Predicting sentinel node positivity in patients with melanoma: external validation of a risk-prediction calculator (the Melanoma Institute Australia nomogram) using a large European population-based patient cohort.

BACKGROUND: A nomogram to predict sentinel node (SN) positivity [the Melanoma Institute Australia (MIA) nomogram] was recently developed and externally validated using two large single-institution databases. However, there remains a need to further validate the nomogram's performance using population-based data. OBJECTIVES: To perform further validation of the nomogram using a European national patient cohort. METHODS: Patients with cutaneous melanoma who underwent SN biopsy in the Netherlands between 2000 and 2014 were included. Their data were obtained from the Dutch Pathology Registry. The predictive performance of the nomogram was assessed by discrimination (C-statistic) and calibration. Negative predictive values (NPVs) were calculated at various predicted probability cutoffs. RESULTS: Of the 3049 patients who met the eligibility criteria, 23% (691) were SN positive. Validation of the MIA nomogram (including the parameters Breslow thickness, ulceration, age, melanoma subtype and lymphovascular invasion) showed a good C-statistic of 0·69 (95% confidence interval 0·66-0·71) with excellent calibration (R2 = 0·985, P = 0·40). The NPV of 90·1%, found at a 10% predicted probability cutoff for having a positive SN biopsy, implied that by using the nomogram, a 16·3% reduction in the rate of performing an SN biopsy could be achieved with an error rate of 1·6%. Validation of the MIA nomogram considering mitotic rate as present or absent showed a C-statistic of 0·70 (95% confidence interval 0·68-0·74). CONCLUSIONS: This population-based validation study in European patients with melanoma confirmed the value of the MIA nomogram in predicting SN positivity. Its use will spare low-risk patients the inconvenience, cost and potential risks of SN biopsy while ensuring that high-risk patients are still identified.

Desmoplastic melanoma: a review of its pathology and clinical behaviour, and of management recommendations in published guidelines.

Desmoplastic melanomas are uncommon. Their behaviour differs from that of other melanoma subtypes; therefore, management guidelines for non-desmoplastic melanomas may not be applicable. This review sought to examine all available evidence relating to the behaviour and management of desmoplastic melanomas, based on review of all relevant English-language publications, and to critically assess the recommendations for their management in current published melanoma management guidelines. Compared with other melanoma subtypes, patients with 'pure' desmoplastic melanomas (where ≥90% of the invasive melanoma is of desmoplastic melanoma subtype) have much lower rates of sentinel node positivity and distant metastasis. Local recurrence rates are higher for desmoplastic melanomas, but resection margins wider than those recommended for non-desmoplastic melanomas have not been shown to be of benefit. Adjuvant radiotherapy reduces the risk of local recurrence when a satisfactory histological clearance (≥8 mm) cannot be achieved. Of 29 published melanoma management guidelines identified, only 11 specified management for desmoplastic melanomas, while seven simply stated that the feature should be reported. Desmoplastic melanoma is a unique melanoma subtype with biology that differs from that of other melanoma subtypes. It requires specific management strategies but few current guidelines address these.

VEGF(121)b, a new member of the VEGF(xxx)b family of VEGF-A splice isoforms, inhibits neovascularisation and tumour growth in vivo.

BACKGROUND: The key mediator of new vessel formation in cancer and other diseases is VEGF-A. VEGF-A exists as alternatively spliced isoforms - the pro-angiogenic VEGF(xxx) family generated by exon 8 proximal splicing, and a sister family, termed VEGF(xxx)b, exemplified by VEGF(165)b, generated by distal splicing of exon 8. However, it is unknown whether this anti-angiogenic property of VEGF(165)b is a general property of the VEGF(xxx)b family of isoforms. METHODS: The mRNA and protein expression of VEGF(121)b was studied in human tissue. The effect of VEGF(121)b was analysed by saturation binding to VEGF receptors, endothelial migration, apoptosis, xenograft tumour growth, pre-retinal neovascularisation and imaging of biodistribution in tumour-bearing mice with radioactive VEGF(121)b. RESULTS: The existence of VEGF(121)b was confirmed in normal human tissues. VEGF(121)b binds both VEGF receptors with similar affinity as other VEGF isoforms, but inhibits endothelial cell migration and is cytoprotective to endothelial cells through VEGFR-2 activation. Administration of VEGF(121)b normalised retinal vasculature by reducing both angiogenesis and ischaemia. VEGF(121)b reduced the growth of xenografted human colon tumours in association with reduced microvascular density, and an intravenous bolus of VEGF(121)b is taken up into colon tumour xenografts. CONCLUSION: Here we identify a second member of the family, VEGF(121)b, with similar properties to those of VEGF(165)b, and underline the importance of the six amino acids of exon 8b in the anti-angiogenic activity of the VEGF(xxx)b isoforms.

VEGF 165 b, an antiangiogenic VEGF-A isoform, binds and inhibits bevacizumab treatment in experimental colorectal carcinoma: balance of pro- and antiangiogenic VEGF-A isoforms has implications for therapy.

Bevacizumab, an anti-vascular endothelial growth factor (VEGF-A) antibody, is used in metastatic colorectal carcinoma (CRC) treatment, but responses are unpredictable. Vascular endothelial growth factor is alternatively spliced to form proangiogenic VEGF(165) and antiangiogenic VEGF(165)b. Using isoform-specific enzyme-linked immunosorbent assay and quantitative polymerase chain reaction, we found that over 90% of the VEGF in normal colonic tissue was VEGF(xxx)b, but there was a variable upregulation of VEGF(xxx) and downregulation of VEGF(xxx)b in paired human CRC samples. Furthermore, cultured colonic adenoma cells expressed predominantly VEGF(xxx)b, whereas colonic carcinoma cells expressed predominantly VEGF(xxx). However, adenoma cells exposed to hypoxia switched their expression from predominantly VEGF(xxx)b to predominantly VEGF(xxx). VEGF(165)b overexpression in LS174t colon cancer cells inhibited colon carcinoma growth in mouse xenograft models. Western blotting and surface plasmon resonance showed that VEGF(165)b bound to bevacizumab with similar affinity as VEGF(165). However, although bevacizumab effectively inhibited the rapid growth of colon carcinomas expressing VEGF(165), it did not affect the slower growth of tumours from colonic carcinoma cells expressing VEGF(165)b. Both bevacizumab and anti-VEGF(165)b-specific antibodies were cytotoxic to colonic epithelial cells, but less so to colonic carcinoma cells. These results show that the balance of antiangiogenic to proangiogenic isoforms switches to a variable extent in CRC, regulates tumour growth rates and affects the sensitivity of tumours to bevacizumab by competitive binding. Together with the identification of an autocrine cytoprotective role for VEGF(165)b in colonic epithelial cells, these results indicate that bevacizumab treatment of human CRC may depend upon this balance of VEGF isoforms.

Expression of VEGF(xxx)b, the inhibitory isoforms of VEGF, in malignant melanoma.

Malignant melanoma is the most lethal of the skin cancers and the UK incidence is rising faster than that of any other cancer. Angiogenesis - the growth of new vessels from preexisting vasculature - is an absolute requirement for tumour survival and progression beyond a few hundred microns in diameter. We previously described a class of anti-angiogenic isoforms of VEGF, VEGF(xxx)b, that inhibit tumour growth in animal models, and are downregulated in some cancers, but have not been investigated in melanoma. To determine whether VEGF(xxx)b expression was altered in melanoma, PCR and immunohistochemistry of archived human tumour samples were used. In normal epidermis and in a proportion of melanoma samples, VEGF(xxx)b staining was seen. Some melanomas had much weaker staining. Subsequent examination revealed that expression was significantly reduced in primary melanoma samples (both horizontal and vertical growth phases) from patients who subsequently developed tumour metastasis compared with those who did not (analysis of variance (ANOVA) P<0.001 metastatic vs nonmetastatic), irrespective of tumour thickness, while the surrounding epidermis showed no difference in expression. Staining for total VEGF expression showed staining in metastatic and nonmetastatic melanomas, and normal epidermis. An absence of VEGF(xxx)b expression appears to predict metastatic spread in patients with primary melanoma. These results suggest that there is a switch in splicing as part of the metastatic process, from anti-angiogenic to pro-angiogenic VEGF isoforms. This may form part of a wider metastatic splicing phenotype.

Laparoscopic anterior resection and uterine manipulation: why make things difficult?

The uterus continues to be a source of difficulty in mobilization of the rectum. These difficulties are compounded in laparoscopic operations, particularly anterior resection, proctectomy and vaginal sacrocolpopexy. Techniques to overcome this have in general proved unsatisfactory. We have adopted a technique of using an extended Vesellum forceps from gynaecological practice and recommend its use by all. The technique is described.