Diagnosis and treatment of prostate cancer

November 5, 2019, 10:12 194

Prostate cancer is the second most commonly occurring cancer in men and the fourth most commonly occurring cancer overall. There were 1.3 million new cases in 2018. Approximately 60% of cases are diagnosed in men over 65. The average age of diagnosis is 66; the disease rarely occurs before age 40. For unknown reasons, the risk of prostate cancer is about 60% higher in black men than in white men. Most prostate cancers (90%) are found when the disease is confined to the prostate and nearby organs. This is referred to as the local or regional stage. The 5-year survival rate tells you what percent of men live at least 5 years after the cancer is found. Percent means how many out of 100. The 5-year survival rate for most men with local or regional prostate cancer is nearly100%. For men diagnosed with prostate cancer that has spread to other parts of the body, the 5-year survival rate is 30%.

Age-adjusted incidence rates of prostate cancer have increased dramatically and this is largely because of the increased availability of screening for prostate-specific antigen (PSA) in men without symptoms of the disease. This test leads to detection of many prostate cancers that are small and/or would otherwise remain unrecognized, and which may or may not develop further into higher stage disease.

Prostate specific membrane antigen (PSMA) is highly overexpressed in prostate cancer. Many PSMA analogue radiotracers for PET/CT imaging of prostate cancer staging have been developed such as 68Ga-PSMA-11. This radiotracer has achieved good results in multiple clinical trials, but because of superior imaging characteristics of 18F-fluoride, 18F-PSMA-11 was developed. PSMA-targeted PET/CT has become a fundamental tool in the management of patients with prostate cancer, especially to rule out local recurrence after surgery or radiation. However, the assessment of the prostatic fossa is difficult due to the renal excretion of PSMA-targeted radionuclides. PET/CT studies using Ga-PSMA-11 PET/CT and F-PSMA-1007 of a 61-year-old man after radical prostatectomy illustrates that F-PSMA-1007 is an ideal radionuclide for the detection of local recurrence of prostate cancer and is superior to Ga-PSMA-11, especially in case of pelvic lesions. 

Image result for Ga-PSMA-11 prostate

Targeted alpha and gamma therapy is a promising approach for the treatment of cancer. The use of alpha and gamma emitters for cancer therapy has two distinct advantages over conventional therapies. The short range of alpha radiation in human tissue (less than 0.1 mm), corresponding to only a few cell diameters, allows selective killing of targeted cancer cells while sparing surrounding healthy tissue. At the same time, the high energy (several MeV) of alpha radiation and its associated high linear energy transfer leads to highly effective cell kill. Consequently, alpha radiation can destroy cells which otherwise exhibit resistance to treatment with beta or gamma irradiation or chemotherapeutic drugs, and can thus offer a therapeutic option for tumors resistant to conventional therapies.

A number of targeted radiopharmaceuticals are used in the treatment of prostate cancer. The 177Lu-psma, 213Bi, and 225Ac peptide compounds are successfully used in nuclear medicine.

Image result for Ga-PSMA-11

References:

  1. Bruchertseifer FKellerbauer AMalmbeck RMorgenstern A. etc., Targeted alpha therapy with bismuth-213 and actinium-225: Meeting future demand, J Labelled Comp Radiopharm. 2019
  2. Frederik L. Giesel, Leon Will, Kiryl Paddubny, Christophe Kremer, etc., [18F]PSMA-1007 PET Improves the Diagnosis of Local Recurrence and Lymph Node Metastases in a Prostate Cancer Patient With a History of Bilateral Hip Arthroplasty, Clinical Genitourinary Cancer April 2018
  3. Clemens Kratochwil, Frank Bruchertseifer, etc., Hendrik Rathke1, Targeted a-Therapy of Metastatic Castration-Resistant Prostate Cancer with 225Ac-PSMA-617: Swimmer-Plot Analysis Suggests Efficacy Regarding Duration of Tumor Control, J Nucl Med. 2018

 

By Shukurov R.