Long-term survival outcomes following breast cancer surgery in Western Australia

Lowering Re-excision Rates After Breast-Conserving Surgery: Unraveling the Intersection Between Surgeon Case Volumes and Techniques

BACKGROUND

The re-excision rates after breast-conserving surgery (BCS) are significantly varied, with surgeon case volume as one influential factor. Surgeons with higher case volumes have been shown to have lower reoperation rates. This study attempted to determine whether this may be attributable to excessive breast tissue removal during initial BCS.

METHODS

A retrospective study analyzed referrals to the authors' cancer center during 3 years. Patients undergoing initial BCS for ductal carcinoma in situ or T1-T3 breast cancers were included. Patient age, tumor factors, surgeon case volume, and the calculated resection ratio (CRR) were analyzed. The total resection volume was divided by the optimal resection volume to produce the CRR, which reflected the magnitude of excess tissue resected during initial BCS. Comparison of the mean CRR between surgeon case-volume categories was performed with a repeated measures analysis of variance. A multivariate regression model assessed the effects of the CRR and surgeon case volume on re-excision rates.

RESULTS

Larger tumor size, lobular histology, and lower CRR were associated with increased re-excision rates. The CRR was similar for each surgeon case-volume group. Surgeon case volume was not independently associated with re-excision rates, but surgeons with very high case volumes had lower odds of re-excision than surgeons with intermediate case volumes (odds ratio 0.44; 95% confidence interval 0.21-0.91).

CONCLUSIONS

When control was used for the CRR, apparent differences in re-excision rates between surgeon case-volume groups were observed, suggesting that surgeons with higher case volumes may be more accurate when performing BCS.

Factors influencing breast cancer outcomes in Australia: A systematic review

PURPOSE

This systematic review evaluates factors influencing breast cancer outcomes for women treated in Australia, facilitating the exploration of disparities in breast cancer outcomes for certain groups of women in Australia.

METHOD

A systematic literature search was performed using MEDLINE and Scopus focusing on breast cancer in Australia with outcome measures being breast cancer survival and recurrence with no restrictions on date. Risk of bias was assessed using Cairns Assessment Scale for Observational studies of Risk factors (CASOR).

RESULTS

Fifteen quantitative studies were included: two were high quality, 11 were intermediate quality, and two were low quality. Traditional risk factors such as invasive tumour type, larger size, higher grade and stage, lymph node involvement and absence of hormone receptors were found to be associated with breast cancer mortality. Being younger (<40 years old) and older (>70 years old), having more comorbidities, being of lower socioeconomic status, identifying as Aboriginal or Torres Strait Islander, living in more rural areas or having a mastectomy were factors found to be associated with poorer breast cancer outcomes.

CONCLUSION

Despite the heterogeneity of the studies, this review identified significant risk factors for breast cancer mortality and recurrence. The use of this data would be most useful in developing evidence-based interventions and in optimising patient care through creation of a prediction model.

PROSPERO REGISTRATION

CRD42017072857.

Variations in outcomes by residential location for women with breast cancer: a systematic review

OBJECTIVES

To systematically assess the evidence for variations in outcomes at each step along the breast cancer continuum of care for Australian women by residential location.

DESIGN

Systematic review.

METHODS

Systematic searches of peer-reviewed articles in English published from 1 January 1990 to 24 November 2017 using PubMed, EMBASE, CINAHL and Informit databases. Inclusion criteria were: population was adult female patients with breast cancer; Australian setting; outcome measure was survival, patient or tumour characteristics, screening rates or frequencies, clinical management, patterns of initial care or post-treatment follow-up with analysis by residential location or studies involving non-metropolitan women only. Included studies were critically appraised using a modified Newcastle-Ottawa Scale.

RESULTS

Seventy-four quantitative studies met the inclusion criteria. Around 59% were considered high quality, 34% moderate and 7% low. No eligible studies examining treatment choices or post-treatment follow-up were identified. Non-metropolitan women consistently had poorer survival, with most of this differential being attributed to more advanced disease at diagnosis, treatment-related factors and socioeconomic disadvantage. Compared with metropolitan women, non-metropolitan women were more likely to live in disadvantaged areas and had differing clinical management and patterns of care. However, findings regarding geographical variations in tumour characteristics or diagnostic outcomes were inconsistent.

CONCLUSIONS

A general pattern of poorer survival and variations in clinical management for Australian female patients with breast cancer from non-metropolitan areas was evident. However, the wide variability in data sources, measures, study quality, time periods and geographical classification made direct comparisons across studies challenging. The review highlighted the need to promote standardisation of geographical classifications and increased comparability of data systems. It also identified key gaps in the existing literature including a lack of studies on advanced breast cancer, geographical variations in treatment choices from the perspective of patients and post-treatment follow-up.

Understanding the effects of socioeconomic status along the breast cancer continuum in Australian women: a systematic review of evidence

Background

Globally, the provision of equitable outcomes for women with breast cancer is a priority for governments. However, there is growing evidence that a socioeconomic status (SES) gradient exists in outcomes across the breast cancer continuum – namely incidence, diagnosis, treatment, survival and mortality. This systematic review describes this evidence and, because of the importance of place in defining SES, findings are limited to the Australian experience.

Methods

An on-line search of PubMed and the Web of Science identified 44 studies published since 1995 which examined the influence of SES along the continuum. The critique of studies included the study design, the types and scales of SES variable measured, and the results in terms of direction and significance of the relationships found. To aid in the interpretation of results, the findings were discussed in the context of a systems dynamic feedback diagram.

Results

We found 67 findings which reported 107 relationships between SES within outcomes along the continuum. Results suggest no differences in the participation in screening by SES. Higher incidence was reported in women with higher SES whereas a negative association was reported between SES and diagnosis. Associations with treatment choice were specific to the treatment choice undertaken. Some evidence was found towards greater survival for women with higher SES, however, the evidence for a SES relationship with mortality was less conclusive.

Conclusions

In a universal health system such as that in Australia, evidence of an SES gradient exists, however, the strength and direction of this relationship varies along the continuum. This is a complex relationship and the heterogeneity in study design, the SES indicator selected and its representative scale further complicates our understanding of its influence. More complex multilevel studies are needed to better understand these relationships, the interactions between predictors and to reduce biases introduced by methodological issues.

Optimising Breast Conservation Treatment for Multifocal and Multicentric Breast Cancer: A Worthwhile Endeavour?

BACKGROUND

Breast conservation treatment (BCT) is an accepted treatment modality for early breast cancer. However, multifocal and multicentric breast cancer (MFMCBC) is a relative contraindication to BCT. This study was performed to compare BCT rates in MFMCBC and unifocal tumours and its outcomes.

METHODS

A retrospective analysis was performed for patients with breast malignancies who underwent operative treatment between 2009 and 2011. Successful BCT was defined as the ability to obtain clear margins for all tumour foci through a single incision with acceptable resultant cosmesis.

RESULTS

A total of 160 patients were analysed, of which 40 were MFMCBC. Thirty-four of the 40 patients with MFMCBC underwent BCT (85 %). After a mean follow-up period of 55 months, there were no local recurrences in patients with MFMCBC.

CONCLUSION

BCT was achieved in 85 % of the patients with MFMCBC in this cohort without evidence of poorer local control. Further investigation is needed to confirm this finding for its potential contribution to improved survival outcomes.

Oesophagectomy rates and post-resection outcomes in patients with cancer of the oesophagus and gastro-oesophageal junction: a population-based study using linked health administrative linked data

Background

Hospital performance is being benchmarked increasingly against surgical indicators such as 30-day mortality, length-of-stay, survival and post-surgery complication rates. The aim of this paper was to examine oesophagectomy rates and post-surgical outcomes in cancers of the oesophagus and gastro-oesophageal junction and to determine how the addition of gastro-oesophageal cancer to oesophageal cancer impacts on these outcomes.

Methods

Our study population consisted of patients with a primary invasive oesophageal or gastro-oesophageal cancer identified from the NSW Cancer Registry from July 2000-Dec 2007. Their records were linked to the hospital separation data for determination of resection rates and post-resection outcomes. We used multivariate logistic regression analyses to examine factors associated with oesophagectomy and post-resection outcomes. Cox-proportional hazard regression analysis was used to examine one-year cancer survival following oesophagectomy.

Results

We observed some changes in resection rates and surgical outcomes with the addition of gastro-oesophageal cancer patients to the oesophageal cancer cohort. 14.6% of oesophageal cancer patients and 26.4% of gastro-oesophageal cancer patients had an oesophagectomy; an overall oesophagectomy rate of 18.2% in the combined cohort. In the combined cohort, oesophagectomy was associated with younger age, being male and Australian-born, having non-metastatic disease or adenocarcinoma and being admitted in a co-located hospital. Rates of length-of-stay >28 days (20.9% vs 19.7%), 30-day mortality (3.8% vs 2.7%) and one-year survival post-surgery (24.5% vs 23.1%) were similar between oesophageal cancer alone and the combined cohort; whilst 30-day complication rates were 21.5% versus 17.0% respectively. Some factors statistically associated with post-resection complication in oesophageal cancer alone were not significant in the overall cohort. Poorer post-resection outcomes were associated with some patient (older age, birthplace) and hospital-related characteristics (fiscal sector, area health service).

Conclusion

Outcomes following oesophagectomy in oesophageal and gastro-oesophageal cancer patients in NSW are within world benchmarks. Our study demonstrates that the inclusion of gastro-oesophageal cancer did alter some outcomes compared to analysis based solely on oesophageal cancer. As such, care must be taken with analyses based on administrative health data to capture all populations eligible for treatment and to understand the contribution of these subpopulations to overall outcomes.

Hospital discharge diagnostic and procedure codes for upper gastro-intestinal cancer: how accurate are they?

BACKGROUND

Population-level health administrative datasets such as hospital discharge data are used increasingly to evaluate health services and outcomes of care. However information about the accuracy of Australian discharge data in identifying cancer, associated procedures and comorbidity is limited. The Admitted Patients Data Collection (APDC) is a census of inpatient hospital discharges in the state of New South Wales (NSW). Our aim was to assess the accuracy of the APDC in identifying upper gastro-intestinal (upper GI) cancer cases, procedures for associated curative resection and comorbidities at the time of admission compared to data abstracted from medical records (the 'gold standard').

METHODS

We reviewed the medical records of 240 patients with an incident upper GI cancer diagnosis derived from a clinical database in one NSW area health service from July 2006 to June 2007. Extracted case record data was matched to APDC discharge data to determine sensitivity, positive predictive value (PPV) and agreement between the two data sources (κ-coefficient).

RESULTS

The accuracy of the APDC diagnostic codes in identifying site-specific incident cancer ranged from 80-95% sensitivity. This was comparable to the accuracy of APDC procedure codes in identifying curative resection for upper GI cancer. PPV ranged from 42-80% for cancer diagnosis and 56-93% for curative surgery. Agreement between the data sources was >0.72 for most cancer diagnoses and curative resections. However, APDC discharge data was less accurate in reporting common comorbidities - for each condition, sensitivity ranged from 9-70%, whilst agreement ranged from κ = 0.64 for diabetes down to κ < 0.01 for gastro-oesophageal reflux disorder.

CONCLUSIONS

Identifying incident cases of upper GI cancer and curative resection from hospital administrative data is satisfactory but under-ascertained. Linkage of multiple population-health datasets is advisable to maximise case ascertainment and minimise false-positives. Consideration must be given when utilising hospital discharge data alone for generating comorbidity indices, as disease burden at the time of admission is under-reported.

Investigating reasons for ethnic inequalities in breast cancer survival in New Zealand

OBJECTIVE

This study investigated the role that demographic and tumour factors play in explaining ethnic inequalities in breast cancer survival.

DESIGN

Breast cancer cases notified to the New Zealand Cancer Registry (NZCR) from April 2005 to April 2007 were followed up to April 2009. Māori, Pacific and non-Māori/non-Pacific women were categorised according to ethnicity on the NZCR. Deprivation was analysed as quintiles of the New Zealand area-based index of socio-economic position. Relative survival rates were estimated using ethnic-specific life tables. Missing values were imputed and excess mortality modelling was used to estimate the contribution of demographic and tumour factors to ethnic inequalities in survival.

RESULTS

There were 2968 breast cancer cases (76.5% non-Māori/non-Pacific, 17% Māori, and 6.5% Pacific) included and 433 recorded deaths. Relative survival rates at 4 years were 91.5% (95% confidence interval (CI) 89.7 to 92.9) for non-Māori/non-Pacific, 86.2% (CI 80.3 to 90.4) for Māori, and 79.6% (CI 68.2 to 87.2) for Pacific women. Using non-Māori/non-Pacific as the reference group, the age-adjusted hazard ratio (HR) dropped for Māori from 1.76 (CI 1.22 to 2.48) to 1.43 (CI 0.97 to 2.10) when further adjusted by deprivation. For Pacific the HR dropped from 2.49 (CI 1.57 to 3.94) to 1.94 (CI 1.20 to 3.13). Inequalities persisted after adjustment for subtype variables (ER/PR/HER2), but adjusting for access to care variables (extent/size) eliminated the ethnic inequalities in excess mortality.

CONCLUSION

Ethnic disparities in breast cancer survival in New Zealand can be attributed to deprivation and differential access to health care rather than differences in breast cancer subtypes.

Socioeconomic status and gastric cancer survival in Japan

BACKGROUND

Few studies have investigated the association between socioeconomic status and the survival of cancer patients in Japan.

METHODS

We examined whether occupation or educational level was associated with the survival of 725 gastric cancer patients who were diagnosed within an ongoing large population-based cohort study.

RESULTS

After adjustment for age at diagnosis, and sex, we found that, compared with professionals or office workers, unemployed subjects (hazard ratio [HR], 2.23; 95% confidence interval [CI], 1.27-3.92) and manual laborers (HR, 1.68; 95% CI, 1.07-2.62) had an increased risk of gastric cancer death. After further adjustment for the clinical extent of disease, the increased risk disappeared. Educational level was not associated with the risk.

CONCLUSIONS

These findings suggest that a disparity in survival by occupation exists among Japanese gastric cancer patients, largely due to a lower proportion of early disease among the unemployed and manual laborers.

Do lifestyle or social factors explain ethnic/racial inequalities in breast cancer survival?

Despite numerous studies documenting ethnic inequalities in breast cancer survival between minority and majority ethnic groups worldwide, reasons for these inequalities remain unclear. The authors performed a systematic review of published literature to identify studies that investigated the explanatory power of smoking, alcohol consumption, body mass index (BMI), and socioeconomic position (SEP) on ethnic inequalities in breast cancer survival. Sixteen studies were included in the review. From 5 studies, the authors found that differences in breast cancer survival between ethnic groups may be in part explained by BMI, but there was little evidence to implicate smoking or alcohol consumption as explanatory factors of this inequality. From 12 studies, the authors found that SEP explains part of the ethnic inequality in all-cause survival but that it was not evident for breast-cancer-specific survival. SEP explains more of the disparities among African-American versus white women in the United States compared with other ethnic comparisons. Furthermore, given social patterning of BMI and other lifestyle habits, it is possible that results for SEP and BMI are measuring the same effect. In this review, the authors make suggestions regarding the role of epidemiology in facilitating further research to better inform the development of effective policies to address ethnic differences in survival.

Does Center Volume Correlate with Survival from Breast Cancer?

With its high incidence and long history of patient advocacy, breast cancer has generated the most concern about the quality of its care and the volume-outcome relationship. In breast cancer surgery, the risk of perioperative morbidity or mortality is low, but surgery is only one single piece in the mosaic of multidisciplinary care that eventually determines survival. Only a limited number of articles is available investigating the relationship between case volume of physicians and hospitals and specialization of surgeons and survival. In summary, there is evidence to support the hypothesis that specialization, research interest, and caseload of physicians and hospitals is positively correlated with providing state-of-the-art care and with survival. However, it is less clear what impact might be attributed to the surgical routine gained with increasing number of procedures compared to the deeper insight into the biology of breast cancer that comes with specialization in oncology and the weight of the multidisciplinary setting that is more easily established and maintained with a higher caseload.

Five-year survival from breast cancer in Western Australia over a decade

The aim of the present study was to investigate whether 5-year survival of patients with breast cancer in Western Australia has improved over time. We used a population-based study conducted in the State of Western Australia, to identify all cases of invasive breast cancer cases diagnosed in 1989, 1994 and 1999. Information on presentation, investigation and management was extracted from medical records of each case and status at 5 years after date of diagnosis was determined. Comparison of 5-year overall survival for women diagnosed in the three calendar years, and hazard ratios for survival calculated for prognostic variables were measured. We found that survival from breast cancer has improved in Western Australia since 1989. Earlier diagnosis, living in the Perth metropolitan area and use of breast-conserving surgery are associated with better survival, irrespective of year of diagnosis. Further research needs to be carried out to determine the reason for this improvement.

Rural–urban differences in the presentation, management and survival of breast cancer in Western Australia

From all women diagnosed with invasive breast cancer in 1999 in Western Australia, rural and urban women were compared with regard to mode of detection, tumour characteristics at presentation, diagnostic investigations, treatment and survival. Women from rural areas with breast cancer (n=206, 23%) were less likely to have open biopsy with frozen section (P<0.001), breast-conserving surgery (P<0.001), adjuvant radiotherapy (P=0.004) and hormonal therapy (P=0.03), and were less likely to be treated by a high caseload breast cancer surgeon (P<0.001). Adjusting for age and tumour characteristics, rural women had an increased likelihood of death within 5 years of breast cancer diagnosis (HR 1.62, 95% CI 1.10-2.38). This difference was not significant after adjustment for treatment factors (HR 1.36, 95% CI 0.90-2.04).

Breast-Conserving Surgery Versus Mastectomy for Survival from Breast Cancer: the Western Australian Experience

BACKGROUND

The focus of this study was the relative survival rates of breast cancer patients whose treatment was breast-conserving surgery compared with that of mastectomy, adjusting for tumor size and nodal status because these factors may be intrinsically associated with mastectomy being the treatment of choice. Patient age was also accounted for in the model. By adjusting for these factors, we mitigate them as confounders of treatment choice in assessing effects on survival rates.

METHODS

Data were sourced from linked administrative data from the Western Australian Department of Health Record Linkage Unit. The data consisted of linked records containing the diagnosis, subsequent hospital admission, and death records of about 3000 women diagnosed with cancer in Western Australia between 1 January 1995 and 31 December 1999. Cox proportional hazards regression was used to investigate survival outcomes of breast-conserving surgery compared with that of mastectomy, adjusting for tumor size, nodal status, and subject age.

RESULTS

The hazard of death is reduced by a factor of about one half for subjects whose treatment was breast-conserving surgery over treatment by mastectomy. Furthermore, the hazard of death increases substantially for subjects with nodal involvement over subjects for whom there has been no identified spread to regional lymph nodes. Hazard of death increases as both age and tumor size increase.

CONCLUSIONS

Western Australian breast cancer patients treated with breast-conserving surgery have improved survival outcomes over those treated with mastectomy, after allowing for tumor size, patient age, and lymph node involvement.

Mastectomy or breast conserving surgery? Factors affecting type of surgical treatment for breast cancer--a classification tree approach

BACKGROUND

A critical choice facing breast cancer patients is which surgical treatment--mastectomy or breast conserving surgery (BCS)--is most appropriate. Several studies have investigated factors that impact the type of surgery chosen, identifying features such as place of residence, age at diagnosis, tumor size, socio-economic and racial/ethnic elements as relevant. Such assessment of "propensity" is important in understanding issues such as a reported under-utilisation of BCS among women for whom such treatment was not contraindicated. Using Western Australian (WA) data, we further examine the factors associated with the type of surgical treatment for breast cancer using a classification tree approach. This approach deals naturally with complicated interactions between factors, and so allows flexible and interpretable models for treatment choice to be built that add to the current understanding of this complex decision process.

METHODS

Data was extracted from the WA Cancer Registry on women diagnosed with breast cancer in WA from 1990 to 2000. Subjects' treatment preferences were predicted from covariates using both classification trees and logistic regression.

RESULTS

Tumor size was the primary determinant of patient choice, subjects with tumors smaller than 20 mm in diameter preferring BCS. For subjects with tumors greater than 20 mm in diameter factors such as patient age, nodal status, and tumor histology become relevant as predictors of patient choice.

CONCLUSION

Classification trees perform as well as logistic regression for predicting patient choice, but are much easier to interpret for clinical use. The selected tree can inform clinicians' advice to patients.