The Value of Combined Peritumoral and Subdermal Injection Techniques for Lymphoscintigraphy in Detection of Sentinel Lymph Node in Breast Cancer

Radiolocalization of atypical lesions for intraoperative identification: technical factors, localization quality, success rates, patient safety, and spectrum of applications

Background

To retrospectively analyze perilesional technetium Tc-99m MAA injection for intraoperative localization of atypical soft-tissue and bone lesions within a single tertiary referral center in order to determine technique, safety, and clinical utility of these procedures.

Methods

An IRB compliant, retrospective electronic chart review (2010–2017) exploring surgical excision of atypical (non-pulmonary, non-breast, non-sentinel node) lesions guided by Tc-99m MAA perilesional injection. Patient demographics, lesion location, lesion size, radiotracer injection technique, radiotracer injection complications, scintigraphy technique, scintigraphic quality, intraoperative time, lesion identification in surgery, and pathological diagnoses were recorded.

Results

Twenty-two atypical radiolocalization exams were identified. Lesion sites included rib (7), lymph node (4), abdominal wall (3), mesenteric (3), gallbladder fossa (1), retroperitoneum (1), parietal pleura (1), anterior mediastinum (1), and iliac bone (1). Average lesion size was 14 mm (range 5–23 mm). Eighteen (82%) radiotracer injections used computed tomography guidance and 4 (18%) used ultrasound guidance. The mean activity of Tc-99m MAA administered was 11.8 MBq (0.32 mCi). A 22-gauge needle was most often used for perilesional injection. No injection complications were reported. The lesions were identified with a hand-held gamma probe during surgery in 100% of cases. Of the samples sent to pathology, 100% were identified and given a diagnosis.

Conclusion

Radiolocalization of atypical lesions may be a valuable technique, guiding minimally invasive surgical removal of lesions that would otherwise be difficult to identify intraoperatively such as non-palpable rib, central mesenteric nodal, and abdominal wall lesions.

Triple-site radiotracer application in breast lymphoscintigraphy and sentinel node discordance

Sentinel lymph node (SLN) biopsy (SLNB) has demonstrated accuracy in the axillary staging of breast cancer patients. Despite variability in selection criteria and technique, an SLN is consistently identified in approximately 96% of cases and in most series predicts the status of remaining axillary LNs in >95% of cases. The false-negative rate of sentinel lymph node biopsy (SLNB) was originally reported as 5%–10% (sensitivity 90%–95%), but improved rates are attainable by experienced surgeons. Radiolocalization with lymphoscintigraphy (LSG) increases SLN identification rates. LSG is a useful tool to establish the abnormal lymphatic drainage patterns and to detect the extra-axillary nodes, particularly internal mammary nodes. Despite controversy regarding the optimal injection method, studies have generally suggested high concordance between the various radiotracer application sites and axillary SLN identification. Discordant SLN identification would have implications for nodal staging as the true SLN might not be identified with individual injection techniques. In the current study, imaging from consecutive patients presenting for breast LSG over a-19 month period was retrospectively reviewed. Radiotracer application was performed with simultaneous injection of peritumoral, subcutaneous, and subareolar regions. This application method provided a mechanism to assess the LSG drainage patterns with a view to assessing injection site concordance and SLN identification rates. Data from 123 breast LSG patients were reviewed. Using our radiotracer technique, the axillary SLN identification rate was 98%. A single axillary node was detected in 110, two axillary nodes were detected in 10, and no axillary node was detected in three patients. Among those 10 patients in whom two axillary nodes were seen, at least two cases of discordant drainage occurred from different injection sites. This study demonstrates that different LSG injection sites can result in the identification of different axillary sentinel nodes although this appears to be a rare event. This finding may be of clinical importance if the true SLN is sought. In addition, the multisite injection technique appears to be an optimal method of axillary SLN identification, with high SLN detection rates.

Status of sentinel lymph node for breast cancer

Long-awaited results from randomized clinical trials designed to test the validity of sentinel lymph node biopsy (SLNB) as replacement of axillary lymph node dissection (ALND) in management of early breast cancer have recently been published. All the trials conclude SLNB has survival rates comparable to those of ALND (up to 10 years in one study) and conclude SLNB has less morbidity than ALND. All the trials support replacing ALND with SLNB for staging in early breast cancer; all support SLNB as the standard of care for such cancer. The SLNB protocols used in the trials varied, and no consensus that would suggest a standard protocol exists. The results of the trials and of other peer-reviewed research do, however, suggest a framework for including some specific methodologies in accepted practice. This article highlights the overall survival and disease-free survival data as reported from the clinical trials. This article also reviews the status of SLN procedures and the following: male breast cancer, the roles of various imaging modalities (single-photon emission computed tomography/computed tomography, positron emission tomography/computed tomography, and ultrasound), ductal carcinoma in situ, extra-axillary SLNs, SLNB after neoadjuvant chemotherapy, radiation exposure to patients and medical personnel, and a new radiotracer that is the first to label SLNs not by particle trapping but by specific macrophage receptor binding. The proper Current Procedural Terminology (CPT) code for lymphoscintigraphy and SLN localization prior to surgery is 78195.

Ultrasound-guided sentinel node procedure for nonpalpable breast carcinoma

PURPOSE

Peritumoral and periareolar tracer injection techniques lead to different lymphatic drainage in sentinel lymph node biopsy procedures. In a prospective study, the visualization and identification rates of the ultrasound (US)-guided tracer injection technique for palpable and nonpalpable breast tumors were evaluated.

METHODS

In 1262 consecutive patients with cT₁₋₂N0 breast cancer, sentinel lymph node biopsy was performed following peritumoral tracer injection. In the case of nonpalpable breast lesions, Tc-99m nanocolloid injections were given using a 7.5 MHz US probe. In the case of ultrasonographically nonvisible microcalcifications, the US-guided injection technique was wire guided.

RESULTS

In 331 patients with nonpalpable breast lesions (26.2%), the lymphoscintigraphic visualization and surgical retrieval rates of axillary sentinel lymph nodes (SLNs) were 98.5 and 99.4%, respectively. For internal mammary (IM) SLNs, these rates were 21.1 and 17.8%, respectively. These rates were similar in patients with palpable and nonpalpable tumors. Axillary metastases were detected in 38.7% of the patients with palpable tumors versus 16.5% of those with nonpalpable tumors (P<0.001), whereas IM metastases were found in 4.8 and 3.0% of patients, respectively (P=0.165).

CONCLUSION

In nonpalpable breast lesions, the US-guided injection technique is an accurate technique for SLN identification and retrieval. The substantial rates of IM metastases in both palpable and nonpalpable lesions favor a peritumoral tracer injection technique.

The effect of the excisional biopsy in the detection of the sentinel lymph node by lymphoscintigraphy and intraoperative gamma probe in breast cancer

OBJECTIVE

Sentinel lymph node (SLN) scintigraphy is used widespread in breast cancer, but the effect of the radionuclide agent, injection technique, the method of biopsy, tumor localization, breast size remain controversial. We examined the effects of the excisional biopsy in the rate of the SLN identification with lymphoscintigraphy (LS) and intraoperative gamma probe (IGP).

MATERIAL AND METHODS

One hundred patients (age range: 28-79 yr) with breast cancer were included in the study. They consisted of two groups: Group 1; there were 58 patients without excisional biopsy Group 2; there were 42 patients with excisional biopsy LS: 2 hours before the operation, 37 MBq/ ml Tc 99m colloidal rhenium sulphide was injected at the periaerolar region intradermally Anterior and lateral static images were acquired. IGP: The hot spot of greatest radioactivity were marked on the skin during the surgery with IGP and removed. Excised SLNs were examined with frozen section. After that histopathological and immunohistochemical examinations were performed.

RESULTS

SLNs were found in all patients in group 1 (100%), in 39 patients of group 2 (93%) with LS. SLNs were excised in 57 of the 58 patients of group 1 (98%), in 38 of the 42 patients of group 2 (90%) with IGF. Metastases were found in SLNs in 27 patients (28%). Axillary dissection was performed in these patients.

CONCLUSION

According to results of our study the excisional biopsy was not the only factor but also other factors such as breast mass, calcified or metastatic lymph node may be affected the success rate of the SLN.

CONFLICT OF INTEREST

None declared.

Stability of the mixture of technetium-99m human serum albumin and lidocaine hydrochloride for clinical application

AIM

To evaluate the stability of the mixture of technetium-99m (99mTc) human serum albumin (HSA) with the local anesthetic lidocaine hydrochloride.

MATERIALS AND METHODS

We assessed three preparations of the radiotracer, 99mTc-HSA, filtered 99mTc-HSA, and a mixture of 99mTc-HSA with lidocaine hydrochloride and then filtered. Time sequence evaluation was performed on all the specimens (n= 10) at 0, 30, 60, 90, 120, 150, and 180 min after preparation. Measurements of radiochemical purity as labeling stability and pH value change were conducted for each group of specimens.

RESULTS

We found no definite difference in the stability before and after the filtering procedure for 99mTc-HSA. However, we showed a decline of stability in the mixture of 99mTc-HSA with lidocaine. The filtered specimens showed a relatively higher pH value, towards a more neutral status, as compared with the unfiltered specimens.

CONCLUSION

Though pain relief for the patient receiving sentinel lymph node mapping is important, a preparation of a mixture of 99mTc-HSA and lidocaine may cause radiolabeling instability. Furthermore, compared with the filtered 99mTc-sulfur colloid, a filtering procedure does not change the labeling stability of the 99mTc-HSA. On the contrary, the filtered preparation was neutralized closer to the physiologic condition. For lymphoscintigraphic studies,our results suggested that pretreatment with local anesthesia followed by subdermal injection of a filtered 99mTc-HSA rather than a pre-mixture with lidocaine is appropriate for clinical application.