Evaluating DCIS treatments — do you know your “survival” statistics?

“There is strong evidence that treatment of DCIS in most women has no clear effect on mortality reduction.” – Finding the balance between over- and under-treatment of ductal carcinoma in situ (DCIS)

“Risk of development of metastases and/or death in a patient diagnosed with pure DCIS is very low (<1%).” Ductal Carcinoma-In-Situ of the Breast with Subsequent Distant Metastasis and Death

SURGERY

• “For low-grade DCIS, the weighted 10-year breast cancer-specific survival of the non-surgery group was 98.8% and that of the surgery group was 98.6%.” – Survival Benefit of Breast Surgery for Low-Grade Ductal Carcinoma In Situ: A Population-Based Cohort Study

RADIATION

• Prospective randomized data show no difference in breast cancer-specific survival, regardless of treatment after excision – Should all Patients Undergoing Breast Conserving Therapy for DCIS Receive Radiation Therapy? No. One Size Does Not Fit All: An Argument Against the Routine Use of Radiation Therapy for All Patients With Ductal Carcinoma In Situ of the Breast Who Elect Breast Conservation
• Although radiotherapy is associated with substantial reductions in local recurrence, no differences have been reported in metastatic disease or overall survival. – Effect of tamoxifen and radiotherapy in women with locally excised ductal carcinoma in situ: long-term results from the UK/ANZ DCIS trial
• Among patients who received lumpectomy, radiotherapy was associated with a reduction in the risk of ipsilateral invasive recurrence at 10 years, but not of breast cancer–specific mortality at 10 years – Breast Cancer Mortality After a Diagnosis of Ductal Carcinoma In Situ
• “Radiation for DCIS is prophylactic; it reduces the risk of invasive recurrence, the only lethal form of breast cancer, while increasing the probability of eventual mastectomy. The absolute magnitude of both effects is modest, such that personal patient preferences should drive decision-making. – Radiation therapy for ductal carcinoma in situ: A decision analysis
• “Significant improvements in survival in the RT group compared with the non-RT group were only observed in patients with higher nuclear grade, younger age, and larger tumor size.” – Patient Prognostic Score and Associations With Survival Improvement Offered by Radiotherapy After Breast-Conserving Surgery for Ductal Carcinoma In Situ: A Population-Based Longitudinal Cohort Study

TAMOXIFEN

• While tamoxifen after local excision for DCIS (with or without adjuvant radiotherapy) reduced the risk of recurrent DCIS (in the ipsi- and contralateral breast), it did not reduce the risk of overall mortality. – Postoperative tamoxifen for ductal carcinoma in situ.
• Warrick and Allred in their editorial piece conclude that tamoxifen is probably overused, and advocate more selective use. They particularly note that the major benefit would be seen in patients who are younger (premenopausal) with extensive high grade disease and/or narrow margins, and clearly only those that are ER positive.In conclusion, the clinical benefit of tamoxifen intervention based on the randomized trials is meager at best. There appears to be no benefit, at least in the UK/ANZ trial for tamoxifen amongst irradiated patients, and the benefits when claimed are very small. – Tamoxifen as an Adjuvant Agent for Ductal Carcinoma In Situ (DCIS)