First-in-human clinical study of novel technique to diagnose malignant melanoma via thermal conductivity measurements

Abstract

Melanoma is an aggressive skin cancer that originates from melanocytes and, especially in the case of early-stage melanoma, is distributed adjacent to the epidermis and superficial dermis. Although early-stage melanoma can be distinguished from benign nevus via a dermoscopy, it is difficult to distinguish invasive melanoma in its early stages from in situ melanoma. Because invasive melanoma must undergo a sentinel lymph node biopsy to be diagnosed, a non-invasive method to detect the micro-invasion of early-stage melanoma is needed for dermato-oncologists. This paper proposes a novel quantitative melanoma identification method based on accurate measurements of thermal conductivity using a pen-shaped device. This method requires skin temperature data for one minute to determine the effective thermal conductivity of the skin, allowing it to distinguish melanoma lesions from healthy skin. Results suggest that effective thermal conductivity was negative for in situ melanoma. However, in accordance with tumour progression, effective thermal conductivity was larger in invasive melanoma. The proposed thermal conductivity measurement is a novel tool that detects the micro-invasion of melanoma.

A novel technique to diagnose non‐melanoma skin cancer by thermal conductivity measurements: Correlations with cancer stromal factors

“…This method only requires skin temperature data for 1 minute to determine the ETC of the skin and to distinguish between invasive and non‐invasive skin cancers by measuring the differences in ETC between lesions and healthy skin. Indeed, as we previously reported, this method could distinguish invasive and non‐invasive malignant melanomas before surgical treatment . However, the stromal factors that contribute to modulate thermal conductivity of skin cancer are still unknown.…”

“…A guard‐heated thermistor probe, developed in our previous studies, was used to accurately and rapidly measure the ETC of the skin. The probe consisted of two glass‐coated thermistors (PSB‐S9 type, Shibaura Electronics Co., Ltd.) that were previously calibrated using a standard thermometer system (1560 black stack thermometer and 5640 thermistor standard probe, FLUKE and were inserted into a pen‐shaped probe holder for practical use and solidity.…”

“…Some phenotypes of these advanced cancers are resistant to radiotherapies and chemotherapies, and the treatment options are limited . Therefore, sentinel lymph node biopsy is recommended when tumor is suspected to progress into invasive phenotypes, but in the real world, even skin surgeons do unnecessary sentinel lymph node biopsies for non‐melanoma skin cancer in situ. Since sentinel lymph node biopsy requires radioisotopes, skin surgeons should avoid such unnecessary invasive procedures .…”

“…Therefore, sentinel lymph node biopsy is recommended when tumor is suspected to progress into invasive phenotypes, but in the real world, even skin surgeons do unnecessary sentinel lymph node biopsies for non‐melanoma skin cancer in situ. Since sentinel lymph node biopsy requires radioisotopes, skin surgeons should avoid such unnecessary invasive procedures . Therefore, the development of rapid and accurate tools to distinguish in situ skin cancers and dermal invasive skin cancers is needed.…”

“…However, the stromal factors that contribute to modulate thermal conductivity of skin cancer are still unknown. In this report, the diagnostic methods for invasive and non‐invasive skin cancers, SCC and EMPD, were tested by measuring the absolute value of skin surface temperature and the ETC of the skin . In addition, immunohistochemical staining for stromal factors that could stimulate tumor‐associated macrophages (TAMs) and angiogenetic factors that are expected to be produced by TAMs in SCC and EMPD was performed.…”