Women with luminal A subtype of breast cancer did not benefit from adjuvant chemotherapy
Premenopausal women whose invasive breast cancers were of the luminal A subtype had comparable 10-year disease-free survival rates regardless of whether or not they received adjuvant chemotherapy, according to data from the phase III DBCG77B clinical trial presented at the 2015 San Antonio Breast Cancer Symposium, held Dec. 8-12. "Luminal A is a relatively common subtype of breast cancer, and is defined by high expression of hormone receptors [estrogen receptor (ER) and progesterone receptor (PR)], and low expression of the cell-growth marker Ki67 and the oncoprotein HER2. It is the form of breast cancer with the best prognosis," said Torsten Nielsen, MD, PhD, professor of pathology at the University of British Columbia in Vancouver, Canada.
"We wanted to address the clinical question of whether or not women with molecularly low-risk luminal A breast cancer actually benefit from chemotherapy," added Nielsen. "Instead of starting a new trial and waiting for 10 years to find answers, we used an older, completed trial that had saved tissue samples for future studies."
Between 1977 and 1983, 1,146 premenopausal women who had lymph node-positive invasive breast cancer that was larger than 5 cm were randomized to two chemotherapy arms and two no- chemotherapy arms in the Dutch Breast Cancer Cooperative Group 77B trial. Women in the chemotherapy arms received either cyclophosphamide or a combination of cyclophosphamide, methotrexate, and fluorouracil. All women received radiotherapy but no endocrine therapy.
Nielsen and colleagues analyzed the tissue samples that were available from 709 patients for the presence of ER, PR, HER2, and Ki67, and identified 165 of them as having had the luminal A subtype.
The researchers found that there was no difference in 10-year invasive disease-free survival rates between women with luminal A disease who did and did not receive chemotherapy. Patients with nonluminal A disease (which included the luminal B, HER2E, and triple-negative subtypes) who received chemotherapy were 50 percent less likely to have their disease recur in 10 years, compared with women with nonluminal A disease who did not receive chemotherapy.
Nielsen explained that none of the women in this trial received hormone therapy as adjuvant treatment. In that respect, the trial used in this study may not mirror the current standard of care. However, endocrine therapies are known to decrease the tumors' sensitivity to chemotherapy. "Given that women with luminal A subtype of breast cancer did not benefit from chemotherapy in our study, it would certainly be expected that women with similar tumor characteristics getting endocrine therapy would also receive no benefit from chemotherapy," he said.
"The trial was positive for chemotherapy benefit because women who had the luminal B and basal subtypes, in contrast to those who had luminal A, greatly benefited from cyclophosphamide-based adjuvant chemotherapy," Nielsen said. "We would like to thank the women of Denmark who agreed to sign up to be randomized to different treatments. Even decades later, they are contributing to our scientific understanding of breast cancer and have helped a new generation of women make better-informed decisions about what treatments they need, or do not need," he added.
Source: American Association for Cancer Research
Articles on the same topic
- Drug provides another treatment option for an early form of breast cancerFri, 11 Dec 2015, 14:21:58 UTC
- Survival and time to surgery, chemotherapy for patients with breast cancerThu, 10 Dec 2015, 16:29:57 UTC
- Delaying chemotherapy in breast cancer patients reduces overall survival, especially for those with triple-negative breast cancerThu, 10 Dec 2015, 16:29:36 UTC
- Breast-conserving therapy yielded better outcomes than mastectomy for early-stage patientsThu, 10 Dec 2015, 14:14:41 UTC
- Adding carboplatin to presurgery chemo improved disease-free survival for patients with TNBCThu, 10 Dec 2015, 14:14:27 UTC
- Capecitabine improved outcomes for breast cancer patients with disease after presurgery chemoThu, 10 Dec 2015, 14:14:06 UTC
- Denosumab improves disease-free survival for postmenopausal patients w HR+ breast cancerThu, 10 Dec 2015, 14:13:32 UTC
- Pathologic complete response to presurgery chemo improves survival for patients with TNBCThu, 10 Dec 2015, 14:13:13 UTC
- SABCS15: 'Weeding the garden' with radiation while continuing breast cancer therapyThu, 10 Dec 2015, 14:12:55 UTC
- Phase 1 results point to larger trial of enzalutamide and fulvestrant in breast cancerThu, 10 Dec 2015, 14:12:37 UTC
- Drugs prevent heart damage during breast cancer treatment, study showsWed, 9 Dec 2015, 20:38:55 UTC
Other sources
- Chemotherapy delay for breast cancer reduces survival chancesfrom UPIFri, 11 Dec 2015, 18:22:06 UTC
- Older Breast Cancer Patients Defy Survival Modelsfrom Science DailyWed, 9 Dec 2015, 20:32:57 UTC
- One-two punch of palbociclib, paclitaxel shows promise against advanced breast cancerfrom Science DailyWed, 9 Dec 2015, 20:32:31 UTC
- Aspirin use does not improve outcomes for cancer patients, but may lower breast tissue density, allowing for earlier detectionfrom Science DailyWed, 9 Dec 2015, 19:51:42 UTC
- ABCSG 18: Monoclonal antibody increases disease-free survival in breast cancerfrom Science DailyWed, 9 Dec 2015, 18:39:13 UTC
- Aspirin doesn't help breast cancer outcomes, may aid detectionfrom UPIWed, 9 Dec 2015, 17:43:20 UTC
- Five out of six women at higher risk reject drugs to prevent breast cancerfrom Science DailyWed, 9 Dec 2015, 15:57:02 UTC
- SABCS15: 'Weeding the garden' with radiation while continuing breast cancer therapyfrom Science DailyTue, 8 Dec 2015, 20:14:42 UTC