Effect of patient age, breast density, and topical anesthetic cream on perceived pain with sentinel lymph node scintigraphy.

Unlabelled: Although an extremely useful technique for sentinel lymph node (SLN) identification in breast cancer, injections of (99m)Tc-sulfur colloid can be quite painful. The purpose of this study was to determine whether there is a correlation between perceived pain of injection and age, breast density, or timing of topical anesthetic cream administration.

Methods: A retrospective review was conducted of women with breast cancer who received injections for sentinel lymphoscintigraphy from 2008 to 2010. After receiving 4 unilateral, intradermal, periareolar injections, women ranked their pain using a comparative scale (0 = no pain; 10 = unbearable pain). There were 3 categories based on length of time that topical anesthetic cream (2.5% lidocaine and 2.5% prilocaine) was applied before injection (1 h prior, 20 min prior, or no cream). In addition, other demographic information and breast density on mammography were analyzed for correlation with the comparative pain scale.

Results: Among the 82 women (mean age, 58 y; range, 32-87 y), a wide spectrum on the comparative pain scale was recorded (mean, 4.0; SD, 2.6), with 35% attesting to significant pain, rated 5 or greater. The demographic information and breast density per the Breast Imaging Reporting and Data System were retrospectively reviewed (density: fatty, 14.6%; scattered fibroglandular, 36.6%; heterogeneous, 39.0%; extremely dense, 9.8%). Using bivariate linear regression, no correlation between the comparative pain scale and age (R(2) = 0.0029, P = 0.63) or breast density (R(2) = 0.00049, P = 0.84) was identified. Most patients had topical anesthetic cream applied 20 min before injection (n = 47, or 57.3%) with 24 (29.3%) having topical anesthetic cream applied 1 h beforehand. Eleven women (13.4%) had no topical anesthetic cream applied because of patient preference or concern about allergy. Again, no correlation was found between comparative pain scale and time of application or use of topical anesthetic cream (Kruskal-Wallis: χ(2)(2) = 1.0, P = 0.61).

Conclusion: A wide range of pain is experienced with sentinel lymphoscintigraphy injections. In this study, the severity of perceived pain did not correlate with age or breast density. There was no correlation between the use or timing of anesthetic cream and perceived pain from injection. The use of topical anesthetic cream may need to be reexamined, and other means of pain control should be further investigated.