Synchronous rectal and prostate cancer – The impact of MRI on incidence and imaging findings

• Prostate and rectal cancers are two of the most common cancers in male.
• Synchronous diagnosis of prostate and rectal cancer is a rare identity.
• Strong increase in the synchronous diagnosis likely due to improved diagnostic methods.
• Pre-treatment MRI for rectal cancer has led to increased synchronous diagnosis.

ObjectiveTo evaluate the incidence of synchronous diagnosis of rectal and prostate cancer and to identify how the role of magnetic resonance imaging (MRI) for preoperative staging of rectal cancer has affected the incidence.MethodsRegional data from the Swedish Colorectal Cancer Registry and the Regional Cancer Registry in Stockholm-Gotland area (two million inhabitants) between the years 1995–2011 were used. Patients were included when the rectal cancer was diagnosed prior to the prostate cancer. Medical records and pre-treatment MRI were retrospectively reviewed.ResultsOf 29,849 patients diagnosed with either disease, synchronous diagnosis was made in 29 patients (0.1%). Two patients were diagnosed in the years 1995–1999, seven patients between the years 2000–2005 and 20 patients between the years 2006–2011. The most common presentation, for the prostate cancer was incidental finding during staging for rectal cancer, n = 20, and of those led MRI to the diagnosis in 14 cases.At retrospective review, all patients had focal lesions in the prostate on MRI and patients with higher suspicion of malignancy on MRI had more locally advanced disease.ConclusionSynchronous rectal and prostate cancer are a rare entity, but a strong increase in synchronous diagnosis is seen which may be attributed to improved diagnostic methods, including the use of pre-treatment MRI in routine work-up for rectal cancer.