Oncology Physicians' Perspectives on Practices and Barriers to Fertility Preservation and the Feasibility of a Prospective Study of Pregnancy After Breast Cancer.

PURPOSE: POSITIVE (Pregnancy Outcome and Safety of Interrupting Therapy for women with endocrine responsIVE breast cancer) is a prospective clinical trial assessing safety and pregnancy outcomes in premenopausal hormone receptor-positive breast cancer survivors (age ≤42) who interrupt endocrine therapy (ET) to attempt pregnancy. We sought to assess interest in this study and perspectives on fertility preservation (FP) among United States medical oncologists who had previously enrolled women at their institutions on select premenopausal endocrine studies. METHODS: From August 2015 to December 2015, 301 investigators were invited to complete a web-based survey on behalf of their institution. We assessed FP practices and attitudes, barriers to discussing FP, and willingness to open/enroll women on POSITIVE. RESULTS: Of 93 respondents (31%), most were affiliated with an National Cancer Institute (NCI)-designated comprehensive cancer center (44%). Almost all said they usually or always discussed the issue of future fertility with patients (98%) and referred patients with fertility questions to specialists (97%). Over half of respondents cited discomfort with recommending women to stop ET, as well as perceived patient concern regarding ET interruption, as factors seen as influencing POSITIVE enrollment; however, 84% were willing to recommend trial participation for selected patients. CONCLUSIONS: Most providers reported discussing fertility with their young patients, indicating awareness of FP guidelines for cancer patients. While most oncologists said that they would be willing to recommend POSITIVE, many also expressed discomfort in endorsing women to stop ET temporarily, underscoring the need for prospective data regarding the safety of ET interruption. High willingness to recommend POSITIVE suggests the potential for successful accrual to this study, which addresses a critical issue for young breast cancer survivors.

ESR1 and ESR2 polymorphisms in the BIG 1-98 trial comparing adjuvant letrozole versus tamoxifen or their sequence for early breast cancer.

Estrogen receptor 1 (ESR1) and ESR2 gene polymorphisms have been associated with endocrine-mediated physiological mechanisms, and inconsistently with breast cancer risk and outcomes, bone mineral density changes, and hot flushes/night sweats. DNA was isolated and genotyped for six ESR1 and two ESR2 single-nucleotide polymorphisms (SNPs) from tumor specimens from 3691 postmenopausal women with hormone receptor-positive breast cancer enrolled in the BIG 1-98 trial to receive tamoxifen and/or letrozole for 5 years. Associations with recurrence and adverse events (AEs) were assessed using Cox proportional hazards models. 3401 samples were successfully genotyped for five SNPs. ESR1 rs9340799(XbaI) (T>C) variants CC or TC were associated with reduced breast cancer risk (HR = 0.82,95% CI = 0.67-1.0), and ESR1 rs2077647 (T>C) variants CC or TC was associated with reduced distant recurrence risk (HR = 0.69, 95% CI = 0.53-0.90), both regardless of the treatments. No differential treatment effects (letrozole vs. tamoxifen) were observed for the association of outcome with any of the SNPs. Letrozole-treated patients with rs2077647 (T>C) variants CC and TC had a reduced risk of bone AE (HR = 0.75, 95% CI = 0.58-0.98, P interaction = 0.08), whereas patients with rs4986938 (G>A) genotype variants AA and AG had an increased risk of bone AE (HR = 1.37, 95% CI = 1.01-1.84, P interaction = 0.07). We observed that (1) rare ESR1 homozygous polymorphisms were associated with lower recurrence, and (2) ESR1 and ESR2 SNPs were associated with bone AEs in letrozole-treated patients. Genes that are involved in estrogen signaling and synthesis have the potential to affect both breast cancer recurrence and side effects, suggesting that individual treatment strategies can incorporate not only oncogenic drivers but also SNPs related to estrogen activity.

Bone mineral density and circulating biomarkers in the BIG 1-98 trial comparing adjuvant letrozole, tamoxifen and their sequences.

The purpose of the study is to determine the effects of the BIG 1-98 treatments on bone mineral density. BIG 1-98 compared 5-year adjuvant hormone therapy in postmenopausal women allocated to four groups: tamoxifen (T); letrozole (L); 2-years T, 3-years L (TL); and 2-years L, 3-years T (LT). Bone mineral density T-score was measured prospectively annually by dual energy X-ray absorption in 424 patients enrolled in a sub-study after 3 (n = 150), 4 (n = 200), and 5 years (n = 74) from randomization, and 1 year after treatment cessation. Prevalence of osteoporosis and the association of C-telopeptide, osteocalcin, and bone alkaline phosphatase with T-scores were assessed. At 3 years, T had the highest and TL the lowest T-score. All arms except for LT showed a decline up to 5 years, with TL exhibiting the greatest. At 5 years, there were significant differences on lumbar T-score only between T and TL, whereas for femur T-score, differences were significant for T versus L or TL, and L versus LT. The 5-year prevalence of spine and femur osteoporosis was the highest on TL (14.5 %, 7.1 %) then L (4.3 %, 5.1 %), LT (4.2 %, 1.4 %) and T (4 %, 0). C-telopeptide and osteocalcin were significantly associated with T-scores. While adjuvant L increases bone mineral density loss compared with T, the sequence LT has an acceptable bone safety profile. C-telopeptide and osteocalcin are useful markers of bone density that may be used to monitor bone health during treatment. The sequence LT may be a valid treatment option in patients with low and intermediate risk of recurrence.

A risk score based on histopathological features predicts higher risk of distant recurrence in premenopausal patients with lymph node-negative endocrine-responsive breast cancer.

PURPOSE: To develop a Risk Score (RS) to predict distant recurrence among premenopausal women with node-negative endocrine-responsive early breast cancer. METHODS: The Cox model was used to develop the RS using clinical and histopathological features from 378 women participating in the IBCSG Trial VIII who received endocrine therapy alone or following chemotherapy. The performance of the resulting model was validated on a cohort of 1005 patients from a single institution who received endocrine therapy alone. RESULTS: In a multivariable analysis, the risk of distant recurrence was associated with tumor size, ER, Ki-67 and peritumoral vascular invasion. In the validation cohort, patients with high RS were at greater risk of distant recurrence compared to patients with low RS (HR, 17.41; 95% CI, 5.72-52.95). CONCLUSION: In premenopausal women with node-negative endocrine-responsive early breast cancer, the RS identifies patients at higher risk of distant recurrence.

Classical cyclophosphamide, methotrexate, and fluorouracil chemotherapy is more effective in triple-negative, node-negative breast cancer: results from two randomized trials of adjuvant chemoendocrine therapy for node-negative breast cancer.

PURPOSE: Retrospective studies suggest that primary breast cancers lacking estrogen receptor (ER) and progesterone receptor (PR) and not overexpressing human epidermal growth factor receptor 2 (HER2; triple-negative tumors) are particularly sensitive to DNA-damaging chemotherapy with alkylating agents. PATIENTS AND METHODS: Patients enrolled in International Breast Cancer Study Group Trials VIII and IX with node-negative, operable breast cancer and centrally assessed ER, PR, and HER2 were included (n = 2,257). The trials compared three or six courses of adjuvant classical cyclophosphamide, methotrexate, and fluorouracil (CMF) with or without endocrine therapy versus endocrine therapy alone. We explored patterns of recurrence by treatment according to three immunohistochemically defined tumor subtypes: triple negative, HER2 positive and endocrine receptor absent, and endocrine receptor present. RESULTS: Patients with triple-negative tumors (303 patients; 13%) were significantly more likely to have tumors > 2 cm and grade 3 compared with those in the HER2-positive, endocrine receptor-absent, and endocrine receptor-present subtypes. No clear chemotherapy benefit was observed in endocrine receptor-present disease (hazard ratio [HR], 0.90; 95% CI, 0.74 to 1.11). A statistically significantly greater benefit for chemotherapy versus no chemotherapy was observed in triple-negative breast cancer (HR, 0.46; 95% CI, 0.29 to 0.73; interaction P = .009 v endocrine receptor-present disease). The magnitude of the chemotherapy effect was lower in HER2-positive endocrine receptor-absent disease (HR, 0.58; 95% CI, 0.29 to 1.17; interaction P = .24 v endocrine receptor-present disease). CONCLUSION: The magnitude of benefit of CMF chemotherapy is largest in patients with triple-negative, node-negative breast cancer.

Prognostic and predictive impact of central necrosis and fibrosis in early breast cancer: results from two International Breast Cancer Study Group randomized trials of chemoendocrine adjuvant therapy.

A minority of early invasive breast cancers show a pattern of central necrosis and fibrosis (CNF). Previous studies have documented an adverse prognostic impact and association with other adverse pathological features, but its predictive importance for therapy selection is unknown. We examined the prognostic and predictive value of CNF in two randomized clinical trials comparing chemoendocrine therapy with endocrine therapy alone in patients with node-negative breast cancer. A total of 1,850 patients randomly assigned to treatment groups comparing endocrine with chemoendocrine therapy, and with centrally-assessed CNF, ER, PgR and HER2 were included in the analytic cohort. The median follow up was 10 years. CNF was present in 84 of 1,850 trial patients (4.5%). It was associated with tumor characteristics suggesting poor outcome, but was an independent adverse factor for disease-free survival. In the presence of CNF outcome was worse regardless of tumor grade, whereas in the absence of CNF, patients with grade 3 tumors had poorer outcome than those with grade 1-2 tumors. Among patients with estrogen receptor-absent tumors chemoendocrine therapy was superior to endocrine therapy alone only in the absence of CNF [HR (chemoendocrine:endocrine) = 0.46 in CNF-absent, 0.90 in CNF-present], while among those with receptor-positive disease chemoendocrine therapy was beneficial only in the presence of CNF [HR = 0.34 CNF-present, 0.96 CNF-absent]. The results suggest that the presence of CNF reflects a biological difference in early breast cancer that is important in modulating the efficacy of standard therapies. Accordingly we believe that its presence should be routinely reported.

Bone Quality Test (BQT) scores of fingernails in postmenopausal patients treated with adjuvant letrozole or tamoxifen for early breast cancer.

BACKGROUND: The relationship between nail and bone may be measurable, thus making the fingernail a potentially valuable tool for assessing bone health for women receiving treatment for breast cancer. In the BIG 1-98 Fingernail Pilot Substudy, Bone Quality Test (BQT) scores of fingernails were measured at two assessment timepoints. METHODS: Thirteen eligible patients were enrolled into the substudy during their treatment with tamoxifen (four patients) or letrozole (nine patients). Two fingernails were tested and BQT scores averaged for two assessments six months apart. RESULTS: BQT scores collected six months later (second assessment) significantly decreased compared with those at first collection (p=0.007) regardless of treatment and prior fracture. CONCLUSION: The reduction of BQT scores observed in the patients of our small exploratory study during exposure to bone-altering breast cancer treatments is an incentive for larger studies using this technique.

Is adjuvant chemotherapy of benefit for postmenopausal women who receive endocrine treatment for highly endocrine-responsive, node-positive breast cancer? International Breast Cancer Study Group Trials VII and 12-93.

To compare the efficacy of chemoendocrine treatment with that of endocrine treatment (ET) alone for postmenopausal women with highly endocrine responsive breast cancer. In the International Breast Cancer Study Group (IBCSG) Trials VII and 12-93, postmenopausal women with node-positive, estrogen receptor (ER)-positive or ER-negative, operable breast cancer were randomized to receive either chemotherapy or endocrine therapy or combined chemoendocrine treatment. Results were analyzed overall in the cohort of 893 patients with endocrine-responsive disease, and according to prospectively defined categories of ER, age and nodal status. STEPP analyses assessed chemotherapy effect. The median follow-up was 13 years. Adding chemotherapy reduced the relative risk of a disease-free survival event by 19% (P = 0.02) compared with ET alone. STEPP analyses showed little effect of chemotherapy for tumors with high levels of ER expression (P = 0.07), or for the cohort with one positive node (P = 0.03). Chemotherapy significantly improves disease-free survival for postmenopausal women with endocrine-responsive breast cancer, but the magnitude of the effect is substantially attenuated if ER levels are high.

Chemoendocrine compared with endocrine adjuvant therapies for node-negative breast cancer: predictive value of centrally reviewed expression of estrogen and progesterone receptors--International Breast Cancer Study Group.

PURPOSE: To centrally assess estrogen receptor (ER) and progesterone receptor (PgR) levels by immunohistochemistry and investigate their predictive value for benefit of chemo-endocrine compared with endocrine adjuvant therapy alone in two randomized clinical trials for node-negative breast cancer. PATIENTS AND METHODS: International Breast Cancer Study Group Trial VIII compared cyclophosphamide, methotrexate, and fluorouracil (CMF) chemotherapy for 6 cycles followed by endocrine therapy with goserelin with either modality alone in pre- and perimenopausal patients. Trial IX compared three cycles of CMF followed by tamoxifen for 5 years versus tamoxifen alone in postmenopausal patients. Central Pathology Office reviewed 883 (83%) of 1,063 patients on Trial VIII and 1,365 (82%) of 1,669 on Trial IX and determined ER and PgR by immunohistochemistry. Disease-free survival (DFS) was compared across the spectrum of expression of each receptor using the Subpopulation Treatment Effect Pattern Plot methodology. RESULTS: Both receptors displayed a bimodal distribution, with substantial proportions showing no staining (receptor absent) and most of the remainder showing a high percentage of stained cells. Chemo-endocrine therapy yielded DFS superior to endocrine therapy alone for patients with receptor-absent tumors, and in some cases also for those with low levels of receptor expression. Among patients with ER-expressing tumors, additional prediction of benefit was suggested in absent or low PgR in Trial VIII but not in Trial IX. CONCLUSION: Low levels of ER and PgR are predictive of the benefit of adding chemotherapy to endocrine therapy. Low PgR may add further prediction among pre- and perimenopausal but not postmenopausal patients whose tumors express ER.

Predictive value of tumor Ki-67 expression in two randomized trials of adjuvant chemoendocrine therapy for node-negative breast cancer.

Several small studies have reported that having a high percentage of breast tumor cells that express the proliferation antigen Ki-67 (ie, a high Ki-67 labeling index) predicts better response to neoadjuvant chemotherapy. However, the predictive value of a high Ki-67 labeling index for response to adjuvant chemotherapy is unclear. To investigate whether Ki-67 labeling index predicts response to adjuvant chemoendocrine therapy, we assessed Ki-67 expression in tumor tissue from 1924 (70%) of 2732 patients who were enrolled in two randomized International Breast Cancer Study Group trials of adjuvant chemoendocrine therapy vs endocrine therapy alone for node-negative breast cancer. A high Ki-67 labeling index was associated with other factors that predict poor prognosis. Among the 1521 patients with endocrine-responsive tumors, a high Ki-67 labeling index was associated with worse disease-free survival but the Ki-67 labeling index did not predict the relative efficacy of chemoendocrine therapy compared with endocrine therapy alone. Thus, Ki-67 labeling index was an independent prognostic factor but was not predictive of better response to adjuvant chemotherapy in these studies.

Adjuvant chemotherapy with sequential or concurrent anthracycline and docetaxel: Breast International Group 02-98 randomized trial.

BACKGROUND: Docetaxel is more effective than doxorubicin for patients with advanced breast cancer. The Breast International Group 02-98 randomized trial tested the effect of incorporating docetaxel into anthracycline-based adjuvant chemotherapy and compared sequential vs concurrent administration of doxorubicin and docetaxel. METHODS: Patients with lymph node-positive breast cancer (n = 2887) were randomly assigned to one of four treatments: 1) sequential control (four cycles of doxorubicin at 75 mg/m2, followed by three cycles of cyclophosphamide, methotrexate, and 5-fluorouracil [CMF]); 2) concurrent control (four cycles of doxorubicin at 60 mg/m2 plus cyclophosphamide at 600 mg/m2, followed by three cycles of CMF); 3) sequential docetaxel (three cycles of doxorubicin at 75 mg/m2, followed by three cycles of docetaxel at 100 mg/m2, followed by three cycles of CMF); 4) concurrent docetaxel (four cycles of doxorubicin at 50 mg/m2 plus docetaxel at 75 mg/m2, followed by three cycles of CMF). The primary comparison evaluated the efficacy of including docetaxel regardless of schedule and was planned after 1215 disease-free survival (DFS) events (ie, relapse, second primary cancer, or death from any cause). Docetaxel and control treatment groups were compared by log-rank tests, and hazard ratios (HR) of DFS events were calculated by Cox modeling. All statistical tests were two-sided. RESULTS: Due to a lower-than-anticipated rate of relapse, this analysis was performed after 5 years with 732 events. Patients in control arms had a 5-year DFS of 73% (95% confidence interval [CI] = 70% to 75%). Docetaxel treatment resulted in an improvement in DFS of borderline statistical significance compared with control treatment (HR = 0.86, 95% CI = 0.74 to 1.00; P = .05). However, DFS in the sequential docetaxel arm was better than that in the concurrent docetaxel arm (HR = 0.83, 95% CI = 0.69 to 1.00) and in the sequential control arm (HR = 0.79, 95% CI = 0.64 to 0.98). CONCLUSIONS: Incorporating docetaxel into anthracycline-based therapy resulted in an improvement in DFS that was of borderline statistical significance. However, important differences may be related to doxorubicin and docetaxel scheduling, with sequential but not concurrent administration, appearing to produce better DFS than anthracycline-based chemotherapy.

Age of menopause among women who remain premenopausal following treatment for early breast cancer: long-term results from International Breast Cancer Study Group Trials V and VI.

BACKGROUND: The likelihood of premature menopause has not been thoroughly explored in women who remain premenopausal after adjuvant chemotherapy for breast cancer. METHODS: We used data from the International Breast Cancer Study Group (IBCSG) Trials V and VI. Trial V enrolled 1407 eligible premenopausal women randomised to no systemic therapy (No CT) or 1 cycle of perioperative CMF-based chemotherapy (PeCT) if node negative, and 6 cycles of CMF-based chemotherapy postoperatively (CMFx6) or 1 cycle perioperative CMF-based chemotherapy plus CMFx6 postoperatively (CMFx7) if node positive. From Trial VI (a 2x2 factorial designed study of 3 versus 6 initial cycles of CMF and a reintroduction of three additional courses of CMF), we included 375 women randomised to receive only six initial cycles of CMF (CMFx6). FINDINGS: We excluded women who reported no menses during 12-24 months after randomisation (N=934), hysterectomy (N=16) or bilateral oophorectomy (N=8), or missing menses data (N=57), creating a cohort of 767 women; 540 women had been randomised to PeCT or no CT, 227 randomised to CMFx6 or 7. A Cox proportional hazards model revealed that CMFx6 or 7 (HR=2.03, p<0.0001) and temporary amenorrhea (HR=1.96, p<0.0001) were associated with premature menopause. INTERPRETATION: Women who remain premenopausal after 6 or 7 cycles of CMF-based chemotherapy have a higher likelihood of going through menopause at an earlier age than women who received little or no chemotherapy. Temporary cessation of menses appears to be a marker for earlier onset of menopause. These findings may assist women and clinicians when making treatment and reproductive decisions after a diagnosis of breast cancer.

Effects of a treatment gap during adjuvant chemotherapy in node-positive breast cancer: results of International Breast Cancer Study Group (IBCSG) Trials 13-93 and 14-93.

BACKGROUND: The International Breast Cancer Study Group (IBCSG) conducted two complementary randomized trials to assess whether a treatment-free gap during adjuvant chemotherapy influenced outcome. PATIENTS AND METHODS: From 1993 to 1999, IBCSG Trials 13-93 and 14-93 enrolled 2215 premenopausal and postmenopausal women with axillary node-positive, operable breast cancer. All patients received cyclophosphamide (Cytoxan, C) plus either doxorubicin (Adriamycin, A) or epirubicin (E) for four courses followed immediately (No Gap) or after a 16-week delay (Gap) by classical cyclophosphamide, methotrexate, and fluorouracil (CMF) for three courses. The median follow-up was 7.7 years. RESULTS: The Gap and No-Gap groups had similar disease-free survival (DFS) and overall survival (OS). No identified subgroup showed a statistically significant difference, but exploratory subgroup analysis noted a trend towards decreased DFS for Gap compared with No Gap for women with estrogen receptor (ER)-negative tumors not receiving tamoxifen, especially evident during the first 2 years. CONCLUSIONS: A 16-week gap between adjuvant AC/EC and CMF provided no benefit and may have increased early recurrence rates in patients with ER-negative tumors.

Adjuvant chemotherapy followed by goserelin compared with either modality alone: the impact on amenorrhea, hot flashes, and quality of life in premenopausal patients--the International Breast Cancer Study Group Trial VIII.

PURPOSE: The purpose of this article is to compare quality of life (QOL) and menopausal symptoms among premenopausal patients with lymph node-negative breast cancer receiving chemotherapy, goserelin, or their sequential combination, and to investigate differential effects by age. PATIENTS AND METHODS: We evaluated QOL data from 874 pre- and perimenopausal women with lymph node-negative breast cancer who were randomly assigned to receive six courses of classical cyclophosphamide, methotrexate, and fluorouracil (CMF) chemotherapy, ovarian suppression with goserelin for 24 months, or six courses of classical CMF followed by 18 months of goserelin. We report QOL data collected during 3 years after random assignment in patients without disease recurrence. RESULTS: Overall, patients receiving goserelin alone showed a marked improvement or less deterioration in QOL measures over the first 6 months than those patients treated with CMF. There were no differences at 3 years after random assignment according to treatment except for hot flashes. As reflected in the hot flashes scores, patients in all three treatment groups experienced induced amenorrhea, but the onset of ovarian function suppression was slightly delayed for patients receiving chemotherapy. Younger patients (< 40 years) who received goserelin alone returned to their premenopausal status at 6 months after the cessation of therapy, while those who received CMF showed marginal changes from their baseline hot flashes scores. CONCLUSION: Age-adjusted risk profiles that consider patient-reported outcomes enable patients to adapt to their disease and treatment, such as considering the trade-offs between delayed endocrine symptoms, but higher risk of permanent menopause with chemotherapy, and immediate but reversible endocrine symptoms with goserelin, in younger premenopausal patients.

Relation between chemotherapy dose, oestrogen receptor expression, and body-mass index.

Clinicians often reduce chemotherapy doses when treating obese patients because of concerns about overdosing. We assessed dose-response according to body-mass index (BMI) and oestrogen receptor (ER) expression of the primary tumour in premenopausal patients with node-positive breast cancer treated with classical CMF (cyclophosphamide, methotrexate, and 5-fluorouracil). Obese patients were significantly more likely to receive a lower chemotherapy dose (<85% of expected dose) for the first course than were those with normal or intermediate BMI (39%vs 16%, p<0.0001). For obese patients and for the total population, reducing the dose of chemotherapy was associated with a significantly worse outcome for the ER-negative cohort (total population hazards ratio 85%vs <85% 0.68 [95% CI 0.54-0.86] for disease free survival; 0.72 [0.56-0.94] for overall survival) but not for the ER-positive cohort (1.16 [0.97-1.40] for disease-free survival; 1.16 [0.94-1.44] for overall survival) [interaction p values=0.0001 for disease-free survival and 0.0019 for overall survival]. Our findings suggest that for women with ER-absent or ER-low tumours, reduction in chemotherapy dose should be avoided.

Adjuvant chemotherapy followed by goserelin versus either modality alone for premenopausal lymph node-negative breast cancer: a randomized trial.

BACKGROUND: Although chemotherapy and ovarian function suppression are both effective adjuvant therapies for patients with early-stage breast cancer, little is known of the efficacy of their sequential combination. In an International Breast Cancer Study Group (IBCSG) randomized clinical trial (Trial VIII) for pre- and perimenopausal women with lymph node-negative breast cancer, we compared sequential chemotherapy followed by the gonadotropin-releasing hormone agonist goserelin with each modality alone. METHODS: From March 1990 through October 1999, 1063 patients stratified by estrogen receptor (ER) status and radiotherapy plan were randomly assigned to receive goserelin for 24 months (n = 346), six courses of "classical" CMF (cyclophosphamide, methotrexate, 5-fluorouracil) chemotherapy (n = 360), or six courses of classical CMF followed by 18 months of goserelin (CMF --> goserelin; n = 357). A fourth arm (no adjuvant treatment) with 46 patients was discontinued in 1992. Tumors were classified as ER-negative (30%), ER-positive (68%), or ER status unknown (3%). Twenty percent of patients were aged 39 years or younger. The median follow-up was 7 years. The primary outcome was disease-free survival (DFS). RESULTS: Patients with ER-negative tumors achieved better disease-free survival if they received CMF (5-year DFS for CMF = 84%, 95% confidence interval [CI] = 77% to 91%; 5-year DFS for CMF --> goserelin = 88%, 95% CI = 82% to 94%) than if they received goserelin alone (5-year DFS = 73%, 95% CI = 64% to 81%). By contrast, for patients with ER-positive disease, chemotherapy alone and goserelin alone provided similar outcomes (5-year DFS for both treatment groups = 81%, 95% CI = 76% to 87%), whereas sequential therapy (5-year DFS = 86%, 95% CI = 82% to 91%) provided a statistically nonsignificant improvement compared with either modality alone, primarily because of the results among younger women. CONCLUSIONS: Premenopausal women with ER-negative (i.e., endocrine nonresponsive), lymph node-negative breast cancer should receive adjuvant chemotherapy. For patients with ER-positive (i.e., endocrine responsive) disease, the combination of chemotherapy with ovarian function suppression or other endocrine agents, and the use of endocrine therapy alone should be studied.