NEW ORLEANSPreliminary results of National Surgical Adjuvant
Breast and Bowel Project (NSABP) protocol B-21 have ended the
lingering, perhaps illusory hope of identifying a subset of
women in whom radiation could be eliminated or replaced with another
intervention for treating early-stage invasive breast cancer,
said Norman Wolmark, MD, chairman of the NSABP.
Addressing the 36th ASCO meeting, Dr. Wolmark reported
data comparing radiation plus placebo, radiation plus tamoxifen
(Nolvadex), and tamoxifen alone in women with node-negative tumors of
1 cm or smaller who had lumpectomy and axillary lymph node
Tamoxifen cannot replace radiotherapy even in these favorable
lesions, he stated. Data from NSABP show that the
standard of care should remain unchanged, even for these small,
At a median follow-up of 68.3 months, cumulative 5-year risk of
recurrence was over 10% with tamoxifen vs 4.8% with radiation plus
placebo (P = .01). Cumulative 5-year risk with radiation plus
tamoxifen was 2% vs 4.8% with radiation plus placebo (P =
.0001). The magnitude of differences is somewhat
surprising, Dr. Wolmark said. This is a big difference
even for small tumors. Offering both therapies should become standard practice.
The NSABP trial enrolled 1,009 women, of whom 999 were evaluable.
Five-year follow-up data were available for 73% of patients. Patients
were randomized to tamoxifen alone (arm 1), radiotherapy plus placebo
(arm 2), or radiotherapy plus tamoxifen (arm 3). Arms 2 and 3 were double-blinded.
The principal study objectives were to determine whether tamoxifen
was as effective as radiotherapy in controlling ipsilateral breast
tumor recurrence and whether the addition of tamoxifen to
radiotherapy was superior to either modality alone.
Secondary endpoints included the effect of these treatments on
disease-free survival and the occurrence of contralateral breast
Dr. Wolmark reported that the rate of ipsilateral recurrence [Table]
was 2.8% with radiation plus tamoxifen vs 10.7% with tamoxifen alone (P
= .0000002). The rate of ipsilateral recurrence was twofold greater
in the group treated with tam-oxifen alone, compared to radiation
alone (P = .009). Eighty percent of the ipsilateral
recurrences were invasive.
The rate of contralateral recurrence was 3.0% with radiation alone vs
0.6% with radiation plus tamoxifen (P = .04). Contralateral
breast cancers occurred in 11 of 336 patients (3.3%) randomized to
radiation alone and in 8 of 673 patients (1.2%) receiving tamoxifen
(with or without radiation), a 65% reduction (P = .04).
There were no significant differences in overall or
breast-cancer-related mortality in the three treatment groups.
Tamoxifen cannot replace radiation therapy for controlling
ipsilateral breast cancer recurrences, and the combination of
tamoxifen plus radiation therapy is superior to either therapy
alone, Dr. Wolmark said.
He noted that tamoxifen also reduced the incidence of
contralateral breast cancer, as it has in every other NSABP trial in
which tamoxifen was tested.