Assessment of Residual Cancer Burden and Event-Free Survival in Neoadjuvant Treatment for High-risk Breast Cancer: An Analysis of Data From the I-SPY2 Randomized Clinical Trial.

IMPORTANCE: Residual cancer burden (RCB) distributions may improve the interpretation of efficacy in neoadjuvant breast cancer trials. OBJECTIVE: To compare RCB distributions between randomized control and investigational treatments within subtypes of breast cancer and explore the relationship with survival. DESIGN, SETTING, AND PARTICIPANTS: The I-SPY2 is a multicenter, platform adaptive, randomized clinical trial in the US that compares, by subtype, investigational agents in combination with chemotherapy vs chemotherapy alone in adult women with stage 2/3 breast cancer at high risk of early recurrence. Investigational treatments graduated in a prespecified subtype if there was 85% or greater predicted probability of higher rate of pathologic complete response (pCR) in a confirmatory, 300-patient, 1:1 randomized, neoadjuvant trial in that subtype. Evaluation of a secondary end point was reported from the 10 investigational agents tested in the I-SPY2 trial from March 200 through 2016, and analyzed as of September 9, 2020. The analysis plan included modeling of RCB within subtypes defined by hormone receptor (HR) and ERBB2 status and compared control treatments with investigational treatments that graduated and those that did not graduate. INTERVENTIONS: Neoadjuvant paclitaxel plus/minus 1 of several investigational agents for 12 weeks, then 12 weeks of cyclophosphamide/doxorubicin chemotherapy followed by surgery. MAIN OUTCOMES AND MEASURES: Residual cancer burden (pathological measure of residual disease) and event-free survival (EFS). RESULTS: A total of 938 women (mean [SD] age, 49 [11] years; 66 [7%] Asian, 103 [11%] Black, and 750 [80%] White individuals) from the first 10 investigational agents were included, with a median follow-up of 52 months (IQR, 29 months). Event-free survival worsened significantly per unit of RCB in every subtype of breast cancer (HR-positive/ERBB2-negative: hazard ratio [HZR], 1.75; 95% CI, 1.45-2.16; HR-positive/ERBB2-positive: HZR, 1.55; 95% CI, 1.18-2.05; HR-negative/ERBB2-positive: HZR, 2.39; 95% CI, 1.64-3.49; HR-negative/ERBB2-negative: HZR, 1.99; 95% CI, 1.71-2.31). Prognostic information from RCB was similar from treatments that graduated (HZR, 2.00; 95% CI, 1.57-2.55; 254 [27%]), did not graduate (HZR, 1.87; 95% CI, 1.61-2.17; 486 [52%]), or were control (HZR, 1.79; 95% CI, 1.42-2.26; 198 [21%]). Investigational treatments significantly lowered RCB in HR-negative/ERBB2-negative (graduated and nongraduated treatments) and ERBB2-positive subtypes (graduated treatments), with improved EFS (HZR, 0.61; 95% CI, 0.41-0.93) in the exploratory analysis. CONCLUSIONS AND RELEVANCE: In this randomized clinical trial, the prognostic significance of RCB was consistent regardless of subtype and treatment. Effective neoadjuvant treatments shifted the distribution of RCB in addition to increasing pCR rate and appeared to improve EFS. Using a standardized quantitative method to measure response advances the interpretation of efficacy. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01042379.

Association Between Breast Cancer Recurrence and Immunosuppression in Rheumatoid Arthritis and Inflammatory Bowel Disease: A Cohort Study.

OBJECTIVE: Breast cancer recurrence may be promoted by immunosuppression due to decreased immune surveillance. The aim of this study was to examine the rates of breast cancer recurrence in patients with immune-mediated disease and treated breast cancer who received therapy with methotrexate, thiopurines, or anti-tumor necrosis factor (anti-TNF). METHODS: Three retrospective cohort studies within Medicare (2000-2012) included women with rheumatoid arthritis (RA) or inflammatory bowel disease (IBD) who underwent surgery for primary breast cancer. Recurrent or second primary breast cancers occurring more than 365 days after the initial surgery were identified. Separate Cox regression models were used to examine the risk of cancer recurrence in patients treated with methotrexate, thiopurines, or anti-TNF agents after surgery, each compared with no use. Analyses were matched for type of breast surgery and receipt and type of adjuvant therapy. RESULTS: Across all medication groups, 107 women experienced breast cancer recurrence during 5,196 person-years. The incidence rates were 20.3 and 19.6 per 1,000 person-years in methotrexate users and nonusers, respectively, 32.3 and 17.6 in thiopurine users and nonusers, respectively, and 22.3 and 19.5 in anti-TNF users and nonusers, respectively. There was no significantly increased risk of breast cancer recurrence with use of methotrexate (adjusted hazard ratio [HR] 1.07, 95% confidence interval [95% CI] 0.67-1.69), anti-TNF therapy (HR 1.13, 95% CI 0.65-1.97), or thiopurines (HR 2.10, 95% CI 0.62-7.14). CONCLUSION: The risk of breast cancer recurrence in patients who received methotrexate, thiopurine, or anti-TNF therapy was not statistically significantly increased, although we cannot rule out a 2-fold or greater increased risk in those treated with thiopurines. These data provide reassurance to clinicians choosing to start methotrexate or anti-TNF therapy in RA or IBD patients with treated breast cancer.

CDK 4/6 inhibitor palbociclib (PD0332991) in Rb+ advanced breast cancer: phase II activity, safety, and predictive biomarker assessment.

PURPOSE: The G1-S checkpoint of the cell cycle is frequently dysregulated in breast cancer. Palbociclib (PD0332991) is an oral inhibitor of CDK4/6. Based upon preclinical/phase I activity, we performed a phase II, single-arm trial of palbociclib in advanced breast cancer. EXPERIMENTAL DESIGN: Eligible patients had histologically confirmed, metastatic breast cancer positive for retinoblastoma (Rb) protein and measureable disease. Palbociclib was given at 125 mg orally on days 1 to 21 of a 28-day cycle. Primary objectives were tumor response and tolerability. Secondary objectives included progression-free survival (PFS) and assessment of Rb expression/localization, KI-67, p16 loss, and CCND1 amplification. RESULTS: Thirty-seven patients were enrolled; 84% hormone-receptor (HR)(+)/Her2(-), 5% HR(+)/Her2(+), and 11% HR(-)/Her2(-), with a median of 2 prior cytotoxic regimens. Two patients had partial response (PR) and 5 had stable disease ≥ 6 months for a clinical benefit rate (CBR = PR + 6moSD) of 19% overall, 21% in HR(+), and 29% in HR(+)/Her2(-) who had progressed through ≥2 prior lines of hormonal therapy. Median PFS overall was 3.7 months [95% confidence interval (CI), 1.9-5.1], but significantly longer for those with HR(+) versus HR(-) disease (P = 0.03) and those who had previously progressed through endocrine therapy for advanced disease (P = 0.02). Grade 3/4 toxicities included neutropenia (51%), anemia (5%), and thrombocytopenia (22%). Twenty-four percent had treatment interruption and 51% had dose reduction, all for cytopenias. No biomarker identified a sensitive tumor population. CONCLUSIONS: Single-agent palbociclib is well tolerated and active in patients with endocrine-resistant, HR(+), Rb-positive breast cancer. Cytopenias were uncomplicated and easily managed with dose reduction.

Racial disparities in colon cancer survival: a matched cohort study.

BACKGROUND: Differences in colon cancer survival by race are a recognized problem among Medicare beneficiaries. OBJECTIVE: To determine to what extent the racial disparity in survival is due to disparity in presentation characteristics at diagnosis or disparity in subsequent treatment. DESIGN: Black patients with colon cancer were matched with 3 groups of white patients: a "demographic characteristics" match controlling for age, sex, diagnosis year, and Survey, Epidemiology, and End Results (SEER) site; a "presentation" match controlling for demographic characteristics plus comorbid conditions and tumor characteristics, including stage and grade; and a "treatment" match, including presentation variables plus details of surgery, radiation, and chemotherapy. SETTING: 16 U.S. SEER sites. PATIENTS: 7677 black patients aged 65 years or older diagnosed between 1991 and 2005 in the SEER-Medicare database and 3 sets of 7677 matched white patients, followed until 31 December 2009. MEASUREMENTS: 5-year survival. RESULTS: The absolute difference in 5-year survival between black and white patients was 9.9% (95% CI, 8.3% to 11.4%; P<0.001) in the demographic characteristics match. This disparity remained unchanged between 1991 and 2005. After matching for presentation characteristics, the difference decreased to 4.9% (CI, 3.6% to 6.1%; P<0.001). After additional matching for treatment, this difference decreased to 4.3% (CI, 2.9% to 5.5%; P<0.001). The disparity in survival attributed to treatment differences made up only an absolute 0.6% of the overall 9.9% survival disparity. LIMITATION: An observational study limited to elderly Medicare fee-for-service beneficiaries living in selected geographic areas. CONCLUSION: Racial disparities in colon cancer survival did not decrease among patients diagnosed between 1991 and 2005. This persistent disparity seemed to be more related to presentation characteristics at diagnosis than to subsequent treatment differences. PRIMARY FUNDING SOURCE: Agency for Healthcare Research and Quality and National Science Foundation.

Characteristics associated with differences in survival among black and white women with breast cancer.

IMPORTANCE: Difference in breast cancer survival by race is a recognized problem among Medicare beneficiaries. OBJECTIVE: To determine if racial disparity in breast cancer survival is primarily attributable to differences in presentation characteristics at diagnosis or subsequent treatment. DESIGN, SETTING, AND PATIENTS: Comparison of 7375 black women 65 years and older diagnosed between 1991 to 2005 and 3 sets of 7375 matched white control patients selected from 99,898 white potential controls, using data for 16 US Surveillance, Epidemiology and End Results (SEER) sites in the SEER-Medicare database. All patients received follow-up through December 31, 2009, and the black case patients were matched to 3 white control populations on demographics (age, year of diagnosis, and SEER site), presentation (demographics variables plus patient comorbid conditions and tumor characteristics such as stage, size, grade, and estrogen receptor status), and treatment (presentation variables plus details of surgery, radiation therapy, and chemotherapy). MAIN OUTCOMES AND MEASURES: 5-Year survival. RESULTS: The absolute difference in 5-year survival (blacks, 55.9%; whites, 68.8%) was 12.9% (95% CI, 11.5%-14.5%; P < .001) in the demographics match. This difference remained unchanged between 1991 and 2005. After matching on presentation characteristics, the absolute difference in 5-year survival was 4.4% (95% CI, 2.8%-5.8%; P < .001) and was 3.6% (95% CI, 2.3%-4.9%; P < .001) lower for blacks than for whites matched also on treatment. In the presentation match, fewer blacks received treatment (87.4% vs 91.8%; P < .001), time from diagnosis to treatment was longer (29.2 vs 22.8 days; P < .001), use of anthracyclines and taxols was lower (3.7% vs 5.0%; P < .001), and breast-conserving surgery without other treatment was more frequent (8.2% vs 7.3%; P = .04). Nevertheless, differences in survival associated with treatment differences accounted for only 0.81% of the 12.9% survival difference. CONCLUSIONS AND RELEVANCE: In the SEER-Medicare database, differences in breast cancer survival between black and white women did not substantially change among women diagnosed between 1991 and 2005. These differences in survival appear primarily related to presentation characteristics at diagnosis rather than treatment differences.