Existing guidelines offer little help, according to Pavani Chalasani, MD, MPH, who presented the study at the San Antonio Breast Cancer Symposium. “They just say [do an] annual mammogram, but they don’t say, ‘Do we need to do screening? Do we need to do breast MRIs?’”
Her personal experience also reflected a general confusion. “I asked my colleagues and got different answers from seven colleagues,” said Dr. Chalasani, who is an oncologist at the University of Arizona Cancer Center, Tucson.
She noted that diagnostic mammograms are generally similar to screening mammograms, but the radiologist is viewing the images in real time and can take additional views as needed while the patient is still present. “That is the biggest difference,” said Dr. Chalasani. No studies have been conducted to determine which method produces better results.
To get a snapshot of current practice, she and her colleagues developed a survey, which the American Society of Clinical Oncology sent to 1,000 randomly selected members between Oct. 19 and Nov. 22, 2021. 244 individuals responded; 93.5% were physicians, and half identified as female. A total of 174 respondents were medical oncologists, 31 were radiation oncologists, and 20 were surgical oncologists. The imbalance among respondents is a limitation of the study. That “may or may not be reflective of our real-time practices (among surgeons), but we do think that since a lot of times patients are seen by medical oncologists, there could be overlap,” said Dr. Chalasani.
About 50% of respondents said that they use breast MRI in the diagnosis of 25% or fewer patients. Approximately 64% of respondents said they used diagnostic mammograms versus about 31% who used imaging mammograms at first imaging. About 53% said they ordered mammograms within the first 6 months after treatment.
38% of those who ordered diagnostic mammograms for surveillance used it for 3-5 years, while 29% continued it for 5 years or more. One-quarter employed additional imaging during follow-up, most commonly breast ultrasound. About 65% said they had no stop date for screening mammograms, as long as the patient remained healthy. The choice of screening or diagnostic mammography was about 50:50, though about 55% said they use screening mammography for patients 80 years of age or older.
Dr. Chalasani pointed out that both screening and diagnostic mammograms provide similar imaging quality. Screening mammograms are completely covered by insurance, while diagnostic mammograms typically require a copay. “We’re doing this [diagnostic mammography] with no guidelines, but there is this out of pocket cost, without knowing if it’s the right thing to do,” she said.
National Comprehensive Cancer Network guidelines indicate that diagnostic mammograms can be conducted for 5 years after a ductal carcinoma in situ diagnosis, but it doesn’t provide guidance for invasive cancers. Some past studies suggested that doing diagnostic mammograms for 3 years may increase diagnosis, but it isn’t clear if any such advantage would actually result in a clinical difference, according to Dr. Chalasani. “With the treatments we have, we still might cure [the cancer]. So what endpoints are we looking for? Are we changing care to add on toxicity to the patient, and stress to the patient and also for the health care system?”
She hopes that physicians will look at the results and understand that diagnostic mammograms, while they intuitively feel superior, are not supported by guidelines, and patients must incur an extra cost.
Her team also plans to conduct cost-effectiveness analysis of diagnostic mammograms.
Dr. Chalasani has no relevant financial disclosures.