Tumour regression in the randomized Stockholm III Trial of radiotherapy regimens for rectal cancer.

BACKGROUND: The Stockholm III Trial randomized patients with primary operable rectal cancers to either short-course radiotherapy (RT) with immediate surgery (SRT), short-course RT with surgery delayed 4-8 weeks (SRT-delay) or long-course RT with surgery delayed 4-8 weeks. This preplanned interim analysis examined the pathological outcome of delaying surgery. METHODS: Patients randomized to the SRT and SRT-delay arms in the Stockholm III Trial between October 1998 and November 2010 were included, and data were collected in a prospective register. Additional data regarding tumour regression grade, according to Dworak, and circumferential margin were obtained by reassessment of histopathological slides. RESULTS: A total of 462 of 545 randomized patients had specimens available for reassessment. Patients randomized to SRT-delay had earlier ypT categories, and a higher rate of pathological complete responses (11·8 versus 1·7 per cent; P = 0·001) and Dworak grade 4 tumour regression (10·1 versus 1·7 per cent; P < 0·001) than patients randomized to SRT without delay. Positive circumferential resection margins were uncommon (6·3 per cent) and rates did not differ between the two treatment arms. CONCLUSION: Short-course RT induces tumour downstaging if surgery is performed after an interval of 4-8 weeks.

Preoperative tumour staging with multidisciplinary team assessment improves the outcome in locally advanced primary rectal cancer.

AIM: Multidisciplinary team meetings have been introduced as a result of developments in preoperative radiological tumour staging and neoadjuvant treatment. Multidisciplinary team recommendations will influence treatment decisions but their effect on patient outcome is unknown. The aim of this study was to assess outcome in relation to preoperative local and distant staging, with or without multidisciplinary team assessment. METHODS: A population-based registry of all patients with rectal cancer, treated in the Stockholm region from 1995 to 2004, identified 303 patients with locally advanced primary rectal cancer. The patients were classified into three groups: group 1, preoperative local and distant radiological tumour staging with discussion at a multidisciplinary team meeting; group 2, preoperative staging but no multidisciplinary team assessment; and group 3, no proper preoperative radiological staging. RESULTS: Neoadjuvant treatment was more prevalent in groups 1 and 2 than in group 3. The incidence of R0 resection differed significantly between the groups (52% in group 1, 43% in group 2 and 21% in group 3; P < 0.001). Local tumour control was achieved in 57%, 36%, and 19% of patients in groups 1, 2 and 3, respectively (P < 0.001). The estimated overall 5-year survival of patients was 30%, 28% and 12% in groups 1, 2 and 3, respectively. CONCLUSION: Preoperative radiological tumour staging in patients with locally advanced primary rectal cancer and discussion at a multidisciplinary team meeting increases the proportion of patients receiving neoadjuvant treatment and cancer-specific end-points.

Interim analysis of the Stockholm III trial of preoperative radiotherapy regimens for rectal cancer.

BACKGROUND: To address issues regarding the fractionation of radiotherapy (RT) and timing of surgery for rectal cancer, a multicentre trial has randomized patients to preoperative short-course RT with two different intervals to surgery, or long-course RT with delayed surgery. The present interim analysis assessed feasibility, compliance and complications after RT and surgery. METHODS: Some 303 patients were randomized to either short-course RT (5 x 5 Gy) and surgery within 1 week (group 1), short-course RT and surgery after 4-8 weeks (group 2) or long-course RT (25 x 2 Gy) and surgery after 4-8 weeks (group 3). RESULTS: Demographic data were similar between groups and there were few protocol violations (5.0-6 per cent). Eight patients (2.6 per cent) developed radiation-induced acute toxicity. There were no significant differences in postoperative complications between groups (46.6, 40.0 and 32 per cent in groups 1, 2 and 3 respectively; P = 0.164). Patients receiving short-course RT with surgery 11-17 days after the start of RT had the highest complication rate (24 of 37). CONCLUSION: Compliance was acceptable and severe acute toxicity was low, irrespective of fractionation. Short-course RT with immediate surgery had a tendency towards more postoperative complications, but only if surgery was delayed beyond 10 days after the start of RT. REGISTRATION NUMBER: NCT00904813 (http://www.clinicaltrials.gov).

Gender differences in the treatment of rectal cancer: a population based study.

AIMS: Colorectal cancer is the second most common type of cancer in both women and men in Sweden. A National Quality Register for rectal adenocarcinoma in Sweden has included 97% of all rectal cancer patients since 1995. A previous study, based on data from the treatment program register in the Stockholm-Gotland region, found that women in Stockholm received preoperative radiotherapy (RT) less often than men [Martling A. Rectal cancer: staging, radiotherapy and surgery, ISBN: 91-7349-461-5. Stockholm: Karolinska Institute; 2003].(1) The aim of this study was to assess if women and men with rectal cancer receive equal treatment on a national level, and whether any potential dissimilarity causes measurable consequences in outcome, regarding postoperative morbidity and mortality, tumour recurrence and survival. METHODS: All patients with rectal cancer included in the National Quality Register between 1995 and 2002 (11,774 patients) were analysed. Gender was correlated to treatment, postoperative morbidity and mortality, local recurrence and death. RESULTS: The proportion of women selected for preoperative RT was significantly lower than that of men (42.5% vs. 50.1%, p<0.001). After adjustment for other prognostic factors, the significant difference in the treatment strategy among women and men persisted. Postoperative mortality was significantly higher in men than in women and the gender difference was most pronounced in irradiated patients. RT improved local control significantly in both women and men but it had no effect on cancer specific survival. CONCLUSIONS: For unknown reasons women less often received adjuvant RT than men. The opposite appeared to be a more adequate alternative. There is a need of improved selection criteria for RT in both men and women with rectal cancer.

The Swedish rectal cancer registry.

BACKGROUND: An audit of all patients with rectal cancer in Sweden was launched in 1995. This is the first report from the Swedish Rectal Cancer Registry (SRCR). METHODS: Between 1995 and 2003, 13 434 patients treated for adenocarcinoma of the rectum were registered with the SRCR; there were approximately 1500 new patients annually. RESULTS: Approximately half had an anterior resection, a quarter an abdominoperineal resection and 15 per cent a Hartmann's procedure. The median 30-day postoperative mortality rate was 2.4 per cent and the overall postoperative morbidity rate was 35.0 per cent. The 5-year cancer-specific survival rate was 62.3 per cent. The 5-year relative survival rate was 70.1 per cent after anterior resection, 59.8 per cent after abdominoperineal resection and 39.8 per cent after a Hartmann's procedure. The crude 5-year local recurrence rate was 9.5 per cent overall, 6.1 per cent after preoperative radiotherapy and 11.4 per cent after surgery alone. For 3868 patients who had a locally curative procedure the local recurrence rate was 7.4 per cent overall, 5.9 per cent for those who had radiotherapy and 10.2 per cent for those who did not. The local recurrence rate was 2.9 per cent (28 of 968) for stage I disease, 7.9 per cent (112 of 1418) for stage II, 13.9 per cent (188 of 1357) for stage III and 8.5 per cent (45 of 532) for stage IV. CONCLUSION: These good population-based results are due, in part, to the nationwide prospective quality assurance registration.

Colon cancer management and outcome in relation to individual hospitals in a defined population.

BACKGROUND: The Stockholm and Gotland region in Sweden has a common management protocol for the treatment of colon cancer. The aim of this study was to assess the management and treatment of colon cancer in the region and to try to identify ways to improve the outcome further. METHODS: Clinical data on all patients diagnosed with colon cancer in the region's nine hospitals between January 1996 and December 2000 were prospectively collected. Patients were followed until December 2004, and their management and outcome analysed. RESULTS: Colon cancer was diagnosed in 2775 patients. An elective operation was performed in 2116 (76.3 per cent) patients and an emergency procedure in 590 (21.3 per cent). Emergency surgery was an independent risk factor for death. The crude overall cumulative 5-year survival was 46.2 per cent. A multivariable analysis of risk of dying and risk of local recurrence showed significant differences between hospitals. The number of lymph nodes examined in the specimens also differed between hospitals. CONCLUSION: Differences in the management and outcome of colon cancer in the nine hospitals, despite a common management protocol, indicate a need for improving collaboration between hospitals and multidisciplinary management.

A population-based study on the management and outcome in patients with locally recurrent rectal cancer.

BACKGROUND: Although outcome in patients with rectal cancer has improved with preoperative radiotherapy and total mesorectal excision, local recurrence still remains a problem. The condition is difficult to cure and little is known on whether the prognosis for patients with locally recurrent tumours has changed over time. Few population-based studies have been performed. METHOD: Two thousand three hundred and eighteen patients in Stockholm, Sweden had a potentially curative resection for rectal cancer between 1995 and 2003. Until 2005, 141 (6%) developed a local recurrence. Management and outcome for these patients were studied and compared to a previously analysed cohort of 156 patients with local recurrence, treated 1980-1991. RESULTS: Of the 141 patients, 57 (40%) had surgery with a curative intent, 48 (34%) radio- and/or chemotherapy and 36 (26%) symptomatic palliation only. The total 5-year survival was 9%. Twenty-five patients had a potentially curative resection, with a 5-year survival of 57%. The corresponding figures for the 156 patients in the earlier cohort were 4 and 42%. CONCLUSION: Although outcome for patients with local recurrence of rectal cancer is dismal, the prognosis has improved slightly over time. A radical resection is a prerequisite for cure and the proportion having a potentially curative resection has increased. Multidisciplinary management, including optimised preoperative staging and patient selection for surgery, radical surgical approach and more effective adjuvant treatments are necessary to further improve the prognosis.

Late adverse effects of short-course preoperative radiotherapy in rectal cancer.

BACKGROUND: Preoperative radiotherapy improves local control and survival in rectal cancer, but there are few reports on long-term morbidity. The aims of this study were to compare long-term morbidity and quality of life in patients undergoing rectal cancer surgery with or without preoperative radiotherapy. METHODS: A total of 252 patients, randomized within the two Stockholm trials on preoperative radiotherapy in rectal cancer, were alive at a mean of 15 years after surgery. Some 139 of these patients were available for follow-up by questionnaires and clinical examination. Questionnaires regarding medical history and quality of life were completed by all patients. All patients had a clinical examination, and those without a stoma underwent rigid sigmoidoscopy. RESULTS: Overall, patients who had preoperative radiotherapy experienced significantly more late complications than those who did not (69 versus 43 per cent; P = 0.002). This morbidity consisted mainly of cardiovascular disease (35 versus 19 per cent; P = 0.032), faecal incontinence (12 of 21 versus 11 of 42 patients having anterior resection; P = 0.013) and urinary incontinence (45 versus 27 per cent; P = 0.023). No significant differences between groups were found for hip or pelvic fractures, small bowel obstruction or global quality of life. CONCLUSION: Preoperative short-course, high-dose radiotherapy in patients with rectal cancer increases the risk of anal and urinary dysfunction, and may lead to increased cardiovascular morbidity, at long-term follow-up.

Outcome after the introduction of a multimodality treatment program for locally advanced rectal cancer.

AIM: This prospective study reports the results of a multimodality treatment protocol in patients with locally advanced rectal cancer and assesses outcome after curative vs non-curative surgery and in relation to primary advanced vs locally recurrent cancer. METHODS: Between 1991 and 2002, 122 patients completed the protocol. Fifty-eight had primary advanced and sixty-four had locally recurrent rectal cancer. Median follow up was 82 months (5-143). RESULTS: A potentially curative resection was achieved in 59% of the patients with primary advanced and in 34% of patients with locally recurrent cancer. After curative resection, 53 and 59%, respectively, were free from recurrence during the observation time (median 82 months) and the overall 5-year survival was 34 and 40%. Overall 5-year survival in all patients with primary advanced cancer was 29 and 16% in all patients with locally recurrent rectal cancer. CONCLUSION: Multimodality treatment may cure at least a third of patients with locally advanced rectal cancer provided a radical resection is performed. As the post-operative morbidity is high, an optimised patient selection for neo-adjuvant treatment and surgery is essential. However, palliative surgery may benefit the patient if local control is achieved. Future studies should focus on the problem of distant metastasis.

Impact of a surgical training programme on rectal cancer outcomes in Stockholm.

BACKGROUND: Total mesorectal excision (TME) and use of adjuvant radiotherapy are major advances in the treatment of rectal cancer that have emerged in the past 20 years. The aim of this study was to evaluate the effects of an initiative to teach the TME technique on outcomes at 5 years after surgery. METHODS: TME-based surgery was introduced in Stockholm in 1994. The study population comprised all 447 patients who underwent abdominal operations for rectal cancer in Stockholm County during 1995 and 1996. Outcomes were compared with those in the Stockholm I (790 patients) and Stockholm II (542 patients) radiotherapy trials. RESULTS: The permanent stoma rate was reduced from 60.3 and 55.3 per cent in the Stockholm I and II trials respectively to 26.5 per cent in the TME project (P < 0.001). Five-year local recurrence rates decreased from 21.9 and 19.1 per cent to 8.2 per cent respectively (P < 0.001). Five-year cancer-specific survival rates increased from 66.0 and 65.7 per cent in the Stockholm trials to 77.3 per cent in the TME project (hazard ratio 0.62 (95 per cent confidence interval 0.49 to 0.80); P < 0.001). CONCLUSION: A surgical teaching programme had a major impact on rectal cancer outcome.

The potential for improved outcome in patients with hepatic metastases from colon cancer: a population-based study.

AIMS: Reports from specialized centres suggest that 20-25% of patients with hepatic metastases from colorectal cancer have resectable disease, with 5-year survival rates of 30-40%, and that an additional 13-38% may become resectable after chemotherapy. The purpose of this study was to assess the potential for improvement in outcome for patients with hepatic metastases from colon cancer in an unselected population. PATIENTS AND METHODS: All patients diagnosed with colon cancer in the Stockholm/Gotland region between 1 January 1996 and 31 December 1999 were identified and followed until 31 December 2002. Treatment and outcome in patients with hepatic metastases was analyzed and CT-scans and MR images of the liver were reviewed to re-evaluate resectability. RESULTS: In 2280 patients with colon cancer, hepatic metastases were diagnosed in 537 patients. Only 21 of these patients underwent a hepatic resection. Retrospective evaluation of liver images indicated that 10% of the patients had potentially resectable hepatic disease. CONCLUSION: The rate of potentially resectable liver metastases from colon cancer in a population is lower than suggested from hospital-based series. With structured management programs including follow-up routines and multidisciplinary treatment protocols the proportion of patients amenable for liver resection may be increased. In this study preoperative chemotherapy might have increased the resectability rate to at the most 17%. To significantly improve prognosis for patients with hepatic metastases from colon cancer more effective treatment modalities are needed.

Prognostic significance of both surgical and pathological assessment of curative resection for rectal cancer.

BACKGROUND: Information on whether surgery has been 'curative' is essential for prediction of prognosis and for selection of patients for adjuvant treatment. The aim of this study was to analyse the prognostic value of surgeons' and pathologists' assessments of tumour clearance in patients with primary rectal cancer who underwent resection. METHODS: A total of 1550 patients were studied prospectively. Data were collected from reports made by surgeons and pathologists on whether tumour clearance had been 'complete', 'uncertain' or 'incomplete'. The predictive value in relation to outcome after at least 5 years of follow-up was assessed. RESULTS: In patients assessed as having a complete surgical clearance, tumour recurrence developed in 33.3 per cent. For patients with an uncertain or incomplete clearance the recurrence rate was 59.5 and 61 per cent respectively (P < 0.001). The relative risk of recurrence was twice as high when the surgeon and pathologist disagreed than when they both agreed on the complete clearance. Survival in patients with a complete, uncertain or incomplete surgical clearance was 55.3, 23.0 and 10 per cent respectively (P = 0.050). CONCLUSION: Assessments of tumour clearance were of strong prognostic value in relation to outcome. When the surgeon or pathologist was uncertain, or there was disagreement about the completeness of clearance, the risk of recurrence was similar to that among patients in whom an incomplete resection had been performed.

Prognostic value of preoperative magnetic resonance imaging of the pelvis in rectal cancer.

BACKGROUND: Despite radiotherapy and improved surgical techniques, local recurrence rates after treatment of rectal cancer still vary between 3 and 30 per cent. Tumour involvement of the circumferential resection margin (CRM) predicts a high risk of local recurrence. Magnetic resonance imaging (MRI) allows accurate description of the tumour and its spread within the mesorectum. The aim of this study was to assess the prognostic impact of an involved CRM identified at preoperative MRI in patients with rectal cancer. METHODS: Preoperative MRI was performed in 115 patients with rectal cancer between 1995 and 1999. The images were evaluated retrospectively. The shortest distance from the tumour to the CRM was measured, correlated with patient outcome and compared with histopathological findings. RESULTS: The risk of any recurrence in patients with or without a tumour-involved margin on MRI was nine of 29 and nine of 57 respectively (P = 0.036). Overall survival at 5 years was 43 and 77 per cent (P = 0.012) respectively. Twenty-four of 30 patients who had an involved CRM on histopathology were correctly identified by MRI. CONCLUSION: Patients with a potentially involved CRM identified by MRI had a significantly higher risk of recurrence and cancer-related death. Preoperative MRI may be of prognostic value in rectal cancer and may be used to select patients for neoadjuvant radiochemotherapy and/or more radical surgery.

The surgeon as a prognostic factor after the introduction of total mesorectal excision in the treatment of rectal cancer.

BACKGROUND: With conventional blunt surgical resection of rectal cancer, local recurrence rates are high and the individual surgeon putatively influences patient outcome. With total mesorectal excision (TME) local recurrence rates have been reduced and intersurgeon variability may be less important. The 'TME project' was a collaborative project that included surgical workshops in Stockholm between 1994 and 1997. The aim of this study was to assess the impact of the project on the practice of rectal cancer surgery in Stockholm and to analyse whether surgeon case volume and participation in the workshops influenced patient outcome. METHODS: All 652 patients who had an abdominal resection for rectal cancer in Stockholm between 1995 and 1997 were included. Outcome was compared in patients operated on by teams that included high-volume surgeons (more than 12 operations per year) with teams that included low-volume surgeons (12 operations or fewer per year), as well as between teams that including workshop participants and non-participants. RESULTS: Forty-six surgeons operated on the 652 patients. Five high-volume surgeons operated on 48 per cent of the patients. In these, outcome was significantly better than in patients treated by low-volume surgeons (local recurrence rate 4 versus 10 per cent (P = 0.02); rate of rectal cancer death 11 versus 18 per cent (P = 0.007)). Twenty-six surgeons were workshop participants and performed 93 per cent of the operations. Radiotherapy, TME and sphincter-preserving surgery were more common among patients treated by workshop participants. CONCLUSION: The TME project has had an impact on rectal cancer surgical practice in Stockholm. Variability in patient outcome was mainly related to case volume, with better results obtained in patients treated by high-volume surgeons.

The Stockholm II trial on preoperative radiotherapy in rectal carcinoma: long-term follow-up of a population-based study.

BACKGROUND: The Stockholm II trial is a population-based prospective randomized trial on preoperative radiotherapy in rectal carcinoma. METHODS: Eligibility criteria were age younger than 80 years and biopsy-proven adenocarcinoma of the rectum judged resectable for cure with an abdominal procedure. Between 1987 and 1993, 557 patients were included. Patients were randomized to preoperative radiotherapy (RT+) followed by surgery within a week (n = 272) or surgery alone (RT-; n = 285). Radiotherapy was given with 25 grays in 1 week to the rectum and pararectal tissues. Curative resection was performed in 481 patients (86%). Median follow-up was 8.8 years. RESULTS: Among patients who underwent curative surgery, the incidence of pelvic recurrence was 12% (RT+) and 25% (RT-), respectively (P < 0.001). The overall survival rate in irradiated patients who underwent curative surgery was improved (46%) versus (39%; P < 0.03). For all included patients, the difference was 39% (RT+) compared with 36% (RT-; P = 0.2). Within 6 months of surgery, 13 of 272 (5%) of the irradiated patients died of intercurrent disease versus 4 of 285 (1%) of the nonirradiated (P = 0.02). Cardiovascular death was the main cause of intercurrent death and occurred in 35 of 272 (13%) of the irradiated patients compared with 20 of 285 (7%) among the nonirradiated (P = 0.07). CONCLUSIONS: Preoperative short-term radiotherapy reduces the risk of pelvic recurrence and can improve survival after curative surgery for rectal carcinoma. An increased risk of intercurrent death may reduce the benefit especially in elderly patients.

Tumour location and the effects of preoperative radiotherapy in the treatment of rectal cancer.

BACKGROUND: Preoperative radiotherapy improves local control and survival in rectal cancer, but may also increase postoperative morbidity and mortality rates. Establishing selection criteria for preoperative radiotherapy is crucial. The tumour level above the anus may be one such criterion. The effect of preoperative radiotherapy in relation to the distance between the tumour and the anus was therefore assessed. METHODS: In 457 patients operated for cure included in the Stockholm II Trial the local recurrence rate in irradiated and non-irradiated patients was analysed in relation to the tumour location (low, mid or upper rectum). RESULTS: Radiotherapy reduced the local recurrence rate from 30 to 20 per cent in low rectal cancer, from 25 to 11 per cent in mid rectal cancer and from 21 to 5 per cent for tumours in the upper rectum. CONCLUSION: With conventional surgical techniques preoperative radiotherapy plays an important role in rectal cancer irrespective of the location of the tumour. To irradiate only patients with tumours in the lower rectum and to omit this treatment for patients with tumours in the mid and upper rectum cannot be recommended. Whether this statement is valid with standardized total mesorectal excision (TME) surgery is not known. Until this knowledge is available the current indications for preoperative radiotherapy should probably also be used with TME surgery.

Comparative genomic hybridization identifies loss of 18q22-qter as an early and specific event in tumorigenesis of midgut carcinoids.

Carcinoid tumors are rare neuroendocrine tumors occurring in the lung or in the digestive tract where they are further subclassified as foregut, midgut, or hindgut carcinoids. To gain a better understanding of the genetic basis of the different types of carcinoid tumors, we have characterized numerical imbalances in a series of midgut carcinoids, and compared the results to previous findings in carcinoids from the lung. Numerical imbalances were revealed in 16 of the 18 tumors, and the most commonly detected aberrations were losses of 18q22-qter (67%), 11q22-q23 (33%), and 16q21-qter (22%), and gain of 4p14-qter (22%). The total number of alterations found in the metastases was significantly higher than in the primary tumors, indicating the accumulation of acquired genetic changes in the tumor progression. Losses of 18q and 11q were present both in primary tumors and metastases, whereas loss of 16q and gain of 4 were only detected in metastases. Furthermore, the pattern of comparative genomic hybridization alterations varied depending on the total number of detected alterations. Taken together, the findings would suggest a progression of numerical imbalances, in which loss of 18q and 11q represent early events, and loss of 16q and gain of 4p are late events in the tumor progression of midgut carcinoids. When compared to previously published comparative genomic hybridization abnormalities in lung carcinoids, loss of 11q was found to occur in both tumor types, whereas loss of 18q and 16q and gain of 4 were not revealed in lung carcinoids. The results indicate that inactivation of a putative tumor suppressor gene in 18q22-qter represents a frequent and early event that is specific for the development of midgut carcinoids.

[Improved therapeutic results in rectal cancer. Preoperative radiotherapy and continuing education of the surgeons is efficient]. / Förbättrade behandlingsresultat vid rektalcancer. Preoperativ strålbehandling och vidareutbildning av kirurger verksamt.

The aim of the Stockholm Colorectal Cancer Study Group is to improve treatment results in colorectal cancer. Between 1980 and 1993 the group conducted two randomised trials on preoperative radiotherapy in rectal cancer including 1406 patients. In both trials radiotherapy significantly reduced local recurrence and improved cancer specific survival. To further improve treatment results, four workshops have been held to introduce the "TME concept" to surgeons in Stockholm. The workshops included live surgical demonstrations and histopathology sessions. When patients included in the Stockholm trials (1980-1993) were compared to patients included in the "TME project" (1995-1996) the rate of abdominoperineal procedures was reduced from 60 to 27 per cent. Within two years of follow up the local recurrence rate was reduced from 15 to 6 per cent and cancer related deaths from 16 to 9 per cent. It is concluded that surgical teaching initiatives may have a significant impact on cancer outcomes.

[Quality registry for better treatment of rectal cancer established. Economical support is required to use the benefits of the information]. / Kvalitetsregister etablerat för bättre rektalcancerbehandling. Nu krävs ekonomiskt stöd för att informationen skall komma till nytta.

The treatment of rectal cancer has changed significantly during the last 30 years. With improved surgical technique and the introduction of preoperative radiotherapy sphincter preserving surgery is now predominant and the rate of local recurrence has been reduced substantially. However, new therapy concepts may also introduce an increased risk of complications. A register to monitor quality control in rectal cancer treatment in Sweden was established in 1995. It covers over 95 per cent of the patients with rectal cancer reported to the Swedish National Cancer Registry. Collection of data and validation are done by six regional oncology centres under supervision of surgeons appointed by the hospitals involved. The results are then collated to a nationwide quality register, enabling regions to compare themselves with other regions, and hospitals with other hospitals.