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We compared the management and outcome of glottic cancer in Ontario, Canada to that in the Surveillance, Epidemiology and End Results (SEER) Program areas in the United States to determine whether the greater use of primary radiotherapy with surgery reserved for salvage in Ontario was associated with similar survival and better larynx retention rates than the U.S. approach where primary surgery is used more often. Electronic, clinical and hospital data were linked to cancer registry data and supplemented by chart review where necessary. Initial treatment and survival in patients diagnosed in the SEER areas from 1988 through 1994 were compared to patients from Ontario diagnosed from 1982 through 1995. Actuarial laryngectomy rates were compared for patients over 65 at diagnosis in the two regions. Analyses were conducted over all cases and stratified by disease stage. In localized disease (T1 or T2), conservative treatment was the most common initial treatment in both regions, although total laryngectomy was used more often in SEER than Ontario (6.2% vs. 0.2%, respectively, P P ⩽ .001). Over all cases, the relative survival rate was 80% in Ontario at 5 years compared to 78% in SEER ( P = .33). In localized disease, the relative survival rates were 4 to 5% higher in Ontario from the second year on, while in advanced disease 2 to 3% higher rates in SEER did not approach statistical significance. Actuarial laryngectomy rates at 3 years differed between the two regions, with a 4% higher rate in SEER ( P = .01). In localized disease, 12.6% of Ontario patients had a laryngectomy by 3 years postdiagnosis compared to 17.9% in SEER ( P = .05). In advanced disease, the rates were 63.3% and 79.2%, respectively ( P = .07). There are large differences in the management of glottic cancer between the SEER areas of the U.S. and Ontario and no evidence that a policy emphasizing radiotherapy with surgery reserved for salvage is associated with worse survival. Ultimate laryngectomy rates are lower in Ontario for localized disease and may be lower for advanced disease. Conservation treatment should be used for localized disease while the treatment decision in advanced disease may be especially sensitive to patient values for voice retention versus initial cure.

BACKGROUND The objectives of this study were 1) to describe patterns of use of computed tomography (CT) in laryngeal carcinoma, and 2) to characterize the contribution of CT to the T classification of laryngeal carcinoma. METHODS The study population comprised 1195 patients with laryngeal carcinoma diagnosed from 1982 through 1995 chosen randomly from the Ontario provincial cancer registry. A chart review was conducted to obtain data on each case. Patient-related, tumor-related, and health-system-related factors were analyzed to identify factors associated with the use of CT. Descriptions of clinical exams and CT reports were reviewed to see how CT information modified T classification. Actuarial local control and cause specific survival curves were plotted by clinical T classification without and with CT to evaluate stage migration. The percentage of the variance in outcome explained by T classification in a Cox analysis was used to evaluate whether the prognostic accuracy of T classification was improved with the use of information from CT. RESULTS Patients with glottic (20.1%) and supraglottic (41.7%) carcinoma underwent CT. The use of CT increased over time in glottic and supraglottic carcinoma combined from 17.2% in 1982–5 to 33.9% in 1991–5. Computed tomography was used less often in older patients with a 16% (95% confidence interval, 5– 27%) decrease in the odds of having CT with each 10-year age increment. Computed tomography use varied considerably across the cancer center regions in Ontario. Computed tomography altered the T classification in 20.2% of those patients who had CT, with most being “upstages.” Stage migration due to CT was demonstrated. Using information from CT in the assignment of T classification for 27.8% of this study population did not make a significant contribution to the ability of T classification to predict outcome over the entire group. CONCLUSIONS There is large variation in the use of CT among different age groups and regions. The ability to compare outcomes by stage across geographic areas is compromised when the use of CT varies. Cancer 2001;91:394–407. © 2001 American Cancer Society.

We conducted a population-based study of practice patterns and outcome across the regional cancer centres providing care to patients with laryngeal cancer in the Province of Ontario, Canada.: This was a retrospective cohort study of 1547 patients with cancers of the glottic or supraglottic larynx diagnosed between 1982 and 1995. Data were collected via chart review, including: patient and disease characteristics, treatment, waiting times and treatment volumes. Vital status was obtained from the Ontario Cancer Registry. Variations across the nine regional cancer centres are described and their effect on outcome explored. All analyses were stratified by stage I and II separately from stage III and IV.Treatments differed across centres (P0.0001); for instance, in the stage I and II group, use of a daily dose of2.54Gy varied from 0 to 87.6% and in the stage III and IV group, total laryngectomy rates varied from a low of 6% to a high of 53%. The percentage of patients waiting more than 6 weeks from diagnosis to first treatment varied from 17 to 49% (P0.0001). Multivariate analysis revealed cause-specific survival differences that were not explained by control for case mix, treatment or waiting times. Differences ranged from an 82% risk reduction in one centre compared with the reference (stage I and II group, P=0.008) to a 153% increase in risk (stage III and IV group, P=0.02). Centre case volumes were not associated with cause-specific survival.This study quantifies the degree of variation that can occur in the treatment and outcome of people with cancer. We cannot properly assess whether care delivery is of high quality until we have a better understanding of the factors that drive such variations.

Introduction People with lower socioeconomic status (SES) experience shorter survival times after a cancer diagnosis for many disease sites. We determined whether area-level SES was associated with the outcomes: cause-specific survival and local-regional failure in laryngeal cancer in Ontario, Canada. When we found an association we sought explanations that might be related to access to care including age, sex, rural residence, tumor stage, lymph node status, use of diagnostic imaging, treatment type, percentage of prescribed radiotherapy delivered, number of radiotherapy interruption days, treatment waiting time, and treating cancer center. Materials and Methods The study population consisted of 661 glottic and 495 supraglottic stage-stratified randomly-sampled patients identified using the Ontario Cancer Registry. Area-level SES quintiles were assigned using adjusted median household income from the Canadian Census. Other data were collected from patient charts. Explanations for SES effects were determined by measuring whether the effect moved toward the null value by at least 10% when an access indicator was added to a the model. Results Socioeconomic status was not related to either outcome for those with supraglottic cancer, but an association was present in glottic cancer. With the highest socioeconomic status quintile as the referent group, the relative risks for patients in the lowest socioeconomic quintile were 2.75 (95% CI 1.48, 5.12) for cause-specific survival and 1.90 (95% CI 1.24, 2.93) for local-regional failure. Disease stage as measured by T-category explained between 3% and 23% of these socioeconomic effects. None of the other access indicators met our 10% change criterion. Conclusion We question why people in lower socioeconomic quintiles were not diagnosed earlier in the disease progression. Having ruled out several variables that may be related to access to care, additional biologic and social variables should be examined to further understand socioeconomic status effects.

Purpose: We compared the management and outcome of supraglottic cancer in Ontario, Canada, with that in the Surveillance, Epidemiology, and End Results (SEER) Program areas in the United States. Methods: Electronic, clinical, and hospital data were linked to cancer registry data and supplemented by chart review where necessary. Stage-stratified analyses compared initial treatment and survival in the SEER areas (n = 1,643) with a random sample from Ontario (n = 265). We also compared laryngectomy rates at 3 years in those patients 65 years and older at diagnosis. Results: Radical surgery was more commonly used in SEER, with absolute differences increasing with increasing stage: I/II, 17%; III, 36%; and IV, 45%. The 5-year survival rates were 74% in Ontario and 56% in SEER for stage I/II disease (P = .01), 55.7% in Ontario and 46.8% in SEER for stage III disease (P = .40), and 28.5% in Ontario and 29.1% in SEER for stage IV disease (P = .28). Cancer-specific survival results mirrored the overall survival results with the exception of stage IV disease, for which 34.6% of Ontario patients survived their cancer compared with 38.1% in SEER (P = .10). This stage IV difference was more pronounced when we further controlled for possible cause of death errors by restricting the comparison to patients with a single primary cancer (P = .01). Three-year actuarial laryngectomy rates differed. In stage I/II, these rates were 3% in Ontario compared with 35% in SEER (P < 10−3). In stage III disease, the rates were 30% and 54%, respectively (P = .03), and in stage IV disease they were 33% and 64% (P = .002). Conclusion: There are large differences in the management of supraglottic cancer between the SEER areas of the United States and Ontario. Long-term larynx retention was higher in Ontario, where radiotherapy is widely regarded as the treatment of choice and surgery is reserved for salvage. In stages I to III, survival was similar in the two regions despite the differences in treatment policy. In stage IV, there may be a small survival advantage in the U.S. SEER areas related to the higher use of primary surgery.