Validating Restricted Mean Survival Time Estimates From Reconstructed Kaplan-Meier Data Against Original Trial Individual Patient Data From Trials Conducted by the Canadian Cancer Trials Group.

OBJECTIVES: The development of novel cancer therapies, including immuno-oncology agents, has increased interest in reconstructed individual patient data (IPD) based restricted mean survival time (RMST) analyses. Additionally, reconstructed IPD-based RMST is recommended in cost-effectiveness analyses when original trial IPD are not available. Nevertheless, recently concerns regarding potential bias of reconstructed-IPD RMST have been presented, because reconstructed-IPD RMSTs have not been validated and previous validation endpoints may not capture the entire Kaplan-Meier (KM) curve, especially the "tail." Our study aims to validate the recommended method of IPD reconstruction by comparing reconstructed IPD- and original trial IPD-based RMST. METHODS: Canadian Cancer Trials Group trials from 1990 to 2017 were included. Overall survival and progression-free survival IPD were reconstructed based on published KM curves using the Guyot method. Analysts were blinded to original trial IPD. RMST was calculated at 1 year and over the entire KM curve. Reconstructed-IPD and original trial-IPD (gold-standard) RMSTs were compared for accuracy and predictive error via mean deviation, mean absolute error (MAE), mean percentage bias, and Bland-Altman plots and across KM curve quality (vector traced or bitmapped). RESULTS: We identified 39 trials. The mean deviation, MAE, and mean percentage bias of RMST between the reconstructed IPD and original trial IPD were small. In particular, the mean deviation was -0.01 months and -0.04 months, MAE was 0.19 months and 0.24 months, and mean percentage bias was 0.82% and 0.84% in overall survival KM curves in control and experimental arms, respectively. Accuracy was generally not associated with KM curve quality. CONCLUSIONS: RMST derived from reconstructed IPD displayed excellent accuracy and predictive error compared with the gold standard. Reconstructed IPD could be used to calculate RMST in lieu of original trial IPD, to facilitate decision making for clinicians, researchers, and policy makers.

Pilot study of the ability to probabilistically link clinical trial patients to administrative data and determine long-term outcomes.

BACKGROUND: Clinical trials are important but extremely costly. Utilization of routinely collected administrative data may simplify and enhance clinical trial data collection. PURPOSE: The aim of this study was to test the feasibility of use of administrative databases in Ontario, Canada, for long-term clinical trial follow-up, specifically (a) to determine whether limited patient identifiers held by the Canadian Cancer Trials Group can be used to probabilistically link with individuals in the Institute for Clinical Evaluative Sciences databases and if so, (b) the level of concordance between the two data sets. METHODS: This retrospective study was conducted through collaboration of established health service (Institute for Clinical Evaluative Sciences) and clinical trial (Canadian Cancer Trials Group) research groups in the province of Ontario, Canada, where healthcare is predominantly funded by the government. Adults with pre-treated metastatic colorectal cancer previously enrolled in the Canadian Cancer Trials Group CO.17 and CO.20 randomized phase III trials were included, limited to those in Ontario. The main outcomes were rate of successful probabilistic linkage and concordance of survival data, stated a priori. RESULTS: Probabilistic linkage was successful in 266/293 (90.8%) participants. In those patients for whom linkage was successful, the Canadian Cancer Trials Group (trial) and the Institute for Clinical Evaluative Sciences (administrative) data sets were concordant with regard to the occurrence of death during the period of clinical trial follow-up in 206/209 (98.6%). Death was recorded in the Institute for Clinical Evaluative Sciences, but not the Canadian Cancer Trials Group, for 57 cases, where the event occurred after the clinical trial cut-off dates. The recorded date of death matched closely between both databases. During the period of clinical trial conduct, administrative databases contained details of hospitalizations and emergency room visits not captured in the clinical trial electronic database. CONCLUSION: Prospective use of administrative data could enhance clinical trial data collection, both for long-term follow-up and resource utilization for economic analyses and do so less expensively than current primary data collection. Recording a unique identifier (e.g. health insurance number) in trial databases would allow deterministic linkage for all participants.

Mrs. Robinson's Revenge: Pete Seeger, Earl Robinson, and the Medicare Protest Song.

In 1962, Pete Seeger recorded "The Ballad of Doctor Dearjohn" about Canadian Medicare and the Saskatchewan doctors' strike of the same year. How had this New Yorker, recently relieved of a jail sentence, learned of Medicare in the distant prairie province? And why was his song never released? This paper traces the ballad's fortunes through the papers of composer Earl Robinson (University of Washington) and the archives of the American Medical Association. It is situated in the historiography of folk revival and the expatriate adventures of artistic Americans persecuted in the McCarthy era.

En 1962, Pete Seeger a enregistré « La ballade du docteur Dearjohn ¼ à propos de l'assurance-maladie canadienne et de la grève des médecins en Saskatchewan la même année. Comment ce New-Yorkais, récemment libéré de prison, a-t-il eu connaissance des événements survenant dans une province éloignée ? Et pourquoi sa chanson n'a-t-elle jamais été commercialisée ? Cet article retrace le parcours de la ballade à travers les archives du compositeur Earl Robinson (Université de Washington) et les archives de l'American Medical Association (Chicago). Il se situe dans l'historiographie du renouveau folk et des aventures d'artistes américains expatriés suite aux persécutions vécues à l'époque du maccarthysme.

Mrs. Robinson's Revenge: Pete Seeger, Earl Robinson, and the Medicare Protest Song.

In 1962, Pete Seeger recorded "The Ballad of Doctor Dearjohn" about Canadian Medicare and the Saskatchewan doctors' strike of the same year. How had this New Yorker, recently relieved of a jail sentence, learned of Medicare in the distant prairie province? And why was his song never released? This article traces the ballad's fortunes through the papers of composer Earl Robinson (University of Washington) and the archives of the American Medical Association. It is situated in the historiography of folk revival and the expatriate adventures of artistic Americans persecuted in the McCarthy era.

A Canadian Prospective Study of Linkage of Randomized Clinical Trial to Cancer and Mortality Registry Data.

In a prospective study, we sought to determine acceptability of linkage of administrative and clinical trial data among Canadian patients and Research Ethics Boards (REBs). The goal is to develop a more harmonized approach to data, with potential to improve clinical trial conduct through enhanced data quality collected at reduced cost and inconvenience for patients. On completion of the original LY.12 randomized clinical trial in lymphoma (NCT00078949), participants were invited to enrol in the Long-term Innovative Follow-up Extension (LIFE) component. Those consenting to do so provided comprehensive identifying information to facilitate linkage with their administrative data. We prospectively designed a global assessment of this innovative approach to clinical trial follow-up including rates of REB approval and patient consent. The pre-specified benchmark for patient acceptability was 80%. Of 16 REBs who reviewed the research protocol, 14 (89%) provided approval; two in Quebec declined due to small patient numbers. Of 140 patients invited to participate, 115 (82%, 95% CI 76 to 88%) from across 9 Canadian provinces provided consent and their full name, date of birth, health insurance number and postal code to facilitate linkage with their administrative data for long-term follow-up. Linkage of clinical trial and administrative data is feasible and acceptable. Further collaborative work including many stakeholders is required to develop an optimized secure approach to research. A more coordinated national approach to health data could facilitate more rapid testing and identification of new effective treatments across multiple jurisdictions and diseases from diabetes to COVID-19.

Application of Value Frameworks to the Design of Clinical Trials: The Canadian Cancer Trials Group Experience.

BACKGROUND: Use of value framework thresholds in the design of clinical trials may increase the proportion of randomized controlled trials that identify clinically meaningful advances for patients. Existing frameworks have not been applied to the research output of a cooperative cancer trials group. We apply value frameworks to the randomized controlled trial output of the Canadian Cancer Trials Group (CCTG). METHODS: Statistical design, study characteristics, and results of all published phase III trials of CCTG were abstracted. We applied the European Society for Medical Oncology-Magnitude of Clinical Benefit Scale (ESMO-MCBS) and American Society of Clinical Oncology Net Health Benefit to study results and the statistical power calculations to identify the proportion of all trials that were designed to detect a substantial clinical benefit. RESULTS: During 1979 to 2017, CCTG published 113 phase III trials; 52.2% (59 of 113) of these trials were positive. One-half (50.4%, 57 of 113) of the trials were conducted in the palliative setting. In 37.2% (42 of 113) of trials, the primary endpoint was overall survival; disease-free survival or progression-free survival was used in 38.9% (44 of 113) of trials. The ESMO-MCBS could be applied to the power calculation for 69 trials; 73.9% (51 of 69) of these trials were designed to detect an effect size that could meet ESMO-MCBS thresholds for substantial benefit. Among the 51 positive trials for which the ESMO-MCBS could be applied, 41.1% (21 of 51) met thresholds for substantial benefit. CONCLUSIONS: Most CCTG phase III trials were designed to detect clinically meaningful differences in outcome, although less than one-half of positive trials met the threshold for substantial benefit. Application of value frameworks to the design of clinical trials is practical and may improve research efficiency and treatment options for patients.

Drug-induced Thrombotic Microangiopathy with Concurrent Proteasome Inhibitor Use in the Treatment of Multiple Myeloma: A Case Series and Review of the Literature.

Thrombotic microangiopathy (TMA) is a life-threatening clinical syndrome characterized by hemolytic anemia, thrombocytopenia, and microvascular thrombosis, resulting in ischemia and organ damage. Multiple myeloma (MM) is a neoplasm arising from clonal plasma cells within the bone marrow. The treatment frequently includes multi-agent immunochemotherapy, often with the use of proteasome inhibitors (PIs) such as bortezomib, carfilzomib, or ixazomib. There are increasing reports of TMA in association with PI exposure. This review summarizes the epidemiology, pathogenesis, and diagnosis of PI-related drug-induced TMA. We will outline the definition and diagnosis of TMA and explore an important cause of hemolysis in patients with MM: drug-induced TMA after PI exposure, an increasingly recognized therapeutic complication. This will be emphasized through the description of 3 novel cases of TMA. These illustrative cases occurred after treatment with high-dose weekly carfilzomib, cyclophosphamide, and dexamethasone as part of the MCRN003/MYX1 phase II clinical trial (NCT02597062) in relapsed MM.

Cardiovascular risk of celecoxib in 6 randomized placebo-controlled trials: the cross trial safety analysis.

BACKGROUND: Observational studies and randomized trials have reported increased cardiovascular risk associated with cyclooxygenase-2 inhibitors. Prior placebo-controlled randomized studies had limited ability to assess the relationship of either celecoxib dose or pretreatment cardiovascular status to risk associated with celecoxib. Our aim was to assess the cardiovascular risk associated with celecoxib in 3 dose regimens and to assess the relationship between baseline cardiovascular risk and effect of celecoxib on cardiovascular events. METHODS AND RESULTS: We performed a patient-level pooled analysis of adjudicated data from 7950 patients in 6 placebo-controlled trials comparing celecoxib with placebo for conditions other than arthritis with a planned follow-up of at least 3 years. Patients were administered celecoxib in 3 dose regimens: 400 mg QD, 200 mg BID, or 400 mg BID. From the pooled data, we calculated a hazard ratio for all dose regimens combined and individual hazard ratios for each dose regimen and examined whether celecoxib-related risk was associated with baseline cardiovascular risk. The primary end point was the combination of cardiovascular death, myocardial infarction, stroke, heart failure, or thromboembolic event. With 16,070 patient-years of follow-up, the hazard ratio for the composite end point combining the tested doses was 1.6 (95% CI, 1.1 to 2.3). The risk, which increased with dose regimen (P=0.0005), was lowest for the 400-mg-QD dose (hazard ratio, 1.1; 95% CI, 0.6 to 2.0), intermediate for the 200-mg-BID dose (hazard ratio, 1.8; 95% CI, 1.1 to 3.1), and highest for the 400-mg-BID dose (hazard ratio, 3.1; 95% CI, 1.5 to 6.1). Patients at highest baseline risk demonstrated disproportionately greater risk of celecoxib-related adverse events (P for interaction=0.034). CONCLUSIONS: We observed evidence of differential cardiovascular risk as a function of celecoxib dose regimen and baseline cardiovascular risk. By further clarifying the extent of celecoxib-related cardiovascular risk, these findings may help guide treatment decisions for patients who derive clinical benefit from selective cyclooxygenase-2 inhibition.

A randomized trial of letrozole in postmenopausal women after five years of tamoxifen therapy for early-stage breast cancer.

BACKGROUND: In hormone-dependent breast cancer, five years of postoperative tamoxifen therapy--but not tamoxifen therapy of longer duration--prolongs disease-free and overall survival. The aromatase inhibitor letrozole, by suppressing estrogen production, might improve the outcome after the discontinuation of tamoxifen therapy. METHODS: We conducted a double-blind, placebo-controlled trial to test the effectiveness of five years of letrozole therapy in postmenopausal women with breast cancer who have completed five years of tamoxifen therapy. The primary end point was disease-free survival. RESULTS: A total of 5187 women were enrolled (median follow-up, 2.4 years). At the first interim analysis, there were 207 local or metastatic recurrences of breast cancer or new primary cancers in the contralateral breast--75 in the letrozole group and 132 in the placebo group--with estimated four-year disease-free survival rates of 93 percent and 87 percent, respectively, in the two groups (P< or =0.001 for the comparison of disease-free survival). A total of 42 women in the placebo group and 31 women in the letrozole group died (P=0.25 for the comparison of overall survival). Low-grade hot flashes, arthritis, arthralgia, and myalgia were more frequent in the letrozole group, but vaginal bleeding was less frequent. There were new diagnoses of osteoporosis in 5.8 percent of the women in the letrozole group and 4.5 percent of the women in the placebo group (P=0.07); the rates of fracture were similar. After the first interim analysis, the independent data and safety monitoring committee recommended termination of the trial and prompt communication of the results to the participants. CONCLUSIONS: As compared with placebo, letrozole therapy after the completion of standard tamoxifen treatment significantly improves disease-free survival.

A phase III randomized, double-blind, placebo-controlled study evaluating dextromethorphan plus slow-release morphine for chronic cancer pain relief in terminally ill patients.

This multicenter trial examined the efficacy and safety of dextromethorphan (DM) as an enhancer of analgesia and modulator of opioid tolerance in cancer patients with pain. Eligible patients were randomized to slow-release morphine plus DM or slow-release morphine plus placebo. The initial DM dose was 60 mg four times daily for seven days, with an increase to 120 mg four times daily, if tolerated, for another seven days. During the study, patients recorded medications and scores for pain, nausea, drowsiness, and insomnia. Sixty-five patients were randomized. Although average pain scores (12.6 vs. 15.8), number of breakthrough doses (9 vs. 11.3), and change in total morphine consumption (550.9 mg vs. 597.1mg) were less in the DM group than placebo group, the differences were not statistically significant (P=0.31-0.33). Side-effect scores were not statistically significantly different. Dizziness was greater in the DM (58%) than placebo (36%) group. This study showed a statistically nonsignificant enhancement of analgesia or modulation of opioid tolerance in cancer patients with pain when DM was added to morphine. Participants receiving the DM also had more toxicity, particularly dizziness. This toxicity and the limited evidence of effect do not support the use of DM to enhance opioid analgesia or to modulate opioid tolerance in cancer patients.

Assessment of quality of life in MA.17: a randomized, placebo-controlled trial of letrozole after 5 years of tamoxifen in postmenopausal women.

PURPOSE: To evaluate the impact of letrozole compared with placebo after adjuvant tamoxifen on quality of life (QOL) in the MA.17 trial. METHODS: Patients completed the Short Form 36-item Health Survey (SF-36) and the Menopause Specific Quality of Life Questionnaire (MENQOL) at baseline, 6 months, and annually. Mean change scores from baseline were compared between groups for summary measures and domains. A response analysis compared the proportion of patients who demonstrated an important change in QOL. RESULTS: Of 5,187 randomly assigned women in the trial, 3,612 (69.9%) participated in the QOL substudy: 1,799 were allocated to placebo and 1,813 were allocated to letrozole. No differences were seen between groups in mean change scores from baseline for the SF-36 physical and mental component summary scores at 6, 12, 24, and 36 months. Small (< 0.2 standard deviations) but statistically significant differences in mean change scores from baseline were seen for the SF-36 domains of physical functioning (12 months), bodily pain (6 months) and vitality (6 and 12 months), and the MENQOL vasomotor (6, 12, and 24 months) and sexual domains (12 and 24 months). On the response analysis, a significant difference was seen between groups for the bodily pain domain (percentage of patients reporting a worsening of QOL, 47% placebo v 51% letrozole; P = .009) and the vasomotor domain (22% placebo v 29% letrozole; P = .001). CONCLUSION: Letrozole did not have an adverse impact on overall QOL. Small effects were seen in some domains consistent with a minority of patients experiencing changes in QOL compatible with a reduction in estrogen synthesis.

Enrollment of older patients in cancer treatment trials in Canada: why is age a barrier?

PURPOSE: To evaluate the enrollment of older patients (>/= 65 years) in Canadian cancer treatment trials and compare accrual of older patients in Canada and the United States. PATIENTS AND METHODS: A retrospective analysis of the number of older patients enrolled in National Cancer Institute of Canada Clinical Trials Group (NCIC CTG) treatment trials between 1993 and 1996 was performed. These rates were compared with the corresponding rates in the general population of patients who were >/= 65 years old and had cancer, obtained from Statistics Canada, and those published by the Southwest Oncology Group (SWOG) in the United States. RESULTS: Between 1993 and 1996, 4,174 patients were enrolled onto 69 NCIC CTG trials of 16 tumor types. Older patients accounted for 22% of trial enrollees, compared with 58% of the Canadian population with cancer. This discrepancy existed in all cancer types except for multiple myeloma. The percentages of older patients enrolled were also analyzed by study type: 15% in adjuvant trials, 25% in metastatic trials, 29% in investigational new drug trials, 24% in phase I trials, and 21% in supportive care trials. The overall proportion of older patients enrolled onto Canadian trials (22%) was slightly lower than that in SWOG trials (25%). CONCLUSION: Age remains a barrier for accrual onto cancer treatment trials, even when reimbursement is not an issue. Strategies to overcome this barrier, including the implementation of trials specifically tailored to patients aged >/= 65 years, are prudent in light of our aging population.

Clinical predictive value of the in vitro cell line, human xenograft, and mouse allograft preclinical cancer models.

PURPOSE: We looked at the value of three preclinical cancer models, the in vitro human cell line, the human xenograft, and the murine allograft, to examine whether they are reliable in predicting clinical utility. EXPERIMENTAL DESIGN: Thirty-one cytotoxic cancer drugs were selected. Literature was searched for drug activity in Phase II trials, human xenograft, and mouse allografts in breast, non-small cell lung, ovary, and colon cancers. Data from the National Cancer Institute Human Tumor Cell Line Screen were used to calculate drug in vitro preclinical activity for each cancer type. Phase II activity versus preclinical activity scatter plot and correlation analysis was conducted for each model, by tumor type (disease-oriented approach), using one tumor type as a predictor of overall activity in the other three tumor types combined (compound-oriented approach) and for all four tumor types together. RESULTS: The in vitro cell line model was predictive for non-small cell lung cancer under the disease-oriented approach, for breast and ovarian cancers under the compound-oriented approach, and for all four tumor types together. The mouse allograft model was not predictive. The human xenograft model was not predictive for breast or colon cancers, but was predictive for non-small cell lung and ovarian cancers when panels of xenografts were used. CONCLUSIONS: These results suggest that under the right framework and when panels are used, the in vitro cell line and human xenograft models may be useful in predicting the Phase II clinical trial performance of cancer drugs. Murine allograft models, as used in this analysis, appear of limited utility.

Correlation of single arm versus randomised phase 2 oncology trial characteristics with phase 3 outcome.

BACKGROUND AND AIM: The primary aim of this study was to determine whether randomised phase 2 (RP2) trials predict phase 3 trial outcome better than single arm phase 2 (SAP2) studies. Although theoretical superiority of RP2 trials has been postulated, no empiric studies have been conducted. METHODS: Published phase 3 trials testing systemic cancer therapy were identified through a Medline search. Those of superiority design, which cited phase 2 trials supporting the experimental arm, were included. Trial design and outcome details were extracted. Statistical analysis was performed using the Generalized Estimating Equation method correlating phase 2 features with phase 3 outcome, accounting for any phase 3 duplication. RESULTS: Of 189 eligible phase 3 trials, 18.5% were in haematological malignancies and 81.5% in solid tumors. The primary outcome was positive in 79 (41.8%). These were supported by 336 phase 2 trials (range 1-9 per phase 3 trial) including 66 RP2 trials. Positive phase 2 outcome, randomised or not, correlated with positive phase 3 outcome (p=0.03). RP2 studies were not superior to SAP2 studies at predicting phase 3 study success. Phase 2 trial features not predictive of phase 3 outcome included primary endpoint, sponsorship, sample size, similarity in patient population and therapy. CONCLUSIONS: RP2 studies were not superior to SAP2 trials at predicting phase 3 study success. Further research into phase 2 trial design is required given the added resources required to conduct RP2 studies and the lack of empiric evidence supporting superiority over single arm studies.

Randomized phase III trial of single versus fractionated thoracic radiation in the palliation of patients with lung cancer (NCIC CTG SC.15).

PURPOSE: This multi-institutional Phase III randomized study compared 10 Gy single-fraction radiotherapy (RT) with 20 Gy in five fractions in the palliation of thoracic symptoms from lung cancer. METHODS AND MATERIALS: The primary end point was palliation of thoracic symptoms at 1 month after RT, evaluated by a patient-completed daily diary card. Secondary end points included quality of life, toxicity, and survival. RESULTS: Most (69%) of 230 patients randomized had locally advanced disease unsuitable for curative treatment. The treatment arms were well balanced with respect to the known prognostic factors. At 1 month after RT, no difference was found in symptom control between the two arms, as judged by the daily diary scores. The changes in the scores on the Lung Cancer Symptom Scale indicated that the fractionated RT (five fractions) group had greater improvement in symptoms related to lung cancer (p = 0.009), pain (p = 0.0008), ability to carry out normal activities (p = 0.037), and better global quality of life (p = 0.039). The European Organization for Research and Treatment of Cancer QLQ-C30 scores showed that patients receiving five fractions had a greater improvement in scores with respect to pain (p = 0.04). No significant difference was found in treatment-related toxicity. Patients who received five fractions survived on average 2 months longer (p = 0.0305) than patients who received one fraction. CONCLUSION: Although the two treatment strategies provided a similar degree of palliation of thoracic symptoms, the difference in survival between the two study arms was of a clinically relevant magnitude.

Quality of life in MAP.3 (Mammary Prevention 3): a randomized, placebo-controlled trial evaluating exemestane for prevention of breast cancer.

PURPOSE: Exemestane, a steroidal aromatase inhibitor, reduced invasive breast cancer incidence by 65% among 4,560 postmenopausal women randomly assigned to exemestane (25 mg per day) compared with placebo in the National Cancer Institute of Canada (NCIC) Clinical Trials Group MAP.3 (Mammary Prevention 3) trial, but effects on quality of life (QOL) were not fully described. PATIENTS AND METHODS: Menopause-specific and health-related QOL were assessed by using the four Menopause-Specific Quality of Life Questionnaire (MENQOL) domains and the eight Medical Outcomes Study Short Form Health Survey (SF-36) scales at baseline, 6 months, and yearly thereafter. MENQOL questionnaire completion was high (88% to 98%) in both groups at each follow-up visit. Change scores for each MENQOL and SF-36 scale, calculated at each assessment time relative to baseline, were compared by using the Wilcoxon rank-sum test. Clinically important worsened QOL was defined as a MENQOL change score increase of more than 0.5 (of 8) points and an SF-36 change score decrease of more than 5 (of 100) points from baseline. RESULTS: Exemestane had small negative effects on women's self-reported vasomotor symptoms, sexual symptoms, and pain, which occurred mainly in the first 6 months to 2 years after random assignment. However, these changes represented only a small excess number of women being given exemestane with clinically important worsening of QOL at one time or another; specifically, 8% more in the vasomotor domain and 4% more each in the sexual domain and for pain. No other between-group differences were observed. Overall, slightly more women in the exemestane arm (32%) than in the placebo arm (28%) discontinued assigned treatment. CONCLUSION: Exemestane given for prevention has limited negative impact on menopause-specific and health-related QOL in healthy postmenopausal women at risk for breast cancer.

Efficacy, toxicity, and quality of life in older women with early-stage breast cancer treated with letrozole or placebo after 5 years of tamoxifen: NCIC CTG intergroup trial MA.17.

PURPOSE: National Cancer Institute of Canada Clinical Trials Group trial MA.17 randomly assigned 5,187 postmenopausal, hormone-receptor-positive patients with early breast cancer who completed 5 years of tamoxifen to receive either letrozole or placebo. At 30 months median follow-up, letrozole significantly improved disease-free survival (DFS) in all patients and overall survival (OS) in node-positive patients. Breast cancer incidence increases with age and more than 1,300 women age 70 years or older were enrolled onto MA.17, making it ideal to explore the benefits, toxicities, and quality of life (QOL) impact of letrozole on older women. PATIENTS AND METHODS: In this study, 5,169 randomly assigned patients were divided into three age groups: younger than 60 years (n = 2,152), 60 to 69 years (n = 1,694), and >or= 70 years (n = 1,323). Log-rank test was used to compare differences in DFS, distant-disease-free survival, and OS between age and treatment groups, and Cox models were used to estimate hazard ratios and associated 95% CIs. QOL was measured using the Medical Outcomes Short Form-36 and the Menopause-Specific Quality-of-Life questionnaire. RESULTS: At 4 years, DFS demonstrated statistically significant differences favoring letrozole only in patients age younger than 60 years (hazard ratio = 0.46; P = .0004); there was no interaction between age and treatment, indicating a similar effect of letrozole among all age groups. There was no difference in toxicity or QOL at 24 months among letrozole- and placebo-treated patients age >or= 70 years. CONCLUSION: Healthy patients age 70 years and older completing 5 years of tamoxifen should be considered for extended adjuvant therapy with letrozole.

Late extended adjuvant treatment with letrozole improves outcome in women with early-stage breast cancer who complete 5 years of tamoxifen.

PURPOSE: The National Cancer Institute of Canada Clinical Trials Group MA.17 trial examined the efficacy of letrozole (LET) started within 3 months of 5 years of adjuvant tamoxifen in postmenopausal hormone receptor-positive early-stage breast cancer. When the trial was unblinded, patients who received placebo (PLAC) were offered LET. PATIENTS AND METHODS: This cohort analysis describes the outcomes of women assigned PLAC at the initial random assignment after unblinding. Efficacy outcomes of women who chose LET (PLAC-LET group) were compared with those who did not (PLAC-PLAC group) by the hazard ratios and by P values calculated from Cox models that adjusted for imbalances between the groups. Toxicity analyses included only events that occurred after unblinding. RESULTS: There were 1,579 women in the PLAC-LET group (median time from tamoxifen, 2.8 years) and 804 in the PLAC-PLAC group. Patients in the PLAC-LET group were younger; had a better performance status; and were more likely to have had node-positive disease, axillary dissection, and adjuvant chemotherapy than those in the PLAC-PLAC group. At a median follow-up of 5.3 years, disease-free survival (DFS; adjusted hazard ratio [HR], 0.37; 95% CI, 0.23 to 0.61; P < .0001) and distant DFS (HR, 0.39; 95% CI, 0.20 to 0.74; P = .004) were superior in the PLAC-LET group. More self-reported new diagnoses of osteoporosis and significantly more clinical fractures occurred in the women who took LET (5.2% v 3.1%, P = .02). CONCLUSION: Interpretation of this cohort analysis suggests that LET improves DFS and distant DFS even when there has been a substantial period of time since the discontinuation of prior adjuvant tamoxifen.

Efficacy of letrozole extended adjuvant therapy according to estrogen receptor and progesterone receptor status of the primary tumor: National Cancer Institute of Canada Clinical Trials Group MA.17.

PURPOSE: Controversy exists regarding estrogen (ER) and progesterone (PgR) receptor expression on efficacy of adjuvant endocrine therapy. In the ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial, the benefit of anastrozole over tamoxifen was substantially greater in ER+/PgR-than ER+/PgR+ tumors. In BIG 1-98 (Breast International Group), the benefits of letrozole over tamoxifen were the same in ER+ tumors irrespective of PgR. MA.17 randomized postmenopausal women after 5 years of tamoxifen, to letrozole or placebo. We present outcomes according to tumor receptor status. PATIENTS AND METHODS: Disease-free survival (DFS) and other outcomes were assessed in subgroups by ER and PgR status using Cox's proportional hazards model, adjusting for nodal status and prior adjuvant chemotherapy. RESULTS: The DFS hazard ratio (HR) for letrozole versus placebo in ER+/PgR+ tumors (N = 3,809) was 0.49 (95% CI, 0.36 to 0.67) versus 1.21 (95% CI, 0.63 to 2.34) in ER+/PgR-tumors (n = 636). ER+/PgR+ letrozole patients experienced significant benefit in distant DFS (DDFS; HR = 0.53; 95% CI, 0.35 to 0.80) and overall survival (OS; HR = 0.58; 95% CI, 0.37 to 0.90). A statistically significant difference in treatment effect between ER+/PgR+ and ER+/PgR-subgroups for DFS was observed (P = .02), but not for DDFS (P = .06) or OS (P = .09). CONCLUSION: These results suggest greater benefit for letrozole in DFS, DDFS, and OS in patients with ER+/PgR+ tumors, implying greater activity of letrozole in tumors with a functional ER. However, because this is a subset analysis and receptors were not measured centrally, we caution against using these results for clinical decision making.