Prostate cancer: Brachytherapy linked to long-term risk of secondary malignancies
When cancer patients are treated with radiation, it’s possible that the therapy itself may cause new tumors to form in the body later. Radiation kills cancer cells by damaging their DNA, but if the treatments cause genetic damage to normal cells near the radiation target, there’s a small risk that these secondary malignancies may arise over time.
Just over 10 years ago, Canadian researchers set out to assess the risk of secondary malignancy among men with prostate cancer who were treated with a type of radiation called brachytherapy. Unlike radiation delivered from sources outside the body, brachytherapy is accomplished by implanting dozens of radioactive pellets, or “seeds,” directly into the tumor site. Those seeds, which are never removed, emit radiation at a dose that declines toward zero over the course of a year.
Brachytherapy has the advantage of convenience. Instead of traveling for repeat sessions of radiation, men need only one treatment, usually given in an outpatient setting. But brachytherapy is also falling out of favor, in part because newer types of external beam radiation deliver high-precision doses with fewer side effects.
Study methodology and results
The Canadian study compared rates of secondary malignancies in the pelvis among men treated either with brachytherapy or with surgery to remove the prostate. All the treatments took place in British Columbia between 1998 and 2000. The brachytherapy group included 2,418 men with an average age of 66, while the surgically-treated group contained 4,015 men whose average age was 62. Within that group, 2,643 men had been treated with surgery alone, and 1,372 men with surgery plus external beam radiation given later.
After median follow-ups of between 5.8 years (brachytherapy) and 6.4 years (surgery), the study team reported in 2014 that there was no difference in rates of secondary malignancies between the groups, or with cancer incidence in the general population.
But that’s no longer the case: In April 2024, the researchers published updated findings. This time, rates of new cancers in the pelvis — including the bladder and rectum — were higher in the brachytherapy group. Specifically, 6.4% of brachytherapy-treated men had secondary malignancies at 15 years of follow-up, increasing to 9.8% after 20 years. By contrast, 3.2% and 4.2% of surgically-treated men developed secondary pelvic malignancies over the same durations. There was no difference in deaths from secondary malignancies between the groups.
The strength of the association with bladder cancer in particular is “similar to that seen with smoking,” wrote the author of an accompanying editorial. Results from the study “should be considered when treating men with localized prostate cancer who have a long life expectancy,” the authors concluded.
Commentary from experts
“I do believe that this study reveals a dark truth about radiation for prostate cancer that has been long suspected,” says Dr. Anthony Zietman, a professor of radiation oncology at Harvard Medical School and Massachusetts General Hospital, and a member of the advisory and editorial board for the Harvard Medical School Guide to Prostate Diseases. “As the decades pass after radiation therapy of any kind — brachytherapy or external beam — the risk for radiation-induced malignancies rises.
“These malignancies are usually in adjacent organs like the bladder and rectum, or within the prostate itself. They may be very curable, and thus the survival rates are the same for radiation or surgically treated patients, but there is little doubt that, for these patients, they represent a ‘sting in the tail’ long after the radiation has been given and forgotten. This data certainly gives us pause when offering radiation to very young men with several decades of life expectancy ahead of them, and it also reminds us of the value of follow-up visits.”
“The fact that second cancers arise in the area where radiation was given is not surprising, but the magnitude of the long-term increases is concerning,” added Dr. Marc Garnick, the Gorman Brothers Professor of Medicine at Harvard Medical School and Beth Israel Deaconess Medical Center, and editor in chief of the Harvard Medical School Guide to Prostate Diseases. “There are other common and troublesome urinary side effects of brachytherapy — independent of second cancers — that patients should fully consider before selecting it as a treatment option. This is especially true given the availability of other convenient and similarly effective prostate cancer therapies.”
About the Author
Charlie Schmidt, Editor, Harvard Medical School Annual Report on Prostate Diseases
Charlie Schmidt is an award-winning freelance science writer based in Portland, Maine. In addition to writing for Harvard Health Publishing, Charlie has written for Science magazine, the Journal of the National Cancer Institute, Environmental Health Perspectives, … See Full Bio View all posts by Charlie Schmidt
About the Reviewer
Marc B. Garnick, MD, Editor in Chief, Harvard Medical School Annual Report on Prostate Diseases; Editorial Advisory Board Member, Harvard Health Publishing
Dr. Marc B. Garnick is an internationally renowned expert in medical oncology and urologic cancer. A clinical professor of medicine at Harvard Medical School, he also maintains an active clinical practice at Beth Israel Deaconess Medical … See Full Bio View all posts by Marc B. Garnick, MD
Power your paddle sports with three great exercises
On the Gulf Coast of Florida where I live, the telltale sign of summer is not an influx of beachcombers, afternoon storms that arrive exactly at 2 p.m., or the first hurricane warning, but the appearance of hundreds of paddleboarders dotting the inlet waters.
From afar, paddleboarding looks almost spiritual — people standing on nearly invisible boards and gliding across the surface as if walking on water.
But this popular water sport offers a serious workout, just as kayaking and canoeing do. While floating along and casually dipping a paddle in the water may look effortless, much goes on beneath the surface, so to speak.
As warm weather beckons and paddle season arrives, it pays to get key muscles in shape before heading out on the water.
Tuning up muscles: Focus on core, back, arms, and shoulders
“Paddling a kayak, canoe, or paddleboard relies on muscles that we likely haven’t used much during winter,” says Kathleen Salas, a physical therapist with Spaulding Adaptive Sports Centers at Harvard-affiliated Spaulding Rehabilitation Network. “Even if you regularly weight train, the continuous and repetitive motions involved in paddling require endurance and control of specific muscles that need to be properly stretched and strengthened.”
While paddling can be a whole-body effort (even your legs contribute), three areas do the most work and thus need the most conditioning: the core, back, and arms and shoulders.
- Core. Your core comprises several muscles, but the main ones for paddling include the rectus abdominis (that famed “six-pack”) and the obliques, located on the side and front of your abdomen. The core acts as the epicenter around which every movement revolves — from twisting to bending to stabilizing your trunk to generate power.
- Back: Paddling engages most of the back muscles, but the ones that carry the most load are the latissimus dorsi muscles, also known as the lats, and the erector spinae. The lats are the large V-shaped muscles that connect your arms to your vertebral column. They help protect and stabilize your spine while providing shoulder and back strength. The erector spinae, a group of muscles that runs the length of the spine on the left and right, helps with rotation.
- Arms and shoulders: Every paddle stroke engages the muscles in your arms (biceps) and the top of your shoulder (deltoids).
Many exercises specifically target these muscles, but here are three that can work multiple paddling muscles in one move. Add them to your workouts to help you get ready for paddling season. If you haven’t done these exercises before, try the first two without weights until you can do the movement smoothly and with good form.
Three great exercises to prep for paddling
Wood chop
Muscles worked: Deltoids, obliques, rectus abdominis, erector spinae
Reps: 8–12 on each side
Sets: 1–3
Rest: 30–90 seconds between sets
Starting position: Stand with your feet about shoulder-width apart and hold a dumbbell with both hands. Hinge forward at your hips and bend your knees to sit back into a slight squat. Rotate your torso to the right and extend your arms to hold the dumbbell on the outside of your right knee.
Movement: Straighten your legs to stand up as you rotate your torso to the left and raise the weight diagonally across your body and up to the left, above your shoulder, while keeping your arms extended. In a chopping motion, slowly bring the dumbbell down and across your body toward the outside of your right knee. This is one rep. Finish all reps, then repeat on the other side. This completes one set.
Tips and techniques:
- Keep your spine neutral and your shoulders down and back
- Reach only as far as is comfortable.
- Keep your knees no farther forward than your toes when you squat.
Make it easier: Do the exercise without a dumbbell.
Make it harder: Use a heavier dumbbell.
Bent-over row
Muscles worked: Latissimus dorsi, deltoids, biceps
Reps: 8–12
Sets: 1–3
Rest: 30–90 seconds between sets
Starting position: Stand with a weight in your left hand and a bench or sturdy chair on your right side. Place your right hand and knee on the bench or chair seat. Let your left arm hang directly under your left shoulder, fully extended toward the floor. Your spine should be neutral, and your shoulders and hips squared.
Movement: Squeeze your shoulder blades together, then bend your elbow to slowly lift the weight toward your ribs. Return to the starting position. Finish all reps, then repeat with the opposite arm. This completes one set.
Tips and techniques:
- Keep your shoulders squared throughout.
- Keep your elbow close to your side as you lift the weight.
- Keep your head in line with your spine.
Make it easier: Use a lighter weight.
Make it harder: Use a heavier weight.
Superman
Muscles worked: Deltoids, latissimus dorsi, erector spinae
Reps: 8–12
Sets: 1–3
Rest: 30–90 seconds between sets
Starting position: Lie face down on the floor with your arms extended, palms down, and legs extended.
Movement: Simultaneously lift your arms, head, chest, and legs off the floor as high as is comfortable. Hold. Return to the starting position.
Tips and techniques:
- Tighten your buttocks before lifting.
- Don’t look up.
- Keep your shoulders down, away from your ears.
Make it easier: Lift your right arm and left leg while keeping the opposite arm and leg on the floor. Switch sides with each rep.
Make it harder: Hold in the “up” position for three to five seconds before lowering.
About the Author
Matthew Solan, Executive Editor, Harvard Men's Health Watch
Matthew Solan is the executive editor of Harvard Men’s Health Watch. He previously served as executive editor for UCLA Health’s Healthy Years and as a contributor to Duke Medicine’s Health News and Weill Cornell Medical College’s … See Full Bio View all posts by Matthew Solan
About the Reviewer
Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing
Dr. Howard LeWine is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD