[Descriptive analysis of cutaneous recurrence patterns in patients with melanoma]

Predictive Value of Baseline [18F]FDG PET/CT for Response to Systemic Therapy in Patients with Advanced Melanoma

Background/Aim: To evaluate the association between baseline [18F]FDG-PET/CT tumor burden parameters and disease progression rate after first-line target therapy or immunotherapy in advanced melanoma patients. Materials and Methods: Forty four melanoma patients, who underwent [18F]FDG-PET/CT before first-line target therapy (28/44) or immunotherapy (16/44), were retrospectively analyzed. Whole-body and per-district metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were calculated. Therapy response was assessed according to RECIST 1.1 on CT scan at 3 (early) and 12 (late) months. PET parameters were compared using the Mann–Whitney test. Optimal cut-offs for predicting progression were defined using the ROC curve. PFS and OS were studied using Kaplan–Meier analysis. Results: Median (IQR) MTVwb and TLGwb were 13.1 mL and 72.4, respectively. Non-responder patients were 38/44, 26/28 and 12/16 at early evaluation, and 33/44, 21/28 and 12/16 at late evaluation in the whole-cohort, target, and immunotherapy subgroup, respectively. At late evaluation, MTVbone and TLGbone were higher in non-responders compared to responder patients (all p < 0.037) in the whole-cohort and target subgroup and MTVwb and TLGwb (all p < 0.022) in target subgroup. No significant differences were found for the immunotherapy subgroup. No metabolic parameters were able to predict PFS. Controversially, MTVlfn, TLGlfn, MTVsoft + lfn, TLGsoft + lfn, MTVwb and TLGwb were significantly associated (all p < 0.05) with OS in both the whole-cohort and target therapy subgroup. Conclusions: Higher values of whole-body and bone metabolic parameters were correlated with poorer outcome, while higher values of whole-body, lymph node and soft tissue metabolic parameters were correlated with OS.

Improved detection of in-transit metastases of malignant melanoma with BSREM reconstruction in digital [18F]FDG PET/CT

OBJECTIVES

To compare block sequential regularized expectation maximization (BSREM) and ordered subset expectation maximization (OSEM) for the detection of in-transit metastasis (ITM) of malignant melanoma in digital [¹⁸F]FDG PET/CT.

METHODS

We retrospectively analyzed a cohort of 100 [¹⁸F]FDG PET/CT scans of melanoma patients with ITM, performed between May 2017 and January 2020. PET images were reconstructed with both OSEM and BSREM algorithms. SUVmax, target-to-background ratio (TBR), and metabolic tumor volume (MTV) were recorded for each ITM. Differences in PET parameters were analyzed with the Wilcoxon signed-rank test. Differences in image quality for different reconstructions were tested using the Man-Whitney U test.

RESULTS

BSREM reconstruction led to the detection of 287 ITM (39% more than OSEM). PET parameters of ITM were significantly different between BSREM and OSEM reconstructions (p < 0.001). SUVmax and TBR were higher (76.5% and 77.7%, respectively) and MTV lower (49.5%) on BSREM. ITM missed with OSEM had significantly lower SUVmax (mean 2.03 vs. 3.84) and TBR (mean 1.18 vs. 2.22) and higher MTV (mean 2.92 vs. 1.01) on OSEM compared to BSREM (all p < 0.001).

CONCLUSIONS

BSREM detects significantly more ITM than OSEM, owing to higher SUVmax, higher TBR, and less blurring. BSREM is particularly helpful in small and less avid lesions, which are more often missed with OSEM.

KEY POINTS

• In melanoma patients, [¹⁸F]FDG PET/CT helps to detect in-transit metastases (ITM), and their detection is improved by using BSREM instead of OSEM reconstruction. • BSREM is particularly useful in small lesions.

The course of stage III melanoma in accordance with the severity of node involvement

Objectives: Pathological stage III melanoma patients have variable clinical presentation and outcome when divided by substages, and the number of metastatic lymph nodes is the most significant independent factor. We aimed to determine the clinical features and natural course of node positive melanoma, such as first relapse and final outcome, and other factors influencing them. Methods: A total of 362 node positive melanoma patients were included in the study and reviewed retrospectively. Results: Cases were as follows: N1 (56.6%); N2 (27.1%); and N3 (16.3%). Lymphovascular invasion was found significant among node positive subtypes; it was predominant in patients with involvement of two or more nodes (p < .05). The majority of the relapses were locoregional alone (43.4%) and distant alone (31.3%). The lung/pleura was the most frequently metastasized site (32.1%). Time to relapse was the longest for N1 (20.8 months) (p < .05). Five and 10 year relapse-free survival (RFS) rates were 40% and 38%, respectively. Nodular histopathology, ulcerated lesion and higher mitotic rates carried worse RFS for all patients and also for N1. Five- and 10 year overall survival (OS) rates were 49% and 40%, respectively. Older age, nodular histopathology, higher mitotic rates and relapse of disease (p = .001) were the independent variables that were inversely correlated with OS for all patients. Conclusion: Comparative analyses of node positive melanoma suggested that there was not only a remarkable heterogeneity in the recurrence and survival rates but also a distinctive pattern among independent prognostic indicators in accordance with the severity of nodal involvement.

HF ultrasound vs PET-CT and telethermography in the diagnosis of In-transit metastases from melanoma: a prospective study and review of the literature

BACKGROUND

Over the past several years the incidence of cutaneous melanoma has rapidly increased. This tumor develops often in-transit metastases that significantly reduce patient survival at 5 years. To improve prognosis and quality of life in patients with melanoma metastases, a mini invasive procedure like electrochemotherapy (ECT) is adopted to remove superficial tissue lesions. To detect the melanoma metastases, high frequency (HF) ultrasound (US) is used. This technique, though, can be time-consuming and it needs an expert operator and a high performing machine. Therefore, we asked whether the US could be replaced or integrated with other less time-consuming techniques such as 18-FDG positron emission tomography/computed tomography (PET-CT) and telethermography (TT).

METHODS

Fifteen patients (4 males and 11 females - age range: 63-91) affected whit advanced stage melanoma were enrolled. They presented 52 in-transit metastases as detected by the three techniques used, HF-US, PET/CT and TT within 30 days before ECT.

RESULTS

All the 52 lesions were detected by HF-US (100%), 24/52 were detected by PET-CT (42,6%) and 15/52 were detected by TT (27,7%). PET-CT reported 3.7% false positives, while no false positive were reported by TT.

CONCLUSIONS

As US detected 100% lesions, compared to the other two techniques used, US, along with clinical examination, has still to be considered as gold standard in the diagnosis of metastatic lesions. US, associated with an exhaustive anamnesis and accurate clinical examination, cannot be replaced by either PET-CT or TT. When US performing devices and experienced operators are not available, though, it is highly recommended to integrate US with at least one of the other techniques. Under certain circumstances, as in the case of obese and non-collaborating patients or in patients with lymphatic stasis, these techniques should be integrated to obtain exact in-transit metastases evaluation.

Risk factors for the development of locoregional cutaneous metastases as the sole form of recurrence in patients with melanoma

BACKGROUND

While locoregional cutaneous metastases (in transit and satellite) in melanoma have received little attention from researchers to date, they have pathogenic and prognostic features that distinguish them from other forms of locoregional recurrence. Identifying predictors of these metastases would be of great value for their prevention, early diagnosis, and treatment. The aim of this study was to identify the risk factors associated with locoregional cutaneous metastases as the first form of recurrence in the metastatic progression of melanoma.

MATERIAL AND METHODS

Between 2000 and 2010, we prospectively collected the data of 1327 patients diagnosed with stage I and II melanoma. During follow up, 112 patients (8.4%) developed metastases. Of these, 36 had exclusively locoregional cutaneous metastases. The clinical and histological characteristics of this subgroup were evaluated.

RESULTS

In the univariate analysis, significant predictors were patient age, primary tumor thickness, site, ulceration, mitotic index, and histological type. After multivariate analysis, the independent risk factors were tumor thickness (risk ratio [RR] 5.6; 95% CI: 2.7-11.5) and the location of the primary tumor on the lower limbs (RR 3.4; 95% CI: 1.0-11.5), on the head or neck (RR 4.8; 95% IC: 1.7-13.5), or in acral sites (RR 6.7; 95% IC: 2.2-20.8).

CONCLUSION

Patients who have melanomas with a Breslow thickness of more than 2mm located on the lower limbs, head, neck, or acral sites have a higher risk of developing locoregional cutaneous metastases. These findings could be useful in the design of future guidelines for the monitoring and management of melanoma.