Investigating potential disparities in clinical trial eligibility and enrollment at an NCI-designated comprehensive cancer center.

BACKGROUND: Although barriers to trial accrual are well-reported, few studies have explored trial eligibility and trial offers as potential drivers of disparities in cancer clinical trial enrollment. METHODS: We identified patients with gastrointestinal (GI) or head/neck (HN) malignancies who were seen as new patients at the University of Michigan Health Rogel Cancer Center in 2016. By exhaustive review of the electronic medical record, we assessed the primary outcomes: (1) eligibility for, (2) documented offer of, and (3) enrollment in a clinical trial. All 41 of the clinical trials available to these patients were considered. Independent variables included clinical and non-clinical patient-related factors. We assessed associations between these variables and the primary outcomes using multivariable regression. RESULTS: Of 1446 patients, 43% were female, 15% were over age 75, 6% were Black. 305 (21%) patients were eligible for a clinical trial. Among eligible patients, 154 (50%) had documentation of a trial offer and 90 (30%) enrolled. Among the GI cohort, bivariate analyses demonstrated that older age was associated with decreased trial eligibility. Bivariate analyses also demonstrated that Black race was associated with increased trial offer. After adjustment, patients 75 or older were less likely to be eligible for a clinical trial in the GI cohort; however, we found no significant associations between race and any of the outcomes after adjustment. Among eligible GI patients, we found no significant associations between non-clinical factors and enrollment. Among the HN cohort, bivariate analyses demonstrated that female sex, older age, Black race, and unpartnered marital status were associated with decreased likelihood of trial offer; however, we found no significant associations between race, age, and marital status and any of the outcomes after adjustment. We found no significant associations between non-clinical factors and eligibility after adjustment; however, women were less likely to be offered and to enroll in a clinical trial in the HN cohort. CONCLUSION: Factors associated with eligibility, documented offer, and enrollment differed between disease site cohorts at our institution. Future work is needed to ensure the equitable inclusion of women and elderly patients in clinical trials.

Heterogeneous estrogen receptor expression in circulating tumor cells suggests diverse mechanisms of fulvestrant resistance.

Fulvestrant is a dose dependent selective estrogen receptor (ER) down-regulator (SERD) used in ER-positive metastatic breast cancer (MBC). Nearly all patients develop resistance. We performed molecular analysis of circulating tumor cells (CTC) to gain insight into fulvestrant resistance. Preclinical studies were performed with cultured breast cancer cells spiked into human blood and analyzed on the CellSearch(®) system. Clinical data are limited to a subset of patients with ER-positive MBC from a previously reported pilot trial whose disease was progressing on fulvestrant (N = 7) or aromatase inhibitors (AIs) (N = 10). CTCs were enumerated and phenotyped for ER and B-cell lymphoma (BCL2) using the CellSearch(®) CXC kit. In preclinical modeling, tamoxifen and AIs resulted in stabilized ER expression, whereas fulvestrant eliminated it. Five of seven patients progressing on fulvestrant had ≥5CTC/7.5 ml WB. Two of these five, treated with 500 mg/month fulvestrant, had no detectable CTC-expression of ER and BCL2 (an ER regulated gene). Three patients had heterogeneous CTC-ER and BCL2 expression indicating incomplete degradation of the ER target by fulvestrant. Two of these patients received 250 mg/month whereas the third patient received 500 mg/month fulvestrant. Her cancer harbored a mutation (Y537S) in the estrogen receptor alpha gene (ESR1). All seven ER positive patients progressing on AIs had heterogeneous CTC-ER expression. These results suggest heterogeneous mechanisms of resistance to fulvestrant, including insufficient dosage, ESR1 mutation, or conversion to dependence on non-ER pathways. CTC enumeration, phenotyping, and genotyping might identify patients who would benefit from fulvestrant dose escalation versus switching to alternative therapies.

Predictors and temporal trends of adjuvant aromatase inhibitor use in breast cancer.

After the first report of the ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial, adjuvant aromatase inhibitor use increased rapidly among National Comprehensive Cancer Network member institutions. Increased aromatase inhibitor use was associated with older age, vascular disease, overexpression of human epidermal growth factor receptor 2 (HER2), or more advanced stage, and substantial variation was seen among institutions. This article examines adjuvant endocrine therapy in postmenopausal women after the first report of the trial, identifies temporal relationships in aromatase inhibitor use, and examines characteristics associated with choice of endocrine therapy among 4044 postmenopausal patients with hormone receptor-positive nonmetastatic breast cancer presenting from July 1997 to December 2004. Multivariable logistic regression analysis examined temporal associations and characteristics associated with aromatase inhibitor use. Time-trend analysis showed increased aromatase inhibitor and decreased tamoxifen use after release of ATAC results (P < .0001). In multivariable regression analysis, institution (P <. 0001), vascular disease (P <. 0001), age (P = .0002), stage (P = .0002), and HER2 status (P = .0009) independently predicted aromatase inhibitor use. Institutional rates of use ranged from 15% to 66%. Adjuvant aromatase inhibitor use increased after the first report of ATAC, with this increase associated with older age, vascular disease, overexpression of HER2, or more advanced stage. Substantial variation was seen among institutions.

Comprehensive axillary evaluation in neoadjuvant chemotherapy patients with ultrasonography and sentinel lymph node biopsy.

BACKGROUND: There is ongoing debate regarding the optimal sequence of sentinel lymph node (SLN) biopsy and neoadjuvant chemotherapy (CTX) for breast cancer. We report the accuracy of comprehensive pre-neoadjuvant CTX and post-neoadjuvant CTX axillary staging via ultrasound imaging, fine-needle aspiration (FNA) biopsy, and SLN biopsy. METHODS: From 2001 to 2004, 91 neoadjuvant CTX patients at the University of Michigan Comprehensive Cancer Center underwent axillary staging by ultrasonography, ultrasound-guided FNA biopsy, SLN biopsy, or a combination of these. RESULTS: Axillary staging was pathologically negative by pre-neoadjuvant CTX SLN biopsy in 53 cases (58%); these patients had no further axillary surgery. In 38 cases (42%), axillary metastases were confirmed at presentation by either ultrasound-guided FNA or SLN biopsy. These 38 patients underwent completion axillary lymph node dissection (ALND) after delivery of neoadjuvant CTX. Follow-up lymphatic mapping was attempted in 33 of these cases, and the SLN was identified in 32 (identification rate, 97%). One third of these cases were completely node negative on ALND. Residual metastatic disease was identified in 22 cases, and the SLN was falsely negative in 1 (4.5%). CONCLUSIONS: Patients receiving neoadjuvant CTX can have accurate axillary nodal staging by ultrasound-guided FNA or SLN biopsy. In cases of documented axillary metastasis at presentation, repeat axillary staging with SLN biopsy can document the post-neoadjuvant CTX nodal status. This strategy optimizes pre-neoadjuvant CTX and post-neoadjuvant CTX staging information by distinguishing the patients who are node negative at presentation from those who have been downstaged to node negativity and offers the potential for avoiding unnecessary ALNDs in both of these patient subsets.