In which of the following cancer screening is least useful?

Screening for Ca Lungs require chest X rays every 6 months and sputum cytology. It is not recommended or practical. According to the U.S. Preventive Services Task Force (USPSTF), there is insufficient evidence to recommend for or against screening for lung cancer and prostate cancer in men under 75. There is insufficient evidence to recommend for or against screening for skin cancer and oral cancer. Routine screening is not recommended for bladder cancer, testicular cancer, ovarian cancer and pancreatic cancer.