Secondary Bladder Cancer After Prostate Cancer Treatment: An Age-matched Comparison Between Radiation and Surgery (2023, Full Text)
"
Abstract
BackgroundSecondary malignancy is a long-term risk of radiation. External beam radiation therapy (EBRT) for prostate cancer treatment has been associated with later development of bladder cancer and worse bladder cancer features.
ObjectiveWe sought to provide an updated comparison of the long-term risk of bladder cancer after different localized prostate cancer treatments.
Design, setting, and participantsUsing the Surveillance, Epidemiology, and End Results (SEER) cancer registry, we compared an age-matched subset of patients who underwent radical prostatectomy (RP) with those who underwent EBRT, brachytherapy (BT), EBRT + BT, and RP followed by EBRT (RPtoEBRT) between 2000 and 2018. Our final cohort included 261 609 patients with a median follow-up of 11.6 yr.
Outcome measurements and statistical analysisOur primary outcomes were time to bladder cancer diagnosis, muscle-invasive bladder cancer diagnosis, and bladder cancer death. We used cause-specific hazard models considering death as a competing event. A similar analysis was performed on lung cancer, as a surrogate marker for smoking. We also compared proportions of variant histology, high-grade, and invasive disease among bladder cancers that occurred after radiation versus RP using chi-square testing.
Results and limitations
All radiation groups were associated with bladder cancer diagnosis; hazard ratios (HRs) were 1.72, 1.85, 1.80, and 1.53 for EBRT, BT, EBRT + BT, and RPtoEBRT, respectively, using RP as a referent (all p < 0.001). HRs for bladder cancer death were even higher: 2.39, 2.57, and 3.02 for EBRT, BT, and EBRT + BT, respectively (all p < 0.001), except for RPtoEBRT (HR 1.43, p = 0.28). Lung cancer diagnosis was also associated with radiation but at lower HRs—1.63, 1.32, 1.42, and 1.30 for EBRT, BT, EBRT + BT, and RPtoEBRT, respectively (all p < 0.001). There were a higher proportion of ≥T2, ≥T3, and sarcomatoid variant bladder cancers after radiation (all p < 0.01)ConclusionsThe risk of developing and dying from bladder cancer is increased in patients treated with radiation compared with those treated with RP. The risk was similar for BT and EBRT. Bladder cancers after radiation are more likely to be sarcomatoid variant and present as muscle invasive.
Patient summaryWe observed the rates of bladder cancer after patients had undergone surgery or radiation for prostate cancer, and found higher rates of bladder cancer after radiation. We also observed that bladder cancers that occur after radiation tend to be more aggressive."
_____________________
The stats for bladder cancer are similar to what I've seen in the past; I wasn't aware of the increased risk for lung cancer.
Note: The use of "secondary" here can be confusing. It does
not mean prostate cancer that has metastasized to the bladder or lung, but rather a new and different cancer--bladder (or lung) cancer that occurs for any reason (including the radiation that was used years earlier to treat the prostate cancer). It is actually a second (and related),
primary cancer (of the bladder or lung). In other words, this cancer started from bladder (or lung) cells that became malignant and proliferated: in a biopsy the pathologist sees bladder (or lung) tissue that has gone awry and become cancerous, as opposed to the malignant prostate tissue seen in a prostate biopsy or in a bladder biopsy from someone with prostate-cancer mets in the bladder.
Today I had a dental panoramic x-ray and cleaning. The tech put a lead vest on me so that the x-rays used to reveal tumors (among other things) have a greatly reduced chance of themselves inducing tumors--at least under the areas the vest covers. Of course the tech steps out of the room before starting the automated x-ray procedure. The Word of the Day is
iatrogenic: relating to illness caused by medical examination or treatment.