Evaluation of the international Ki67 working group cut point recommendations for early breast cancer: comparison with 21-gene assay results in a large integrated health care system.

PURPOSE: The International Ki67 Working Group (IKWG) has developed training for immunohistochemistry (IHC) scoring reproducibility and recommends cut points of ≤ 5% and ≥ 30% for prognosis in ER+, HER2-, stage I/II breast cancer. We examined scoring reproducibility following IKWG training and evaluated these cut points for selecting patients for further testing with the 21-gene Recurrence Score (RS) assay. METHODS: We included 307 women aged 50+ years with node-negative, ER+PR+HER2- breast cancer and with available RS results. Slides from the diagnostic biopsy were stained for Ki67 and scored using digital image analysis (IA). Two IHC pathologists underwent IKWG training and visually scored slides, blinded to each other and IA readings. Interobserver reproducibility was examined using intraclass correlation (ICC) and Kappa statistics. RESULTS: Depending on reader, 8.8-16.0% of our cohort had Ki67 ≤ 5% and 11.4-22.5% had scores ≥ 30%. The ICC for Ki67 scores by the two pathologists was 0.82 (95% CI 0.78-0.85); it was 0.79 (95% CI 0.74-0.83) for pathologist 1 and IA and 0.76 (95% CI 0.71-0.80) for pathologist 2 and IA. For Ki67 scores ≤ 5%, the percentages with RS < 26 were 92.6%, 91.8%, and 90.9% for pathologist 1, pathologist 2, and IA, respectively. For Ki67 scores ≥ 30%, the percentages with RS ≥ 26 were 41.5%, 51.4%, and 27.5%, respectively. CONCLUSION: The IKWG's Ki67 training resulted in moderate to strong reproducibility across readers but cut points had only moderate overlap with RS cut points, especially for Ki67 ≥ 30% and RS ≥ 26; thus, their clinical utility for a 21-gene assay testing pathway remains unclear.

Germline Genetic Testing Among Women ≤ 45 Years of Age with Ductal Carcinoma In Situ Versus Invasive Breast Cancer in a Large Integrated Health Care System.

BACKGROUND: We compared the results of hereditary cancer multigene panel testing among patients ≤ 45 years of age diagnosed with ductal carcinoma in situ (DCIS) versus invasive breast cancer (IBC) in a large integrated health care system. METHODS: A retrospective cohort study of hereditary cancer gene testing among women ≤ 45 years of age diagnosed with DCIS or IBC at Kaiser Permanente Northern California between September 2019 and August 2020 was performed. During the study period, institutional guidelines recommended the above population be referred to genetic counselors for pretesting counseling and testing. RESULTS: A total of 61 DCIS and 485 IBC patients were identified. Genetic counselors met with 95% of both groups, and 86.4% of DCIS patients and 93.9% of IBC patients (p = 0.0339) underwent gene testing. Testing differed by race/ethnicity (p = 0.0372). Among those tested, 11.76% (n = 6) of DCIS patients and 16.71% (n = 72) of IBC patients had a pathogenic variant (PV) or likely pathogenic variant (LPV) based on the 36-gene panel (p = 0.3650). Similar trends were seen in 13 breast cancer (BC)-related genes (p = 0.0553). Family history of cancer was significantly associated with both BC-related and non-BC-related PVs in IBC, but not DCIS. CONCLUSION: In our study, 95% of patients were seen by a genetic counselor when age was used as an eligibility criterion for referral. While larger studies are needed to further compare the prevalence of PVs/LPVs among DCIS and IBC patients, our data suggest that even in younger patients, the prevalence of PVs/LPVs in BC-related genes is lower in DCIS patients.

Evaluation of approaches to recruitment of racially and ethnically diverse breast cancer patients from an integrated health care setting for collection of observational social network data.

PURPOSE: We compared approaches to recruitment of diverse women with breast cancer in a study designed to collect complex social network data. METHODS: We recruited 440 women from the Kaiser Permanente Northern California population newly diagnosed with breast cancer, either in person at a clinic, by email, or by mailed letter. In clinic and mail recruitment, women completed a brief 3-page paper survey (epidemiologic data only), and women had the option to complete a separate, longer (30-40 min) personal social network survey online. In email recruitment, we administered epidemiologic and personal social network measures together in a single online survey. In email and mail recruitment, we limited the sample of non-Hispanic white (NHW) women to 30% of their total. We used descriptive analysis and multinomial logistic regression to examine odds of recruitment vs. mailed letter. RESULTS: Women responded to the social network surveys on average 3.7 months post-diagnosis. Mean age was 59.3 (median = 61.0). In-person clinic recruitment was superior with a 52.1% success rate of recruitment compared with 35.6% by mail or 17.3% by email (χ2 = 65.9, p < 0.001). Email recruitment produced the highest completion rate (82.1%) of personal network data compared with clinic (36.5%) or mail (28.7%), (χ2 = 114.6, p < 0.001). Despite intentional undersampling of NHW patients, response rates for Asian, Hispanic, and Black women by email were lower. However, we found no significant differences in recruitment rates by race and ethnicity for face-to-face clinic recruitment vs. by letter. Letter recruitment produced the highest overall response. CONCLUSION: Mailed letter was the best approach to representative recruitment of diverse women with breast cancer and collection of social network data, and further yielded the highest absolute response.

Intraoperative Radiation Therapy: A Large Integrated Health Care System's Approach and Outcomes.

Introduction Intraoperative radiation therapy (IORT) may not be as effective in the community compared with clinical trials. Methods The authors reviewed data from the electronic health records of patients who received IORT between February 2014 and February 2020 at a single center within a large integrated health care system. The primary outcome was ipsilateral breast tumor recurrence. Results Of 5731 potentially eligible patients, 245 (4.3%) underwent IORT (mean age: 65.4 ± 0.4 years; median follow-up time: 3.5 years ± 2.2 months). According to the American Society for Radiation Oncology's accelerated partial breast irradiation guidelines based on final pathology, 51% of patients were suitable candidates for IORT, 38.4% were cautionary, and 10.6% were unsuitable. For adjuvant therapy, 6.5% had consolidative whole breast irradiation, and 66.4% received endocrine treatment. At the median follow-up time of 3.5 years, overall ipsilateral breast tumor recurrence was 3.7%. Recurrences tended to be more frequent in patients who refused or did not complete endocrine treatment than in those who received it (7.4% vs 1.9%, p = 0.07). The complication rate was 14.7%, with seroma being the most common (8.2%). Discussion The IORT ipsilateral breast tumor recurrence rate of 3.7% confirms a higher-than-expected rate compared to randomized clinical trials, possibly due to less compliance with endocrine therapy. Conclusion The authors subsequently revised their IORT protocol to require endocrine treatment as a part of the IORT treatment plan and to strongly recommend adjuvant whole breast irradiation for all patients deemed cautionary or unsuitable for IORT according to the American Society for Radiation Oncology's accelerated partial breast irradiation guidelines.

Implementation of Intraoperative Ultrasound Localization for Breast-Conserving Surgery in a Large, Integrated Health Care System is Feasible and Effective.

BACKGROUND: Intraoperative ultrasound (IUS) localization for breast cancer is a noninvasive localization technique. In 2015, an IUS program for breast-conserving surgery (BCS) was initiated in a large, integrated health care system. This study evaluated the clinical results of IUS implementation. METHODS: The study identified breast cancer patients with BCS from 1 January to 31 October 2015 and from 1 January to 31 October 2019. Clinicopathologic characteristics were collected, and localization types were categorized. Clinical outcomes were analyzed, including localization use, surgeon adoption of IUS, day-of-surgery intervals, and re-excision rates. Multivariate logistic regression analysis was performed to evaluate predictors of re-excision. RESULTS: The number of BCS procedures increased 23%, from 1815 procedures in 2015 to 2226 procedures in 2019. The IUS rate increased from 4% of lumpectomies (n = 79) in 2015 to 28% of lumpectomies (n = 632) in 2019 (p < 0.001). Surgeons using IUS increased from 6% (5 of 88 surgeons) in 2015 to 70% (42 of 60 surgeons) in 2019. In 2019, 76% of IUS surgeons performed at least 25% of lumpectomies with IUS. The mean time from admission to incision was shorter with IUS or seed localization than with wire localization (202 min with IUS, 201 with seed localization, 262 with wire localization in 2019; p < 0.001). The IUS re-excision rates were lower than for other localization techniques (13.6%, vs 19.6% for seed localization and 24.7% for wire localization in 2019; p = 0.006), and IUS predicted lower re-excision rates in a multivariable model (odds ratio [OR], 0.59). CONCLUSIONS: In a high-volume integrated health system, IUS was adopted for BCS by a majority of surgeons. The use of IUS decreased the time from admission to incision compared with wire localization, and decreased re-excision rates compared with other localization techniques.

Patients Older 65 Years With Early Breast Cancer Prefer Intraoperative Radiation as a Locoregional Treatment Choice.

BACKGROUND: Patients 65 years old or older with early endocrine-responsive breast cancer have many treatment options, including no radiation. This study aimed to evaluate treatment preference when intraoperative radiation therapy (IORT) is offered in this population. METHODS: The study reviewed patients 65 years old or older with a diagnosis of early-stage endocrine-responsive breast cancer in 2016-2019 at a single hospital in a large integrated health care system. Electronic medical records of multidisciplinary breast tumor board discussion, treatment options documented by the treatment team, and final treatment offered were reviewed. Variables including age at biopsy, language, endocrine treatment, and comorbidities were collected. Regression analysis was used to evaluate for variables associated with patients' choice regarding radiation treatment. RESULTS: The institutional IORT guidelines were met by 63 patients in the described age group who had a documented offer of all radiation treatment options. The median age of the patients was 70 years (interquartile range 63-77 years). Overall, 74.6% of the patients chose IORT, and 14.3% opted for whole-breast irradiation. Only 4.8% chose to omit radiation after breast-conserving surgery, and 6.3% chose mastectomy. The patients who chose IORT were more likely to receive endocrine treatment (odds ratio 3.70; p = 0.03). Age, race, language, and comorbidities were not associated with preference for IORT (p < 0.05). CONCLUSIONS: Patients 65 years old or older with early-stage endocrine-responsive breast cancer preferred to have IORT despite counsel about the lack of survival benefit. This study suggests that local cancer control with the convenient radiation delivery method is important to the described patient population.

Outpatient Mastectomy: Factors Influencing Patient Selection and Predictors of Return to Care.

BACKGROUND: After implementation of the Surgical Home Recovery (SHR) initiative for mastectomy within a large, integrated health delivery system, most patients are discharged on the day of the procedure. We sought to identify predictors of SHR and unplanned return to care (RTC). STUDY DESIGN: Mastectomy cases with and without reconstruction from October 2017 to August 2019 were analyzed. Patient characteristics, operative variables, and multimodal pain management were compared between admitted patients and SHR patients using logistic regression. We identified predictors of RTC in SHR patients, defined as 7-day readmission, reoperation, or emergency department visit. RESULTS: Of 2,648 mastectomies, 1,689 (64%) were outpatient procedures and the mean age of patients was 58.5 years. Predictors of SHR included perioperative IV acetaminophen (odds ratio [OR] 1.59; 95% CI, 1.28 to 1.97), perioperative opiates (OR 1.47; 95% CI, 1.06 to 2.02), and operation performed by a high-volume breast surgeon (OR 2.12; 95% CI, 1.42 to 3.18). Bilateral mastectomies (OR 0.70; 95% CI, 0.54 to 0.91), immediate reconstruction (OR 0.52; 95% CI, 0.39 to 0.70), and American Society of Anesthesiologists class 3 to 4 (OR 0.69; 95% CI, 0.54 to 0.87) decreased the odds of SHR. Of SHR patients, 111 of 1,689 patients (7%) experienced RTC. Patients with American Society of Anesthesiologists class 3 to 4 (OR 2.01; 95% CI, 1.29 to 3.14) and African American race (OR 2.30; 95% CI, 1.38 to 4.91) were more likely to RTC; receiving IV acetaminophen (OR 0.56; 95% CI, 0.35 to 0.88) and filling an opiate prescription (OR 0.51; 95% CI, 0.34 to 0.77) decreased the odds of RTC. CONCLUSIONS: Surgeon volume and multimodal pain medication increased the odds of SHR. Within the SHR group, American Society of Anesthesiologists Class 3 to 4 and African American patients increased the likelihood of RTC. This study helps optimize patient selection and perioperative practice for successful SHR.