Palliative chemotherapy among people living in poverty with metastasised colon cancer: facilitation by primary care and health insurance.

BACKGROUND: Many Americans with metastasised colon cancer do not receive indicated palliative chemotherapy. We examined the effects of health insurance and physician supplies on such chemotherapy in California. METHODS: We analysed registry data for 1199 people with metastasised colon cancer diagnosed between 1996 and 2000 and followed for 1 year. We obtained data on health insurance, census tract-based socioeconomic status and county-level physician supplies. Poor neighbourhoods were oversampled and the criterion was receipt of chemotherapy. Effects were described with rate ratios (RR) and tested with logistic regression models. RESULTS: Palliative chemotherapy was received by less than half of the participants (45%). Facilitating effects of primary care (RR=1.23) and health insurance (RR=1.14) as well as an impeding effect of specialised care (RR=0.86) were observed. Primary care physician (PCP) supply took precedence. Adjusting for poverty, PCP supply was the only significant and strong predictor of chemotherapy (OR=1.62, 95% CI 1.02 to 2.56). The threshold for this primary care advantage was realised in communities with 8.5 or more PCPs per 10 000 inhabitants. Only 10% of participants lived in such well-supplied communities. CONCLUSIONS: This study's observations of facilitating effects of primary care and health insurance on palliative chemotherapy for metastasised colon cancer clearly suggested a way to maximise Affordable Care Act (ACA) protections. Strengthening America's system of primary care will probably be the best way to ensure that the ACA's full benefits are realised. Such would go a long way towards facilitating access to palliative care.

Stomach Cancer Following Hodgkin Lymphoma, Testicular Cancer and Cervical Cancer: A Pooled Analysis of Three International Studies with a Focus on Radiation Effects.

To further understand the risk of stomach cancer after fractionated high-dose radiotherapy, we pooled individual-level data from three recent stomach cancer case-control studies. These studies were nested in cohorts of five-year survivors of first primary Hodgkin lymphoma (HL), testicular cancer (TC) or cervical cancer (CX) from seven countries. Detailed data were abstracted from patient records and radiation doses were reconstructed to the site of the stomach cancer for cases and to the corresponding sites for matched controls. Among 327 cases and 678 controls, mean doses to the stomach were 15.3 Gy, 24.7 Gy and 1.9 Gy, respectively, for Hodgkin lymphoma, testicular cancer and cervical cancer survivors, with an overall mean dose of 10.3 Gy. Risk increased with increasing radiation dose to the stomach cancer site (P < 0.001) with no evidence of nonlinearity or of a downturn at the highest doses (≥35 Gy). The pooled excess odds ratio per Gy (EOR/Gy) was 0.091 [95% confidence interval (CI): 0.036-0.20] with estimates of 0.049 (95% CI: 0.007-0.16) for Hodgkin lymphoma, 0.27 (95% CI: 0.054-1.44) for testicular cancer and 0.096 (95% CI: -0.002-0.39) for cervical cancer (P homogeneity = 0.25). The EOR/Gy increased with time since exposure (P trend = 0.004), with an EOR/Gy of 0.38 (95% CI: 0.12-1.04) for stomach cancer occurring ≥20 years postirradiation corresponding to odds ratios of 4.8 and 10.5 at radiation doses to the stomach of 10 and 25 Gy, respectively. Of 111 stomach cancers occurring ≥20 years after radiotherapy, 63.8 (57%) could be attributed to radiotherapy. Our findings differ from those based on Japanese atomic-bomb survivors, where the overall EOR/Gy was higher and where there was no evidence of an increase with time since exposure. By pooling data from three studies, we demonstrated a clear increase in stomach cancer risk over a wide range of doses from fractionated radiotherapy with the highest risks occurring many years after exposure. These findings highlight the need to directly evaluate the health effects of high-dose fractionated radiotherapy rather than relying on the data of persons exposed at low and moderate acute doses.

Breast Cancer Care in California and Ontario: Primary Care Protections Greatest Among the Most Socioeconomically Vulnerable Women Living in the Most Underserved Places.

BACKGROUND: Better health care among Canada's socioeconomically vulnerable versus America's has not been fully explained. We examined the effects of poverty, health insurance and the supply of primary care physicians on breast cancer care. METHODS: We analyzed breast cancer data in Ontario (n = 950) and California (n = 6300) between 1996 and 2000 and followed until 2014. We obtained socioeconomic data from censuses, oversampling the poor. We obtained data on the supply of physicians, primary care and specialists. The optimal care criterion was being diagnosed early with node negative disease and received breast conserving surgery followed by adjuvant radiation therapy. RESULTS: Women in Ontario received more optimal care in communities well supplied by primary care physicians. They were particularly advantaged in the most disadvantaged places: high poverty neighborhoods (rate ratio = 1.65) and communities lacking specialist physicians (rate ratio = 1.33). Canadian advantages were explained by better health insurance coverage and greater primary care access. CONCLUSIONS: Policy makers ought to ensure that the newly insured are adequately insured. The Medicaid program should be expanded, as intended, across all 50 states. Strengthening America's system of primary care will probably be the best way to ensure that the Affordable Care Act's full benefits are realized.

Increased pancreatic cancer risk following radiotherapy for testicular cancer.

BACKGROUND: Pancreatic cancer risk is elevated among testicular cancer (TC) survivors. However, the roles of specific treatments are unclear. METHODS: Among 23 982 5-year TC survivors diagnosed during 1947-1991, doses from radiotherapy to the pancreas were estimated for 80 pancreatic cancer patients and 145 matched controls. Chemotherapy details were recorded. Logistic regression was used to estimate odds ratios (ORs). RESULTS: Cumulative incidence of second primary pancreatic cancer was 1.1% at 30 years after TC diagnosis. Radiotherapy (72 (90%) cases and 115 (80%) controls) was associated with a 2.9-fold (95% confidence interval (CI) 1.0-7.8) increased risk. The OR increased linearly by 0.12 per Gy to the pancreas (P-trend<0.001), with an OR of 4.6 (95% CI 1.9-11.0) for ⩾25 Gy vs <25 Gy. Radiation-related risks remained elevated ⩾20 years after TC diagnosis (P=0.020). The risk increased with the number of cycles of chemotherapy with alkylating or platinum agents (P=0.057), although only one case was exposed to platinum. CONCLUSIONS: A dose-response relationship exists between radiation to the pancreas and subsequent cancer risk, and persists for over 20 years. These excesses, although small, should be considered when radiotherapy with exposure to the pancreas is considered for newly diagnosed patients. Additional data are needed on the role of chemotherapy.

Disparities Report: Disparities Among Minority Women With Breast Cancer Living in Impoverished Areas of California.

BACKGROUND: Interaction effects of poverty and health care insurance coverage on overall survival rates of breast cancer among women of color and non-Hispanic white women were explored. METHODS: We analyzed California registry data for 2,024 women of color (black, Hispanic, Asian, Pacific Islander, American Indian, or other ethnicity) and 4,276 non-Hispanic white women (Anglo-European ancestries and no Hispanic-Latin ethnic backgrounds) diagnosed with breast cancer between the years 1996 and 2000 who were then followed until 2011. The 2000 US census categorized rates of neighborhood poverty. Health care insurance coverage was either private, Medicare, Medicaid, or none. Cox regression was used to model rates of survival. RESULTS: A 3-way interaction between ethnicity, health care insurance coverage, and poverty was observed. Women of color inadequately insured and living in poor or near-poor neighborhoods in California were the most disadvantaged. Women of color adequately insured and who lived in such neighborhoods in California were also disadvantaged. The incomes of such women of color were typically lower than the incomes of non-Hispanic white women. CONCLUSIONS: Women of color with or without insurance coverage are disadvantaged in poor and near-poor neighborhoods of California. Such women may be less able to bare the indirect, direct, or uncovered costs of health care for breast cancer treatment.

Colon cancer care and survival: income and insurance are more predictive in the USA, community primary care physician supply more so in Canada.

BACKGROUND: Our research group advanced a health insurance theory to explain Canada's cancer care advantages over America. The late Barbara Starfield theorized that Canada's greater primary care-orientation also plays a critically protective role. We tested the resultant Starfield-Gorey theory by examining the effects of poverty, health insurance and physician supplies, primary care and specialists, on colon cancer care in Ontario and California. METHODS: We analyzed registry data for people with non-metastasized colon cancer from Ontario (n = 2,060) and California (n = 4,574) diagnosed between 1996 and 2000 and followed to 2010. We obtained census tract-based socioeconomic data from population censuses and data on county-level physician supplies from national repositories: primary care physicians, gastroenterologists and other specialists. High poverty neighborhoods were oversampled and the criterion was 10 year survival. Hypotheses were explored with standardized rate ratios (RR) and tested with logistic regression models. RESULTS: Significant inverse associations of poverty (RR = 0.79) and inadequate health insurance (RR = 0.80) with survival were observed in the California, while they were non-significant or non-existent in Ontario. The direct associations of primary care physician (RRs of 1.32 versus 1.11) and gastroenterologist (RRs of 1.56 versus 1.15) supplies with survival were both stronger in Ontario than California. The supply of primary care physicians took precedence. Probably mediated through the initial course of treatment, it largely explained the Canadian advantage. CONCLUSIONS: Poverty and health insurance were more predictive in the USA, community physician supplies more so in Canada. Canada's primary care protections were greatest among the most socioeconomically vulnerable. The protective effects of Canadian health care prior to enactment of the Affordable Care Act (ACA) clearly suggested the following. Notwithstanding the importance of insuring all, strengthening America's system of primary care will probably be the best way to ensure that the ACA's full benefits are realized. Finally, Canada's strong primary care system ought to be maintained.

Breast Cancer among Women Living in Poverty: Better Care in Canada than in the United States.

This historical study estimated the protective effects of a universally accessible, single-payer health care system versus a multi-payer system that leaves many uninsured or underinsured by comparing breast cancer care of women living in high poverty neighborhoods in Ontario or California between 1996 and 2011. Women in Canada experienced better care particularly as compared to women who were inadequately insured in the United States. Women in Canada were diagnosed earlier (rate ratio [RR] = 1.12) and enjoyed better access to breast conserving surgery (RR = 1.48), radiation (RR = 1.60) and hormone therapies (RR = 1.78). Women living in high poverty Canadian neighborhoods even experienced shorter waits for surgery (RR = 0.58) and radiation therapy (RR = 0.44) than did such women in the US. Consequently, women in Canada were much more likely to survive longer. Regression analyses indicated that health insurance could explain most of the better care and better outcomes in Canada. Over this study's 15-year timeframe 31,500 late diagnoses, 94,500 sub-optimum treatment plans and 103,500 early deaths were estimated in high poverty US neighborhoods due to relatively inadequate health insurance coverage. Implications for social work practice, including advocacy for future reforms of US health care are discussed.

Multiplicative disadvantage of being an unmarried and inadequately insured woman living in poverty with colon cancer: historical cohort exploration in California.

BACKGROUND: Many Americans diagnosed with colon cancer do not receive indicated chemotherapy. Certain unmarried women may be particularly disadvantaged. A 3-way interaction of the multiplicative disadvantages of being an unmarried and inadequately insured woman living in poverty was explored. METHODS: California registry data were analyzed for 2,319 women diagnosed with stage II to IV colon cancer between 1996 and 2000 and followed until 2014. Socioeconomic data from the 2000 census classified neighborhoods as high poverty (≥30% of households poor), middle (5-29%) or low poverty (<5% poor). Primary health insurance was private, Medicare, Medicaid or none. Comparisons of chemotherapy rates used standardized rate ratios (RR). We respectively used logistic and Cox regression models to assess chemotherapy and survival. RESULTS: A statistically significant 3-way marital status by health insurance by poverty interaction effect on chemotherapy receipt was observed. Chemotherapy rates did not differ between unmarried (39.0%) and married (39.7%) women who lived in lower poverty neighborhoods and were privately insured. But unmarried women (27.3%) were 26% less likely to receive chemotherapy than were married women (37.1%, RR = 0.74, 95% CI 0.58, 0.95) who lived in high poverty neighborhoods and were publicly insured or uninsured. When this interaction and the main effects of health insurance, poverty and chemotherapy were accounted for, survival did not differ by marital status. CONCLUSIONS: The multiplicative barrier to colon cancer care that results from being inadequately insured and living in poverty is worse for unmarried than married women. Poverty is more prevalent among unmarried women and they have fewer assets so they are probably less able to absorb the indirect and direct, but uncovered, costs of colon cancer care. There seem to be structural inequities related to the institutions of marriage, work and health care that particularly disadvantage unmarried women that policy makers ought to be cognizant of as future reforms of the American health care system are considered.

Stomach cancer risk after treatment for hodgkin lymphoma.

PURPOSE: Treatment-related stomach cancer is an important cause of morbidity and mortality among the growing number of Hodgkin lymphoma (HL) survivors, but risks associated with specific HL treatments are unclear. PATIENTS AND METHODS: We conducted an international case-control study of stomach cancer nested in a cohort of 19,882 HL survivors diagnosed from 1953 to 2003, including 89 cases and 190 matched controls. For each patient, we quantified cumulative doses of specific alkylating agents (AAs) and reconstructed radiation dose to the stomach tumor location. RESULTS: Stomach cancer risk increased with increasing radiation dose to the stomach (Ptrend < .001) and with increasing number of AA-containing chemotherapy cycles (Ptrend = .02). Patients who received both radiation to the stomach ≥ 25 Gy and high-dose procarbazine (≥ 5,600 mg/m(2)) had strikingly elevated stomach cancer risk (25 cases, two controls; odds ratio [OR], 77.5; 95% CI, 14.7 to 1452) compared with those who received radiation < 25 Gy and procarbazine < 5,600 mg/m(2) (Pinteraction < .001). Risk was also elevated (OR, 2.8; 95% CI, 1.3 to 6.4) among patients who received radiation to the stomach ≥ 25 Gy but procarbazine < 5,600 mg/m(2); however, no procarbazine-related risk was evident with radiation < 25 Gy. Treatment with dacarbazine also increased stomach cancer risk (12 cases, nine controls; OR, 8.8; 95% CI, 2.1 to 46.6), after adjustment for radiation and procarbazine doses. CONCLUSION: Patients with HL who received subdiaphragmatic radiotherapy had dose-dependent increased risk of stomach cancer, with marked risks for patients who also received chemotherapy containing high-dose procarbazine. For current patients, risks and benefits of exposure to both procarbazine and subdiaphragmatic radiotherapy should be weighed carefully. For patients treated previously, GI symptoms should be evaluated promptly.

Breast cancer detection and survival among women with cosmetic breast implants: systematic review and meta-analysis of observational studies.

OBJECTIVES: To evaluate whether the stage distribution among women diagnosed as having breast cancer differs between those who have received breast implants for cosmetic purposes and those with no implants and to evaluate whether cosmetic breast augmentation before the detection of breast cancer is a predictor of post-diagnosis survival. DESIGN: Systematic review of observational studies with two meta-analyses. DATA SOURCES: Systematic search of the literature published before September 2012 conducted in Medline, Embase, Global health, CINAHL, IPAB, and PsycINFO. STUDY SELECTION: Eligible publications were those that included women diagnosed as having breast cancer and who had had augmentation mammaplasty for cosmetic purposes. RESULTS: The overall odds ratio of the first meta-analysis based on 12 studies was 1.26 (95% confidence interval 0.99 to 1.60; P=0.058; I(2)=35.6%) for a non-localized stage of breast cancer at diagnosis comparing women with implants who had breast cancer and women without implants who had breast cancer. The second meta-analysis, based on five studies, evaluated the relation between cosmetic breast implantation and survival. This meta-analysis showed reduced survival after breast cancer among women who had implants compared with those who did not (overall hazard ratio for breast cancer specific mortality 1.38, 95% confidence interval 1.08 to 1.75). CONCLUSIONS: The research published to date suggests that cosmetic breast augmentation adversely affects the survival of women who are subsequently diagnosed as having breast cancer. These findings should be interpreted with caution, as some studies included in the meta-analysis on survival did not adjust for potential confounders. Further investigations are warranted regarding diagnosis and prognosis of breast cancer among women with breast implants.

Mediation of the effects of living in extremely poor neighborhoods by health insurance: breast cancer care and survival in California, 1996 to 2011.

BACKGROUND: We examined the mediating effect of health insurance on poverty-breast cancer care and survival relationships and the moderating effect of poverty on health insurance-breast cancer care and survival relationships in California. METHODS: Registry data for 6,300 women with breast cancer diagnosed between 1996 and 2000 and followed until 2011 on stage at diagnosis, surgeries, adjuvant treatments and survival were analyzed. Socioeconomic data were obtained for residences from the 2000 census to categorize neighborhoods: high poverty (30% or more poor), middle poverty (5%-29% poor) and low poverty (less than 5% poor). Primary payers or health insurers were Medicaid, Medicare, private or uninsured. RESULTS: Evidence of survival mediation was observed for women with node negative breast cancer. The apparent effect of poverty disappeared in the presence of Medicare or private health insurance. Women who were so insured were advantaged on 8-year survival compared to the uninsured or those insured by Medicaid (OR = 1.89). Evidence of payer moderation by poverty was also observed for women with node negative breast cancer. The survival advantaging effect of Medicare or private insurance was stronger in low poverty (OR = 1.81) than it was in middle poverty (OR = 1.57) or in high poverty neighborhoods (OR = 1.16). This same pattern of mediated and moderated effects was also observed for early stage at diagnosis, shorter waits for adjuvant radiation therapy and for the receipt of sentinel lymph node biopsies. These findings are consistent with the theory that more facilitative social and economic capital is available in low poverty neighborhoods, where women with breast cancer may be better able to absorb the indirect and direct, but uncovered, costs of care. As for treatments, main protective effects as well as moderator effects indicative of protection, particularly in high poverty neighborhoods were observed for women with private health insurance. CONCLUSIONS: America's multi-tiered health insurance system mediates the quality of breast cancer care. The system is inequitable and unjust as it advantages the well insured and the well to do. Recent health care reforms ought to be enacted in ways that are consistent with their federal legislative intent, that high quality health care be truly available to all.

Better colon cancer care for extremely poor Canadian women compared with American women.

Extremely poor Canadian women were recently observed to be largely advantaged on most aspects of breast cancer care as compared with similarly poor, but much less adequately insured, women in the United States. This historical study systematically replicated the protective effects of single- versus multipayer health care by comparing colon cancer care among cohorts of extremely poor women in California and Ontario between 1996 and 2011. The Canadian women were again observed to have been largely advantaged. They were more likely to have received indicated surgery and chemotherapy, and their wait times for care were significantly shorter. Consequently, the Canadian women were much more likely to experience longer survival times. Regression analyses indicated that health insurance nearly completely explained the Canadian advantages. Implications for contemporary and future reforms of U.S. health care are discussed.

Effects of being uninsured or underinsured and living in extremely poor neighborhoods on colon cancer care and survival in California: historical cohort analysis, 1996-2011.

BACKGROUND: We examined the mediating effects of health insurance on poverty-colon cancer care and survival relationships and the moderating effects of poverty on health insurance-colon cancer care and survival relationships among women and men in California. METHODS: We analyzed registry data for 3,291 women and 3,009 men diagnosed with colon cancer between 1996 and 2000 and followed until 2011 on lymph node investigation, stage at diagnosis, surgery, chemotherapy, wait times and survival. We obtained socioeconomic data for individual residences from the 2000 census to categorize the following neighborhoods: high poverty (30% or more poor), middle poverty (5-29% poor) and low poverty (less than 5% poor). Primary health insurers were Medicaid, Medicare, private or none. RESULTS: Evidence of mediation was observed for women, but not for men. For women, the apparent effect of poverty disappeared in the presence of payer, and the effects of all forms of health insurance seemed strengthened. All were advantaged on 6-year survival compared to the uninsured: Medicaid (RR = 1.83), Medicare (RR = 1.92) and private (RR = 1.83). Evidence of moderation was also only observed for women. The effects of all forms of health insurance were stronger for women in low poverty neighborhoods: Medicaid (RR = 2.90), Medicare (RR = 2.91) and private (RR = 2.60). For men, only main effects of poverty and payers were observed, the advantaging effect of private insurance being largest. Across colon cancer care processes, Medicare seemed most instrumental for women, private payers for men. CONCLUSIONS: Health insurance substantially mediates the quality of colon cancer care and poverty seems to make the effects of being uninsured or underinsured even worse, especially among women in the United States. These findings are consistent with the theory that more facilitative social and economic capital is available in more affluent neighborhoods, where women with colon cancer may be better able to absorb the indirect and direct, but uncovered, costs of care.

Do breast implants adversely affect prognosis among those subsequently diagnosed with breast cancer? Findings from an extended follow-up of a Canadian cohort.

BACKGROUND: Cosmetic breast implants may impair the ability to detect breast cancers. The aims of this study were to examine whether implants and implant characteristics are associated with more advanced breast tumors at diagnosis and poorer survival. METHODS: Study population includes all invasive breast cancer cases diagnosed during follow-up of the large Canadian Breast Implant Cohort. A total of 409 women with cosmetic breast implants and 444 women with other cosmetic surgery were diagnosed with breast cancer. These women were compared for stage at diagnosis using multinomial logistic regression models. Cox proportional hazards regression models were used for breast cancer-specific mortality analyses. Comparisons were also conducted according to implant characteristics. RESULTS: Compared with women with other cosmetic surgery, those with cosmetic breast implants had at later stage breast cancer diagnosis (OR of having stage III/IV vs. stage I at diagnosis: 3.04, 95% confidence interval (CI): 1.81-5.10; P < 0.001). A nonstatistically significant increase in breast cancer-specific mortality rate for women with breast implants relative to surgical controls was observed (HR = 1.32, 95% CI: 0.94-1.83, P = 0.11). No statistically significant differences in stage and breast cancer mortality were observed according to implant characteristics. CONCLUSIONS: At diagnosis, breast cancers tended to be at more advanced stages among women with cosmetic breast implants. Breast cancer-specific survival was lower in these women although the reduction did not reach statistical significance. IMPACT: Further investigations of the effect of breast implants on breast cancer prognosis are warranted.

Canadian breast implant cohort: extended follow-up of cancer incidence.

Cosmetic breast implants are not associated with increased breast cancer incidence, but variations of risk according to implant characteristics are still poorly understood. As well, the assessment of cancer risk for sites other than breast needs to be clarified. The purpose of this study was to fill these research gaps. This study presents an extended analysis of 10 more years of follow-up of a large Canadian cohort of women who received either cosmetic breast implants (n = 24,558) or other cosmetic surgery (15,893). Over 70% of the implant cohort was followed for over 20 years. Cancer incidence among implant women was compared to those of controls using multivariate Poisson models and the general female population using the standardized incidence ratios (SIRs). Women with breast implants had reduced rates of breast and endometrial cancers compared to other surgery women. Subglandular implants were associated to a reduced rate of breast cancer compared to submuscular implants [incidence rate ratio (IRR) = 0.78, 95% confidence interval (CI) = 0.63-0.96] and this reduction persisted over time. We observed a sevenfold increased rate (IRR = 7.36, 95% CI = 1.86-29.12) of breast cancer in the first 5 years after the date of surgery for polyurethane-coated subglandular implant women but this IRR decreased progressively over time (p value for trend = 0.02). We also observed no increased risk of rarer forms of cancer among augmented women. A reduction in breast cancer incidence was observed for women with subglandular implants relative to women with submuscular implants. Possible increase of breast cancer incidence shortly after breast augmentation with polyurethane implants needs to be verified.

A geographical analysis of breast cancer clustering in southern Ontario: generating hypotheses on environmental influences.

This article presents the results of spatial analysis of breast cancer clustering in southern Ontario. Data from the Cancer Care Ontario were analyzed using the Scan Statistic at the level of county, with further analysis conducted within counties that were identified as primary clusters at the dissemination area level. The results identified five counties as primary clusters of women diagnosed with breast cancer between 1986 and 2002: Essex (relative risk [RR] =1.096-1.061; p<0.001), Lambton (RR=1.05-1.167), Chatham-Kent (RR=1.133-1.191), Niagara (RR=1.228-1.290) and Toronto (RR=1.152-1.146). The within county analysis revealed several DAs with significantly higher (RR>3, p<0.05) rates of breast cancer, and supports our hypothesis that breast cancer risk in southern Ontario may be associated with industrial and environmental (such as pesticides) pollutants. Further research is needed to verify the environmental links within the identified clusters.

The supply of physicians and care for breast cancer in Ontario and California, 1998 to 2006.

INTRODUCTION: We examined the differential effects of the supply of physicians on care for breast cancer in Ontario and California. We then used criteria for optimum care for breast cancer to estimate the regional needs for the supply of physicians. METHODS: Ontario and California registries provided 951 and 984 instances of breast cancer diagnosed between 1998 and 2000 and followed until 2006. These cohorts were joined with the supply of county-level primary care physicians (PCPs) and specialists in cancer care and compared on care for breast cancer. RESULTS: Significant protective PCP thresholds (7.75 to = 8.25 PCPs per 10 000 inhabitants) were observed for breast cancer diagnosis (odds ratio [OR] 1.62), receipt of adjuvant radiotherapy (OR 1.64) and 5-year survival (OR 1.87) in Ontario, but not in California. The number of physicians seemed adequate to optimize care for breast cancer across diverse places in California and in most Ontario locations. However, there was an estimated need for 550 more PCPs and 200 more obstetrician-gynecologists in Ontario's rural and small urban areas. We estimated gross physician surpluses for Ontario's 2 largest cities. CONCLUSION: Policies are needed to functionally redistribute primary care and specialist physicians. Merely increasing the supply of physicians is unlikely to positively affect the health of Ontarians.

Associations of physician supplies with colon cancer care in Ontario and California, 1996 to 2006.

BACKGROUND: This study examined the differential effects of physician supplies on colon cancer care in Ontario and California. The associations of physician supplies with colon cancer stage at diagnosis, receipt of surgery and adjuvant chemotherapy, and 5-year survival were observed within each country and compared between-country. METHODS: Random samples of Ontario and California cancer registries provided 2,461 and 2,200 colon cancer cases that were diagnosed between 1996 and 2000, and followed until 2006. Both registries included data on the stage of disease at the time of diagnosis, receipt of cancer-directed surgery, receipt of adjuvant chemotherapy, and survival. Census tract-level data on low-income prevalence were, respectively, taken from 2001 and 2000 Canadian and United States population censuses. County-level primary care physician and gastroenterologist densities were computed for the same years. RESULTS: Significant income-adjusted, gastroenterologist density threshold effects (2.0 or more vs. less than 2.0 per 100,000 inhabitants) were observed for early diagnosis (OR = 1.57) and 5-year survival (OR = 1.63) in Ontario, but not in California. Significant incremental threshold effects of primary care physician densities on chemotherapy receipt (8.0 and 9.0 or more per 10,000 inhabitants, respective ORs of 1.79 and 2.37) were also only observed in Ontario. CONCLUSIONS: These colon cancer care findings support the theory that while personal economic resources are more predictive in America, community-level resources such as physician supplies are more predictive of health care access and effectiveness in Canada.

Effects of socioeconomic status on colon cancer treatment accessibility and survival in Toronto, Ontario, and San Francisco, California, 1996-2006.

OBJECTIVES: We examined the differential effects of socioeconomic status on colon cancer care and survival in Toronto, Ontario, Canada, and San Francisco, California. METHODS: We analyzed registry data for colon cancer patients from Ontario (n = 930) and California (n = 1014), diagnosed between 1996 and 2000 and followed until 2006, on stage, surgery, adjuvant chemotherapy, and survival. We obtained socioeconomic data for individuals' residences from population censuses. RESULTS: Income was directly associated with lymph node evaluation, chemotherapy, and survival in San Francisco but not in Toronto. High-income persons had better survival rates in San Francisco than in Toronto. After adjustment for stage, survival was better for low-income residents of Toronto than for those of San Francisco. Middle- to low-income patients were more likely to receive indicated chemotherapy in Toronto than in San Francisco. CONCLUSIONS: Socioeconomic factors appear to mediate colon cancer care in urban areas of the United States but not in Canada. Improvements are needed in screening, diagnostic investigations, and treatment access among low-income Americans.