The anticancer benefits of nonsteroidal anti-inflammatory drugs (NSAIDs), seen in studies of colon cancer risk, may extend to human breast cancer as well. A study of NSAID use in breast cancer patients at the Moffitt Cancer Center, Tampa, Fla, showed that women who used the drugs regularly had smaller tumors and were less likely to have lymph node involvement.
"At this point, any recommendations would be premature, but chemopreventive use of these drugs probably would not be so inappropriate and might represent a logical step, at least on the basis of these findings," David V. Schapira, MD, said in an interview at the San Antonio Breast Cancer Symposium.
Interest in the chemopreventive potential of NSAIDs stems from evidence that prostaglandin-E (PGE) plays a role in cyclic AMP-regulated cell proliferation and that some patients with malignancies have elevated PGE levels. By inhibiting PGE synthesis or activity, NSAIDs conceivably could have a favorable effect on cancer risk or prognosis.
Dr. Schapira noted that several NSAIDs have been shown to inhibit the growth of breast and colon tumors induced in rodents. These studies also demonstrate that indomethacin inhibits bone metastasis in laboratory animals injected with mouse mammary tumor cells.
At the San Antonio symposium, Dr. Schapira reported data on NSAID use in 341 consecutive newly diagnosed breast cancer patients. The data were then correlated with tumor size, lymph node involvement, estrogen/progesterone receptor status, DNA ploidy, and S-phase fraction.
The analysis showed significant associations between the number of NSAID pills and two prognostic factors: tumor size and lymph node involvement (see Table on page 544). Almost 60% of the women who took 10 or more pills monthly had tumors smaller than 2 cm. In contrast, about 60% of women who reported no NSAID ingestion had tumors that were 2 cm or larger.
A similar association occurred with respect to node involvement: 63% of women in the 10-pill category had negative nodes and 60% in the zero-pill group had positive nodes.
"These results are compatible with the earlier findings on the effect of NSAIDs on the growth and metastatic potential of breast cancer," said Dr. Schapira, currently director of the Stanley S. Scott Cancer Center at the Louisiana State University Medical Center, New Orleans. "The findings suggest that NSAIDs may favorably affect the prognosis of breast cancer and, additionally, that the drugs may have a role in breast cancer chemoprevention."
Different NSAIDs may differ in their ability to inhibit prostaglandin synthesis, but the investigators did not evaluate that issue. About 75% to 80% of the patients in the study named ibuprofen(Drug information on ibuprofen) as their NSAID of choice.
"The data on colon cancer prevention and regular NSAID use are quite positive," Dr. Schapira said. "The next logical step would be to do a randomized, prospective study to see if these drugs can prevent breast cancer."