Breslow thickness is a measure of the size of a melanoma growth expressed in terms of how deeply into the epidermis the growth has penetrated. The deeper the Breslow thickness, the greater the possibility of metastases and the worse the prognosis for the patient. This is one among several measures used in the assessment of patients with melanoma to develop an appropriate treatment plan.
When unusual skin growths are identified in a patient, the growths are removed and examined in a lab to determine whether they are malignant and to collect more information about them. In the case of a melanoma, the pathologist will measure the height of the tumor to determine the Breslow thickness, expressed in millimeters. If the tumor is less than 1 millimeter high, there is a 95 to 100% five-year survival rate for the patient, a very good prognosis. Cancers between 1 and 2 millimeters have a five-year survival rate of 80 to 96%, while growths over 2 millimeters and smaller than 4 millimeters high have a reduced survival rate, around 60 to 70%.
The biggest tumors, over 4 millimeters in height, come with an estimated 37 to 50% survival rate for the patient. A high Breslow thickness is an indicator for aggressive treatment to increase the patient's chances, paired with careful monitoring for any sign of metastases to allow doctors to address additional growths as soon as possible. Medical imaging studies may be recommended to look for growths in other areas of the body and the patient can receive aggressive chemotherapy and other treatments to address the melanoma.
Doctor Alexander Breslow is generally credited with recognizing the connection between the level of tumor invasion and the prognosis for the patient, during research conducted in the 1970s. Measurements of the thickness of melanoma growths are known as the Breslow thickness in honor of his research. Doctors may also use other terms to describe a melanoma, including Clark level, looking specifically at how many layers of skin have been penetrated by the cancer, and staging, referring to the aggressiveness of the cancer and the possibility for metastases.
A melanoma diagnosis can be frightening, especially when technical terms like Breslow thickness start getting thrown around. Patients are entitled to ask for clear, understandable descriptions of their medical conditions and to get information about treatment options, prognosis with different kinds of treatment, and what to expect from treatment so they can make informed choices and their options.