SAN ANTONIO—A European metaanalysis suggests that breast cancer patients over age 73 may live just as long if treated with tamoxifen(Drug information on tamoxifen) (Nolvadex) instead of surgery.
Speaking at the 21st Annual San Antonio Breast Cancer Symposium, Dr. Giorgio Mustacchi, director of the University of Trieste Cancer Center, Italy, reported long-term results from a combined analysis of data from Italy’s Group for Research on Endocrine Therapy in the Elderly (GRETA) and the United Kingdom’s Cancer Research Centre (CRC) trials.
“Since in these studies tamoxifen alone and tamoxifen plus surgery yielded the same overall survival rates, minimal surgery plus tamoxifen for very frail, elderly women should be sufficient,” Dr. Mustacchi said.
Between 1984 and 1992, 913 operable patients over age 70 with mostly T2 tumors (2 to 5 cm) were randomized to either tamoxifen alone or tamoxifen plus surgery. Although the GRETA study encompassed more T1 tumors (42% vs 24% in the CRC), mastectomy was more common (84% vs 30% in the CRC).
Dosing schedules were also markedly different: GRETA used a 1-day 160 mg tamoxifen loading dose with 20 mg daily thereafter in the nonsurgical arm and 20 mg daily without the loading dose in the surgical arm. The CRC used a 40 mg daily dose in both arms.
Merged data, first presented at the 1998 American Society of Clinical Oncology (ASCO) annual meeting, showed that patients randomized to primary surgery did not have a significant advantage in terms of overall survival (RR = 0.86, P = .09). However, the risk of death from breast cancer was significantly reduced by surgery, with a hazard ratio of 0.70 (95% CI, 0.51 to 0.95).
These data translate to a “a highly significant 30% less probability of death from breast cancer with surgery—along with a 95% probability that the difference is related to treatment, and not chance,” Dr. Mustacchi said.
Further analysis of 13-year survival data showed that surgery did significantly improve overall survival in patients aged 70 through 73. However, it had no significant effect on overall survival in the three age groups over 73 years of age (74 to 76, 77 to 79, and over 80).
Real or an Artifact?
Professor Mustacchi told Oncology News International that “the apparent benefit for younger women could be real or could be a statistical artifact” (less than 25% of the whole study population was under the age of 73).
Another intriguing idea, he said, “is that the time to relapse could be longer than the ‘given’ time (lifespan), and that patients may have died for other reasons prior to relapse.”
Also, in terms of overall survival, it may be that tamoxifen is reducing deaths from causes other than breast cancer, such as heart disease and fractures resulting from osteoporosis.
