Both new and recurring cancers will differ significantly from original tumors, regardless of how long a woman has been cancer-free, and treatment should be tailored to the specific qualities of the second tumor, its status as a new or recurrent case notwithstanding.
So suggests new data from a Fox Chase Cancer Center (Philadelphia, Pennsylvania) investigation. As senior author and Fox Chase attending surgeon Richard J. Bleicher, MD, explained in a statement announcing his group’s results, “Sometimes women will worry more if they believe their original cancer is back, meaning they didn’t ‘beat it’ the first time around. These findings suggest they should not get hung up on that idea, because any subsequent diagnosis—whether it’s a recurrence or a new tumor—will look significantly different from their first cancer.”
According to Bleicher, practitioners often approach a new tumor differently depending on whether they believe it to be a recurrence of the first tumor or a completely new one. However, there is no official way to distinguish between the two types other than a few criteria, such as how long the woman has been cancer-free, with the reasoning being that the longer this interval, the less likely a tumor is to be related to the original tumor.
To assess whether histologic phenotypes shifted significantly at any particular disease-free interval to help distinguish a true local recurrence from a new tumor, the researchers reviewed information from more than 4,300 breast cancer patients (median age 51 years).
Over a median of 60.5 months, 235 patients eventually developed a second tumor in the same breast. Shifts were seen in first tumor and relapse phenotypes in terms of histology, estrogen receptor (ER) expression, progesterone receptor (PR) expression, and method of presentation, but time to relapse was not predictive of any of these. In all, 60% of the relapses differed from the first tumor by at least two characteristics, including whether or not the tumor would respond to hormones, how it was diagnosed, and whether at least 25% of the tumor was confined to the ducts and therefore less able to metastasize.
The finding that time to relapse is not predictive of change in relapse characteristics suggests that the disease-free interval should not be considered when defining a relapse as a new tumor or a recurrence. “Frequent change in relapse characteristics makes [drawing this] distinction difficult,” concluded the investigators in their study abstract, which will be presented by lead author Anita Patt, MD—a surgical oncology fellow at Fox Chase—at the American Society of Clinical Oncology annual meeting, to be held June 3-7 in Chicago, Illinois (http://abstract.asco.org/AbstView_102_83738.html).
“As genetic analysis plays a greater role in characterization of tumor behavior, [new tumor vs. local recurrence] clinical distinctions will likely become less significant.”