Twenty-five eligible patients were enrolled in the study, their age ranging from 35 to 72 years old, median 58 (Table 1). Saturation of the key concepts, i.e., no new concepts were being spontaneously reported by participants pertaining to the experience of oral versus IM ET for ER+ HER2− ABC, was achieved with 18 participants. Most patients identified as white (22/25, 88%) and as not Hispanic nor Latino (20/25, 80%). All participants had at least a high school education. In terms of employment status, most patients were not working and only nine patients were employed full-time or part-time (Table 1). The average time from initial BC diagnosis to time of interview was 12.6 years (SD 8.4) with a median of 10.0 and range of 3–35 years (Table 1). Most patients (18/25, 72%) were currently receiving injectable ET, and seven (7/25, 28%) were taking oral ET.

Twenty eligible HCPs (10 oncologists and 10 oncology nurses) were enrolled in the study (Table 2). Their ages ranged between 27 and 72 years, median age of 45, and a little more than half female (12/20, 60%) (Table 2). Almost all were not Hispanic nor Latino, half were white (10/20, 50%), and five (5/20, 25%) each were Black/ African American or Asian. HCPs had 12.5 years of median time in oncology practice. More than half (11/20, 55%) identified BC as the primary cancer they treated, and almost all HCPs (18/20, 90%) saw more than 20 patients with BC per month. Half of the HCPs practiced in an oncology office (10/20, 50%) (Table 2).

When the patients were asked about their preferred mode of administration, most patients chose the oral therapy (16/25, 64%), seven chose IM injection, and two did not have a clear preference (Table 3). Among those patients who preferred oral treatment, the most frequently cited reason for their preference was convenience (13/16, 81%). Example quotes from patients articulating their preference for oral ET are in Table 4. Among those who preferred IM injection, nearly all (6/7, 86%) attributed their preference to the monthly frequency of the injections.

Nearly all HCPs (18/20, 90%) said that their patients preferred oral therapy. Interestingly, one oncology nurse said that treatment preference may vary by age, with older patients often preferring injections and younger patients tending to prefer oral treatments. Younger patients are able to keep up with daily dosing whereas older patients might be forgetful and thus an ET injection appointment might be more suitable (Tables 4, 5).

Among the probed benefits of oral treatment, patients most frequently selected convenience (22/25, 88%) and the ability to take the pill along with their other oral medications (15/25, 83%) (Table 6). Among those who liked the convenience of the oral treatment, almost half (12/22, 48%) noted that they could take it at home or while traveling without being tied to monthly appointments. Additionally, the patients mentioned spontaneously that oral ET was easy to obtain through their insurance, did not require copay, was easily accessible at the pharmacy or via mail, and had minimal impact on their daily life (Table 6).

Regarding the IM injection therapy benefits, when probed, approximately half of the patients (12/22, 55%) liked not having to remember to take medication daily (Tables 5, 6). The benefit shared spontaneously by most patients (14/25, 56%) was their feeling that the injections were effective in treating their cancer (Table 6).

Regarding the probed oral therapy benefits, convenience was discussed by all HCPs (20/20, 100%) (Table 6). Also, most HCPs (18/20, 90%; nine oncologists and nine oncology nurses) stated that their patients liked not having to receive injections (Table 6). Example quotes from HCPs regarding the convenience of oral ET highlight increased autonomy, tolerable side effects, and reduced transportation burden are in Table 4. Additional spontaneously mentioned benefits were the once-a-day dosing of oral ET (4/20, 20%), the favorable safety profile (2/20, 10%), and the lack of injection site pain (2/20, 10%) (Table 6). HCPs also mentioned that oral ET was well known and familiar to the patients, that patients felt their disease was less severe, and that it protects patients from frequent interactions with the healthcare system.

Regarding the injectable ET, when probed all HCPs mentioned the benefit that patients did not have to remember taking the medication (20/20, 100%) (Tables 5, 6). HCPs also spontaneously mentioned the accompanying frequent interaction with their provider (Table 6) allowing increased oversight and opportunity to ask questions as a perceived benefit for patients. Moreover, four of the 20 HCPs (20%) mentioned a decrease in worry about daily medication or drug interactions, two HCPs (10%) cited increased compliance, and two HCPs (2/20, 10%) said that the injectable treatment was well tolerated (Table 6).

Only some of the patients responded affirmatively when probed on the burdens of oral therapy; four patients discussed taste of the medication or dosing frequencies (Table 6). However, most patients spontaneously mentioned side effects as a burden of oral therapy (18/25, 72%) (Tables 4, 6). Additionally, four (4/25, 16%) patients shared that the oral medication was a daily reminder of their cancer diagnosis, which they found burdensome, while three (3/25, 12%) patients said they had difficulties obtaining their medication as a result of insurance or pharmacy issues (example quotes in Table 4).

Of the burdens patients were probed on regarding injection therapy, the most frequently mentioned was the pain associated with the injections (21/25, 84%) (Table 6). Two patients spontaneously attributed this pain to the viscosity of the medication necessitating a large injection needle (Table 5). The second most common burden was the inconvenience of having to travel for monthly injections (14/22, 64%) (Table 6). Some patients spontaneously mentioned anxiety related to the monthly injections (5/25, 20%) and side effects resulting from the injections (2/25, 8%) as additional burdens. Patients described eloquently how the long commutes to the oncology clinic for the injections consumed their entire day and articulated the anxiety associated with organizing their lives around this visit (Table 5).

HCPs most frequently selected duration of treatment (14/20, 70%) as the most burdensome aspects of oral ET (Table 6). The most frequent spontaneously mentioned burdens were insurance and pharmacy challenges (11/20, 55%) (Table 6). Additional burdens included side effects such as fatigue (8/20, 40%), and not remembering to take the medication (6/20, 30%).

As per burdens of injection treatment, HCPs most frequently discussed the associated pain during and after the injection (17/20, 85%), the commute time needed to receive the monthly injections (14/20, 70%) and navigating work or school to attend injection appointments (10/20, 50%) (Tables 5, 6). Other burdens mentioned spontaneously by the HCPs included the cost of the medication itself (7/20, 35%) and difficulty with transportation to appointments (4/20, 20%) (Tables 5, 6).

Most patients (23/25, 92%) said that it was easy to adhere to oral therapy and only two (2/25, 8%) found it difficult to adhere (Fig. 1a, Table 4). When elaborating on why they considered adherence easy, some highlighted that it could be incorporated in their daily routine (9/23, 39%) and others felt they had easy pharmacy access to it (5/23, 22%).

Patients and HCPs ease of adherence to a oral and b intramuscular injection therapy. HCP healthcare professionals

Ten patients (10/25, 40%) reported that adherence to the injection was easy (Fig. 1b, Table 5), because the injection was scheduled at the same time with their monthly appointment to the doctor (3/10%) or that the once-a-month regimen facilitated adherence (2/10%) (Table 5). Eight patients (8/25, 32%) said that adherence to injection therapy was difficult. Only two explanations were given for this choice: one patient said that the injection was “uncomfortable”, and another referred to the inconvenience of the process. Seven other patients (7/25, 28%) had mixed feelings about whether adherence to injection therapy was easy or difficult (Fig. 1b). Two patients said that getting injected was initially challenging but became easier over time. Four patients said that, although it was easy, they just did not want to receive injections, or they would rather take pills.

Sixteen HCPs (16/20, 80%) said that their patients found it easy to adhere to oral therapy, whereas four HCPs (4/20, 20%) had the opposite opinion (Fig. 1a). Five (5/20, 25%) HCPs elaborated, and believed adherence to oral therapy was easy because it was just one pill per day.

Sixteen HCPs (16/20, 80%) said that their patients found it easy to adhere to injection therapy whereas four (4/20, 20%) said their patients found it difficult (Fig. 1b). HCPs shared that the primary reason for adherence being considered easy was that only one day per month was required to be engaged for treatment administration (6/20, 35%). Per the HCPs, three factors made adherence difficult: distance to the clinic while not having transportation, being fearful of needles, and navigating insurance approval.