Breast cancer

Research

1. Does diabetes affect breast cancer survival? (opens on the publisher’s website)

   Cancer Reports · 2024

   Lawrenson R, Lao C, Stanley J, Teng A, Kuper-Hommel M, Campbell I, Krebs J, Sika-Paotonu D, Koea J, Meredith I, Gurney J

   What it found

   3,137 of the 26,968 women (11.6%) had diabetes at diagnosis. Unadjusted survival was lower with diabetes present (5-year cancer-specific survival 87% versus 89%; 10-year 79% versus 84%), but once the analysis adjusted for age, tumour characteristics and treatment, diabetes was not associated with worse breast-cancer-specific survival (adjusted hazard ratio 0.99, 95% CI 0.89-1.11). Adjusted hazard ratios for Māori and Pacific women with diabetes were 1.01 and 0.88; for Asian women with diabetes, 0.67.

   How it was done

   retrospective population-based cohort, 26,968 women with invasive breast cancer, 2005-2020, from Te Rēhita Mate Ūtaetae (the Breast Cancer Foundation National Register) linked to the Virtual Diabetes Register, hospital and mortality data

   Why it matters

   The raw survival gap by diabetes status looks meaningful but mostly reflects other factors already captured in stage and treatment, which matters for how this comparison gets used in any resource discussing comorbidity and outcomes.

   What it does not settle

   The authors note the register does not distinguish diabetes type or give a diagnosis date, and had no data on BMI, smoking, alcohol or diet, so residual confounding is possible. Competing mortality risk in the diabetes group is also flagged. I read the full text via PMC.

   Full textfull text (PMC10953831, open access)

   Read it free: Does diabetes affect breast cancer survival? (opens on another organisation’s website)DOI 10.1002/cnr2.2040

2. Ethnic differences in time to surgery for women with early stage breast cancer in Aotearoa/New Zealand: a population-based study (opens on the publisher’s website)

   The Lancet Regional Health – Western Pacific · 2024

   Boyle L, Lawrenson R, Ronald M, Campbell I, Nosa V, Tin Tin S

   What it found

   In a cohort of 16,365 women having surgery for early-stage (stage 1–3a) breast cancer across four NZ urban regions between 2000 and 2020, only 58.2% had surgery within the 31-day Faster Cancer Treatment target. Māori women had 18% higher adjusted odds of missing that target than NZ European women (OR 1.18, 95% CI 1.05–1.33), and Pacific women 42% higher odds (OR 1.42, 95% CI 1.22–1.65); there was no significant difference for Asian women. Deprivation and treatment in the public rather than private system explained most of the gap – women treated publicly had close to seven times the odds of a delay past 31 days. The gap did not close after the Faster Cancer Treatment policy was introduced in 2012.

   How it was done

   population-based cohort, 16,365 women, four NZ urban regions, 2000–2020

   Why it matters

   Time to surgery is a direct, government-tracked equity measure, and this shows Māori and Pacific women are still waiting longer for it despite a policy meant to close that gap.

   What it does not settle

   Confined to four urban regions using the Breast Cancer Foundation's clinical register, so may not generalise to rural areas or regions outside the four studied. Read the full open-access text via PubMed Central.

   Full textfull text

   Read it free: Ethnic differences in time to surgery for women with early stage breast cancer in Aotearoa/New Zealand: a population-based study (opens on another organisation’s website)DOI 10.1016/j.lanwpc.2024.101091

3. Receipt of mastectomy and adjuvant radiotherapy following breast conserving surgery (BCS) in New Zealand women with BCS-eligible breast cancer, 2010–2015: an observational study focusing on ethnic differences (opens on the publisher’s website)

   BMC Cancer · 2023

   Bartholomew K, Ghafel M, Tin Tin S, Aye PS, Elwood JM, Hardie C, Scott N, Kidd J, Ramsaroop R, Campbell I

   What it found

   Among women eligible for breast-conserving surgery, 22% had a mastectomy instead and 91% of those who had breast-conserving surgery went on to radiotherapy. Asian women were around twice as likely as the reference group to have a mastectomy for invasive cancer. Pacific women had substantially lower odds of receiving radiotherapy after breast-conserving surgery, for both invasive cancer and DCIS. Māori women's rates did not differ significantly from the reference group on either measure. The most common reason radiotherapy was missed was that a clinician had not referred the woman for it.

   How it was done

   retrospective observational study, New Zealand Breast Cancer Registry, 5,520 BCS-eligible women 2010-2015 (4,541 invasive, 979 DCIS)

   Why it matters

   It shows the treatment gap for BCS-eligible women sits mainly with Pacific and Asian ethnicity rather than with Māori in this cohort, which matters for where equity effort in breast cancer treatment pathways is targeted.

   What it does not settle

   Registry-based observational study covering 2010-2015 only, so it cannot establish why the differences occurred and may not reflect current practice.

   Full textfull text, read via PMC (PMC10436661)

   Read it free: Receipt of mastectomy and adjuvant radiotherapy following breast conserving surgery (BCS) in New Zealand women with BCS-eligible breast cancer, 2010–2015: an observational study focusing on ethnic differences (opens on another organisation’s website)DOI 10.1186/s12885-023-11248-9

4. The impact of the COVID-19 pandemic on cancer diagnosis and service access in New Zealand–a country pursuing COVID-19 elimination (opens on the publisher’s website)

   2021

   What it found

   Using national data on cancer registrations, diagnostic testing (including endoscopy) and treatment volumes, the authors compare 2020 against 2018-2019, split by ethnicity. Registrations dropped by around 40% during the March-April 2020 lockdown, then recovered to pre-lockdown levels by around August-September 2020. Surgery and medical oncology saw comparatively little disruption; radiation therapy volumes were down about 8% year-on-year, which the authors attribute partly to a shift toward shorter treatment courses rather than fewer patients treated. Outcome patterns were broadly similar across ethnic groups, though lung cancer diagnosis for Māori is again flagged as an area of concern.

   How it was done

   descriptive national service-data report, 2020 compared with 2018-2019, stratified by ethnicity

   Why it matters

   It offers early evidence that a country pursuing COVID-19 elimination was able to protect its cancer diagnostic and treatment pathway through the pandemic's first year, in contrast to countries that saw sustained falls in cancer diagnosis during 2020.

   What it does not settle

   This covers 2020 only and does not speak to later, more sustained periods of community transmission after New Zealand moved away from elimination.

   Full textFull text via PMC (thelancet.com itself returned a 403 error)

5. The most commonly diagnosed and most common causes of cancer death for Māori New Zealanders (opens on the publisher’s website)

   New Zealand Medical Journal, vol 133, no 1521, pages 77-96 (4 September 2020) · 2020

   Jason K Gurney, Bridget Robson, Jonathan Koea, Nina Scott, James Stanley, Diana Sarfati

   What it found

   Ranks the most commonly diagnosed cancers and the most common causes of cancer death for Māori using registry and mortality data from 2007-2016. Lung cancer was both the most diagnosed (around 401 registrations a year, 42 per 100,000) and the leading cause of death (around 311 deaths a year, 32 per 100,000), ahead of breast, prostate and colorectal for diagnoses, and breast and colorectal for deaths. Māori incidence exceeded non-Māori for most of these cancers, most markedly for lung, and the paper documents a broader survival gap across cancer types.

   How it was done

   descriptive epidemiology, national cancer registry and mortality data for Māori, 2007-2016

   Why it matters

   Gives a ranked, Māori-specific picture of where the cancer burden actually falls, useful for prioritising advocacy and services rather than working from unranked or non-Māori-specific figures.

   What it does not settle

   Full text read directly on the NZMJ site (confirmed open access, PDF available). Data run to 2016 - now roughly a decade old - so more recent registry updates may have shifted the exact figures even if the ranking holds.

   Full textfull text (nzmj.org.nz, open access)

   Read it free: The most commonly diagnosed and most common causes of cancer death for Māori New Zealanders (opens on another organisation’s website)

6. Stage at diagnosis for Māori cancer patients, disparities, similarities and data limitations (opens on the publisher’s website)

   What it found

   An analysis of New Zealand Cancer Registry records for 196,967 patients diagnosed between 2007 and 2016, checked against separate clinical audit data for breast, colon, rectal, lung and stomach cancer. Māori patients were less likely to be diagnosed with localised disease for several cancers, most markedly prostate (odds ratio 0.50) and lung (odds ratio 0.53), though this did not hold for every cancer type. The registry also understated how many patients had no recorded stage: clinical audits found 38% of Māori lung cancer patients were unstaged, well above what the registry showed. A survival gap between Māori and non-Māori remained even after accounting for stage.

   How it was done

   retrospective registry analysis cross-checked against clinical audit data, 196,967 patients, 2007–2016

   Why it matters

   The registry undercounting missing stage data means Māori cancer outcomes cannot be fully monitored from that registry alone, which is a data problem sitting underneath the clinical one.

   What it does not settle

   Based on the NZMJ abstract as fetched; full text was not read, so detail beyond the stated results and headline odds ratios is not confirmed here.

   Abstract onlyabstract, via the NZMJ journal page

In our library

Nothing in our own library is specific to breast cancer. What we publish is mostly cross-cutting – annual reports, evaluations and reports that span the whole cancer pathway – and all of it is at Rauemi.