[Translated article] Tumor Doubling Time in Skin Cancer: Can It Be Estimated and Is It Useful?

Skin cancer, like other cancers, is characterized by the uncontrolled growth of transformed cells. Tumor growth has been studied for decades. We review different methods for measuring skin tumor growth and propose a new system for estimating tumor doubling time that could be useful in the management of skin cancer.

Tumor growth rate as a prognostic factor of acral melanoma in a Korean population

Rapid growth of cutaneous melanoma is associated with aggressive histopathologic features and poor prognosis. However, the impact of growth rate (GR) in acral melanoma (AM) remains largely unknown.We performed this study to identify the impact of GR on lymph node metastasis and survival in AM.We analyzed cases of invasive AM diagnosed at our institution between 1998 and 2017. We investigated the impact of GR on the prognosis of AM.A total of 126 cases of invasive AM were included. Log (GR) was significant associated with lymph node metastasis in the univariate logistic regression analysis (P = .005). The log-rank test revealed statistically significant differences in disease-free survival (DFS) and disease-specific survival (DSS) among the GR quartiles. In the Cox regression analysis, log (GR) was an independent predictor for DFS (P = .041), but not for DSS in multivariate analysis. In the subgroup analysis, log (GR) was an independent predictor for early-stage (≤2A) AM (DFS, P = .002; DSS, P = .004).The limitations of this study include the retrospective design of the study and possible recall bias.Our results suggest that GR is an important prognostic factor for DFS and DSS in AM patients and an independent predictor for early-stage AM.

Rapid growth rate is associated with poor prognosis in cutaneous squamous cell carcinoma

BACKGROUND

Cutaneous squamous cell carcinoma (cSCC) represents the most common form of skin cancer after basal cell carcinoma, and can be both locally invasive and metastatic to distant sites. Growth rate (GR) has been poorly evaluated in cSCC, despite clinical evidence suggesting that GR is an important risk factor in cSCC.

AIM

To analyse the influence of GR in cSCC prognosis.

METHODS

We retrospectively evaluated GR in a series of 90 cSCCs and tried to correlate GR with prognosis in cSCC.

RESULTS

We demonstrated that tumours with a GR of > 4 mm/month exhibit a higher risk of nodal progression and a shorter progression time to lymph node metastasis in cSCC than those with GR of < 4 mm/month. As expected, GR correlated with tumour proliferation, as determined by Ki-67 expression.

CONCLUSIONS

We consider a GR of 4 mm/month as the cutoff point that distinguishes between rapid- and slow-progressing tumours and, more importantly, to identify a subset of high-risk cSCCs.

The role of BRAF mutations in primary melanoma growth rate and survival

BACKGROUND

The clinical behaviour and prognosis of primary melanomas harbouring BRAF mutations is not fully understood.

OBJECTIVES

To investigate the effect of mutation status on primary melanoma growth rate and melanoma-specific survival (MSS).

METHODS

A prospective cohort of 196 patients with stage I-III primary cutaneous melanoma were followed for a median of 92 months, pre-dating the institution of BRAF inhibitor therapy. Clinicopathological variables were correlated with mutation status and hazard ratios (HRs) estimated for MSS.

RESULTS

Of 196 tumours, 77 (39.2%) were BRAF V600E, 10 (5.1%) BRAF V600K and 33 (16.8%) were NRAS mutant. BRAF V600E mutant melanomas were associated with favourable clinical characteristics and tended to be slower growing compared with BRAF V600K, NRAS mutant or BRAF/NRAS wild-type tumours (0.12 mm per month, 0.61 mm per month, 0.36 mm per month and 0.23 mm per month, respectively; P = 0.05). There were 39 melanoma deaths, and BRAF mutant melanomas were associated with poorer MSS in stage I-III disease [HR 2.60, 95% confidence interval (CI) 1.20-5.63; P = 0.02] and stage I-II disease (HR 3.39, 95% CI 1.12-10.22; P = 0.03) after adjusting for other prognostic variables. Considered separately, BRAF V600E mutant melanomas were strongly associated with MSS independently of thickness and nodal status (HR 3.89, 95% CI 1.67-9.09; P < 0.01) but BRAF V600K mutant tumours were not (HR 1.19, 95% CI 0.36-3.92; P = 0.77).

CONCLUSIONS

The presence of a BRAF mutation does not necessarily 'drive' more rapid tumour growth but is associated with poorer MSS in patients with early-stage disease.

The pan-Aurora kinase inhibitor, PHA-739358, induces apoptosis and inhibits migration in melanoma cell lines

Treatment of metastatic melanoma has long been a challenge because of its resistance to traditional chemotherapeutics, leading to the search for alternative strategies. Aurora kinases are key mitotic regulators that are frequently overexpressed in various cancers including melanoma, making them ideal targets for drug development. Several Aurora kinase inhibitors have been developed and tested preclinically and clinically. PHA-739358 is currently one of the most advanced clinical compounds being tested in phase II clinical trials; however, its antitumor effect has not been tested in melanoma. In this study, the antiproliferative and anti-invasive effects of PHA-739358 were investigated in melanoma cell lines. The results demonstrated that PHA-739358 produces a time-dependent and dose-dependent inhibition of cell proliferation, induction of apoptosis, and inhibition of cell migration. Downregulation of matrix metalloproteinase-2 by the inhibition of NFκB-signaling pathway may contribute to PHA-739358-induced inhibition of migration. Furthermore, PHA-739358 enhanced temozolomide and Plx4032-induced apoptosis. This study suggests that Aurora kinase inhibitors may provide a new strategy for the treatment of advanced melanoma.

Primary dermal melanoma: a case report and a review of the literature

Patients with cutaneous metastatic melanoma of unknown primary origin (stage IV M1a disease according to the American Joint Committee on Cancer melanoma staging system) have an estimated 5-year survival rate of between 5% and 17.9% and a median survival of 6 months. However, certain patients with stage IV M1a disease have much higher survival rates. The existence of this subpopulation has given rise to the term primary dermal melanoma to describe such cases. We report a case of melanoma with characteristics consistent with primary dermal melanoma and review the relevant literature. A diagnosis of primary dermal melanoma requires careful clinical and pathologic correlation and should be considered in all patients with a solitary melanoma confined to the dermis and subcutaneous tissue when there is no evidence of a primary tumor or disease at other sites following appropriate staging studies. We believe that familiarity with this subtype of melanoma is essential in order to provide patients with optimal care and better prognostic information.

Chronology of metastasis in cutaneous melanoma: growth rate model

In humans, it is not possible to obtain experimental evidence of when a cancer begins to metastasize. The purpose of this study was to estimate the time of onset of metastatic dissemination in cutaneous melanoma using a model based on its growth rate (GR). The critical time of onset of metastatic dissemination below which no cases of fatal melanomas were seen may be described with a potential function in which this time is inversely proportional to the GR. The critical time of development beyond which a melanoma may metastasize presents great variation. This time was just 1 month for those melanomas with a fast GR, whereas it was over 5 years for those with a very slow GR. Quantitatively, the fastest-growing melanomas began metastasizing with a greater thickness than the slowest-growing melanomas. A correlation exists between the critical time of onset of metastatic potential and the GR of the melanoma. These results may well have relevance to the understanding of mechanisms of tumor dissemination and for the design of future studies on melanomas, irrespective of whether they are basic studies on biomolecular mechamisms or clinical studies.

Melanoma update: diagnostic and prognostic factors that can effectively shape and personalize management

Routine light microscopy remains a powerful tool to diagnose, stage and prognose melanoma. Although it is very economical and efficient, it requires a significant level of expertise and, in difficult cases the final diagnosis is affected by subjective interpretation. Fortunately, new insights into the genomic aberrations characteristic of melanoma, coupled with ancillary studies, are further refining evaluation and management allowing for more confident diagnosis, more accurate staging and the selection of targeted therapy. In this article, we review the standard of care and new updates including four probe FISH, the 2009 American Joint Commission on Cancer staging of melanoma and mutant testing of melanoma, which will be crucial for targeted therapy of metastatic melanoma.