Kimberly Blackwell, MD: Expectations of Therapy in Breast Cancer

What are the expectations of therapy in this setting?

The considerations when discussing treatment options for this patient really are the classic therapy questions. What are the potential benefits if you're going to add a targeted agent versus what are the risks. Setting an expectation on average that in this third-line metastatic setting that the drugs will work somewhere between 10 to 12 months is kind of what I would discuss with the patient. This is extrapolated from many studies where patients have hormone-sensitive breast cancer. Really, the data for chemotherapy is about the same. The best you would see with oral chemotherapy, in particular capecitabine, is about 9 to 10 months.

So I would explain to her that both options on average is about 10 to 12 months' benefit if she responds initially. I don't see a huge discussion point with patients about how one is clearly going to work better than the other. It really boils down to what are the life impact factors or the potential risk.

Obviously with oral capecitabine there are risks such as the rash and diarrhea, which can be problematic if you don't have the dosing right, but it's very patient-dependent. If I was going to choose exemestane or everolimus, I think we would have a fairly frank discussion that although this is a highly-targeted agent that targets the PI-3 kinase pathway, it can have side effects very similar to chemotherapy. You can get mucositis, and you need to let us know and take it very seriously. There is also an increased incidence of anemia and fatigue very similar to chemotherapy, so I wouldn't set the expectation that adding everolimus or a CDK inhibitor is going to be just like having the anti-estrogen therapy alone. It's not — there will be added side effects, but I think it's worth doing at this point because the side effects are less than the oral chemotherapy. So I'd set an expectation somewhere between 10 months to a year on average for capecitabine or anti-estrogen therapy with a targeted agent, and I would talk to her about why I would choose the anti-estrogen backbone of exemestane because it's dissimilar to what she's had before.

ER+/HER2-Breast Cancer: Case 2

Mary is a 62-year-old woman, who in mid-2014 complained of rib pain. Rib plain films revealed a lytic lesion of the left 5th rib. Bone scan revealed multiple areas of uptake in the lumbosacral spine and ribs.

PET-CT revealed lytic lesions in the lumbosacral spine and ribs, and a 3 cm right upper lobe lesion in the lung with a PET SUV value of 6, indicating malignancy

A mammogram and ultrasound of the left breast revealed a 2 cm speculated mass in the upper outer quadrant of the left breast

Core needle biopsy of this lesion revealed infiltrating ductal carcinoma, ER 80%, Her2 negative

She was placed on denosumab 120 mg SQ monthly, and anastrozole 1 mg orally daily. Her pain resolved within 1 month, and on follow-up CT at 4 months her bone lesions appeared sclerotic and her lung lesion had reduced to 2 cm. Her anastrozole and denosumab were continued

In mid-2015 she again complained of worsening low back pain and left hip pain. Repeat PET-CT demonstrated new lytic lesions in the left iliac crest as well as an enlargement of the lung lesion to 4 cm.

She was placed on fulvestrant 500 mg IM monthly and denosumab was continued. Within 2 months her pain improved, and a repeat CT of the chest in late 2015 demonstrated reduction of the lung lesion to 2 cm

In March 2016 she complained of new right scapular pain. A PET-CT revealed new lytic lesions of the left scapula and right ribs, and a new lung nodule in the left upper lobe 1 cm in diameter with an increase in the right upper lobe lesion to 3 cm