Outcomes of screening-detected ductal carcinoma in situ treated with wide excision alone

Leveraging the variable natural history of ductal carcinoma in situ (DCIS) to select optimal therapy

PURPOSE

Ductal carcinoma in situ (DCIS) is a non-obligate precursor to invasive ductal carcinoma. The authors sought to discuss the evidence suggesting that not all DCIS will progress to invasive disease if left untreated.

RESULTS

Four lines of evidence align to suggest that not all of this in-situ disease progresses to invasive cancer: its prevalence on screening mammography, studies of missed diagnoses, incidental findings in autopsy specimens, and large retrospective reviews of those treated with excision alone.

CONCLUSION

A clearer understanding of the variable history of DCIS coupled with advances in genomic profiling of the disease holds the promise of reducing widespread over-treatment of this non-invasive cancer. Additionally, identification of higher risk of recurrence subsets may select patients for whom more aggressive treatment may be appropriate.

Is DCIS Overrated?

Ductal carcinoma in situ (DCIS), the noninvasive form of breast cancer (BC), comprises just over 20% of breast cancer cases diagnosed each year in the USA. Most patients are treated with local excision of the disease followed by whole breast radiation therapy. Total mastectomy is not an uncommon approach, and total mastectomy with a contralateral risk-reducing mastectomy has been on the rise in the past decade. In estrogen receptor-positive disease, patients are often offered endocrine ablative therapy with a selective estrogen receptor modulator or an aromatase inhibitor as both treatment and prevention. Local regional treatment options have no impact upon ultimate overall survival. Long-term survival rates are higher in patients with DCIS than with any other form of the disease. Are these strikingly high success rates a testament to effective treatment strategies or is there a significant subset of DCIS that was unlikely to ever progress to invasive ductal carcinoma? DCIS was not seen in the US prior to the advent of screening mammography. When compared to other countries, the USA has the highest utilization of screening mammography and the incidence rate of DCIS. Other lines of evidence include autopsy series examining the breast tissue of women who died of other causes, missed-diagnosis series and current retrospective reviews of DCIS, all align in support of the concept of DCIS as indolent in the majority of cases [3-14]. The evidence suggests that both patient and physician misconceptions about DCIS have led to overdiagnosis and over-treatment of DCIS. Recently, a gene expression profiling tool (12 gene assay, Oncotype DCIS) has emerged that shows considerable promise in predicting class in DCIS patients.

Ductal Carcinoma In Situ Biology, Biomarkers, and Diagnosis

Ductal carcinoma in situ (DCIS) is an often-diagnosed breast disease and a known, non-obligate, precursor to invasive breast carcinoma. In this review, we explore the clinical and pathological features of DCIS, fundamental elements of DCIS biology including gene expression and genetic events, the relationship of DCIS with recurrence and invasive breast cancer, and the interaction of DCIS with the microenvironment. We also survey how these various elements are being used to solve the clinical conundrum of how to optimally treat a disease that has potential to progress, and yet is also likely over-treated in a significant proportion of cases.

Do we need to irradiate all small invasive breast cancers and DCIS?

Breast radiotherapy after lumpectomy is considered standard for nearly all patients with invasive breast cancer and is recommended for many patients after lumpectomy for ductal carcinoma in situ (DCIS). However, there is recognition that lumpectomy alone can achieve optimal cancer control for some patients with invasive breast cancer and DCIS. Patients with breast cancers with lower risk of recurrence are less likely to derive benefit from breast radiotherapy. This review will focus on defining populations of patients with invasive breast cancer and DCIS with a low risk of recurrence post-lumpectomy and the evidence supporting omission of breast radiotherapy post-lumpectomy.

Copy number analysis of ductal carcinoma in situ with and without recurrence

Ductal carcinoma in situ (DCIS) is a non-obligate precursor of invasive breast cancer and a frequent mammographic finding requiring treatment. Up to 25% of DCIS can recur and half of recurrences are invasive, but there are no reliable biomarkers for recurrence. We hypothesised that copy number aberrations could predict likelihood of recurrence. We analysed a cohort of pure DCIS cases treated only with wide local excision for genome-wide copy number and loss of heterozygosity using Affymetrix OncoScan MIP arrays. Cases included those without recurrence within 7 years (n = 25) and with recurrence between 1 and 5 years after diagnosis (n = 15). Pure DCIS were broadly similar in copy number changes compared with invasive breast cancer, with the consistent exception of a greater frequency of ERBB2 amplification in DCIS. There were no significant differences in age or ER status between the cases with a recurrence vs those without. Overall, the DCIS cases with recurrence had more copy number events than the DCIS without recurrence. The increased copy number appeared non-random with several genomic regions showing an increase in frequency in recurrent cases, including 20 q gain, ERBB2 amplification and 15q loss. Copy number changes may provide prognostic information for DCIS recurrence, but validation in additional cohorts is required.

Modeling the effectiveness of initial management strategies for ductal carcinoma in situ

BACKGROUND

The prevalence of ductal carcinoma in situ (DCIS) and the marked variability in patterns of care highlight the need for comparative effectiveness research. We sought to quantify the tradeoffs among alternative management strategies for DCIS with respect to disease outcomes and breast preservation.

METHODS

We developed a disease simulation model integrating data from the published literature to simulate the clinical events after six treatments (lumpectomy alone, lumpectomy with radiation, lumpectomy with radiation and tamoxifen, lumpectomy with tamoxifen, and mastectomy with and without breast reconstruction) for women with newly diagnosed DCIS. Outcomes included disease-free, invasive disease-free, and overall survival and breast preservation.

RESULTS

For a cohort of 1 million simulated women aged 45 years at diagnosis, both mastectomy and lumpectomy with radiation and tamoxifen were associated with a 12-month improvement in overall survival relative to lumpectomy alone. Adding radiation therapy to lumpectomy resulted in a 6-month improvement in overall survival but decreased long-term breast-preservation outcomes (likelihood of lifetime breast preservation = 0.781 vs 0.843 for lumpectomy alone). This decrement with radiation therapy was mitigated by the addition of tamoxifen (likelihood of lifetime breast preservation = 0.846).

CONCLUSIONS

Overall survival benefits of the six management strategies for DCIS are within 1 year, suggesting that treatment decisions can be informed by the patient's preference for breast preservation and disutility for recurrence. Our delineation of personalized outcomes for each strategy can help patients understand the implications of their treatment choice, so their decisions may reflect their own personal values and help improve the quality of care for patients with DCIS.

Ductal carcinoma in situ: what can we learn from clinical trials?

Ductal Carcinoma in situ has been diagnosed more frequently in the last few years and now accounts for approximately one-fourth of all treated breast cancers. Traditionally, this disease has been treated with total mastectomy, but conservative surgery has become increasingly used in the absence of unfavourable clinical conditions, if a negative excision margin can be achieved. It is controversial whether subgroups of patients with favourable in situ tumors could be managed by conservative surgery alone, without radiation. As the disease is diagnosed more frequently in younger patients, these issues are very relevant, and much research has focused on this topic in the last two decades. We reviewed randomized trials regarding adjuvant radiation after breast-conservative surgery and compared data with available retrospective studies.

Challenges in ductal carcinoma in situ risk communication and decision-making: report from an American Cancer Society and National Cancer Institute workshop

In September 2010, the American Cancer Society and National Cancer Institute convened a conference to review current issues in ductal carcinoma in situ (DCIS) risk communication and decision-making and to identify directions for future research. Specific topics included patient and health care provider knowledge and attitudes about DCIS and its treatment, how to explain DCIS to patients given the heterogeneity of the disease, consideration of nomenclature changes, and the usefulness of decision tools/aids. This report describes the proceedings of the workshop in the context of the current literature and discusses future directions. Evidence suggests that there is a lack of clarity about the implications and risks of a diagnosis of DCIS among patients, providers, and researchers. Research is needed to understand better the biology and mechanisms of the progression of DCIS to invasive breast cancer and the factors that predict those subtypes of DCIS that do not progress, as well as efforts to improve the communication and informed decision-making surrounding DCIS.