Treatment of primary breast cancer with L-PAM/5-FU and tamoxifen: an interim report.

This trial studied the possibility that tamoxifen, added to L-phenylalanine mustard and 5-fluorouracil, enhances the established benefit of the latter two drugs in treatment of women with breast cancer and positive axillary nodes. The addition of tamoxifen resulted in a 25% decrease in treatment failure at 24 months and a 23% decrease at 36 months. In patients greater than or equal to 50 years old, there was a 48% reduction at 24 months and a 39% reduction at 36 months. This advantage was statistically significant at both two and three years' follow-up (p less than 0.001). Higher receptor levels were associated with a greater probability of disease-free survival. Patients less than or equal to 49 years old were less responsive. There was some evidence at 24 months that patients in this age group with four or more positive nodes who also had high ER levels might benefit from tamoxifen. At 36 months, however, this benefit was no longer evident. This form of adjuvant therapy is not recommended in patients less than or equal to 49 years of age whose tumor estrogen and progesterone levels are below 10 fmol; there is an appearance of benefit in patients greater than or equal to 50 with low estrogen and progesterone levels, and stronger evidence of benefit when these levels are high among the older group of patients.