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

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.

Risk perception of patients with ductal carcinoma in situ (DCIS) of the breast and their healthcare practitioners: The importance of histopathological terminology, and the gaps in our knowledge

Despite ductal carcinoma in situ (DCIS) being a non-obligatory precursor of invasive breast carcinoma, its diagnosis generates substantial psychological distress. The limited knowledge about the natural history of DCIS contributes to the insufficient transmission of information about DCIS to patients and the general population. The uncertainty about the progression risk to invasive carcinoma hampers adequate communication by clinicians. Breast cancer-related mortality after a DCIS diagnosis is low. However, several studies have demonstrated that DCIS patients generally overestimate the risk of developing loco-regional recurrence or dying from breast cancer. Various factors contribute to this perceived risk. Despite the lack of infiltrative growth, DCIS is treated similarly to invasive breast cancer, with surgery, radiotherapy, and hormonal therapy. Additionally, the term 'carcinoma' in DCIS provokes anxiety. Incorrect risk perception by physicians may result in overtreatment. Here, we provide an overview of epidemiologic data on mortality after DCIS. We discuss the impact of the term "ductal carcinoma in situ" on patients' and physicians' perceptions of risk. The available evidence is mostly limited to patients within the Anglosphere. Recent studies, and European studies in particular, are scarce. We identify this as an area of interest for future large-scale European studies. We discuss the potential value of the "ductal intraepithelial neoplasia" (DIN) terminology, introduced in 1998. Although replacing the concept of "DCIS" with the DIN terminology is unlikely to solve the entire problem of risk overestimation, it could be the first step to optimize doctor-patient communication and alter the current risk perception.

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.

Outcomes from low-risk ductal carcinoma in situ: a systematic review and meta-analysis

PURPOSE

The current standard of treatment for ductal carcinoma in situ (DCIS) is surgery with or without adjuvant radiotherapy. With a growing debate about overdiagnosis and overtreatment of low-risk DCIS, active surveillance is being explored in several ongoing trials. We conducted a systematic review and meta-analysis to evaluate the recurrence of low-risk DCIS under various treatment approaches.

METHODS

PubMed, Embase, Web of Science, and Cochrane were searched for studies reporting ipsilateral breast tumour event (IBTE), contralateral breast cancer (CBC), and breast cancer-specific survival (BCSS) rates at 5 and 10 years in low-risk DCIS. The primary outcome was invasive IBTE (iIBTE) defined as invasive progression in the ipsilateral breast.

RESULTS

Thirty three eligible studies were identified, involving 47,696 women with low-risk DCIS. The pooled 5-year and 10-year iIBTE rates were 3.3% (95% confidence interval [CI]: 1.3, 8.1) and 5.9% (95% CI: 3.8, 9.0), respectively. The iIBTE rates were significantly lower in patients who underwent surgery compared to those who did not, at 5 years (3.5% vs. 9.0%, P = 0.003) and 10 years (6.4% vs. 22.7%, P = 0.008). Similarly, the 10-year BCSS rate was higher in the surgery group (96.0% vs. 99.6%, P = 0.010). In patients treated with breast-conserving surgery, additional radiotherapy significantly reduced IBTE risk, but not total-CBC risk.

CONCLUSION

This review showed a lower risk of progression and better survival in women who received surgery and additional RT for low-risk DCIS. However, our findings were primarily based on observational studies, and should be confirmed with the results from the ongoing trials.

Ductal carcinoma in situ of the breast: finding the balance between overtreatment and undertreatment

Ductal carcinoma in situ (DCIS) accounts for 15-25% of all breast cancer diagnoses. Its prognosis is excellent overall, the main risk being the occurrence of local breast events, as most cases of DCIS do not progress to invasive cancer. Systematic screening has greatly increased the incidence of this non-obligate precursor of invasion, lending urgency to the need to identify DCIS that is prone to invasive progression and distinguish it from non-invasion-prone DCIS, as the latter can be overdiagnosed and therefore overtreated. Treatment strategies, including surgery, radiotherapy, and optional endocrine therapy, decrease the risk of local events, but have no effect on survival outcomes. Active surveillance is being evaluated as a possible new option for low-risk DCIS. Considerable efforts to decipher the biology of DCIS have led to a better understanding of the factors that determine its variable natural history. Given this variability, shared decision making regarding optimal, personalised treatment strategies is the most appropriate course of action. Well designed, risk-based de-escalation studies remain a major need in this field.