Tumor doubling time of cutaneous melanoma and its metastasis

The effects of the COVID-19 pandemic on the diagnosis and prognosis of melanoma 2 years after the pandemic in two Romanian counties

Background

The COVID-19 pandemic disrupted the healthcare system and negatively affected the diagnosis and management of melanoma worldwide. The purpose of this study is to investigate the long-term effects of the COVID-19 pandemic on the diagnosis and prognosis of melanoma.

Materials and methods

This retrospective cohort study included histopathologically confirmed melanoma cases from March 2019 to February 2023 in Cluj and Bihor counties. Data from the post-COVID-19 period (March 2021 to February 2023) were compared to the pre-COVID-19 period (March 2019 to February 2020) and the COVID-19 period (March 2020 to February 2021). Patient characteristics, monthly diagnostics, histological subtypes, and key histological features were analyzed using statistical tests.

Results

The number of melanoma cases diagnosed annually decreased by 31.37 and 23.75% in the first and second post-pandemic years, respectively, compared to pre-pandemic numbers. Diagnostic rates also decreased by 14.9 and 5.4% in the first and second post-pandemic years, respectively, compared to the pandemic period. Prognostic factors worsened in the post-pandemic period, with higher Breslow index and mitotic rate, and increased ulceration and thick melanomas compared to the pre-pandemic period.

Conclusion

The COVID-19 pandemic had a long-lasting impact on the diagnosis of melanoma in Romania, resulting in advanced stages and unfavorable prognostic factors. Larger global studies are needed to comprehensively understand the pandemic's long-term effects on the diagnosis of melanoma.

Consulting a neurosurgeon upon initial medical assessment reduces the time to the first surgery and potentially contributes to improved prognosis for glioblastoma patients

BACKGROUND

The neurological status of glioblastoma patients rapidly deteriorates. We recently demonstrated that early diagnosis and surgery within 3 weeks from the initial symptoms are associated with improved survival. While glioblastoma is a semi-urgent disease, the prehospital behaviors and clinical outcomes of glioblastoma patients are poorly understood. We aimed to disclose how prehospital patient behavior influences the clinical outcomes of glioblastoma patients.

METHODS

Isocitrate dehydrogenase-wildtype glioblastoma patients treated at our institution between January 2010 and December 2019 were reviewed. Patients were divided into two groups, neurosurgeon and non-neurosurgeon groups, based on the primary doctor whom patients sought for an initial evaluation. Patient demographics and prognoses were examined.

RESULTS

Of 170 patients, 109 and 61 were classified into the neurosurgeon and non-neurosurgeon groups, respectively. The median age of neurosurgeon group was significantly younger than the non-neurosurgeon group (61 vs. 69 years old, P = 0.019) and in better performance status (preoperative Karnofsky performance status scores $\ge$80: 72.5 vs. 55.7%, P = 0.027). The neurosurgeon group exhibited a significantly shorter duration from the first hospital visit to the first surgery than the non-neurosurgeon group (18 vs. 29 days, P < 0.0001). Furthermore, the overall survival of the neurosurgeon group was significantly more prolonged than that of the non-neurosurgeon group (22.9 vs. 14.0 months, P = 0.038).

CONCLUSION

Seeking an initial evaluation by a neurosurgeon was potentially associated with prolonged survival in glioblastoma patients. A short duration from the first hospital visit to the first surgery is essential in enhancing glioblastoma patient prognosis.

Hydrochlorothiazide increases risk of nonmelanoma skin cancer in an elderly Japanese cohort with hypertension: The Shizuoka study

Background

Hydrochlorothiazide (HCT), a widely used hypertensive drug, has photocarcinogenic potential, leading to concerns about the development of nonmelanoma skin cancers (SCs) after intake. Despite substantial numbers of observational studies, the results remain inconsistent especially among Asian countries.

Objective

To assess the incidence of nonmelanoma SCs in hypertensive Japanese HCT users compared with nonusers.

Methods

A population-based, cohort nested, propensity score-matched study was conducted using the Shizuoka Kokuho database. All participants were patients aged ≥60 years. Hazard ratios for SC incidence were calculated in the matched cohorts using the propensity scores of potential confounders, sex, age category, comorbidities, and administration of methotrexate, cyclosporin, and statins.

Results

The risk of SC was higher in HCT users than in nonusers (hazard ratio, 1.58; 95% confidence interval, 1.04-2.40), with preferential sun-exposed location and a tendency to develop squamous cell carcinoma, but not basal cell carcinoma or Bowen disease.

Limitations

No additional information was available from other than medical records. The data were confined to a Japanese population.

Conclusion

HCT use increases the risk of SC in Japanese patients with hypertension and a dark skin type, highlighting the increased risk of SC among HCT users in the aging society worldwide.

Autoimmune alleles at the major histocompatibility locus modify melanoma susceptibility

Autoimmunity and cancer represent two different aspects of immune dysfunction. Autoimmunity is characterized by breakdowns in immune self-tolerance, while impaired immune surveillance can allow for tumorigenesis. The class I major histocompatibility complex (MHC-I), which displays derivatives of the cellular peptidome for immune surveillance by CD8+ T cells, serves as a common genetic link between these conditions. As melanoma-specific CD8+ T cells have been shown to target melanocyte-specific peptide antigens more often than melanoma-specific antigens, we investigated whether vitiligo- and psoriasis-predisposing MHC-I alleles conferred a melanoma-protective effect. In individuals with cutaneous melanoma from both The Cancer Genome Atlas (n = 451) and an independent validation set (n = 586), MHC-I autoimmune-allele carrier status was significantly associated with a later age of melanoma diagnosis. Furthermore, MHC-I autoimmune-allele carriers were significantly associated with decreased risk of developing melanoma in the Million Veteran Program (OR = 0.962, p = 0.024). Existing melanoma polygenic risk scores (PRSs) did not predict autoimmune-allele carrier status, suggesting these alleles provide orthogonal risk-relevant information. Mechanisms of autoimmune protection were neither associated with improved melanoma-driver mutation association nor improved gene-level conserved antigen presentation relative to common alleles. However, autoimmune alleles showed higher affinity relative to common alleles for particular windows of melanocyte-conserved antigens and loss of heterozygosity of autoimmune alleles caused the greatest reduction in presentation for several conserved antigens across individuals with loss of HLA alleles. Overall, this study presents evidence that MHC-I autoimmune-risk alleles modulate melanoma risk unaccounted for by current PRSs.

Intra-tumor heterogeneity, turnover rate and karyotype space shape susceptibility to missegregation-induced extinction

The phenotypic efficacy of somatic copy number alterations (SCNAs) stems from their incidence per base pair of the genome, which is orders of magnitudes greater than that of point mutations. One mitotic event stands out in its potential to significantly change a cell's SCNA burden-a chromosome missegregation. A stochastic model of chromosome mis-segregations has been previously developed to describe the evolution of SCNAs of a single chromosome type. Building upon this work, we derive a general deterministic framework for modeling missegregations of multiple chromosome types. The framework offers flexibility to model intra-tumor heterogeneity in the SCNAs of all chromosomes, as well as in missegregation- and turnover rates. The model can be used to test how selection acts upon coexisting karyotypes over hundreds of generations. We use the model to calculate missegregation-induced population extinction (MIE) curves, that separate viable from non-viable populations as a function of their turnover- and missegregation rates. Turnover- and missegregation rates estimated from scRNA-seq data are then compared to theoretical predictions. We find convergence of theoretical and empirical results in both the location of MIE curves and the necessary conditions for MIE. When a dependency of missegregation rate on karyotype is introduced, karyotypes associated with low missegregation rates act as a stabilizing refuge, rendering MIE impossible unless turnover rates are exceedingly high. Intra-tumor heterogeneity, including heterogeneity in missegregation rates, increases as tumors progress, rendering MIE unlikely.

Impact of the COVID-19 Pandemic on Melanoma Diagnosis: Increased Breslow Thickness in Primary Melanomas-A Single Center Experience

Early melanoma diagnosis plays a key role in ensuring best prognosis with good survival rates. The ongoing global COVID-19 pandemic has greatly impacted global and national healthcare systems, thus making it a real challenge. The aim of this study was to evaluate the impact of the pandemic on diagnostic delay in melanoma patients in Serbia. In this retrospective study, we included patients treated at the university hospital in Serbia's capitol over a period of five years and three months. We compared the prepandemic (01/JAN/17-14/MAR/20) and pandemic periods (15/MAR/20-31/MAR/22) by evaluating patient demographic data, melanoma subtype, Breslow thickness, Clark level, ulceration status, mitotic index rate and pT staging. We observed a significant reduction in the number of diagnosed patients (86.3 vs. 13.7%; p = 0.036), with melanomas having an increased median Breslow thickness (1.80 vs. 3.00; p = 0.010), a higher percentage of Clark IV-V level lesions (44.0% vs. 63.0%; p = 0.009), an increase in median mitotic index rate (2 vs. 5; p < 0.001) and a trend of increase in lesions thicker than 2 mm (37.8% vs. 53.7%; p = 0.026). We believe that this study can be a useful scenario guide for future similar events, highlighting the importance of preventive measures and timely diagnosis for the best patient outcomes.

Early Diagnosis and Surgical Intervention Within 3 Weeks From Symptom Onset Are Associated With Prolonged Survival of Patients With Glioblastoma

BACKGROUND

Glioblastoma (GBM) is a rapidly growing and most life-threatening malignant brain tumor. The significance of early treatment to the clinical outcomes of patients with GBM is unclear.

OBJECTIVE

To determine whether early diagnosis and surgery improve the preoperative and postoperative Karnofsky performance status (KPS) and prognosis of patients with GBM.

METHODS

Data of isocitrate dehydrogenase-wildtype patients with GBM treated at our institution between January 2010 and December 2019 were reviewed. Patients were classified into early or late diagnosis groups with a threshold of 14 days from initial symptoms. In addition, patients were divided into early, intermediate, and late surgery groups with thresholds of 21 and 35 days. Representative symptoms and patient prognoses were examined.

RESULTS

Of 153 patients, 72 and 81 were classified into the early and late diagnosis groups. The median tumor volume was significantly smaller in the former group. The proportion of patients with preoperative KPS scores 90 was 48.6% and 29.6% in the early and late diagnosis groups ( P = .016). The early, intermediate, and late surgery groups included 43, 24, and 86 patients. The median overall survival was significantly longer in the early surgery group than in the late surgery group (28.4 vs 18.7 months, P = .006). Multivariate analysis demonstrated that significant predictors of shorter survival included extent of tumor resection (partial or biopsy), preoperative and postoperative KPS 60, and O6-methylguanine-DNA-methyltransferase promoter status (unmethylated).

CONCLUSION

Early diagnosis within 2 weeks and surgical interventions within 3 weeks from the symptom onset are associated with prolonged patient survival. Early GBM treatment will benefit patients with GBM.

Advanced-Stage Melanoma at Presentation Following the Peak of the Pandemic: A COVID-19 Cancer Canary in a Coal Mine

Background

For melanoma patients, timely identification and tumor thickness are directly correlated with outcomes. COVID-19 impacted both patients’ ability and desire to see physicians. We sought to identify whether the pandemic correlated with changes in melanoma thickness at presentation and subsequent treatment timeline.

Methods

Retrospective chart review was performed on patients who underwent surgery for melanoma in an academic center surgical oncology practice from May 2019 to September 2021. Patients were split into two cohorts: “pre-pandemic” from May 2019 to May 2020 and “pandemic,” after May 2020, representing when these patients received their initial diagnostic biopsy. Demographic and melanoma-specific variables were recorded and analyzed.

Results

A total of 112 patients were identified: 51 patients from the “pre-pandemic” and 61 from the “pandemic” time period. The pandemic cohort more frequently presented with lesions greater than 1 mm thickness compared to pre-pandemic (68.8% v 49%, p = 0.033) and were found to have significantly more advanced T stage (p = 0.02) and overall stage disease (p = 0.022). Additionally, trends show that for pandemic patients more time passed from patient-reported lesion appearance/change to diagnostic biopsy (5.7 ± 2.0 v 7.1 ± 1.5 months, p = 0.581), but less time from biopsy to operation (42.9 ± 2.4 v 52.9 ± 5.0 days, p = 0.06).

Conclusions

“Pandemic” patients presented with thicker melanoma lesions and more advanced-stage disease. These results may portend a dangerous trend toward later stage at presentation, for melanoma and other cancers with rapid growth patterns, that will emerge as the prolonged effects of the pandemic continue to impact patients’ presentation for medical care.

Modeling the effect of gut microbiome on therapeutic efficacy of immune checkpoint inhibitors against cancer

Immune checkpoint inhibitors have been shown to be highly successful against some solid metastatic malignancies, but only for a subset of patients who show durable clinical responses. The overall patient response rate is limited due to the interpatient heterogeneity. Preclinical and clinical studies have recently shown that the therapeutic responses can be improved through the modulation of gut microbiome. However, the underlying mechanisms are not fully understood. In this paper, we explored the effect of favorable and unfavorable gut bacteria on the therapeutic efficacy of anti-PD-1 against cancer by modeling the tumor-immune-gut microbiome interactions, and further examined the predictive markers of responders and non-responders to anti-PD-1. The dynamics of the gut bacteria was fitted to the clinical data of melanoma patients, and virtual patients data were generated based on the clinical patient survival data. Our simulation results show that low initial growth rate and low level of favorable bacteria at the initiation of anti-PD-1 therapy are predictive of non-responders, while high level of favorable bacteria at the initiation of anti-PD-1 therapy is predictive of responders. Simulation results also confirmed that it is possible to promote patients' response rate to anti-PD-1 by manipulating the gut bacteria composition of non-responders, whereby achieving long-term progression-free survival.

The Risk of Cutaneous Squamous Cell Carcinoma Among Patients with Type 2 Diabetes Receiving Hydrochlorothiazide: A Cohort Study

BACKGROUND

Because of continuous hyperglycemia and hyperinsulinemia and the use of photosensitizing drug, hydrochlorothiazide (HCTZ), the risk of cutaneous squamous cell carcinoma (cSCC) might be increased among patients with diabetes. This study aimed to estimate the risk of cSCC among HCTZ users with type 2 diabetes, and to determine whether thiazide-like diuretics, another drug in the same class with HCTZ, would be safer.

METHODS

We linked the benchmarking database in Dutch primary care, the Netherlands Cancer Registry, and the Dutch Personal Records Database (1998-2019). All 71,648 patients were included, except for those who had a history of skin cancer prior to cohort entry. We used Cox modeling to estimate the HRs and 95% confidence intervals for cSCC. The model was adjusted by cumulative exposure to each antihypertensive, age, sex, smoking, body mass index, blood pressure, serum creatinine, other confounding drug use at cohort entry, and cohort entry year.

RESULTS

There were 1,409 cSCC events (23 among thiazide-like diuretics users), during a follow-up of 679,789 person-years. Compared with no HCTZ use, the adjusted HRs for HCTZ use were 1.18 (1.00-1.40) for ≤2 years, 1.57 (1.32-1.88) for 2 to 4 years, and 2.09 (1.73-2.52) for >4 years. The HR was 0.90 (0.79-1.03) for an additional year of thiazide-like diuretic use.

CONCLUSIONS

In patients with diabetes, exposure to HCTZ for >2 years is associated with an increased risk of cSCC, whereas no increased risk associated with thiazide-like diuretics was observed.

IMPACT

The potential increased risk of cSCC should be a consideration when prescribing HCTZ, with thiazide-like diuretics offering a safer alternative.

Mathematical Model for Delayed Responses in Immune Checkpoint Blockades

We introduce a set of ordinary differential equations (ODEs) that qualitatively reproduce delayed responses observed in immune checkpoint blockade therapy (e.g. anti-CTLA-4 ipilimumab). This type of immunotherapy has been at the forefront of novel and promising cancer treatments over the past decade and was recognised by the 2018 Nobel Prize in Medicine. Our model describes the competition between effector T cells and non-effector T cells in a tumour. By calibrating a small subset of parameters that control immune checkpoint expression along with the patient's immune-system cancer readiness, our model is able to simulate either a complete absence of patient response to treatment, a quick anti-tumour T cell response (within days) or a delayed response (within months). Notably, the parameter space that generates a delayed response is thin and must be carefully calibrated, reflecting the observation that a small subset of patients experience such reactions to checkpoint blockade therapies. Finally, simulations predict that the anti-tumour T cell storm that breaks the delay is very short-lived compared to the length of time the cancer is able to stay suppressed. This suggests the tumour may subsist off an environment hostile to effector T cells; however, these cells are-at rare times-able to break through the tumour immunosuppressive defences to neutralise the tumour for a prolonged period. Our simulations aim to qualitatively describe the delayed response phenomenon without making precise fits to particular datasets, which are limited. It is our hope that our foundational model will stimulate further interest within the immunology modelling field.

Beyond the single average tumor: Understanding IO combinations using a clinical QSP model that incorporates heterogeneity in patient response

A quantitative systems pharmacology model for metastatic melanoma was developed for immuno‐oncology with the goal of predicting efficacy of combination checkpoint therapy with pembrolizumab and ipilimumab. This literature‐based model is developed at multiple scales: (i) tumor and immune cell interactions at a lesion level; (ii) multiple heterogeneous target lesions, nontarget lesion growth, and appearance of new metastatic lesion at a patient level; and (iii) interpatient differences at a population level. The model was calibrated to pembrolizumab and ipilimumab monotherapy in patients with melanoma from Robert et al., specifically, waterfall plot showing target lesion response and overall response rate (Response Evaluation Criteria in Solid Tumors [RECIST] version 1.1), which additionally considers nontarget lesion growth and appearance of new metastatic lesions. We then used the model to predict waterfall and RECIST version 1.1 for combination treatment reported in Long et al. A key insight from this work was that nontarget lesions growth and appearance of new metastatic lesion contributed significantly to disease progression, despite reduction in target lesions. Further, the lesion level simulations of combination therapy show substantial efficacy in warm lesions (intermediary immunogenicity) but limited advantage of combination in both cold and hot lesions (low and high immunogenicity). Because many patients with metastatic disease are expected to have a mixture of these lesions, disease progression in such patients may be driven by a subset of cold lesions that are unresponsive to checkpoint inhibitors. These patients may benefit more from the combinations which include therapies to target cold lesions than double checkpoint inhibitors.

A mathematical model of viral oncology as an immuno-oncology instigator

We develop and analyse a mathematical model of tumour-immune interaction that explicitly incorporates heterogeneity in tumour cell cycle duration by using a distributed delay differential equation. We derive a necessary and sufficient condition for local stability of the cancer-free equilibrium in which the amount of tumour-immune interaction completely characterizes disease progression. Consistent with the immunoediting hypothesis, we show that decreasing tumour-immune interaction leads to tumour expansion. Finally, by simulating the mathematical model, we show that the strength of tumour-immune interaction determines the long-term success or failure of viral therapy.

Mature Dendritic Cells May Promote High-Avidity Tuning of Vaccine T Cell Responses

Therapeutic vaccines can elicit tumor-specific cytotoxic T lymphocytes (CTLs), but durable reductions in tumor burden require vaccines that stimulate high-avidity CTLs. Recent advances in immunotherapy responses have led to renewed interest in vaccine approaches, including dendritic cell vaccine strategies. However, dendritic cell requirements for vaccines that generate potent anti-tumor T-cell responses are unclear. Here we use mathematical modeling to show that, counterintuitively, increasing levels of immature dendritic cells may lead to selective expansion of high-avidity CTLs. This finding is in contrast with traditional dendritic cell vaccine approaches that have sought to harness ex vivo generated mature dendritic cells. We show that the injection of vaccine antigens in the context of increased numbers of immature dendritic cells results in a decreased overall peptide:MHC complex load that favors high-avidity CTL activation and expansion. Overall, our results provide a firm basis for further development of this approach, both alone and in combination with other immunotherapies such as checkpoint blockade.

Determinants of combination GM-CSF immunotherapy and oncolytic virotherapy success identified through in silico treatment personalization

Oncolytic virotherapies, including the modified herpes simplex virus talimogene laherparepvec (T-VEC), have shown great promise as potent instigators of anti-tumour immune effects. The OPTiM trial, in particular, demonstrated the superior anti-cancer effects of T-VEC as compared to systemic immunotherapy treatment using exogenous administration of granulocyte-macrophage colony-stimulating factor (GM-CSF). Theoretically, a combined approach leveraging exogenous cytokine immunotherapy and oncolytic virotherapy would elicit an even greater immune response and improve patient outcomes. However, regimen scheduling of combination immunostimulation and T-VEC therapy has yet to be established. Here, we calibrate a computational biology model of sensitive and resistant tumour cells and immune interactions for implementation into an in silico clinical trial to test and individualize combination immuno- and virotherapy. By personalizing and optimizing combination oncolytic virotherapy and immunostimulatory therapy, we show improved simulated patient outcomes for individuals with late-stage melanoma. More crucially, through evaluation of individualized regimens, we identified determinants of combination GM-CSF and T-VEC therapy that can be translated into clinically-actionable dosing strategies without further personalization. Our results serve as a proof-of-concept for interdisciplinary approaches to determining combination therapy, and suggest promising avenues of investigation towards tailored combination immunotherapy/oncolytic virotherapy.

The advent of biological therapies for anti-cancer treatment has had a significant impact on patient outcomes. Targeted xenobiotics, including oncolytic viruses, in combination with existing, more general, immunotherapies like exogenous cytokines show great promise for continuing to improve cancer care. However, determining optimal combination regimens can be difficult, given that testing proposed schedules would require large cohorts of patients enrolled in clinical trials. Fortunately, computational biology can help to address treatment scheduling while simultaneously helping to unravel the mechanisms driving therapeutic responses. In this work, we integrate a mathematical model of GM-CSF and talimogene laherparepvec (T-VEC) oncolytic virotherapy into a virtual clinical trial to optimize their administration in combination. Using this platform, we inferred a clinically-actionable combination schedule for patients with late-stage melanoma that significantly improved virtual patient outcome when compared to GM-CSF and T-VEC monotherapies, and a standard combination strategy. Our results outline a rational approach to therapy optimization with meaningful consequences for how we effectively design and implement clinical trials to maximize their success, and how we treat melanoma with combined immuno- and virotherapy.

Predicting response to pembrolizumab in metastatic melanoma by a new personalization algorithm

BACKGROUND

At present, immune checkpoint inhibitors, such as pembrolizumab, are widely used in the therapy of advanced non-resectable melanoma, as they induce more durable responses than other available treatments. However, the overall response rate does not exceed 50% and, considering the high costs and low life expectancy of nonresponding patients, there is a need to select potential responders before therapy. Our aim was to develop a new personalization algorithm which could be beneficial in the clinical setting for predicting time to disease progression under pembrolizumab treatment.

METHODS

We developed a simple mathematical model for the interactions of an advanced melanoma tumor with both the immune system and the immunotherapy drug, pembrolizumab. We implemented the model in an algorithm which, in conjunction with clinical pretreatment data, enables prediction of the personal patient response to the drug. To develop the algorithm, we retrospectively collected clinical data of 54 patients with advanced melanoma, who had been treated by pembrolizumab, and correlated personal pretreatment measurements to the mathematical model parameters. Using the algorithm together with the longitudinal tumor burden of each patient, we identified the personal mathematical models, and simulated them to predict the patient's time to progression. We validated the prediction capacity of the algorithm by the Leave-One-Out cross-validation methodology.

RESULTS

Among the analyzed clinical parameters, the baseline tumor load, the Breslow tumor thickness, and the status of nodular melanoma were significantly correlated with the activation rate of CD8+ T cells and the net tumor growth rate. Using the measurements of these correlates to personalize the mathematical model, we predicted the time to progression of individual patients (Cohen's κ = 0.489). Comparison of the predicted and the clinical time to progression in patients progressing during the follow-up period showed moderate accuracy (R² = 0.505).

CONCLUSIONS

Our results show for the first time that a relatively simple mathematical mechanistic model, implemented in a personalization algorithm, can be personalized by clinical data, evaluated before immunotherapy onset. The algorithm, currently yielding moderately accurate predictions of individual patients' response to pembrolizumab, can be improved by training on a larger number of patients. Algorithm validation by an independent clinical dataset will enable its use as a tool for treatment personalization.

Association of Uveal Melanoma Metastatic Rate With Stochastic Mutation Rate and Type of Mutation

Importance

It is necessary to understand the mechanisms of metastasis of uveal melanoma to advise patients and develop treatments for this tumor.

Objective

To examine the stochastic properties of primary uveal melanoma including the mutation rate as a function of tumor size and metastatic rate relative to the type of mutation.

Design, Setting, and Participants

We computed the mutation rate in different sized uveal melanomas using previously published large data sets. Tumor volume was estimated using the spherical cap method. We also calculated the metastatic rate using an updated data set of patients with uveal melanoma with known mutations in BAP1, SF3B1, and EIF1AX provided by the Rotterdam Ocular Melanoma Study Group. Data were analyzed from 2 studies, one taking place from August 25, 1970, to August 27, 2008, and the other taking place between 1993 and 2013. Data were analyzed between 2016 and 2017.

Main Outcomes and Measures

Mutation rates and metastic rates.

Results

Based on the 5-year metastatic rates, mutation rates ranged from 1.09 × 10-8 to 7.86 × 10-7 per cell division, using our calculation algorithm. A higher mutation rate was found for tumors with smaller thicknesses. EIF1AX mutations were not exclusive of other mutations because 2 cases with EIF1AX mutations and metastasis also had BAP1 mutations. None of the tumors with only an EIF1AX mutation metastasized. After plotting the yearly metastatic rate vs time after treatment, we observed a small peak at 1 year and a large peak at 3.5 years after treatment for BAP1 mutations, with peaks between 2 and 3 years and at 7 years for SF3B1 mutations.

Conclusions and Relevance

We observed a higher mutation rate for smaller tumors, which may be explained by a greater number of cell divisions occurring during the expansion phase of smaller uveal melanomas. Regarding time to clinically detected metastases, the first 2 peaks appear to be associated with BAP1-mutated tumors and the late peak to SF3B1-mutated tumors.

Estimation of Solid Tumor Doubling Times from Progression-Free Survival Plots Using a Novel Statistical Approach

Tumor doubling time can significantly affect the outcome of anticancer therapy, but it is very challenging to determine. Here, we present a statistical approach that extracts doubling times from progression-free survival (PFS) plots, which inherently contains information regarding the growth of solid tumors. Twelve cancers were investigated and multiple PFS plots were evaluated for each type. The PFS plot showing fastest tumor growth was deemed to best represent the inherent growth kinetics of the solid tumor, and selected for further analysis. The exponential tumor growth rates were extracted from each PFS plot, along with associated variabilities, which ultimately allowed for the estimation of solid tumor doubling times. The mean simulated doubling times for pancreatic cancer, melanoma, hepatocellular carcinoma (HCC), renal cell carcinoma, triple negative breast cancer, non-small cell lung cancer, hormone receptor positive (HR+) breast cancer, human epidermal growth factor receptor-2 positive (HER-2+) breast cancer, gastric cancer, glioblastoma multiforme, colorectal cancer, and prostate cancer were 5.06, 3.78, 3.06, 2.67, 2.38, 2.40, 4.31, 4.12, and 3.84 months, respectively. For all cancers, clinically reported doubling times were within the estimated ranges. For all cancers, except HCC, the growth rates were best characterized by a log-normal distribution. For HCC, the gamma distribution best described the data. The statistical approach presented here provides a qualified method for extracting tumor growth rates and doubling times from PFS plots. It also allows estimation of the distributional characteristics for tumor growth rates and doubling times in a given patient population.

Immunobiochemical Reconstruction of Influenza Lung Infection-Melanoma Skin Cancer Interactions

It was recently reported that acute influenza infection of the lung promoted distal melanoma growth in the dermis of mice. Melanoma-specific CD8+ T cells were shunted to the lung in the presence of the infection, where they expressed high levels of inflammation-induced cell-activation blocker PD-1, and became incapable of migrating back to the tumor site. At the same time, co-infection virus-specific CD8+ T cells remained functional while the infection was cleared. It was also unexpectedly found that PD-1 blockade immunotherapy reversed this effect. Here, we proceed to ground the experimental observations in a mechanistic immunobiochemical model that incorporates T cell pathways that control PD-1 expression. A core component of our model is a kinetic motif, which we call a PD-1 Double Incoherent Feed-Forward Loop (DIFFL), and which reflects known interactions between IRF4, Blimp-1, and Bcl-6. The different activity levels of the PD-1 DIFFL components, as a function of the cognate antigen levels and the given inflammation context, manifest themselves in phenotypically distinct outcomes. Collectively, the model allowed us to put forward a few working hypotheses as follows: (i) the melanoma-specific CD8+ T cells re-circulating with the blood flow enter the lung where they express high levels of inflammation-induced cell-activation blocker PD-1 in the presence of infection; (ii) when PD-1 receptors interact with abundant PD-L1, constitutively expressed in the lung, T cells loose motility; (iii) at the same time, virus-specific cells adapt to strong stimulation by their cognate antigen by lowering the transiently-elevated expression of PD-1, remaining functional and mobile in the inflamed lung, while the infection is cleared. The role that T cell receptor (TCR) activation and feedback loops play in the underlying processes are also highlighted and discussed. We hope that the results reported in our study could potentially contribute to the advancement of immunological approaches to cancer treatment and, as well, to a better understanding of a broader complexity of fundamental interactions between pathogens and tumors.

Development of a microsimulation of melanoma mortality for evaluating the effectiveness of population-based skin cancer screening

BACKGROUND

A nationwide skin cancer screening (SCS) was implemented in Germany in 2008. It aims at improving early detection of melanoma in order to reduce melanoma mortality. While the idea of early detection is compelling, demonstrating the effectiveness of melanoma screening is crucial. Since it is not feasible to conduct epidemiological studies to investigate the impact of factors such as screening interval or targeted age groups, we developed a microsimulation model that is able to predict melanoma mortality in Germany under several SCS conditions.

METHODS

Using German cancer registry data, population data, and other published data on melanoma progression and screening participation, we developed a stochastic microsimulation model. With this model, 10,000 populations of 100,000 persons and their melanoma-related life histories were simulated separately for women and for men and calibrated to observed melanoma incidence. In a second step, life histories of melanoma were changed by an SCS.

RESULTS

Compared with a nonscreening scenario (age-standardized mortality rate: 1.6 and 2.9 per 100,000 for women and men), a biennial SCS of the 35- to 85-year-old population with a participation probability of 20% for each screening-eligible individual and a test sensitivity of 80% reduced mortality by up to 0.7 and 1.4 deaths per 100,000 person-years for women and men, respectively, corresponding to a relative reduction of melanoma mortality by 45% in women and men.

CONCLUSIONS

We developed a microsimulation model of melanoma mortality that can be used to evaluate the effectiveness of population-based skin cancer screening. The simulation provided plausible melanoma mortality predictions and is a tool for comparing different SCS scenarios. However, it does not provide estimates on total costs of SCS.

Current concepts of metastasis in melanoma

The main cause of death in melanoma patients is widespread metastases. Staging of melanoma is based on the primary tumor thickness, ulceration, lymph node and distant metastases. Metastases develop in regional lymph nodes, as satellite or in-transit lesions, or in distant organs. Lymph flow and chemotaxis is responsible for the homing of melanoma cells to different sites. Standard pathologic evaluation of sentinel lymph nodes fails to find occult melanoma in a significant proportion of cases. Detection of small numbers of malignant melanoma cells in these and other sites, such as adjacent to the primary site, bone marrow or the systemic circulation, may be enhanced by immunohistochemistry, reverse transcription PCR, evaluation of lymphatic vessel invasion and proteomics. In the organs to which melanoma cells metastasize, extravasation of melanoma cells is regulated by adhesion molecules, matrix metalloproteases, chemokines and growth factors. Melanoma cells may travel along external vessel lattices. After settling in the metastatic sites, melanoma cells develop mechanisms that protect them against the attack of the immune system. It is thought that one of the reasons why melanoma cells are especially resistant to killing is the fact that melanocytes (cells from which melanoma cells derive) are resistant to such noxious factors as ultraviolet light and reactive oxygen species. Targeted melanoma therapies are, so far, largely unsuccessful, and new ones, such as adjuvant inhibition of melanogenesis, are under development.

Melanoma patients with unknown primary site or nodal recurrence after initial diagnosis have a favourable survival compared to those with synchronous lymph node metastasis and primary tumour

Background

A direct comparison of prognosis between patients with regional lymph node metastases (LNM) detected synchronously with the primary melanoma (primary LNM), patients who developed their first LNM subsequently (secondary LNM) and those with initial LNM in melanoma with unknown primary site (MUP) is missing thus far.

Patients and Methods

Survival of 498 patients was calculated from the time point of the first macroscopic LNM using Kaplan Meier and multivariate Cox hazard regression analysis.

Results

Patients with secondary LNM (HR = 0.67; p = 0.009) and those with initial LNM in MUP (HR = 0.45; p = 0.008) had a better prognosis compared to patients with primary LNM (median survival time 52 and 65 vs. 24 months, respectively). A high number of involved nodes, the presence of in-transit/satellite metastases and male gender had an additional independent unfavourable effect.

Conclusions

Survival of patients with LNM in MUP and with secondary LNM is similar and considerably more favourable compared to those with primary LNM. This difference needs to be considered during patient counselling and for stratification purposes in clinical trials. The assumption of an immune privilege of patients with MUP which is responsible for rejection of the primary melanoma, and results in a favourable prognosis is not supported by our data.

Anticancer nanomedicine and tumor vascular permeability; Where is the missing link?

Anticancer nanomedicine was coined to describe anticancer delivery systems such as polymer conjugates, liposomes, micelles, and metal nanoparticles. These anticancer delivery platforms have been developed with the enhanced permeability and retention (EPR) effect as a central mechanism for tumor targeting. EPR based nanomedicine has demonstrated, beyond doubt, to selectively target tumor tissues in animal models. However, over the last two decades, only nine anticancer agents utilizing this targeting strategy have been approved for clinical use. In this review, we systematically analyze various aspects that explain the limited clinical progress yet achieved. The influence of nanomedicine physicochemical characteristics, animal tumor models, and variations in tumor biology, on EPR based tumor targeting is closely examined. Furthermore, we reviewed results from over one hundred publications to construct patterns of factors that can influence the transition of EPR based anticancer nanomedicine to the clinic.

Inhibitors targeting mitosis: tales of how great drugs against a promising target were brought down by a flawed rationale

Although they have been advocated with an understandable enthusiasm, mitosis-specific agents such as inhibitors of mitotic kinases and kinesin spindle protein have not been successful clinically. These drugs were developed as agents that would build on the success of microtubule-targeting agents while avoiding the neurotoxicity that encumbers drugs such as taxanes and vinca alkaloids. The rationale for using mitosis-specific agents was based on the thesis that the clinical efficacy of microtubule-targeting agents could be ascribed to the induction of mitotic arrest. However, the latter concept, which has long been accepted as dogma, is likely important only in cell culture and rapidly growing preclinical models, and irrelevant in patient tumors, where interference with intracellular trafficking on microtubules is likely the principal mechanism of action. Here we review the preclinical and clinical data for a diverse group of inhibitors that target mitosis and identify the reasons why these highly specific, myelosuppressive compounds have failed to deliver on their promise.

Metastatic lymph node targeted chemosensitivity test for gastric cancer

BACKGROUND

The objective of this study was to compare the chemosensitivity of primary tumor and metastasized lymph node from patient with gastric adenocarcinoma.

MATERIALS AND METHODS

We studied 26 gastric cancer patients with lymph node metastasis who underwent gastric resection at the Korea University Guro Hospital from Feb 2007 to July 2008. The chemosensitivity of primary tumor and metastatic lymph node were studied using an adenosine triphosphate-based chemotherapy response assay (ATP-CRA).

RESULTS

The concordance rate of the ATP-CRA test was 30.8% (8/26). The concordance rate between primary tumor and metastatic N2 group lymph node was only 9.1% (1/11). The metastatic tumor inhibition rates with 5-fluorouracil, cisplatin, doxorubicin, and oxaliplatin were higher than the inhibition rates for primary tumor. Tumor inhibition rates was significantly different between primary tumor and metastatic tumor after doxorubicin treatment (27.734±20.95 versus 38.403±26.87, P=0.021). We detected simple correlations of tumor inhibition rates between primary and metastatic tumors with cisplatin (r=0.661, P<0.001) and doxorubicin (r=0.475, P=0.031).

CONCLUSIONS

We observed differences between first choice chemotherapeutic agents based on ATPCRA tests of primary tumor and metastatic tumor in lymph node. Therefore, chemotherapeutic agents should be carefully selected for adjuvant chemotherapy using a chemosensitivity test.

Medicolegal liability in surgical pathology: a consideration of underlying causes and selected pertinent concepts

Malpractice actions against surgical pathologists are still relatively uncommon, but they have increased in frequency over time and are associated with sizable indemnity figures. This discussion categorizes areas of liability in surgical pathology into three groups: those that represent health system flaws (problems with specimen identification, or transportation, or both; lack of clinical information or erroneous information; sampling effects and defects; and poorly reproducible or poorly defined diagnostic or prognostic criteria), others that exist at the interface between the system and individuals (allowing clinicians to bypass pathologic review of referred specimens; acceding to clinical demands for inadvisable procedures; and working in a disruptive environment), and truly individual errors by pathologists (lapses in reasoning; deficiencies concerning continuity in the laboratory; invalid assumptions regarding recipients of surgical pathology reports; over-reliance on the results of "special" tests; and problems with peer consultation). Finally, two important topic areas are discussed that commonly enter into lawsuits filed against surgical pathologists; namely, "delay in diagnosis" of malignant neoplasms and "failure to provide adequate prognostic information." Based on a review of the pertinent literature, we conclude that the clinical courses of most common malignancies are not affected in a significant manner by delays in diagnosis. Moreover, the practice of using "personalized external validity" for supposedly prognostic tests is examined, with the resulting opinion that prognostication of tumor behavior in individual patients is not reliable using anything but anatomic staging systems.

Cancer: A medical emergency

Over the last decade clinical trials have established the effectiveness of adjuvant chemotherapy in eradicating micrometastases in many different cancers, including breast, colon, and lung. This success stands in sharp contrast to our failure to cure clinically evident metastatic cancer. These dramatic polarities illustrate the critical importance of treatment timing if residual cancer is to be eradicated. Adjuvant chemotherapy is started only after recovery from surgery, a period of time that can exceed 30 days. During this time any cancer that remains after surgery will continue to divide. Although adjuvant chemotherapy has proven effective despite this time delay, there are reasons, both conceptual and quantitative, to think that its effectiveness could be magnified by a more prompt administration. The extent of this magnification is mathematically modeled in this paper. Surgery and the process of wound healing after surgery create a very favorable environment for the growth of the metastatic clone. Surgery can increase the number of circulating tumor cells and induce an immunosuppressive effect that might facilitate metastatic spread. And the process of wound healing can stimulate growth factors that have been shown to accelerate tumor cell growth. This situation is a double-edged sword. Although the metastatic clone should proliferate rapidly during this time, it should also, at least theoretically, be more sensitive to the effects of chemotherapy as more cells are pushed into a cycling phase. We derive a mathematical model based upon empirical data predicting that the effectiveness of a given chemotherapeutic regimen is inversely proportional to the tumor burden that has to be eradicated, which, in turn, is a function of when chemotherapy is started after surgery. Although the critical importance of timing in the treatment of cancer is intuitive, this knowledge has not yet been fully translated into the clinical practice of medical oncology. If the model presented is accurate, many people are dying unnecessarily of their cancer today because we are waiting too long after surgery to use highly effective chemotherapies, following well-trod clinical paths and established paradigms for how cancer should be treated.

Evidence-based principles and practices in pathology: selected problem areas

Contrary to the intuitive impression of most pathologists, there are still many areas in laboratory medicine where evidence-based medicine (EBM) principles are not applied. These include aspects of both anatomic and clinical pathology. Some non-EBM practices are perpetuated by clinical "consumers" of laboratory services, because of inadequate education, habit, or over-reliance on empirical factors. Other faulty procedures are pathologist-driven, with similar underpinnings. This overview considers several exemplary problem areas representing non-EBM practices in the hospital laboratory. Such examples include ideas and techniques centering on metastatic malignancies, "targeted" oncological therapy, analysis of surgical margins in the excision of neoplasms, general laboratory testing and data utilization, evaluation of selected coagulation defects, administration of blood products, and analysis of hepatic iron-overload syndromes. The concepts illustrating departures from EBM are discussed for each of those topics.

Role of surgery in patients with stage IV melanoma

PURPOSE OF REVIEW

The purpose of this brief review is to highlight recent advances in the surgical treatment of metastatic melanoma; to review factors important in the decision-making process of selecting the most appropriate patients for resection; and to discuss the current literature in the context of site of recurrence.

RECENT FINDINGS

While there are relatively few new findings on the surgical treatment of metastatic melanoma, recent reports do support prior observations in the field. The recently revised staging system for melanoma groups metastatic disease according to prognostic features. There is currently a great deal of interest in the use of 18-fluorodeoxyglucose positron emission tomography (FDG-PET) to more accurately evaluate metastatic disease. The use stereotactic radiosurgery for brain metastases has expanded recently and adds to local treatment options. When procedures are performed with palliative intent, treatment goals must be clearly defined and communicated among the patient, family and surgeon. Improved understanding of the goals of palliative surgery may be facilitated by the concept of a palliative triangle, which helps define the decision making process among the patient, family members, and surgeon.

SUMMARY

Metastatic melanoma is usually associated with a dismal prognosis. When a procedure is performed with palliative intent, appropriately selected patients usually experience reliable relief of symptoms and improved quality of life. Improved survival after a complete resection with curative intent is often predicted by good performance status, longer disease-free interval, limited extent of metastatic disease, and less aggressive tumor biology.