Patients with breast cancer want accurate information on the risk of their cancer recurring once they have completed treatment.
“I would like to know the true stats of how many breast cancers come back no matter what the hell we do for treatment,” comments a typical post on a breast cancer patient bulletin board.
But those statistics have not been available from a robust population-based source.
Now, there is hope that they will – at last – be collected.
A new pilot project at the National Cancer Institute is setting out to collect that information, although the researchers say it is a “long-term goal” that will take a few years.
But it has already been a long time coming. The mother lode of all U.S. cancer data, the NCI’s Surveillance, Epidemiology, and End Results (SEER) Program, started collecting cancer data in 1973.
“When they began to capture cancer data, the focus was primarily on the incidence of cancer, the different types of cancer, and survival,” explained Esmeralda Ramirez-Pena, PhD, MPH, cancer prevention fellow at the NCI.
“Later, SEER expanded to include subgroups of various cancers and different stages at diagnosis,” she added.
But this database has never included information on cancer recurrence.
In a 2017 press statement, the NCI commented: “Collecting recurrence data has been challenging for cancer registries because recurrence can be diagnosed through diverse methods and in a variety of locations.”
New project
The NCI now has a “long-term goal” to implement additional “data elements” into SEER that will allow calculation of breast cancer recurrences, said Dr. Ramirez-Pena.
The Breast Cancer Recurrence Project, a pilot program funded via an NCI–Department of Energy collaboration, “will take a couple of years,” she said.
She presented some details of the new project as a poster at the recent San Antonio Breast Cancer Symposium 2020.
“SEER has added data elements over time,” she said, and this latest move will – at last – include information on breast cancer recurrence.
Why the change now?
“There’s been so much interest [in breast cancer recurrence]. It’s a top cause of cancer death in the United States and globally. The urgent need is evident,” she explained.
Breast cancer advocates have long been calling for SEER to count recurrence, including metastatic recurrence.
Katherine O’Brien, a breast cancer “metser” from Chicago, is credited with especially turning the heat up on the NCI.
In 2015, Ms. O’Brien spearheaded the creation of an online petition on the website change.org, calling on the NCI’s SEER, the Centers for Disease Control and Prevention, and all state cancer registries to start counting all people living with metastatic breast cancer, including those whose early-stage disease progressed. The petition, which is now closed, collected nearly 12,000 signatures.
Tracking recurrences
In the new project, cancer recurrence is defined as a cancer that was treated, reduced to undetectable levels, and later returned either locally, regionally, or distantly.
Tracking recurrence is not a simple matter because posttreatment surveillance to detect it includes clinical exams, biomarker testing, pathologic studies, molecular testing, imaging, and patient-reported symptoms and because recurrence frequency varies by subtype of breast cancer and TNM classification. Additionally, recurrence may depend on age at diagnosis, a variety of risk factors, treatment type, and access to quality of care.
“It’s likely there are many elements that influence recurrence,” said Dr. Ramirez-Pena.
To get a handle on the complexity, the NCI needs to first identify which data are needed to tally recurrence and the frequency at which they are collected, explained Dr. Ramirez-Pena. To do so, she and her coinvestigators conducted a systematic review of phase 3 clinical trials of early-stage breast cancer.
On their own, such trials are not sufficient to provide recurrence estimates at the population level because they lack diversity, represent fewer than 5% of all cancer patients, and the study period may not be long enough to capture recurrences for long-latency breast cancers, such as estrogen receptor–positive malignancies.
Nonetheless, these clinical trials provide a starting place.
The investigators identified 444 early-stage clinical trials. They stratified participants by subtype and tumor characteristics, which will enable analysis of risk-group and treatment-dependent differences in recurrence.
The changing science of breast cancer makes this work a challenge, the investigators said. For example, in clinical trials from the early 1990s through the early 2000s, receptor status and subtyping was not commonly reported, and some treatment endpoints were added during the past few years.
“Our next step will be to extract recurrence rates from these trials so we can eventually provide individualized information about recurrence risk to survivors,” Dr. Ramirez-Pena said, describing the big-picture aims.
The Breast Cancer Recurrence Project is collaborating with external agencies, such as the International Agency for Research on Cancer and Public Health England, in fine-tuning data elements, because “recurrence is not captured well globally either,” said Dr. Ramirez-Pena.
The study was supported by NCI.
A version of this article first appeared on Medscape.com.