Paclitaxel Efficacy and Toxicity in Older Women with Metastatic Breast Cancer: Combined Analysis of CALGB 9342 and 9840

Background: Two Cancer and Leukemia Group B (CALGB) studies were utilized to determine the efficacy and tolerability of paclitaxel (Taxol) in older patients with metastatic breast cancer.

Patients And Methods: CALGB 9840 evaluated weekly paclitaxel (80 mg/m(2)) versus paclitaxel every 3 weeks (175 mg/m(2)); CALGB 9342 evaluated three doses of paclitaxel as follows: 175, 210 and 250 mg/m(2) each over 3 h every 3 weeks. Of the 1048 patients, paclitaxel was used first line in 57%. The groups: (i) <55 years (45%), (ii) 55-64 years (29%), and (iii) ≥65 years (26%).

Results: Tumor response was also similar among age groups. First-line therapy (P = 0.0001) and better performance status (PS) (P = 0.018) were significantly related to higher response. Age did not significantly relate to overall survival (OS) or progression-free survival (PFS). First-line therapy, better PS, estrogen receptor positive status and a fewer number of metastatic sites were significantly related to improved OS and PFS. The grade ≥3 toxic effects that increased linearly with age were leucopenia (P = 0.0099), granulocytopenia (P = 0.022), anorexia (P = 0.028), bilirubin elevation (P = 0.0035) and neurotoxicity (P < 0.0001). Patients over 65 years receiving second-line therapy had the shortest time to neurotoxicity.

Conclusions: Older women with breast cancer derive similar efficacy from treatment with paclitaxel as younger women. Older women are at increased risk for specific toxic effects.