Public Release: 

Addition of anesthetic to radioisotope injection reduces pain in patients undergoing sentinel-lymph-node mapping for breast cancer

Lancet

The addition of the anaesthetic lidocaine to radiocolloid injection for sentinel- lymph-node (SLN) mapping in patients with early breast cancer reduces injection pain and improves patient comfort without compromising SLN identification, and should be introduced as standard practice, concludes an Article published Online First and in the August edition of the Lancet Oncology.

Sentinel-lymph-node (SLN) mapping and biopsy are used to determine how far cancer has progressed into the lymph nodes in early stage breast cancer. A radioactive colloid and/or blue dye are injected into the area of the tumour and follow the path that tumour cells are most likely to take from the tumour to the lymph nodes. The nodes that initially absorb the dye, the sentinel nodes, are removed and biopsied. Although shown to be effective, a radiocolloid injection is a painful procedure for which there is currently no effective pain management.

To investigate methods of pain control, Alexander Stojadinovic from the United States Military Cancer Institute, Washington, USA, and colleagues conducted the first randomised trial to assess whether pH modification of the radioisotope formulation with sodium bicarbonate or addition of the anaesthetic lidocaine could reduce injection pain in patients undergoing SLN mapping.

The authors assessed 121 patients with early stage breast cancer who were randomly assigned to receive either the standard topical 4% lidocaine cream and standard radiocolloid injection (28), or topical placebo cream and radiocolloid injection containing either sodium bicarbonate (31), 1% lidocaine (32), or sodium bicarbonate and 1% lidocaine (30). Immediately after the injection patients were asked to report the pain experienced at the time of injection using a pain rating scale and a pain intensity questionnaire.

Overall, findings showed a significant reduction in pain reported in the two groups of patients whose injection contained 1% lidocaine, without significantly affecting the success of SLN identification. However, pH modification of the radioisotope solution showed no additional benefit compared with the standard preparation.

Mean score on the pain rating scale (0=no pain and 10=most pain) was 6.0 for the standard care group, 4.7 for the sodium bicarbonate group, 1.6 for the 1% lidocaine group, and 1.6 for the sodium bicarbonate plus 1% lidocaine group. Mean pain rating intensity according to the questionnaire (0󈞺) was 17.5 for the standard care group, 15.4 for the sodium bicarbonate group, 4.6 for the 1% lidocaine group, and 3.4 for the sodium bicarbonate plus 1% lidocaine group.

The authors conclude: "For centres that use standard radiocolloid injections for SLN mapping in patients with early breast cancer...adding 1% lidocaine can significantly improve patient comfort...and should be considered a new standard of practice."

In an accompanying Reflection and Reaction comment, Hiram Cody from the Memorial Sloan-Kettering Cancer Center, New York, USA, praises the authors for addressing a problem which has been widely ignored by the surgical community and says: "All of us who use [radiocolloid injections]...are well advised to add lidocaine to our injection protocols; many patients will benefit."

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Alexander Stojadinovic, United States Military Cancer Institute, Washington, USA. T) +1 202 782 9696 E) Alexander.stojadinovic@amedd.army.mil

Professor Hiram Cody, Memorial Sloan-Kettering Cancer Center, New York, USA. T) +1 212 639 5244 E) codyh@MSKCC.org

For full Article and Reflection and Reaction, see: http://press.thelancet.com/tlolidocaine.pdf

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