A quantitative examination of lymph drainage from perilesion skin in human melanoma

Lymphatic Transport Efficiency Determines Metastatic Potential of Cutaneous Melanoma

Background

In staging patients with clinical stage I-II melanoma, the sentinel lymph node (SLN) is the most important prognostic indicator; however, the false negative rate of SLN biopsy (SLNB) is 15%.

Methods

Nine patients with clinical Stage I-II melanoma underwent SLNB with repeated intraoperative radiotracer measurements to determine lymphatic transport efficiency (LTE), which was correlated with clinicopathologic data.

Results

LTE demonstrated the potential to predict SLN status. LTE in patients with occult nodal metastasis is 40 times faster than those with negative SLNBs. There was no confounding of LTE by clinicopathologic factors.

Significance:

LTE may be a novel biomarker for metastasis, with transformative potential for personalized precision diagnostics of early-stage disease and improved patient survival.

Sentinel Node Identification in Melanoma: Current Clinical Impact, New Emerging SPECT Radiotracers and Technological Advancements. An Update of the Last Decade

BACKGROUND

Melanoma is the most lethal skin cancer with a mortality rate of 262 cases per 100.000 cases. The sentinel lymph node (SLN) is the first lymph node draining the tumor. SLN biopsy is a widely accepted procedure in the clinical setting since it provides important prognostic information, which helps patient management, and avoids the side effects of complete lymph node dissection. The rationale of identifying and removing the SLN relies on the low probability of subsequent metastatic nodes in case of a negative histological exam performed in the SLN.

DISCUSSION

Recently, new analytical approaches, based on the evaluation of scintigraphic images are also exploring the possibility to predict the metastatic involvement of the SLN. 99mTc-labeled colloids are still the most commonly used radiotracers but new promising radiotracers, such as 99mTc- Tilmanocept, are now on the market. In the last decades, single photon emission computed tomography- computerized tomography (SPECT/CT) has gained wider diffusion in clinical departments and there is large evidence about its superior diagnostic accuracy over planar lymphoscintigraphy (PL) in the detection of SLN in patients with melanoma. Scientists are also investigating new hybrid techniques combining functional and anatomical images for the depiction of SLN but further evidence about their value is needed.

CONCLUSION

This review examined the predictive and prognostic factors of lymphoscintigraphy for metastatic involvement of SLN, the currently available and emerging radiotracers and the evidence of the additional value of SPECT/CT over PL for the identification of SLN in patients with melanoma. Finally, the review discussed the most recent technical advances in the field.

Inducible Nitric Oxide Synthase and CD11b+Gr1+ Cells Impair Lymphatic Contraction of Tumor-Draining Lymphatic Vessels

Background: Metastatic tumor cells spread through lymphatic vessels and colonize draining lymph nodes (LNs). It is known that tumors induce lymphangiogenesis to enhance lymphatic metastasis and that metastatic cancer cells are carried by lymph flow to LNs. Methods and Results: Here, we investigated the molecular and cellular regulation of collecting lymphatic vessel contraction in vessels draining a metastatic tumor using intravital microscopy. In tumor-draining collecting lymphatic vessels, we found vessel contraction was suppressed. The infiltration of peritumor tissue by inducible nitric oxide synthase positive and CD11b⁺Gr1⁺ myeloid cells played a critical role in the suppression of lymphatic contraction. Depletion of Gr1⁺ cells with an anti-Gr1 antibody improved contraction of tumor-draining lymphatic vessels. In addition, inducing tumor cell death restored lymphatic contraction in nude mice. Conclusions: These findings indicate that tumors contribute to regulation of lymphatic transport in a reversible manner, warranting further investigation into the role of impaired lymphatic transport in cancer progression.

Lymphatic transit rate as a predictive parameter for nodal metastasis in primary limb malignant melanoma

BACKGROUND

The status of sentinel lymph node (SLN) is one of the most predictive prognostic factors in patients with clinically localized malignant melanomas (MMs). However, since the positive SLN metastatic rate is as low as 20%, it is desirable to minimize SLN biopsy performance with imaging. By dynamic lymphoscintigraphy, we have proposed the lymphatic transit rate (LTR), the value that the distance between the primary lesion and SLN is divided by scintigraphic saturation time. LTR represents the scintigraphic saturation velocity and can be used for evaluation of metastasis of skin cancers.

METHODS

Dynamic lymphoscintigraphy data from 36 lymph nodes in 36 patients with primary MM on the limb were analyzed. The initial sites of the MMs were the lower limb in 24 patients and the upper limb in 12 patients. Histopathologically, nodal metastasis was found in 10 patients.

RESULTS

In the lower limb MM, the mean LTRs were 3.49 cm/min in histologically non-metastatic SLNs and 4.49 cm/min in histologically metastatic SLNs (P = 0.0056). In the upper limb MM, the mean LTRs were 2.59 cm/min in non-metastatic SLNs and 3.94 cm/min in metastatic SLNs (P = 0.0162). Thus, significantly higher LTRs were obtained in the metastatic SLNs. All SLNs with LTR < 4.0 cm/min in the lower limb MM and those with LTR < 3.0 cm/min in the upper limb MM were non-metastatic.

CONCLUSION

LTR is a useful predictive indicator for nodal metastasis and SLN biopsy performance in MMs.

Lymphatic transit rate as a novel predictive parameter for nodal metastasis in primary truncal skin cancers

Prediction of nodal metastasis in skin cancer before sentinel lymph node (SLN) biopsies is ideal to avoid unnecessary SLN biopsy performance. Primary truncal skin cancers are characterized by the lymphatic flow that drains from the primary lesion, occasionally to plural nodal basins. The scintigraphic appearance time (SAT), defined as the time between radionuclide injection and first SLN visualization, can potentially predict nodal metastasis, and a short SAT is a predictive parameter for metastasis. We recently introduced a novel method to measure the lymphatic flow rate using dynamic lymphoscintigraphy exhibiting a time-activity curve in the SLN. The time at which the count reaches a plateau in the SLN is termed the scintigraphic saturation time (SST) and can be a good alternative to the SAT. Moreover, the value obtained by division of the distance between the primary lesion and the SLN by the SST was termed the lymphatic transit rate (LTR), which represents the scintigraphic saturation velocity. In the present study, we evaluated LTR as a predictive parameter for nodal metastasis. Data for 22 lymph nodes from 18 patients with primary truncal skin cancers were used. Histopathologically, nodal metastasis was determined in nine nodes of eight patients. Because the mean LTR were 1.84 cm/min in non-metastatic SLN and 2.38 cm/min in metastatic SLN, the LTR was significantly higher in metastatic SLN than in non-metastatic SLN. All SLN with LTR of less than 1.8 cm/min were histopathologically evaluated as non-metastatic. The LTR may be a predictive indicator for nodal metastasis.

Quantitative Imaging In Vivo of Functioning Lymphatic Vessels Around Human Melanoma and Benign Nevi

OBJECTIVES

The density of functioning human lymphatics in vivo and of immunohistochemically defined lymphatics was quantified around melanomas, benign nevi, and matched normal skin, to assess the current lymphangiogenesis paradigm. We investigated whether histological and functioning density increased around melanomas compared with benign nevi or matched skin; whether functioning and histological density increased similarly; and whether larger increases occurred around metastatic melanomas.

METHODS

Functioning density was quantified in vivo as the total amount of human dermal microlymphatics taking up fluorescent marker injected at the lesion margin. After tissue excision, perilesion histological density was quantified using podoplanin marker D2-40.

RESULTS

Histological density was raised similarly around metastasising and non-metastasising melanomas compared with normal skin (+71%, p < 0.0001, n = 32); but was also raised significantly around benign nevi (+17%, p = 0.03, n = 20). In contrast, functioning lymphatic density was substantially reduced around the margins of melanomas (both metastasising and non-metastasising) compared with benign nevi (by 65%, p = 0.02) or normal skin (by 53%, p = 0.0014).

CONCLUSIONS

Raised perilesion histological lymphatic density is not unique to melanoma but occurs also around benign nevi. The findings indicated that the number of functioning lateral lymphatics around human melanomas in vivo but not benign nevi is reduced, despite histologically increased numbers of lymphatics.

Measurement of cutaneous lymphatic flow rates in patients with skin cancer: area extraction method

Some recent reports have revealed that the long scintigraphic appearance time (SAT), defined as the time between radionuclide injection and first sentinel lymph node (SLN) visualization in lymphoscintigraphy, is a negative predictive parameter of nodal metastasis in patients with melanoma. However, most of the methods used to measure the SAT were ambiguous because they utilized visualization in lymphoscintigraphy. We herein introduce a novel method by which to measure the SAT and lymphatic flow rate. The data of 33 patients with primary skin cancer were used. Sequential images were obtained using dynamic lymphoscintigraphy, and a time-activity curve of the SLN was created. The time at which the counts reached plateau was newly defined as an alternative to the SAT and was termed the scintigraphic saturation time (SST). The figure obtained by division of the distance by the SST was newly defined as an alternative to the lymphatic flow rate and termed the lymphatic transit rate (LTR). The SST was clearly determined. It ranged from 220 to 1430 s (mean, 805 s). Pathological examination revealed nodal metastasis in five patients. In 28 patients without metastasis, the mean LTR was in the order of lower limbs (4.07 ± 0.35 cm/min), upper limbs (2.67 ± 0.33 cm/min), trunk (1.79 ± 0.47 cm/min), and head and neck (1.11 ± 0.22 cm/min). The LTRs were higher in patients with nodal metastasis than those without. This method may be effective for accurate measurement of the SAT and lymphatic flow rate.

Isolated primary lymphedema tarda of the upper limb

Primary lymphedema tarda is considered as a congenital disease with late presentation. Primary lymphedema tarda usually affects lower limbs, and primary lymphedema tarda of the upper limbs usually accompanies lower limb lymphedema. In the current case report, we present an 80-year-old male patient with isolated left upper limb swelling that lymphoscintigraphy imaging proved to be lymphedema.