Pain severity and impairment of activity between pegfilgrastim (P) and fixed-dose filgrastim (F) in women with early-stage breast cancer receiving chemotherapy.

Abstract

e19570 Background: In comparative trials of P and F, bone and joint pain are evident and with similar incidences. Also, muscle pain is clinically noted. Pain severity may differ between P and F, especially when a short fixed-dose regimen of F is used. Methods: This is a prospective observational and ethics-approved study. It compares the incidence & severity of muscle and/or joint pain (MJP) in patients (pts) receiving P (6mg SC for 1 day) or fixed-dose F (300mcg SC for 7-8 days) initiated 24 hours after chemotherapy. Eligible were women with breast cancer receiving neo- or adjuvant chemotherapy, and P or F. Choice of P or F were at the oncologist’s discretion based on patient preference & insurance coverage. Pts were ineligible if they could not complete the pain diary, or had received P or F in the past 6 months. Efficacy of P and F was evaluated by comparing febrile neutropenia (FN) and neutropenia (N) requiring delay of the second cycle of chemotherapy. Patient & treatment characteristics were captured to assess for risk factors for developing MJP. A pain diary assessed MJP severity, its management and impact on everyday activities. It was completed starting the evening of chemotherapy for 14 consecutive days. Statistical analysis was performed with Stata 12, including multi-level longitudinal mixed models for MJP scores. Results: 140 pts were enrolled with mean age 52 yr and 58% receiving docetaxel-based chemotherapy. One-third received F and two-thirds received P. Both diary muscle and joint pain peaked in prevalence and severity on days 3 to 6. Over 50% of pts reported MJP at the peak. Pain that increased ≥3 points from baseline was reported by 48% of pts. Daily activities were affected in 48% of 1,960 reporting-days, with 26% reporting moderate or severe impairment. Despite similar incidences of pain, P was associated with lower mean muscle (p=0.0049) and joint (p=0.014) pain scores by regression analyses. FN and N were not different. Use of docetaxel was the sole baseline risk factor for developing MJP. Conclusions: Patients experience substantial MJP with impairment of daily activities but pts receiving pegfilgrastim experience less pain and less burden relating to pain.