Evaluation of Modern MRI in the Diagnosis of Prostate Cancer in a Danish Setup

Prostate cancer (PCa) is now the most frequently diagnosed male malignant disease in Denmark with more than 4000 new cases each year. PCa is the second leading cause of cancer related mortality in the western world. During their lifetime, one in six men will be clinically diagnosed with Prostate cancer and approximately one out of thirty will die of the disease. We know from autopsies that more than half of the male-population above the age of 60 is found to have histological cancer-changes. Therefore, the majority of men with histological proven cancer-changes will never develop a clinical disease that would affect their morbidity and mortality.

An elevated PSA (blood sample) and/or an abnormal rectal examination are indications of PCa. The diagnosis is made by trans-rectal-ultrasound guided biopsies (TRUS-biopsies) followed by histological examination. Each biopsy-session includes 10 to 12 biopsy-cores taken from standard locations throughout the prostate. Since over 40 % of the cancers are isoechoic on ultrasound and cannot be seen, there is a high risk that the tumour is either missed or that the most aggressive part of the tumour is not biopsied.

If you find a prostate cancer, it is important to know if the cancer is localized within the prostate or if it grows outside of the capsule. This is called staging and is essential in determine the best treatment-strategy and the patient's prognosis. In Denmark, staging is determined by digital rectal examination and sometimes by TRUS, even though we know these examinations are inaccurate and have limitations. It is important to improve the diagnostic localization and staging of the tumour for optimal clinical management and therapy selection.

The development of modern multiparametric-high-field-magnetic-imaging (mMRI) offers new possibilities and approaches in detection, localization and staging of prostate cancer due to its high resolution and soft-tissue contrast. mMRI can provide information about the morphological, metabolic and cellular changes and characterize tissue- and tumour- vascularity and correlate it with tumour aggressiveness. This helps to locate and stage a possible tumour and to guide targeted-biopsies towards disease-suspicious areas. Internationally published data support the rapidly growing use of multiparametric MRI, as being the most sensitive and specific imaging tool for prostate cancer patients.

The primary objective of this project is to investigate whether the use of modern MRI in Denmark can:

• Improve the diagnosis of Danish men suspected of prostate cancer and
• Improve the diagnosis and treatment planning of Danish men with biopsy-proven prostate cancer.

The secondary goal is to gain experience in the use of modern MRI in Denmark to evaluate prostatic tumors. This study forms the basis for investigating whether modern MRI should be used as an adjunct diagnostic tool for selected patients in the diagnosis of prostate cancer.

The project contains three separate studies evaluating the adjunct diagnostic value of mMRI to the conventional standard diagnostic evaluation and treatment.

The three studies:

• Study 1 is offered to patients with newly diagnosed localized non-metastatic prostate cancer and is comparing mMRI to TRUS and DRE in clinical classification of the cancer.
• Study 2 is offered to patients with newly diagnosed localized non-metastatic prostate cancer who underwent Brachytherapy and is comparing mMRI to CT-scan performed 4 weeks after surgery in the evaluation of postoperative dosimetry (treatment effect).
• Study 3 is offered to patients scheduled for re-biopsy due to continuing suspicion of prostate cancer after standard TRUS-guided biopsies with negative findings to see if multiparametric MRI can detect prostate cancer invisible on transrectal ultrasound; in order to improve detection rate.