Patterns of treatment and outcome of ductal carcinoma in situ in the Netherlands

Incidence trends of ductal carcinoma in situ in New Zealand women between 1999 and 2022

BACKGROUND

In New Zealand, BreastScreen Aotearoa (BSA), a biennial national breast screening programme, was implemented in 1998. This study examines the incidence trends of ductal carcinoma in situ (DCIS) in New Zealand women from 1999 to 2022.

METHODS

All women with a primary diagnosis of DCIS over the 24-year study period were identified from the New Zealand Cancer Registry and BSA records. Age-standardised incidence rates (ASIR), detection rates (ASDR) and average annual percent changes were calculated.

RESULTS

The annual ASIR was 13.5 per 100,000 New Zealand women, and increased by 0.91% (95% confidence interval (CI): 0.26%, 1.66%) annually. Among women aged 45-69 years during 2006-2022, the annual ASIR was 36.3 for programme-detected DCIS, increasing 1.29% (95%CI: 0.13%, 2.73%) per year, and 14.2 for non-programme-detected DCIS, with no significant changes over the study period. The programme-detected ASIRs were highest for Pacific (38.6), Asian (38.2), and Māori (38.0) women. The programme ASDR was 0.55 per 1000 women screened, with no significant changes over time, and was highest for Asian (0.69), and Māori and Pacific (both at 0.65) women.

CONCLUSION

DCIS incidence increased in New Zealand women from 1999 to 2022, driven by an increase in screening participation, and varied by ethnicity.

Deintensification of Radiotherapy Use in Treatment of Ductal Carcinoma In Situ in the Netherlands-A Nationwide Overview From 2008 Until 2022

AIMS

Ductal Carcinoma In Situ (DCIS) treated by breast-conserving surgery followed by radiotherapy aims to decrease the probability of locally recurrent disease. The role of whole breast irradiation, specifically in DCIS having low recurrence risk and low risk of becoming invasive, is increasingly debated. Also, the added value of applying boost irradiation in DCIS has been questioned. Hence, we evaluated the nationwide radiotherapy use in DCIS treatment in the Netherlands.

MATERIALS AND METHODS

Women diagnosed with DCIS in 2008-2022 were identified in the Netherlands Cancer Registry. Their primary treatment was presented over time and for age groups, stratified for DCIS grade I-II and III. Factors associated with radiotherapy use after breast-conserving surgery and boost irradiation use in whole breast irradiation after breast-conserving surgery were identified.

RESULTS

In women with DCIS grade I-II (N = 16,653), the use of breast-conserving surgery without radiotherapy increased from ∼11% in 2008-2013 to ∼26% in 2017-2022. Furthermore, post-breast-conserving surgery radiotherapy increasingly concerned whole breast irradiation without a boost or partial breast irradiation. Moreover, surgery was omitted more often in recent years (30% in 2022). In DCIS grade III (N = 13,534), the use of breast-conserving surgery without radiotherapy only slightly increased in the most recent years in older patients, while boost irradiation was increasingly omitted. Whole breast irradiation and boost irradiation following breast-conserving surgery were more often applied in case of a higher risk of recurrences: young age, larger lesions, or irradical resection. Variation was observed for hospital-characteristics but not for regions.

CONCLUSION

In DCIS, the process of omitting breast irradiation after breast-conserving surgery is clearly ongoing. Boost irradiation was administered less frequently. Furthermore, the use of partial breast irradiation was introduced in recent years. These effects are more prominent in older women and those with grade I-II DCIS.

An early economic evaluation of active surveillance for low-risk ductal carcinoma in situ

Aim: Perform early economic evaluation comparing active surveillance (AS) to surgery for women with low-risk ductal carcinoma in situ, a precursor of invasive breast cancer.Materials & methods: A 10-year incremental costs (€) and quality-adjusted life years (QALYs) were compared between a simulated cohort of women undergoing breast conserving surgery ± radiotherapy, and a cohort with a low-risk subgroup undergoing AS using a semi-Markov model. Scenario and headroom analyses evaluated a better-performing biomarker to select low-risk women for AS.Results: AS resulted in lower costs and survival, but higher QALYs (±0.40). Scenario analyses maintained survival outcomes and maximized QALYs.Conclusion: AS for low-risk ductal carcinoma in situ is cost-effective, but a better-performing biomarker to select low-risk women can maximize quality-adjusted outcomes.

Invasive recurrence after breast conserving treatment of ductal carcinoma in situ of the breast in the Netherlands: time trends and the association with tumour grade

BACKGROUND

The first aim of this study was to examine trends in the risk of ipsilateral invasive breast cancer (iIBC) after breast-conserving surgery (BCS) of ductal carcinoma in situ (DCIS). A second aim was to analyse the association between DCIS grade and the risk of iIBC following BCS.

PATIENTS AND METHODS

In this population-based, retrospective cohort study, the Netherlands Cancer Registry collected information on 25,719 women with DCIS diagnosed in the period 1989-2021 who underwent BCS. Of these 19,034 received adjuvant radiotherapy (RT). Kaplan-Meier analyses and Cox regression models were used.

RESULTS

A total of 1135 patients experienced iIBC. Ten-year cumulative incidence rates of iIBC for patients diagnosed in the periods 1989-1998, 1999-2008 and 2009-2021 undergoing BCS without RT, were 12.6%, 9.0% and 5.0% (P < 0.001), respectively. For those undergoing BCS with RT these figures were 5.7%, 3.7% and 2.2%, respectively (P < 0.001). In the multivariable analyses, DCIS grade was not associated with the risk of iIBC.

CONCLUSION

Since 1989 the risk of iIBC has decreased substantially and has become even lower than the risk of invasive contralateral breast cancer. No significant association of DCIS grade with iIBC was found, stressing the need for more powerful prognostic factors to guide the treatment of DCIS.

Adherence to guideline recommendations for follow-up in patients with DCIS at a large teaching hospital in the Netherlands

PURPOSE

Ductal-carcinoma in situ (DCIS) is a pre-invasive form of breast cancer with good prognosis. Follow-up guidelines in the Netherlands are currently the same as for invasive breast cancer. Due to fear of invasive breast cancer or recurrence, it is hypothesized that follow-up for DCIS after treatment is more intense in practice resulting in potentially unnecessary high costs. This study investigates the follow-up in practice for patients with DCIS compared to the recommendations in order to inform clinicians and policy makers how to utilize these guidelines.

METHODS

Patients diagnosed with pure DCIS between 2004 and 2014 were followed up until 2018. Information on duration and frequency of follow-up visits, reasons and decision makers for shortening, and prolonging follow-up was collected. Prolonged follow-up was defined as deviation from the Dutch guideline: more than 5 years of follow-up and older than 60 years.

RESULTS

Of the 227 patients the mean number of visits per year was 1.4 and mean years of follow-up was 6.0. Thirty-three percent had prolonged follow-up and 26% shorter follow-up than recommended. A majority (78%) of decision for prolonged follow-up was being made by clinicians.

CONCLUSION

Follow-up duration is in almost half of patients with DCIS according to guidelines and with most prolonged follow-up only up to a year longer than recommended. In most cases suspicious findings and the timing of the population screening program appeared to cause prolonged follow-up. If accepted by patients and clinicians, future DCIS specific guidelines should address these reasons and tailor to the individual risks.

Contemporary Analysis of Reexcision and Conversion to Mastectomy Rates and Associated Healthcare Costs for Women Undergoing Breast-Conserving Surgery

PURPOSE

This study was designed to provide a comprehensive and up-to-date understanding of population-level reoperation rates and incremental healthcare costs associated with reoperation for patients who underwent breast-conserving surgery (BCS).

METHODS

This is a retrospective cohort study using Merative™ MarketScan® commercial insurance data and Medicare 5% fee-for-service claims data. The study included females aged 18-64 years in the commercial cohort and females aged 18 years and older in the Medicare cohort, who underwent initial BCS for breast cancer in 2017-2019. Reoperation rates within a year of the initial BCS and overall 1-year healthcare costs stratified by reoperation status were measured.

RESULTS

The commercial cohort included 17,129 women with a median age of 55 (interquartile range [IQR] 49-59) years, and the Medicare cohort included 6977 women with a median age of 73 (IQR 69-78) years. Overall reoperation rates were 21.1% (95% confidence interval [CI] 20.5-21.8%) for the commercial cohort and 14.9% (95% CI 14.1-15.7%) for the Medicare cohort. In both cohorts, reoperation rates decreased as age increased, and conversion to mastectomy was more prevalent among younger women in the commercial cohort. The mean healthcare costs during 1 year of follow-up from the initial BCS were $95,165 for the commercial cohort and $36,313 for the Medicare cohort. Reoperations were associated with 24% higher costs in both the commercial and Medicare cohorts, which translated into $21,607 and $8559 incremental costs, respectively.

CONCLUSIONS

The rates of reoperation after BCS have remained high and have contributed to increased healthcare costs. Continuing efforts to reduce reoperation need more attention.

The effects of contemporary treatment of DCIS on the risk of developing an ipsilateral invasive Breast cancer (iIBC) in the Dutch population

PURPOSE

To assess the effects of contemporary treatment of ductal carcinoma in situ (DCIS) on the risk of developing an ipsilateral invasive breast cancer (iIBC) in the Dutch female population.

METHODS

Clinical data was obtained from the Netherlands Cancer Registry (NCR), a nationwide registry of all primary malignancies in the Netherlands integrated with the data from PALGA, the Dutch nationwide network and registry of histo- and cytopathology in the Netherlands, on all women in the Netherlands treated for primary DCIS from 2005 to 2015, resulting in a population-based cohort of 14.419 women. Cumulative iIBC incidence was assessed and associations of DCIS treatment type with subsequent iIBC risk were evaluated by multivariable Cox regression analyses.

RESULTS

Ten years after DCIS diagnosis, the cumulative incidence of iIBC was 3.1% (95% CI: 2.6-3.5%) in patients treated by breast conserving surgery (BCS) plus radiotherapy (RT), 7.1% (95% CI: 5.5-9.1) in patients treated by BCS alone, and 1.6% (95% CI: 1.3-2.1) in patients treated by mastectomy. BCS was associated with a significantly higher risk for iIBC compared to BCS + RT during the first 5 years after treatment (HR 2.80, 95% CI: 1.91-4.10%). After 5 years of follow-up, the iIBC risk declined in the BCS alone group but remained higher than the iIBC risk in the BCS + RT group (HR 1.73, 95% CI: 1.15-2.61).

CONCLUSIONS

Although absolute risks of iIBC were low in patients treated for DCIS with either BCS or BCS + RT, risks remained higher in the BCS alone group compared to patients treated with BCS + RT for at least 10 years after DCIS diagnosis.