What percentage of Ductal Carcinoma In Situ (DCIS) becomes invasive?

Progression of Ductal Carcinoma In Situ (DCIS) to Invasive Cancer

Based on the most recent evidence, approximately 20-30% of untreated DCIS will progress to invasive breast cancer over time. 1

Natural History and Progression Risk

DCIS represents a non-obligate precursor to invasive breast cancer with variable progression rates depending on several key factors:

Progression Rates by Grade

• High-grade DCIS: 33% progression rate to invasive cancer (median 38 months to progression) 2
• Intermediate-grade DCIS: 32% progression rate (median 60 months to progression) 2
• Low-grade DCIS: 18% progression rate (median 51 months to progression) 2

Risk Factors for Progression

Several factors influence the likelihood of DCIS progressing to invasive cancer:

• Nuclear grade: High-grade lesions have significantly higher cumulative incidence of invasion compared to lower grades (p=0.0016) 2
• Age: Younger women have higher progression rates (p=0.0002) 2
• Mammographic presentation: Lesions with calcification as the predominant feature have higher progression rates (23/50 vs. 5/25, p=0.042) 2
• Treatment factors: Lack of endocrine therapy is associated with higher progression rates (p=0.048) 2

Long-term Outcomes

The 10-year cumulative incidences in untreated DCIS patients show:

• Ipsilateral invasive cancer: 10.5% (95% CI = 8.5% to 12.4%)
• Contralateral breast cancer: 3.9% (95% CI = 2.6% to 5.2%)
• All-cause mortality: 24.1% (95% CI = 21.2% to 26.9%) 3

For patients with grade I/II DCIS who did not undergo treatment, the 10-year net risk of ipsilateral invasive breast cancer was 12.2% (95% CI = 8.6% to 17.1%), compared with 17.6% (95% CI = 12.1% to 25.2%) for grade III DCIS 3.

Recurrence Patterns After Treatment

When DCIS is treated with breast-conserving surgery:

• Approximately 50% of recurrences are invasive cancer and 50% are DCIS 1
• The 10-year actuarial breast recurrence rate ranges from 6% to 23% with conservative surgery and radiation 1

Clinical Implications

1. Upstaging at surgery: A meta-analysis reported an overall DCIS upstaging rate to invasive cancer of 25.9% at surgical excision after initial core needle biopsy diagnosis 1

2. Surveillance burden: For women who undergo breast-conserving surgery for DCIS, 76.1% will require at least one diagnostic mammogram or invasive procedure within 10 years 4

3. Treatment impact: Radiotherapy after breast-conserving surgery reduces ipsilateral breast tumor recurrence rates by 50-70% 1

Practical Considerations

• The excellent overall prognosis of DCIS (10-year overall survival rate of 97.2-98.6%) 1 must be balanced against the risk of progression
• The detection and treatment of DCIS may be worthwhile for prevention of future invasive disease, as evidenced by a significant negative association between screen-detected DCIS and invasive interval cancers 1
• For every 3 screen-detected cases of DCIS treated, 1 fewer invasive interval cancer occurred in the subsequent 3 years 1

This information should guide discussions about the natural history of DCIS and inform treatment decisions, particularly for patients considering active surveillance versus more aggressive management approaches.