Axillary evaluation in ductal cancer in situ of the breast: challenging the diagnostic accuracy of clinical practice guidelines

BACKGROUND

Staging of the axilla is not routine in ductal cancer in situ (DCIS) although invasive cancer is observed in 20-25 per cent of patients at final pathology. Upfront sentinel lymph node dissection (SLND) is advocated in clinical practice guidelines in certain situations. These include expected challenges in subsequent SLN detection and when the risk for invasion is high. Clinical practice guidelines are, however, inconsistent and lead to considerable practice variability.

METHODS

Clinical practice guidelines for upfront SLND in DCIS were identified and applied to patients included in the prospective SentiNot study. These patients were evaluated by six independent, blinded raters. Agreement statistics were performed to assess agreement and concordance. Receiver operating characteristic curves were constructed, to assess guideline accuracy in identifying patients with underlying invasion.

RESULTS

Eight guidelines with relevant recommendations were identified. Interobserver agreement varied greatly (kappa: 0.23-0.9) and the interpretation as to whether SLND should be performed ranged from 40-90 per cent and with varying concordance (32-88 per cent). The diagnostic accuracy was low with area under the curve ranging from 0.45 to 0.55. Fifty to 90 per cent of patients with pure DCIS would undergo unnecessary SLNB, whereas 10-50 per cent of patients with invasion were not identified as 'high risk'. Agreement across guidelines was low (kappa = 0.24), meaning that different patients had a similar risk of being treated inaccurately.

CONCLUSION

Available guidelines are inaccurate in identifying patients with DCIS who would benefit from upfront SLNB. Guideline refinement with detailed preoperative work-up and novel techniques for SLND identification could address this challenge and avoid overtreatment.

Ductal Carcinoma in Situ: Quantitative Preoperative Breast MR Imaging Features Associated with Recurrence after Treatment

Purpose To investigate whether specific imaging features on breast magnetic resonance (MR) images are associated with ductal carcinoma in situ (DCIS) recurrence risk after definitive treatment. Materials and Methods Patients with DCIS who underwent preoperative dynamic contrast material-enhanced (DCE) MR imaging between 2004 and 2014 with ipsilateral recurrence more than 6 months after definitive surgical treatment were retrospectively identified. For each patient, a control subject with DCIS that did not recur was identified and matched on the basis of clinical, histopathologic, and treatment features known to affect recurrence risk. On DCE MR images, lesion characteristics (longest diameter, functional tumor volume [FTV], peak percentage enhancement [PE], peak signal enhancement ratio [SER], and washout fraction) and normal tissue features (background parenchymal enhancement [BPE] volume, mean BPE) were quantitatively measured. MR imaging features were compared between patients and control subjects by using the Wilcoxon signed-rank test, with adjustment for multiple comparisons. Results Of 415 subjects with DCIS who underwent preoperative MR imaging, 14 experienced recurrence and 11 had an identifiable matching control subject (final cohort, 11 patients and 11 control subjects). Median time to recurrence was 14 months, and median follow-up for control subjects was 102 months. When compared with matched control subjects, patients with DCIS recurrence exhibited significantly greater FTV (median, 9.3 cm³ vs 1.3 cm³, P = .01), lesion peak SER (median, 1.7 vs 1.2; P = .03), and mean BPE (median, 58.3% vs 41.1%; P = .02). Conclusion Quantitative lesion and normal breast tissue characteristics at preoperative MR imaging in women with newly diagnosed DCIS show promise for association with breast cancer recurrence after treatment. ^© RSNA, 2017.

Molecular classification of non-invasive breast lesions for personalised therapy and chemoprevention

Breast cancer screening has led to a dramatic increase in the detection of pre-invasive breast lesions. While mastectomy is almost guaranteed to treat the disease, more conservative approaches could be as effective if patients can be stratified based on risk of co-existing or recurrent invasive disease.Here we use a range of biomarkers to interrogate and classify purely non-invasive lesions (PNL) and those with co-existing invasive breast cancer (CEIN). Apart from Ductal Carcinoma In Situ (DCIS), relative homogeneity is observed. DCIS contained a greater spread of molecular subtypes. Interestingly, high expression of p-mTOR was observed in all PNL with lower expression in DCIS and invasive carcinoma while the opposite expression pattern was observed for TOP2A.Comparing PNL with CEIN, we have identified p53 and Ki67 as predictors of CEIN with a combined PPV and NPV of 90.48% and 43.3% respectively. Furthermore, HER2 expression showed the best concordance between DCIS and its invasive counterpart.We propose that these biomarkers can be used to improve the management of patients with pre-invasive breast lesions following further validation and clinical trials. p53 and Ki67 could be used to stratify patients into low and high-risk groups for co-existing disease. Knowledge of expression of more actionable targets such as HER2 or TOP2A can be used to design chemoprevention or neo-adjuvant strategies. Increased knowledge of the molecular profile of pre-invasive lesions can only serve to enhance our understanding of the disease and, in the era of personalised medicine, bring us closer to improving breast cancer care.

Can MRI biomarkers at 3 T identify low-risk ductal carcinoma in situ?

OBJECTIVE

The objective was to explore whether 3-T magnetic resonance imaging (MRI) can identify low-risk ductal carcinoma in situ (DCIS).

METHODS

Dynamic contrast-enhanced and diffusion-weighted (DWI) MRI features of 36 DCIS lesions [8 low risk, Van Nuys Pathologic Classification (VNPC) 1; 28 high risk, VNPC 2/3] were reviewed. An MRI model that best identified low-risk DCIS was determined using multivariate logistic regression.

RESULTS

Low-risk DCIS exhibited different DWI properties [i.e., higher contrast-to-noise ratio (P=.02) and lower normalized apparent diffusion coefficients (P=.04)] than high-risk DCIS. A model combining these DWI features provided best performance (area under receiver operating characteristic curve =0.86).

CONCLUSIONS

DWI may help identify DCIS lesions requiring less therapy.

Excision alone for small size ductal carcinoma in situ of the breast

This study was performed to determine the risk of tumor recurrence after local excision alone in patients with small size (≤1 cm) ductal carcinoma in situ (DCIS) of the breast. We have treated 107 patients who had DCIS measuring ≤1 cm with margin widths of ≥0.3 cm with excision alone per institutional protocol. With a median follow-up time of 58 months, 4 patients developed ipsilateral breast tumor recurrence (IBTR). Two of the 4 recurrences were invasive, whereas 2 were DCIS. The 5-year rate of IBTR was 6.1%. The patients with resection margin of <1.0 cm had significantly higher rate of IBTR than the patients with resection margin of ≥1.0 cm (23.1% vs. 1.5% at 5-year, p < 0.01). In conclusion, radiotherapy is necessary in the patients with resection margin of <1.0 cm after excision alone because of the substantial risk of IBTR.

Ductal carcinoma in situ of the breast: can biomarkers improve current management?

BACKGROUND

Screening for invasive cancer has led to a marked increase in the detection of ductal carcinoma in situ (DCIS). DCIS is, if appropriately managed, a low-risk disease which has a small chance of impacting on patient life expectancy. However, despite significant advances in prognostic marker development in invasive breast cancer, there are no validated diagnostic assays to inform treatment choice for women with DCIS. Therefore we are unable to target effective treatment strategies to women at high risk and avoid over-treatment of women at low risk of progression to invasive breast cancer. Paradoxically, one effect of this uncertainty is undertreatment of some women.

CONTENT

We review current practice and research in the field to identify key challenges in the management of DCIS. The impact of clinical research, particularly on the over and undertreatment of women with DCIS is assessed. We note slow progress toward development of diagnostic biomarkers and highlight key opportunities to accelerate advances in this area.

SUMMARY

DCIS is a low-risk disease, its incidence is increasing, and current treatment is effective. However, many women are either over- or undertreated. Despite repeated calls for development of diagnostic biomarkers, progress in this area has been slow, reflecting a relative lack of investment of research effort and funding. Given the low event rate in treated patients and the lateness of recurrences, many previous studies have only limited power to identify independent prognostic and predictive biomarkers. However, the potential for such biomarkers to personalize treatment for DCIS is extremely high.

Tailoring treatment for ductal intraepithelial neoplasia of the breast according to Ki-67 and molecular phenotype

Background:

The post-surgical management of ductal intraepithelial neoplasia (DIN) of the breast is still a dilemma. Ki-67 labelling index (LI) has been proposed as an independent predictive and prognostic factor in early breast cancer.

Methods:

The prognostic and predictive roles of Ki-67 LI were evaluated with a multivariable Cox regression model in a cohort of 1171 consecutive patients operated for DIN in a single institution from 1997 to 2007.

Results:

Radiotherapy (RT) was protective in subjects with DIN with Ki-67 LI ≥14%, whereas no evidence of benefit was seen for Ki-67 LI <14%, irrespective of nuclear grade and presence of necrosis. Notably, the higher the Ki-67 LI, the stronger the effect of RT (P-interaction <0.01). Hormonal therapy (HT) was effective in both Luminal A (adjusted hazard ratio (HR)=0.56 (95% CI, 0.33–0.97)) and Luminal B/Her2neg DIN (HR 0.51 (95% CI, 0.27–0.95)).

Conclusion:

Our data suggest that Ki-67 LI may be a useful prognostic and predictive adjunct in DIN patients. The Ki-67 LI of 14% could be a potential cutoff for better categorising this population of women at increased risk for breast cancer and in which adjuvant treatment (RT, HT) should be differently addressed, independent of histological grade and presence of necrosis.

[Radiotherapy for breast cancer: which strategy in 2012?]

Postoperative radiotherapy remains essential in breast cancer in 2012. After conserving surgery, it reduces local recurrence risks from 50 to 70%, both for ductal carcinoma in situ and invasive cancers. This was confirmed in several randomized trials and three meta-analyses. The boost increases local control in invasive cancers, but its role should be better defined in ductal carcinoma in situ. Among the latter, there is no clearly identified subgroup for which radiotherapy could be avoided. Local recurrence risk factors are now well-identified both for ductal carcinoma in situ and invasive cancers, with an inclusion, for the latter, of new molecular subgroups. After mastectomy, radiotherapy reduces local recurrence rates from 60 to 70%, especially among patients with axillary nodal involvement, with, in parallel, a 7 to 9% increased survival rate. In order to reduce the waiting list and to avoid under treatment, especially in the elderly, several hypofractionated radiotherapy schemes have been developed for several years. Three randomized trials confirmed similar results to classical radiotherapy. For ten years, several techniques of partial breast irradiation have been developed, with various doses and treated volumes. The optimal indications should be defined according to the new international guidelines.