Lobular and its imaging issues
Lobular’s imaging issues — both in preventive screening and post-treatment surveillance — fueled the most fiery debate during the symposium, with advocates, radiologists other others decrying mammograms’ lack of efficacy in spotting the disease.
“My lobular tumor was invisible for five years of mammograms,” said Tracy Cushing, MD, a 45-year-old patient advocate and emergency medicine physician from Boulder. “Improving mammography and screening is very important to me. How do we make it better?”
Mammography is used for prevention screening in the U.S., but its inability to capture lobular — especially in dense breast tissue — has caused distrust, frustration and “illness insecurity,” ongoing anxiety regarding the status of their disease, patients and experts argued.
Christiane Kuhl, MD, PhD, director of diagnostic and interventional radiology at University Hospital RWTH Aachen in Germany, said mammograms are simply inadequate for this subtype.
“Mammographic screening is a health care intervention that does not work for lobular cancer — full stop,” she said, pointing to abbreviated breast MRI as a better alternative. “It’s a completely different disease that requires different approaches in early detection, treatment and follow-up.”
Others said mammograms still find around 60% of lobular cancers and questioned the practicality of using MRIs for preventive screening, since the extra sensitivity of MRIs can lead to overdiagnosis (finding low-grade cancers that aren’t life threatening) and/or false positives, where an abnormal scan leads to unnecessary biopsies and undo anxiety.
“False positives are not our main problem, false negatives are,” Kuhl responded. “Nobody dies of a false positive.”
Surveillance after treatment remains another fraught area, since lobular patients are often followed with the same type of imaging that failed to pick up their cancer in the first place.
“Post-treatment, I was told they’re going to monitor me with mammograms,” said Turner, whose repeated mammograms failed to spot her lobular cancer. “That isn’t right.”
Cushing also questioned surveillance methods like CT and FDG-PET scans, often used to diagnose ILC or measure its response to treatment.
“I have no confidence in either for seeing metastatic progression,” she said.
Late metastatic recurrence is higher in ILC than in ductal/NST breast cancers, but there is no lobular-specific protocol for follow-up after early-stage treatment. In a breakout session on imaging, some clinicians said they use circulating tumor DNA, or ctDNA, tests to follow early stagers at high risk for recurrence. Others use MRIs, which experts said have the best sensitivity for capturing metastasis.
But guidelines and protocols vary from country to country and even practice to practice. And data on the efficacy and clinical utility of ctDNA tests in particular are lacking. (Read about Fred Hutch’s recent efforts to evaluate the effectiveness of these new liquid biopsies.)
“What do we do if the test comes back positive?” one oncologist asked during one of the symposium's breakout sessions. “That’s the question.”
Even when recommended by an oncologist, MRIs aren’t always an option, experts said, due to an increase in consumer demand and a post-pandemic shortage of radiologists.