A previous randomized trial (CALGB 9344/Intergroup 0148) compared four cycles of adjuvant
doxorubicin/
cyclophosphamide (AC) to four cycles of AC plus four cycles of
paclitaxel (AC + T) and demonstrated that the addition of
paclitaxel improved locoregional control (LRC) in patients with node-positive
breast cancer. However, it could not be determined whether it was the
paclitaxel or the increased duration of
chemotherapy that led to this improvement. The present study aimed to analyze whether the addition of
paclitaxel to a
doxorubicin-based regimen improves LRC in a cohort of patients who all received eight total cycles of
chemotherapy. Five hundred eleven women with operable
breast cancer were randomized on a single-institution prospective trial to receive
5-fluorouracil,
doxorubicin,
cyclophosphamide (FAC) × 8 cycles (n = 252) or FAC × 4 cycles plus
paclitaxel × 4 cycles (TFAC) (n = 259). Rates of LRC and overall survival (OS) were analyzed. Median follow-up was 124 months (range 5-167 months). The 10-year LRC rate was 92.6 versus 93.1% in the FAC versus TFAC arms, respectively (P = 0.26). The LRC between treatment arms did not differ when analyzed by locoregional treatment group:
breast conservation therapy (BCT),
mastectomy alone (M), and
mastectomy + radiation (M + RT). The 10-year LRC rates were 95.1% (FAC) versus 91.2% (TFAC) after BCT (P = 0.98), 89.5% (FAC) versus 93.4% (TFAC) after M (P = 0.24), and 94.7% (FAC) versus 96.5% (TFAC) after M + RT (P = 0.59). Additionally, there was no difference in OS between the treatment arms, with 10-year OS rates of 78.4% (FAC) versus 81.7% (TFAC) (P = 0.93). The addition of
paclitaxel to a
doxorubicin-based regimen had no impact on LRC, regardless of the type of local
therapy received. Historically inferior LRC with AC
chemotherapy alone versus AC + T may have been due to an inadequate duration of systemic
therapy and not due to the absence of
paclitaxel.