A total of 56 oncologists participated in the survey portion of the study and their sociodemographic and practice characteristics are presented in Table 1. Surveys were sent to 2,968 oncologists from which we received 75 responses, yielding a response rate of 2.5%. Of the initial respondents, 62 were eligible for the study and 56 completed the survey. Six of the eligible respondents were lost to follow-up prior to survey completion. The gender distribution was relatively balanced with females representing slightly more than half of the sample (54%). Most oncologists were Non-Hispanic White (61%) and 23% identified as Asian, 7% as Black, and 4% as Hispanic. The majority (71%) of respondents had > 10 years of oncology work experience and practiced in an academic setting (64%).

Table 1 Provider demographics: n = 56Preferences regarding OFS based on clinical characteristics

Figure 1 shows trends of treatment recommendations considering both tumor staging and gene expression assay recurrence scores. As tumor size and nodal involvement increase, there was a shift toward stronger recommendations of OFS. A notable distinction emerged in treatment recommendations for node-negative patients with intermediate-low scores (11–15) depending on whether or not chemotherapy would be recommended. The majority (68%) of oncologists would not be likely to recommend OFS to these patients if they did not receive chemotherapy, but if chemotherapy was given then only 34% reported not being likely to recommend OFS with 38% reporting that they would now discuss the pros and cons of OFS. Chemotherapy was also frequently used as a surrogate for risk in our interviews. For example, one oncologist stated, “I think if they’re high enough risk to require chemotherapy, then I do strongly consider it [OFS].”

Fig. 1

Responses to question asking how strongly oncologists would recommend OFS for a pre-/peri-menopausal woman with HR + early-stage operable breast cancer. A Responses by tumor stage. B Responses assuming patient has node-negative disease, by gene expression assay recurrence score Note: T1 N0 Missing = 1

These findings were similar when we used clinical vignettes to summarize case details. The first clinical vignette was that of a 25-year-old woman with a screen-detected breast cancer status post-lumpectomy. Pathology showed a grade 2 invasive ductal carcinoma measuring 1.7 cm with 0/3 sentinel lymph nodes involved. The tumor was HR + HER2 negative (ER 100%, PR 100%, HER2 IHC 0), Ki67 10%, and oncotype score was 16. Most (62.5%) of our respondents would not have recommended chemotherapy to this patient. Of these, the recommendation for OFS was almost evenly split with 54% recommending OFS (+ AI/tamoxifen) and 46% recommending tamoxifen only. However, among the 21 oncologists who would have recommended chemotherapy for a similar patient, 95% would also recommend OFS.

The second clinical vignette was that of a 50-year-old pre-menopausal woman with screen-detected right breast cancer status post-lumpectomy which showed grade 3 invasive ductal carcinoma measuring 2.2 cm, 0/3 sentinel lymph nodes involved. The tumor was again HR + HER2 negative (ER 100%, PR 100%, HER2 IHC 0), Ki67 15%, and oncotype score was 21. In total, 61% of oncologists would not have recommended chemotherapy in this case, similar to the first. However, among the oncologists who would have opted against chemotherapy, 74% would have recommended OFS—a notable shift from the first vignette. Of the oncologists who would recommend chemotherapy, 86% would recommend OFS.

Practitioners with 10 or fewer years of oncology experience had a strong preference for recommending OFS as initial endocrine therapy regardless of chemotherapy exposure. All of these oncologists (100%) practitioners would have recommended OFS to patients in both vignettes if they had recommended chemotherapy and about 2/3rds would have recommended OFS to patients in both vignettes if chemotherapy was not recommended. In contrast, among oncologists with more than 10 years of oncology experience, approximately 60% favored tamoxifen alone when not recommending chemotherapy for the patient in the first vignette.

Preferences regarding OFS type, timing, and schedule

There was a high level of consistency among practitioners regarding the use of OFS medications and dosing schedules for pre-/peri-menopausal women with early-stage, HR + breast cancer. The data showed that 94.6% of practitioners prefer either Leuprolide (50%) or Goserelin (44.6%), while other medications such as Triptorelin and Degarelix are used much less frequently. Monthly dosing is preferred (71.4%) to the 3-month schedule (28.6%). Regarding initiation of OFS and endocrine therapy, most oncologists will begin OFS first and then add AI (Fig. 2).

Fig. 2

The rank of treatment plans that oncologists typically use for A pre-menopausal women with HR + early-stage breast cancer, when planning to use OFS and endocrine therapy after chemotherapy, and for B peri-menopausal women >  = 45, with HR + early-stage breast cancer, when planning to use OFS and endocrine therapy without chemotherapy. Notes: Missing responses in Panel A: tamoxifen first then OFS (n = 14), OFS and tamoxifen simultaneously (n = 4), OFS then tamoxifen within 4–8 weeks (n = 7), OFS and AI simultaneously (n = 5), and OFS then AI within 4–8 weeks (n = 1). Missing responses in Panel B: tamoxifen first then OFS (n = 6), OFS and tamoxifen simultaneously (n = 5), OFS then tamoxifen within 4–8 weeks (n = 4), OFS and AI simultaneously (n = 5), and OFS then AI within 4–8 weeks (n = 1)

Resources for OFS decision-making

Most practitioners determined their management plans based on established guidelines (NCCN/ASCO, 42.9%) or clinical trial data (SOFT/TEXT, 26.8%). Eighteen percent used prognostic calculators, such as CTS5, Predict, or RSClin. The majority of respondents (59%) reported that current NCCN guidelines regarding OFS use lack clarity and 70% report lack of clarity in current guidelines as a barrier to OFS use (Table 2).

Table 2 Barriers to OFS utilizationDetermining menopausal status after chemotherapy and monitoring ovarian function

About half of our respondents (53%) used menopausal status at diagnosis to determine menopausal status after chemotherapy (Table 3). That is, if patients were pre-/peri-menopausal at diagnosis, they considered them to be pre-menopausal after chemotherapy even if they were amenorrheic. Thirty-eight percent would check serum estradiol and/or FSH and/or LH and base menopausal status on these lab values. However, only 9% of practitioners felt very confident confirming menopausal status in pre-menopausal women (at diagnosis) with amenorrhea post-chemotherapy (Fig. 3).

Table 3 Responses regarding determination of menopausal status after chemotherapyFig. 3

Confidence in confirming menopausal status post-chemotherapy

The approach to assessing ovarian suppression status after patients initiate OFS varied significantly, with 44.6% reassessing every 3–6 months, 21.4% never reassessing, 19.6% annually, 3.6% monthly, and 10.7% use other frequencies. Our data also demonstrated that most respondents indicated a need for greater specificity in guidelines regarding the initial assessment of menopausal status post-chemotherapy (79%), the assessment of recovery of ovarian function post-chemotherapy (81%), and assessment of ovarian function in peri-menopausal women on treatment with ET ± OFS (89%). This theme was also observed in our qualitative data, with one oncologist describing: “I don’t know if we have good guidelines on when to stop, when to test, how long they should be off their ovarian function suppression before we test hormones. So, I get confused.”