DWI-MRI Predicts Breast Cancer Response to Treatment

Diffusion-weighted MR images (DWI_MRI) acquired 12 weeks after the start of neoadjuvant chemotherapy for breast cancer may provide the best indication of how patients will respond to treatment, according to a study published in Radiology.

The researchers analyzed 242 participants who were randomized to receive 12 weekly doses of paclitaxel with four cycles of anthracycline.   The MRI protocol included, DWI imaging T2-weighted and contrast enhanced sequences.

  

The authors concluded that after 12 weeks of therapy, change in breast tumor apparent diffusion coefficient at MRI predicts complete pathologic response to neoadjuvant chemotherapy

Improved breast cancer screening and treatment may have saved many lives.

A study using data from the Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute published in Cancer estimated as many as 600,000 breast cancer deaths were avoided since 1989 in women aged 40 to 84 years thanks screening and treatment advances. 

The authors report that from 1975 to 1990, female breast cancer mortality rates in the United States increased by 0.4% per year. Since 1990, breast cancer mortality rates have fallen between 1.8% and 3.4% per year, a decrease that is attributed to increased mammography screening and improvements in treatment.

The authors concluded that since 1989, between 384,000 and 614,500 breast cancer deaths have been averted because of widespread use of screening mammography and advances in the treatment of breast cancer.

Gene test reveals which women with breast cancer do not need chemotherapy

Research by Sparano et al published in the NEJM suggests that the gene test known as Oncotype DX may help women with early stage breast cancer avoid chemotherapy.

The authors performed a prospective trial involving women with hormone-receptor–positive, HER2–negative, axillary node–negative breast cancer with tumors of 1.1 to 5.0 cm in the greatest dimension (or 0.6 to 1.0 cm in the greatest dimension and intermediate or high tumor grade). The Oncotype DX assay of 21 genes was performed on the tumor tissue, and the results were used to calculate a score indicating the risk of breast-cancer recurrence; patients were assigned to receive endocrine therapy without chemotherapy if they had a recurrence score of 0 to 10 on a scale 1 to 100, indicating a very low risk of recurrence.

Of the 10,253 eligible women enrolled, 1626 women (15.9%) who had a recurrence score of 0 to 10 were assigned to receive endocrine therapy alone without chemotherapy. At 5 years, in this patient population, the rate of invasive disease–free survival was 93.8%, the lack of metastasis at a distant site was 99.3%, and the rate of overall survival was 98.0%.

The authors concluded that patients with hormone-receptor–positive, HER2-negative, axillary node–negative breast cancer, those with tumors that had a favorable gene-expression profile the test accurately identified the group of women whose cancers are likely to respond to hormone-blocking drugs and adding chemo would do little if any good while exposing them to side effects and other health risks.  The researchers found that patients who skipped chemo based on the test had a small chance of cancer recurrence at 5 years with endocrine therapy alone.

Monitoring Metastatic Breast Cancer with Circulating Tumor DNA

Dawson et al in a NEJM article report on their research on monitoring tumor burden on patients with metastatic breast cancer by means of detecting circulating cell-free DNA carrying tumor specific alterations.

A total of 52 women with metastatic breast cancer were recruited, 30 of whom had genomic alterations suitable for monitoring. Serial blood samples were collected at intervals of 3 or more weeks. Computed tomography (CT) was performed to document response to treatment. They compared the radiographic imaging of tumors with the assay of circulating tumor DNA, CA 15-3, and circulating tumor cells in the 30 women who were receiving systemic therapy. They used targeted or whole-genome sequencing to identify somatic genomic alterations and designed personalized assays to quantify circulating tumor DNA in collected plasma specimens. CA 15-3 levels and numbers of circulating tumor cells were measured at identical time points.

Circulating tumor DNA was successfully detected in 29 of the 30 women (97%) in whom somatic genomic alterations were identified; CA 15-3 and circulating tumor cells were detected in 21 of 27 women (78%) and 26 of 30 women (87%), respectively. Circulating tumor DNA levels showed a greater dynamic range, and greater correlation with changes in tumor burden, than did CA 15-3 or circulating tumor cells. Among the measures tested, circulating tumor DNA provided the earliest measure of treatment response in 10 of 19 women (53%).

Metastatic breast cancer remains an incurable but treatable disease.  Effective monitoring of treatment response is essential in order to avoid continuing ineffective therapies and to prevent side effects.  Their research showed that circulating tumor DNA is an informative, specific, and sensitive biomarker of metastatic breast cancer.