Fox Chase Cancer Center Researchers Recommend Updating the Staging Criteria for Breast Cancers With Skin Involvement
Invasive breast cancers with skin involvement, regardless of size or lymph node involvement, are automatically classified as stage III locally advanced tumors, which suggests that they are a relatively serious form of cancer with poor survival. In a study published in the Journal of the American College of Surgeons, researchers at Fox Chase Cancer Center cast doubt on that standard classification, showing that women with breast cancers with skin involvement have widely varied survival rates that differ by tumor size and nodal involvement.
“Many women with tumors that happen to have spread to the skin may unfortunately be given an inaccurately dire prognosis—along with, perhaps, some unnecessary treatment,” said Richard J. Bleicher, MD, FACS, Associate Professor in the Department of Surgical Oncology and Director of the Breast Fellowship Training Program at Fox Chase Cancer Center. “We need to update our staging criteria to more accurately reflect a woman’s true chances of surviving her cancer because the size of her tumor and the involvement, or lack of involvement, of lymph nodes tells us more about her prognosis than whether skin is involved.”
Study Details
Within the group of tumors that have spread to the skin, there is much variety, both in size and whether or not they have spread to the lymph nodes. Since these tumors occur relatively rarely, however, scientists have struggled to understand how that heterogeneity might impact survival. In this study, Bleicher et al looked at the SEER–Medicare Linked Database. They focused on patients aged 65 or older who had been diagnosed with invasive breast cancer, and had surgery to completely remove or reduce the size of their tumors.
The researchers then created two additional subgroups: those who had extensive skin involvement and those without. From there, they regrouped the cancers by tumor size and nodal involvement using the TNM staging system. Other factors taken into consideration were age, race, sex, histology, grade, estrogen and progesterone receptor status, surgery, chemotherapy, and radiotherapy.
Nearly Half of Cancers Restaged
After excluding some patients who lacked pertinent data and other factors, the researchers compared 924 with significant skin involvement to 66,185 others whose tumors had not spread to skin. All of the patients with significant skin involvement were originally classified as stage III. However, after restaging these tumors based strictly on the size and/or extent of the primary tumor, and whether the cancer had spread to nearby lymph nodes, nearly half (43%) were staged to earlier stages. The women restaged in this fashion did as just well as the women classified to those other stages because they didn’t have skin involvement.
Overall, stage III cancers are associated with a 5-year survival rate that ranges from 41% to 67%; these results suggest that some women diagnosed with tumors that spread to the skin actually have a 96% chance of surviving 5 years, based on their tumor’s size and nodal status—similar to other early-stage tumors that have not spread to the skin.
“Classifying all tumors with skin involvement as stage III belies the purpose of staging, which is to group tumors with a similar prognosis,” said Dr. Bleicher.
It makes sense that not all tumors with skin involvement behave the same, Dr. Bleiche added. “Some small, invasive tumors will spread to the skin simply because they happen to arise close to it,” he noted. “That doesn’t necessarily mean they will have a worse prognosis than a similar tumor that is located far enough away from the skin that it hasn’t reached it yet.”
Authors Recommend New Staging Criteria
Based on these findings, Dr. Bleicher and his colleagues recommend adding a staging category for tumors with skin involvement, and using other criteria such as tumor size and node involvement to determine stage preferentially over skin involvement. Not all of these tumors should be treated the same, he notes. “For the smallest of these lesions, they may not require such aggressive treatment as chemotherapy before surgery,” he adds. “We need to follow a significant number of patients in that specific category before concluding how they should best be treated.”
Dr. Bleicher is the corresponding author for the Journal of the American College of Surgeons article.
The study was supported in part by grants from the U.S. Public Health Services, the Commonwealth of Pennsylvania, and the American Cancer Society. The study authors reported no potential conflicts of interest
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