Widespread Mechanical Pain Hypersensitivity as a Sign of Central Sensitization after Breast Cancer Surgery: Comparison between Mastectomy and Lumpectomy

Objective. To investigate the differences in widespread pressure pain hypersensitivity after two surgery approaches for breast cancer: mastectomy or lumpectomy. Design. A cross-sectional blinded study. Setting. Widespread pressure pain hypersensitivity has been suggested as a sign of central sensitization. No study has previously investigated the presence of widespread pain pressure hypersensitivity after breast cancer surgery. Patients. Twenty-one women (age: 52 +/- 9 years old) who had received lumpectomy after breast cancer, 21 women (mean age: 50 +/- 10 years old) who had received mastectomy surgery after breast cancer, and 21 healthy women (age: 51 +/- 10 years old) participated. Outcome Measures. Pressure pain thresholds (PPT) were bilaterally assessed over C5-C6 zygapophyseal joint, deltoid muscle, second metacarpal, and the tibialis anterior muscle. Results. Women with mastectomy had greater intensity of neck (t = -2.897; P = 0.006) and shoulder/axillary (t = -2.609; P = 0.013) pain as compared with those who received lumpectomy. The results showed that PPT were significantly decreased bilaterally over the C5-C6 zygapophyseal joint, deltoid muscle, second metacarpal, and tibialis anterior muscle in both lumpectomy and mastectomy groups as compared with healthy women in all points (P < 0.001), without differences between both breast cancer groups (P = 0.954). No significant differences in the magnitude of PPT levels between both breast cancer groups were found (all, P > 0.450). PPT levels over some areas were negatively associated with the intensity of pain in the mastectomy, but not lumpectomy, group. Conclusion. The current study found widespread pressure pain hyperalgesia in women who received breast cancer surgery suggesting central spreading sensitization. The degree of central sensitization was similar between lumpectomy and mastectomy surgery.