Sunscreen with UV protection and SPF 50

It is a broad-spectrum test to measure the product's protection from ultraviolet (UV) rays. When a sunscreen passes this test, it is referred to as broad-spectrum sunscreen. There are types of sunscreens that protect against short-range UV rays, affecting the outer layer of the skin and causing sunburn and skin cancer, and long-range UV rays, affecting the inner layer of the skin and causing wrinkles and sagging. Doctors often recommend using a sunscreen with an SPF of 30 or higher to protect the skin from both short and long-range UV rays.

Yes, broad-spectrum sunscreens are considered to prevent skin cancer. According to the Food and Drug Administration (FDA), broad-spectrum sunscreens with a sun protection factor (SPF) of 15 or higher reduce the risk of skin cancer and early skin aging when used frequently and in conjunction with other sun protection measures.

Source: FDA
http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/ucm330694.htm

Exposing the product to high heat for an extended period may damage the product's formulation, causing the ingredients to separate. According to the Food and Drug Administration (FDA), sunscreens often lose their effectiveness after three years of production. However, if the products are exposed to heat, such as leaving them in a hot car or outside under direct sunlight, their expiration date may be closer.

Source: FDA
https://www.fda.gov/drugs/resourcesforyou/consumers/buyingusingmedicinesafely/understandingover-the-countermedicines/ucm239463.htm