Technical effects of adding 1 % lidocaine to technetium sulfur colloid for sentinel lymphatic mapping in early breast cancer: analysis of data from a double-blind randomized controlled trial

A Four-Arm Randomized Clinical Trial of Topical Pain Control for Sentinel Node Radiotracer Injections in Patients with Breast Cancer

BACKGROUND

Radioactive tracer injections for breast cancer sentinel lymph node mapping can be painful. In this randomized trial, we compared four approaches to topical pain control for radiotracer injections.

METHODS

Breast cancer patients were randomized (9 April 2021-8 May 2022) to receive the institutional standard of ice prior to injection (n = 44), or one of three treatments: ice plus a vibrating distraction device (Buzzy®; n = 39), 4% lidocaine patch (n = 44), or 4% lidocaine patch plus ice plus Buzzy® (n = 40). Patients completed the Wong-Baker FACES® pain score (primary outcome) and a satisfaction with pain control received scale (secondary). Nuclear medicine technologists (n = 8) rated perceived pain control and ease of administration for each patient. At study conclusion, technologists rank-ordered treatments. Data were analyzed as intention-to-treat. Wilcoxon rank-sum tests were used to compare pain scores of control versus pooled treatment arms (primary) and then control to each treatment arm individually (secondary).

RESULTS

There were no differences in pain scores between the control and treatment groups, both pooled and individually. Eighty-five percent of patients were 'satisfied/very satisfied' with treatment received, with no differences between groups. No differences in providers' perceptions of pain were observed, although providers perceived treatments involving Buzzy© more difficult to administer (p < 0.001). Providers rated lidocaine patch as the easiest, with ice being second.

CONCLUSION

In this randomized trial, no differences in patient-reported pain or satisfaction with treatment was observed between ice and other topical treatments. Providers found treatments using Buzzy® more difficult to administer. Given patient satisfaction and ease of administration, ice is a reasonable standard.

Moving a neodymium magnet promotes the migration of a magnetic tracer and increases the monitoring counts on the skin surface of sentinel lymph nodes in breast cancer

Background

We suspected that moving a small neodymium magnet would promote migration of the magnetic tracer to the sentinel lymph node (SLN). Higher monitoring counts on the skin surface before making an incision help us detect SLNs easily and successfully. The present study evaluated the enhancement of the monitoring count on the skin surface in SLN detection based on the magnet movement in a sentinel lymph node biopsy (SNB) using superparamagnetic iron oxide (SPIO) nanoparticles.

Methods

After induction of general anesthesia, superparamagnetic iron oxide nanoparticles were injected sub-dermally into the subareolar area or peritumorally. The neodymium magnet was moved over the skin from the injection site to the axilla to promote migration of the magnetic tracer without massage. A total of 62 patients were enrolled from February 2018 to November 2018: 13 cases were subjected to magnet movement 20 times (Group A), 8 were subjected to 1-min magnet movement (Group B), 26 were given a short (about 5 min) interval from injection to 1-min magnet movement (Group C), and 15 were given a long (about 25 min) interval before 1-min magnet movement using the magnetometer’s head (Group D). In all cases, an SNB was conducted using both the radioisotope (RI) and SPIO methods. The monitoring counts on the skin surface were measured by a handheld magnetometer and compared among the four groups. Changes in the monitoring count by the interval and magnet movement were evaluated.

Results

The identification rates of the SPIO and RI methods were 100 and 95.2%, respectively. The mean monitoring counts of Group A, B, C, and D were 2.39 μT, 2.73 μT, 3.15 μT, and 3.92 μT, respectively (p < 0.0001; Kruskal-Wallis test). The monitoring counts were higher with longer magnet movement and with the insertion of an interval. Although there were no relationships between the monitoring count on the skin surface and clinicopathologic factors, magnet movement strongly influenced the monitoring count on the skin surface.

Conclusion

Moving a small neodymium magnet is effective for promoting migration of a magnetic tracer and increasing monitoring counts on the skin surface.

Trial registration

UMIN, UMIN000029475. Registered 9 October 2017

Buffering the Suffering of Breast Lymphoscintigraphy

Breast lymphoscintigraphy with ^99mTc-sulfur colloid is frequently performed before breast-conserving surgery to delineate drainage to a sentinel node. Tracer injection for lymphoscintigraphy can be painful. Our aims were to determine whether administering a solution of buffered lidocaine immediately before lymphoscintigraphy injection could both reduce the patients' pain and increase nuclear medicine technologists' satisfaction with performing the procedure. Methods: A pain scale survey was obtained from patients undergoing breast lymphoscintigraphy with or without buffered lidocaine. Our nuclear medicine technologists were also surveyed for their satisfaction with the procedure, both with and without the addition of buffered lidocaine. Results: The patients' reported pain decreased by 86% with the addition of buffered lidocaine. Technologist satisfaction with performing the procedure increased by 36%. Conclusion: Lidocaine buffered with sodium bicarbonate injected before lymphoscintigraphy significantly reduces pain experienced by the patient and improves nuclear medicine technologist satisfaction in performing the procedure.

Reducing perceived pain levels during nonbreast lymphoscintigraphy

PURPOSE

The aim of this study was to quantify the reduction of perceived pain levels during lymphoscintigraphy for melanoma by altering the pH of the Tc-sulfur colloid to near the physiologic value of 7.40.

PATIENTS AND METHODS

This is an institutional review board- and Food and Drug Administration-approved randomized, double-blinded, prospective crossover trial, registered with clinicaltrials.org. Before beginning the procedure and after signing informed consent, 60 serial enrollees presenting for sentinel lymph node imaging of melanoma of the thorax and appendicular structures completed a questionnaire addressing background information, administered by a research support nurse.An investigator (N.H.) prepared the injections to be used and labeled them such that no one else could discover which injections contained standard-of-care solution and which contained the pH-altered solution (buffered to near pH 7.40 using sodium bicarbonate).After each injection, the enrollee was asked by a research support nurse to quantify the pain of each injection using a scale of 0 to 10. The injection site location (head, thorax, appendicular structures, and other) was also recorded.

RESULTS

Sixty subjects were enrolled in the study, of which 57 had complete data. On average, there was a significant mean (SD) decrease of 1.42 (2.17) points (95% confidence interval, 0.85-2.00) on a pain scale of 0 to 10 when the buffered injections were used as compared with the standard-of-care injections (P < 0.0001). Ordering of injections did not significantly affect perceived pain scores.

CONCLUSIONS

The use of sodium bicarbonate to buffer the pH of Tc-sulfur colloid to near the physiologic value of 7.40 significantly reduced perceived pain levels during nonbreast lymphoscintigraphy.

Intraoperative radiocolloid injection for sentinel node biopsy postneoadjuvant chemotherapy

BACKGROUND

This study sought to determine significance of radiocolloid injection timing for sentinel node biopsy (SNB) after neoadjuvant chemotherapy (NAC).

MATERIAL AND METHODS

A retrospective comparison of intraoperative (IRCI) and preoperative (PRCI) radiocolloid injection for SNB was performed in breast cancer patients who had completed NAC. The sentinel node identification rate (SNIDR) was tested for noninferiority by a two-proportion z-test. The differences between clinical demographics, pathologic demographics, and SNIDR were evaluated by Fisher exact test. The difference in the number of sentinel nodes removed was analyzed by two-sample t-test.

RESULTS

In the 6-y study period, 120 SNB were performed after NAC: 84 received PRCI and 36 received IRCI. The two groups were similar except there were fewer clinical T2 and more clinical T3 and T4 with IRCI (P = 0.0008). The SNIDR was 92.9% with PRCI and 80.6% with IRCI. By two-proportion z-test, IRCI was not "noninferior" (P = 0.5179). By Fisher exact test, the SNIDR of the two groups did not differ. The SNIDR differs only in patients who experience T downstaging (100% versus 80%, P = 0.0173). The mean number of lymph nodes removed was higher with IRCI: 3.38 versus 2.49 nodes (P = 0.0068). There were more positive SNB with IRCI: 32.1% versus 55.2%, (P = 0.0432). The incidence of nontherapeutic axillary dissection was similar between the two groups (3.6% for PRCI versus 5.6% for IRCI).

CONCLUSIONS

IRCI for SNB after NAC may be inferior to PRCI.

Diagnostic accuracy of sentinel node identification is maintained with the addition of local lidocaine and subareolar radioactive colloid injection

Preoperative sentinel node localization (SNL) using a subareolar injection of radiotracer technetium-99m-sulfur colloid (Tc(99m)SC) is associated with significant pain. Lidocaine use during SNL is not widely adopted partly due to a concern that it can obscure sentinel node identification and reduce its diagnostic accuracy. We prospectively identified women with a biopsy-proven infiltrating breast cancer who were awaiting a SNL. The women completed the McGill pain questionnaire, Visual Analog Scale, and Wong-Baker FACES Pain Rating Scale prior to and following SNL. We identified a retrospective cohort of women with similar demographic and tumor characteristics who did not receive lidocaine before SNL. We compared sentinel lymph node identification rates in the two cohorts. We used Wilcoxon rank sum tests to compare continuous measures and Fisher's exact test for categorical measures. Between January 2011 to July 2012, 110 women consented, and 105 were eligible for and received lidocaine prior to Tc(99m)SC injection. The post-lidocaine identification rate of SNL was 95 % with Tc(99m)SC, and 100 % with the addition of intraoperative methylene blue dye/saline. Pain range prior to and following the SNL was unchanged (P = 0.703). We identified 187 women from 2005 to 2009 who did not receive lidocaine during preoperative SNL. There was no significant difference in the success rate of SNL, with or without lidocaine (P = 0.194). The administration of lidocaine during SNL prevents pain related to isotope injection while maintaining the success rate. We have changed our practice at our center to incorporate the use of lidocaine during all SNL.