBC Study Protocol – Acute Colon Resection Versus Bridge to Colon Surgery with Stent Placement or Stoma Diversion: A Prospective Cohort Study

Abstract Background: Approximately 70% of all colon cancer emergencies result from colonic obstruction. Data from the Swedish Colorectal Cancer Registry indicate that patients undergoing emergency surgical resections for colon cancer face higher overall 30-day morbidity and increased mortality rates—5.8% at 30 days and 11.2% at 90 days—compared to those undergoing elective procedures, which have mortality rates of 1.1% and 2.0%, respectively. Other concerns about acute colon cancer resections are oncological outcomes. Long-term outcomes are significantly worse, with higher rates of recurrence and cancer-related death, regardless of the cancer stage or the use of adjuvant chemotherapy. Objectives: To evaluate the short- and long-term outcomes of primary resection for malignant colonic obstruction compared to only decompression using a self-expandable endoscopic metallic stent or diverting stomas as the first intervention (bridge to surgery) followed by later oncological resection. Design: This is a prospective observational study with data collected through the Swedish Colorectal Cancer Registry with an additional electronic case report form. Settings: Swedish multicenter study at both university and regional hospitals. Patients and Methods: Patients with suspected acute malignant large bowel obstruction due to colonic adenocarcinoma will be identified and followed. Analysis will be performed on an intention-to-treat basis. Descriptive statistics of the study cohort will be presented. Primary endpoints will be subjected to multivariate analyses adjusted for confounders. Main Outcome Measures: 30-day severe morbidity (Clavien–Dindo &gt; 3a), 30- and 90-day mortality rates, and overall survival after three and five years. Sample Size: We aim to include 1000 patients, with an interim analysis after the recruitment of 500 patients. Results: The study is ongoing. Conclusions: Acute colon obstruction is associated with substantial morbidity and mortality. We hypothesize that patients with malignant obstruction benefit from avoidance of emergency cancer resection and that bridge to surgery leads to decreased short-term morbidity and mortality and improved long-term oncological outcomes. Limitations: The main limitation is the risk of selection bias when the study is not a randomized controlled trial, which would be a standard process. A prospective observational study is, nevertheless, considered a pragmatic compromise between feasibility and ability to answer the research question. Conflicts of Interest: None.

Implications of pretreatment extramural venous invasion in rectal cancer patients: A population-based study.

Extramural venous invasion detected by MRI (mrEMVI) has in several expert centre studies been identified as an important prognostic factor in rectal cancer, and in guiding neoadjuvant therapy. However, population-based evidence for mrEMVI as a predictor for recurrent disease is lacking. This was a multicentre retrospective study based on the Swedish Colorectal Cancer Registry. The study period encompassed patients operated with abdominal resection for rectal cancer 2017-2021, with follow-up until January 2023. Patients diagnosed at hospitals with radiological registry data coverage <90% or with metastatic disease were excluded. Pretreatment mrEMVI constituted exposure, while recurrence-free survival was the main outcome. Distant and local recurrence, and overall survival were secondary outcomes, and pretreatment and postoperative scenarios were explored using multivariable Cox regression with multiple imputation. Hazard ratios (HRs) with 95% confidence intervals (CIs) were reported. A total of 2737 patients from 13 hospitals were eligible for analysis. Pretreatment mrEMVI was reported in 14.5% of patients, while 71.9% had negative findings and 13.6% had missing data. In the pretreatment scenario, mrEMVI was an independent predictor for worse recurrence-free survival with an adjusted HR of 1.64 (95% CI: 1.31-2.06). In the postoperative MDT setting, the influence of mrEMVI on recurrence-free survival decreased with an adjusted HR of 1.27 (95% CI: 1.00-1.61). mrEMVI at diagnosis is an independent predictor of recurrence-free survival in an unselected population of rectal cancer patients undergoing abdominal resection.

Postoperative complications and emergency surgeries in colorectal cancer patients

The incidence of colorectal cancer (CRC) in Sweden is increasing in individuals <50 years. This study aimed to examine differences in postoperative 30-day complications and rate of emergency surgeries in CRC patients <50 years at diagnosis compared to older age groups since population-based research on this topic is scarce. This population-based study included data from the Swedish Colorectal Cancer Registry for patients undergoing CRC resection between 2010 and 2018. Bivariate analysis and logistic regression were used to analyse the relationship between age groups (<50, 50-79 and ≥80 years) and probability of postoperative 30-day complications adjusted for gender, tumour localization, neoadjuvant (chemo)radiotherapy and American Society of Anesthesiologists score. In total 33 320 patients were included. Patients <50 years had a lower American Society of Anesthesiologists score, more advanced tumours and received more neoadjuvant treatment. Emergency surgeries were less common in the youngest age group (P < 0.001) as well as overall postoperative 30-day complications: ORadj 0.84 (95% CI 0.74-0.96) compared to those ≥80 years. Surgical complications were more common in age groups <50 and 50-79 years (16.5% and 16.9% respectively) compared to patients ≥80 years (14.1%) (P < 0.001). Anastomotic leakage and intra-abdominal infections were more frequent in patients <50 years (5.7% and 3.5% respectively) compared to age groups 50-79 years (5.1% and 2.8% respectively) and ≥80 years (3.5% and 2.1% respectively) (P < 0.001). Wound infections were more common in the two youngest age groups compared to patients ≥80 years (5.3% vs. 3.7% respectively) (P < 0.001). Colorectal cancer patients <50 years and 50-79 years had a higher proportion of surgical complications regarding anastomotic leakage, intra-abdominal infections and wound infections but lower overall postoperative complications. The incidence of surgical emergencies was highest amongst patients ≥80 years. Postoperative diagnostic workup in symptomatic individuals <50 years is warranted.