Long-term Survival Outcomes of 'Low Risk' Ductal Carcinoma in situ from a Territory-wide Cancer Registry

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.

High-value breast cancer care within resource limitations

Breast cancer care is a costly global health issue where effective management depends on early detection and treatment. A breast cancer diagnosis can result in financial catastrophe especially in low- and middle-income countries (LMIC). Large inequities in breast cancer care are observed and represent a global challenge to caregivers and patients. Strategies to improve early diagnosis include awareness and clinical breast examination in LMIC, and screening in high-income countries (HIC). The use of clinical guidelines for the management of breast cancer is needed. Adapted guidelines from HIC can address disparities in populations with limited resources. Locally developed strategies still provide effective guidance in improving survival. Integrated practice units (IPU) with timely multidisciplinary breast care conferences and patient navigators are required to achieve high-value, personalized breast cancer management in HIC as well as LMIC. Breast cancer patient care should include a quality of life evaluation using ideally patient-reported outcomes (PROM) and experience measurements (PREM). Evaluation of breast cancer outcomes must include the financial cost of delivered care. The resulting value perspective should guide resource allocation and program priorities. The value of care must be improved by translating the findings of social and economic research into practice and resolving systemic inequity in clinical breast cancer research. Cancer survivorship programs must be put in place everywhere. The treatment of patients with metastatic breast cancer must require more attention in the future, especially in LMIC.

Imaging Changes and Outcomes of Patients Undergoing Active Monitoring for Ductal Carcinoma In Situ: Seven-Year Follow-up Study

RATIONALE AND OBJECTIVES

To determine the imaging changes and their associated positive predictive value (PPV) for invasive breast cancer in women undergoing active monitoring for ductal carcinoma in situ (DCIS).

MATERIALS AND METHODS

In this seven-year follow-up retrospective IRB-exempted cohort study, we reviewed patients diagnosed with DCIS who elected active monitoring between 2003 and 2022 at a single academic institution. Imaging characteristics, histopathology at initial diagnosis, and subsequent follow-up were recorded. Low-risk DCIS was defined as low or intermediate grade and hormone receptor (HR) positive (estrogen and/or progesterone receptor positive) disease diagnosed in women at least 40 years of age. Progression was defined as subsequent ipsilateral invasive breast cancer diagnosis.

RESULTS

There were 39 patients with a median age of 58.4 years (IQR: 51.1-69.6 years) and a median follow-up of 4.3 years (range: 0.6-16.4 years). Nearly two thirds of patients (64%, 25/39) had stable imaging (range: 0.6-16.4 years) and remained progression-free during active monitoring. Among the remaining 14 patients (36%), there were 24 imaging findings which prompted 22 subsequent core needle biopsies (range: 1-3 biopsies per patient) and two surgical biopsies. The PPV of invasive cancer was 29% (7/24) overall and 38% (3/8) for masses, 33% (3/9) for calcifications, 17% (1/6) for non-mass enhancement, and 0% (0/1) for architectural distortion.

CONCLUSION

Of the radiographic changes prompting an additional biopsy, development of a new mass (38%) and new calcifications (33%) had the highest PPV for invasive progression. Close imaging follow-up should be a critical component for patients undergoing monitoring for DCIS.

Oncological safety of active surveillance for low-risk ductal carcinoma in situ - a systematic review and meta-analysis

INTRODUCTION

Current standard of care for patients diagnosed with "low-risk" ductal carcinoma in situ (DCIS) involves surgical resection. Ongoing phase III clinical trials are hoping to establish the oncological safety of active surveillance (AS) in managing "low-risk" DCIS.

AIMS

To evaluate the oncological safety of AS versus surgery for "low-risk" DCIS.

METHODS

A systematic review was performed in accordance with PRISMA guidelines. Survival outcomes were expressed as dichotomous variables and reported as odds ratios (OR) with 95% confidence intervals (95% CI) using the Mantel-Haenszel method.

RESULTS

Four studies including 9626 patients were included, 3.9% of which were managed using AS (374/9626) and 96.1% with surgery (9252/9626). The mean age of included patients was 50.3 years (range: 30-99 years) and mean follow-up was 6.1 years. Invasive cancer detection after surgery and AS were similar (OR: 0.93, 95% CI: 0.41-2.11, P = 0.860, heterogeneity (I2) = 0%). At 5 years, BCSS (surgery 99.5% vs. AS 98.7%, P = 0.116) and OS (surgery 95.8% vs. AS 95.7%, P = 0.876) were similar for both groups. At 10 years, BCSS (surgery 98.7% vs. AS 98.6%, P = 0.789) and OS (surgery 87.9% vs. AS 90.9%, P = 0.183) were similar for both groups. Overall, 10-year OS outcomes were similar for both management strategies (OR: 0.32, 95% CI: 0.02-6.42, P = 0.460, I2 = 69%).

CONCLUSION

This study outlines the provisional oncological safety of AS for cases of "low-risk" DCIS. While survival outcomes were comparable for both management strategies, ratification of these results in the ongoing phase III clinical trials is still required prior to changes to current management strategies.

PROSPERO REGISTRATION

CRD42022313241.

Should low-risk DCIS lose the cancer label? An evidence review

BACKGROUND

Population mammographic screening for breast cancer has led to large increases in the diagnosis and treatment of ductal carcinoma in situ (DCIS). Active surveillance has been proposed as a management strategy for low-risk DCIS to mitigate against potential overdiagnosis and overtreatment. However, clinicians and patients remain reluctant to choose active surveillance, even within a trial setting. Re-calibration of the diagnostic threshold for low-risk DCIS and/or use of a label that does not include the word 'cancer' might encourage the uptake of active surveillance and other conservative treatment options. We aimed to identify and collate relevant epidemiological evidence to inform further discussion on these ideas.

METHODS

We searched PubMed and EMBASE databases for low-risk DCIS studies in four categories: (1) natural history; (2) subclinical cancer found at autopsy; (3) diagnostic reproducibility (two or more pathologist interpretations at a single time point); and (4) diagnostic drift (two or more pathologist interpretations at different time points). Where we identified a pre-existing systematic review, the search was restricted to studies published after the inclusion period of the review. Two authors screened records, extracted data, and performed risk of bias assessment. We undertook a narrative synthesis of the included evidence within each category.

RESULTS

Natural History (n = 11): one systematic review and nine primary studies were included, but only five provided evidence on the prognosis of women with low-risk DCIS. These studies reported that women with low-risk DCIS had comparable outcomes whether or not they had surgery. The risk of invasive breast cancer in patients with low-risk DCIS ranged from 6.5% (7.5 years) to 10.8% (10 years). The risk of dying from breast cancer in patients with low-risk DCIS ranged from 1.2 to 2.2% (10 years). Subclinical cancer at autopsy (n = 1): one systematic review of 13 studies estimated the mean prevalence of subclinical in situ breast cancer to be 8.9%. Diagnostic reproducibility (n = 13): two systematic reviews and 11 primary studies found at most moderate agreement in differentiating low-grade DCIS from other diagnoses. Diagnostic drift: no studies found.

CONCLUSION

Epidemiological evidence supports consideration of relabelling and/or recalibrating diagnostic thresholds for low-risk DCIS. Such diagnostic changes would need agreement on the definition of low-risk DCIS and improved diagnostic reproducibility.

Clinical Outcomes of Conservative Treatment for Low-Risk Ductal Carcinoma in Situ: A Systematic Review and Pooled Analysis

AIMS

The current gold standard of treatment for ductal carcinoma in situ (DCIS) is surgical resection with or without adjuvant radiotherapy. However, the increased detection and radical treatment of DCIS did not result in a declined incidence of invasive breast cancers, leading to the debate if DCIS has been overtreated. While ongoing randomised controlled trials on active surveillance of DCIS are still in progress, this systematic review aims to evaluate the best evidence on conservative treatment for DCIS from the literature.

MATERIALS AND METHODS

This systematic review was conducted in line with the PRISMA statement. We included all relevant studies published up to June 2022 for analysis. The primary outcomes were overall survival and breast cancer-specific survival (BCSS) of conservative treatment for DCIS.

RESULTS

Three studies, with a total of 34 007 women with low-risk DCIS, were included in the analysis. Active and conservative treatments both resulted in excellent 10-year BCSS, with no statistically insignificant difference (98.6% versus 96.0%, 31 478 women). One study comparing 5-year BCSS of active and conservative treatments only in subjects aged over 80 years also reported [AQ1]an insignificant difference (98.2% versus 96.0%, 2529 women). One study measuring 5- and 10-year overall survival between the treatment groups also reported [AQ1]an insignificant difference (5-year: 96.2% versus 92.4%; 10-year: 85.6% versus 86.7%, 31 106 women).

CONCLUSION

BCSS between active and conservative treatment for women with low-risk DCIS is both excellent and comparable, suggesting that conservative treatment is a possible alternative without compromising survival.

Population-Based Clinical Studies Using Routinely Collected Data in Hong Kong, China: A Systematic Review of Trends and Established Local Practices

Background: Routinely collected health data are increasingly used in clinical research. No study has systematically reviewed the temporal trends in the number of publications and analyzed different aspects of local research practices and their variations in Hong Kong, China, with a specific focus on research ethics governance and approval.

Methods: PubMed was systematically searched from its inception to March 28, 2023, for studies using routinely collected healthcare data from Hong Kong.

Results: A total of 454 studies were included. Between 2000 and 2009, 32 studies were identified. The number of publications increased from 5 to 120 between 2010 and 2022. Of the investigator-led studies using the Hospital Authority (HA)’s cross-cluster data (n = 393), 327 (83.2%) reported receiving ethics approval from a single cluster/university-based REC, whereas 50 studies (12.7%) did not report approval from a REC. For use of the HA Data Collaboration Lab, approval by a single hospital-based or University-based REC is accepted. Repeated submission of identical ethics applications to different RECs is estimated to cost HK$4.2 million yearly.

Conclusions: Most studies reported gaining approval from a single cluster REC before retrieval of cross-cluster HA data. Substantial cost savings would result if repeated review of identical ethics applications were not required.