Prognosis in malignant melanoma

Tumor location and nature of lymphatic vessels are key determinants of cancer metastasis

Tumor metastasis to lymph nodes is a key indicator of patient survival, and is enhanced by the neo-lymphatics induced by tumor-secreted VEGF-C or VEGF-D, acting via VEGFR-3 signalling. These targets constitute important avenues for anti-metastatic treatment. Despite this new understanding, clinical observations linking metastasis with tumor depth or location suggest that lymphangiogenic growth factors are not the sole determinants of metastasis. Here we explored the influence of tumor proximity to lymphatics capable of responding to growth factors on nodal metastasis in a murine VEGF-D over-expression tumor model. We found that primary tumor location profoundly influenced VEGF-D-mediated lymph node metastasis: 89 % of tumors associated with the flank skin metastasised, in contrast with only 19 % of tumors located more deeply on the body wall (p < 0.01). Lymphatics in metastatic tumors arose from small lymphatics, and displayed distinct molecular and morphological profiles compared with those found in normal lymphatics. Smaller lymphatic subtypes were more abundant in skin (2.5-fold, p < 0.01) than in body wall, providing a richer source of lymphatics for VEGF-D(+) skin tumors, a phenomenon also confirmed in human samples. This study shows that the proximity of a VEGF-D(+) primary tumor to small lymphatics is an important determinant of metastasis. These observations may explain why tumor location relative to the lymphatic network is prognostically important for some human cancers.

Microscopic satellitosis in patients with primary cutaneous melanoma: implications for nodal basin staging

BACKGROUND

Microscopic satellitosis in melanoma is uncommon. The role of regional basin staging/therapy in patients with this high-risk feature has not been well defined.

METHODS

Patients presenting from 1996 to 2005 with clinically localized melanoma containing microscopic satellitosis were identified from a prospective, single-institution database. Multiple factors were analyzed to determine their predictive value for recurrence. The management of the draining nodal basin was evaluated to determine its impact on recurrence and survival.

RESULTS

Thirty-eight patients presented to our institution during this time period with clinically localized melanoma containing microscopic satellitosis. The 5-year overall and disease-free survivals in these patients were 34% and 18%, respectively. Sixty-eight percent had pathologically involved regional nodal metastases. With median follow-up of 21 months, 68% recurred, with a median time to recurrence of 9 months. Lymphovascular invasion (LVI) (p = 0.01), tumor regression (p = 0.04), and positive regional lymph nodes (p = 0.02) were associated with an increased risk of recurrence. Of the 31 patients who underwent sentinel lymph node (SLN) biopsy, 22 had metastasis in the SLN (71%). Fifteen of these patients underwent completion lymphadenectomy (CLND) and seven were observed. There was no difference in disease-free survival (DFS), disease-specific survival (DSS), or overall survival (OS) between these groups (p = 0.42).

CONCLUSIONS

Pathological lymph node metastases were more prevalent (68%) than in any group previously defined. Regional nodal status predicted recurrence but not nodal recurrence. In SLN-positive patients, CLND did not improve DFS, DSS, or OS, although the number of patients was small. Further studies are needed to determine the utility of regional nodal staging/therapy in these high-risk patients.

Expression pattern of the lymphatic and vascular markers VEGFR-3 and CD31 does not predict regional lymph node metastasis in cutaneous melanoma

Malignant melanoma of the skin preferentially metastasises via the lymphatic system. Novel molecular biomarkers, which are involved in malignant transformation, proliferation, angiogenesis and lymphangiogenesis, are currently under investigation to elucidate the risk for lymph node metastasis. To this end, the vascular endothelial growth factors VEGF-C and VEGF-D have been identified to promote lymphangiogenesis and lymphatic spread through activation of its receptor, Vascular endothelial growth factor receptor-3 (VEGFR-3). Prompted by this assumption, we estimated the degree of lymphangiogenesis by semiquantitative immunohistochemical analysis of the expression of VEGFR-3 and the panvascular marker CD31 in primary cutaneous melanoma (n=26) and correlated these findings with the sentinel lymph node (SLN) status. The cohort was selected for matched prognostic markers in SLN-positive and SLN-negative patients. In contrast to other studies, we observed an inverse correlation between expression of these markers with lymph node metastases. Additionally, no difference between intratumoral versus peritumoral CD31- or VEGFR-3 expression on blood vessels versus lymphatic capillaries could be detected. Interestingly, VEGFR-3 upregulation was not restrained to vascular structures but also appeared on tumor cells. In summary, in our series VEGFR-3/CD31 immunohistochemical staining of primary melanoma does not serve as a valid marker to predict lymph node involvement. As lymphatic spread is a complex, multi-step process, several different biomarkers have to be combined to define new prognostic subgroups in cutaneous melanoma.

Metastatic malignant melanoma presenting as pancytopenia in a three-year-old boy

Malignant melanoma is rare in childhood and has never been reported to cause pancytopenia due to bone marrow metastases in a child. We report a 3-year-old boy with a large congenital melanocytic nevus who presented with bone pain and pancytopenia due to diffuse bone and bone marrow infiltration with metastatic melanoma without an identifiable primary site. Despite treatment with imatinib mesylate there was no response and the patient died with progressive disease. This case illustrates an unusual presentation of bone marrow failure secondary to malignant melanoma in a young child with symptomatic metastatic marrow infiltration, a rarely reported site of melanoma involvement in adults or children.

Melanoma cutâneo: características clínicas, epidemiológicas e histopatológicas no Hospital Universitário de Brasília entre janeiro de 1994 e abril de 1999

FUNDAMENTOS: A incidência do melanoma cutâneo tem aumentado cerca de 4 a 6% anualmente. Esse tumor ocorre preferencialmente no sexo feminino, entre 30 e 79 anos de idade e predominantemente em indivíduos de cor branca. A forma anatomopatológica mais freqüente é a extensivo-superficial, e sua localização varia com o sexo. OBJETIVOS: O objetivo deste estudo foi avaliar as características clínicas, epidemiológicas e histológicas do melanoma cutâneo primário, no Hospital Universitário de Brasília, em um período de cinco anos. MATERIAL E MÉTODOS: Foi realizado estudo de revisão dos prontuários dos casos de melanoma cutâneo primário, do Hospital Universitário de Brasília, diagnosticados e tratados entre janeiro de 1994 e abril de 1999, totalizando 32 casos. Os pacientes foram analisados, caracterizando-se a distribuição do tumor por sexo, idade, cor da pele, topografia, sintomatologia, tipo de crescimento, nível de Clark, índice de Breslow e presença de metástases. A análise dos dados foi realizada por meio de estatística simples e pelo teste do qui-quadrado (chi2). RESULTADOS: Neste estudo há predomínio das lesões localizadas nos membros, correspondendo a 16 pacientes (50%). Em nove pacientes (45%) a forma primária era do tipo nodular, e 17 pacientes (58,6%) não apresentavam queixas. Pela correlação entre a presença ou não de metástases e o nível de Clark observou-se que os pacientes com nível de invasão até o subcutâneo (Clark V) apresentaram risco relativo de 2,94 (1,24<ic<6,99). CONCLUSÃO: O perfil clínico, epidemiológico e histológico do paciente portador de melanoma cutâneo primário do Hospital Universitário de Brasília entre janeiro de 1994 e abril de 1999 corresponde ao indivíduo do sexo feminino, idoso (de 61 a 80 anos), cor da pele branca, cuja lesão predomina nos membros, sendo mais freqüente o tipo de crescimento nodular e que não apresenta sintomas à época do diagnóstico.

Focus on primary care: from nevus to neoplasm: myths of melanoma in pregnancy

Malignant melanoma is one of the few malignancies that regularly affect women during their childbearing years. Additionally, the incidence of melanoma has been increasing over the last several decades. Early diagnosis of stage I disease may lead to curative therapy; thus it is important for physicians and midwives to do a full examination of the skin. However, the myth that nevi may naturally grow or change during pregnancy has been shown not to be true and should not delay a diagnostic evaluation of a suspicious nevus. Older studies had theorized a worse outcome for pregnant women with melanoma. However, multiple controlled series and investigations have found that stage for stage this cancer is not affected adversely by pregnancy. Prognosis, recurrence, and incidence of melanoma seemed to be unaffected. Estrogen-containing oral contraceptives, as well as hormone replacement therapy, have no adverse affect on the disease.

An endogenous melanocyte-inhibiting tripeptide pyroGlu-Phe-GlyNH2 delays in vivo growth of monoclonal experimental melanoma

The melanocyte-inhibiting tripeptide (MTP) pyroGlu-Phe-GlyNH2 is present in tissue cultures of non-transformed melanocytes and melanoma cells and influences melanocyte growth in vitro. The objective of the present study was to investigate a possible effect of MTP on the in vivo growth of B16A2, a monoclonal experimental melanoma. The B16A2 clone was established by the limited dilution technique. It has a reduced DNA content and displays slower growth both in vivo and in vitro compared to the parent cell line (B16). B16A2 cells were injected subcutaneously into hairless mice at four sites (300 000 cells in 0.25 ml buffer/site). MTP was given by i.p. injection 3 times a week at two concentrations (1 pmol and 1 nmol/animal). The control animals received the equal volume of solvent. The animals were sacrificed 1 and 2 weeks after tumour transplantation, and all tumours were weighed. One week after transplantation, the animals who received 1 pmol MTP had fewer tumours and a reduced tumour load. Two weeks after the transplantation, the differences between control and treated animals were no longer observed. The results indicate that MTP temporarily delays in vivo tumour growth.