High colloidal uptake in axillary nodes with metastatic disease

Preoperative lymphoscintigraphy during lymphatic mapping for breast cancer: improved sentinel node imaging using subareolar injection of technetium 99m sulfur colloid

BACKGROUND

Preoperative lymphoscintigraphy has been recommended to confirm the successful uptake and direction of migration of radiotracer into sentinel nodes during lymphatic mapping for breast cancer. In addition, preoperative lymphatic mapping may provide a visually useful aid to the relative location of sentinel nodes within a nodal basin. One common method of breast lymphoscintigraphy involves injections of unfiltered technetium 99m sulfur colloid (Tc-99m-SC) directly into parenchymal tissues surrounding a tumor or biopsy cavity (IP injection). Because of the many imaging failures and prolonged imaging times of IP lymphoscintigraphy, the procedure has fallen into disfavor by oncologic surgeons. The purpose of this study is to document the increased success rate of preoperative breast lymphoscintigraphy using a new anatomic site of injection, the subareolar lymphatic plexus (SA injection).

STUDY DESIGN

In the 12 months between December 1, 1998, and December 29, 1999, 42 women with stage I and II breast cancer underwent preoperative lymphoscintigraphy by either the IP (n = 12, December 1998 to May 1999) or SA (n = 30, May 1999 to December 1999) route of injection. Both groups were injected with 1 mCi (37 MBq) of unfiltered Tc-99m-SC followed immediately by external gamma-camera imaging. The success rate for preoperative sentinel node imaging and the total imaging time were recorded in both groups.

RESULTS

The success rate of identifying a sentinel node by SA lymphoscintigraphy was 90% (n = 27 of 30 patients), compared with 50% (n = 6 of 12 patients) for IP lymphoscintigraphy (p = 0.009). The imaging time in the SA injection group was 34 +/- 16 minutes, which was 59% shorter than the imaging time in the IP injection group of 82 +/- 48 minutes (p < 0.001). No uptake into internal mammary nodes was seen in either group.

CONCLUSIONS

Moving the site of injection ofunfiltered Tc-99m-SC to the subareolar lymphatic plexus (SA injection) increased the success rate of preoperative lymphoscintigraphy to 90%, compared with 50% using IP injections. Preoperative SA lymphoscintigraphy resulted in the rapid visualization of axillary sentinel nodes within 30 minutes of SA injection, enabling a visual determination of the approximate number of sentinel nodes and their relative locations within the axilla. We conclude SA injection of unfiltered Tc-99m-SC is superior to IP injections when performing preoperative breast lymphoscintigraphy and is a visually useful aid to lymphatic mapping for breast cancer.

Meta-analysis of sentinel lymph node biopsy in breast cancer

BACKGROUND

Sentinel lymph node biopsy (SLNB) is a minimally invasive way to diagnose axillary lymph node (ALN) metastases in breast cancer. The most important features are ability to identify the SLN (I.D. rate), how often the SLN and ALN pathology match (concordance), and how often the SLN is negative for cancer when the ALNs are positive (false negative). Technique and patient criteria for SLNB vary among studies. This study performed meta-analysis of published studies to determine the I.D., concordance, and false negative rate (1) overall and for (2) both blue dye and radiocolloid, (3) the injection method, (3) palpable and nonpalpable ALNs, and (4) invasive and in situ disease.

METHODS

Inclusion criteria were patients with breast cancer who had SLNB followed by ALN dissection with H&E staining. Meta-analysis was performed using analysis of variance with each observation weighted inversely to its variance. P < 0.05 was considered significant.

RESULTS

Eleven studies (n = 912) met the inclusion criteria. Overall, 762 (84%) SLNs were identified, concordance was 747/762 (98%), and 15/296 (5%) were falsely negative. Highest I.D. rates (P < 0.05) were reported with albumin radiocolloid or dye + radiocolloid (97 and 94%, respectively), with injection around an intact tumor (96%), with invasive cancer (95%), and in the clinically negative axilla (96%). Concordance and false negative rates did not vary.

CONCLUSIONS

The SLN can be identified in over 97% of patients if certain techniques and inclusion criteria are used. SLNB reflects the status of the axilla in 97% of cases and has a 5% false negative rate.

Surgical resection and radiolocalization of the sentinel lymph node in breast cancer using a gamma probe

We have recently reported on a technique of gamma probe localization of radiolabelled lymph nodes to identify the sentinel node in malignant melanoma. In order to determine whether this technique is applicable to assist in staging breast cancer, a pilot study was begun to address two questions: (i) can the sentinel lymph node draining a breast cancer be identified for selective resection; and (ii) is the sentinel lymph node predictive of the status of the entire axillary lymph nodes? One to four hours prior to axillary lymph node dissection, 22 consecutive patients had approximately 0.4 mCi of technetium sulfur colloid in 0.5 ml saline injected around the perimeter of the breast lesion. A hand-held gamma counter was used at surgery to locate the lymph node(s) receiving drainage from the breast. A sentinel lymph node was identified in 18 of 22 patients. Of these 18 patients, the sentinel lymph node was positive in seven of seven patients, with pathologically verified metastatic breast cancer to at least one lymph node. In three out of seven patients, the sentinel lymph node was the only lymph node with metastatic cancer. In this pilot study of breast cancer patients, we conclude that: (i) radiolocalization and selective resection of sentinel lymph nodes is possible; and (ii) the sentinel lymph node appears to predict correctly the status of the remaining axilla. These data justify a larger clinical trial to verify the value of this technique.

Lymphoscintigraphy in vulvar cancer: a pilot study

This pilot study was undertaken to correlate the patterns of lymphatic drainage demonstrated by vulvar lymphoscintigraphy with the clinical and pathologic findings of the inguino-femoral lymph nodes in patients with vulvar cancer. Ten patients were studied with the radionuclide Technetium-antimony trisulfide colloid (Tc 99m ASC) using a perilesional technique. Images were obtained at 2-4 hr postinjection. Four of the six patients with central lesions or lesions that crossed the midline had bilateral groin uptake, and two had unilateral uptake to the side on which the lesion was predominantly located. Three of these patients, each with suspicious groin nodes bilaterally, had metastatic nodal disease, two unilateral and one bilateral, in whom the uptake was bilateral and unilateral, respectively. Three of the four patients with unilateral lesions had ipsilateral groin drainage only and one had no drainage. Three underwent a bilateral lymphadenectomy and none had metastasis. The pattern of Tc 99m ASC uptake was not predictive of metastatic nodal disease. In two of the three patients with unilateral groin recurrence the side of recurrence was the same as that demonstrated on lymphoscintigraphy, and in the third case there was bilateral drainage. Further data are needed to determine the role of lymphoscintigraphy in the management of vulvar cancer.

Lack of efficacy of lymphoscintigraphy in detecting axillary lymph node metastases from breast cancer

Preoperative detection of metastases in regional lymph nodes should constitute a fundamental step towards a better management of breast cancer. The National Cancer Institute of Milan has traditionally been engaged in this particular problem, that is, the search for a new imaging technique for detecting lymph nodal metastases from breast cancer. In 1984 axillary lymphoscintigraphy was performed on 26 patients with operable breast cancer by periareolar injection of 100 mu Ci of 99mTc sulphur microcolloid. The regional lymph nodes were identified as spot areas and a comparison was made between the number of primary draining axillary lymph nodes and their pathological examination. In only 2 of the 26 patients have more than 3 spot areas been revealed by axillary scintiscan, but this finding did not correspond to metastatic invasion. The lymphoscintigraphy pattern of the other 24 patients did not suggest any pathological condition. From our experience the method does not appear to help either a precise diagnosis of breast disease or the definition of the extent of mammary cancer.

An evaluation of pelvic lymphoscintigraphy in the staging of colorectal carcinoma

Lymphoscintigraphy was used to delineate the lymphatic drainage of the rectum and distal colon in 18 patients with carcinoma of the rectum or sigmoid colon, in four with inflammatory disease of the large bowel and in 20 controls without colorectal pathology. Abdominal imaging was performed after submucosal injection of either 4 mCi 99mTc-antimony sulphide colloid or 0.5 mCi 99mTc-dextran into the rectum through a proctoscope. In nine patients with colorectal carcinoma, abdominal imaging was performed immediately pre-operatively and the excised specimen of large bowel was also imaged in vitro immediately postoperatively. The presence or absence of nodal uptake of radionuclide on abdominal scanning did not discriminate between normal and diseased large bowel, and the extent of nodal uptake demonstrated either by abdominal scans or by in vitro scans of excised specimens bore no relationship to the presence or absence of nodal metastases demonstrated histologically in the cancer patients. Pelvic lymphoscintigraphy as performed in this study has no demonstrable value in the diagnosis or staging of colorectal cancer.

Assessment of the potential uses of liposomes for lymphoscintigraphy and lymphatic drug delivery. Failure of 99m-technetium marker to represent intact liposomes in lymph nodes

The in vivo fate of subcutaneously injected neutral SUV liposomes in rats was examined using a membrane marker, 99mTc, and an aqueous marker, 125I-labelled poly(vinyl pyrrolidone). Liposomes with entrapped 125I-labelled poly(vinyl pyrrolidone) were labelled with 99mTc by the SnCl2 method. 99mTc-radioactivity was localized several-fold more in the primary and secondary regional lymph nodes than 125I-labelled poly(vinyl pyrrolidone)-radioactivity. Similarly, 99mTc-radioactivity appeared and was subsequently cleared from the circulation much more rapidly than 125I-labelled poly(vinyl pyrrolidone). The gel chromatography of the lymph node homogenate revealed that 60-70% of 125I-labelled poly(vinyl pyrrolidone)-radioactivity was in the liposome fractions, whereas only 3% of 99mTc-radioactivity was co-eluted with the liposomes. Thus, the two markers have different fates in the lymphatics, and the presence of all 99mTc-radioactivity does not represent the 60-70% of intact liposomes present in lymph nodes. Using the aqueous marker 125I-labelled poly(vinyl pyrrolidone), the lymph node localization of positive, negative and neutral small unilamellar vesicles was studied, and it was found that 125I-radioactivity was more localized from negative liposomes than from positive liposomes, which in turn was more localized than that from neutral liposomes. Thus, these findings differ from those reported earlier, where the authors used 99mTc as a liposomal marker. In vitro studies showed that liposomes of preparations containing 20 mol% cholesterol became 'leaky' to low-molecular-weight drugs, for example, methotrexate (Mr 454) to a much greater extent than with a large-molecular-weight substance, 125I-labelled poly(vinyl pyrrolidone) (Mr 30 000-40 000), when incubated with rat lymph at 37 degrees C. Using the two markers 99mTc and 125I-labelled poly(vinyl pyrrolidone) it was found that the localization of both radioactivities was reduced in lymph nodes draining lambda-carrageenan-treated footpads. In conclusion, it is suggested that liposomes can be used for the delivery of drugs to diseased lymph nodes, and it would be worthwhile examining the possibilities of using alternative methods of labelling liposomes with 99mTc rather than using the SnCl2 technique, or using other radionuclides as markers for gamma-scan imaging.

The preoperative detection of axillary lymph node metastases in breast cancer by isotope imaging

Axillary lymphoscintigraphy using 99Tcm-labelled liposomes was carried out in 40 patients with breast cancer as a part of pretreatment staging in an attempt to improve the accuracy of axillary evaluation. Patients were injected interstitially in the periareolar region of each breast with 250–300 μCi of 99Tcm-labelled liposomes. Subsequently the patients were imaged with a gamma-camera using computerized data processing. Interpretation of images was based on prior experimental data; a diminished uptake of isotope by the primary regional lymph node (PRLN) and the group of axillary regional lymph nodes (RLN) draining the tumour, when compared to the control side, was considered to be abnormal and to suggest node metastases. An equal or enhanced uptake by the PRLN or RLN draining the tumour, when compared to the control side, was considered normal, indicating an absence of lymph node metastases. Eighteen patients (45 per cent) had abnormal scans and 14 patients (35 per cent) had normal scans. Eight patients (20 per cent) had technically unsatisfactory images where axillary nodes could not be identified. Twenty-two patients of the 32 with evaluable scans had correlation of preoperative images with postsurgical axillary lymph node histopathology. One patient out of 12 with an abnormal scan had normal lymph nodes on serial sectioning, and 2 patients out of 10 with normal scans had lymph node metastases. Eight of the 32 patients (25 per cent) with evaluable images had enhanced uptake of isotope by the PRLN and RLN draining the tumour. In 3 of these cases a marked reactive hyperplasia only was shown on histopathological examination, in 2 cases the reactive hyperplasia was associated with lymph node metastases, accounting for the 2 false negative interpretations. This preliminary study suggests that axillary lymphoscintigraphy may be of value in preoperative staging in breast cancer. Long term studies are needed to evaluate the prognostic potential of such a test as a measure of macrophage function. Further studies, by blind replication, are required to evaluate the accuracy of axillary lymph node imaging.

Lymphoscintigraphy--techniques and applications in the management of breast carcinoma

Radiocolloid lymphoscintigraphy is a versatile, simple technique which has been utilized extensively in the assessment of lymphatic function and structure in anatomic regions accessible to neither clinical examination nor radiocontrast lymphography, as well as in circumstances where radiocontrast lymphography is not feasible. The most important requirement for an effective study are: (a) Determination of the appropriate injection site for reproducibly visualizing the majority of the lymphatics under study and, (b) use of an agent with the optimum properties of a preformed small, uniform, well-dispersed particle colloid. Multiple applications of lymphoscintigraphy in the patient with breast carcinoma have demonstrated its value in distinguishing abnormalities of the internal mammary lymphatics shown to have significant prognostic implications, in providing accurate localization of the parasternal lymphatics for radiation therapy and its potential for determining the status of axillary lymphatics in lieu of surgical intervention. The following review is based on an experience of over 6500 studies in 5550 patients with breast carcinoma.

Internal mammary lymphoscintigraphy: current status in the treatment of breast cancer

In the management of breast carcinomas, the internal mammary lymphoscintigraphy represents a simple, nontraumatic and reproducible technique to visualize and investigate the internal mammary nodes. As suggested by the total absence of visualization of nodes on the operated side in all or in the two upper intercostal spaces, internal mammary chain invasion concerns 30% of the population. This frequency increases with the clinical staging of the tumor, its size, and the extent of the disease in the axilla. It is higher for tumors of inner rather than of outer quadrants. When internal mammary lymphoscintigrams are compared in frontal view to the limits of the usual irradiation fields, parasternal nodes outside these limits or in borderline position are observed in 15 to 34% of the population according to the X-ray technique used. Furthermore, 40% of the tangential irradiation fields does not give an adequate irradiation dose to the internal mammary nodes. In one case out of four, IMLSc allows the reduction of useless heart- and lung-irradiated volumes. Internal mammary node invasion as demonstrated by lymphoscintigraphy has been demonstrated to have a prognostic value as the anatomopathological axillary node status, concerning both survival and disease evolution rates. IMLSc, when compared to the other possible investigation techniques of these nodes (X-ray computed tomography, echography or surgery, etc.), represents at the present time the investigation method of choice with the widest implications (diagnostic, therapeutic, and prognostic).