Women who have had thyroid cancer often need to take medications that can weaken their bones. Researchers tested whether a special bone-strengthening treatment called 99Tc-MDP could help protect bone density in these women. Over one year, women who received this treatment along with calcium and vitamin D supplements maintained their bone strength better than women who only took calcium and vitamin D. This finding is important because it suggests a new way to help thyroid cancer patients keep their bones strong while undergoing their necessary cancer treatment.

The Quick Take

  • What they studied: Whether adding a bone-strengthening medicine (99Tc-MDP) to regular calcium and vitamin D supplements could prevent bone loss in women with thyroid cancer who need special thyroid medications
  • Who participated: 102 women who had passed menopause, had thyroid cancer, and were taking thyroid-suppressing medications that can weaken bones
  • Key finding: Women who received the bone-strengthening treatment maintained their bone density over 12 months, while women taking only calcium and vitamin D lost bone density. The treatment group showed better bone health markers at 6 and 12 months.
  • What it means for you: If you’re a postmenopausal woman with thyroid cancer on suppressive therapy, this treatment may help protect your bones. However, talk with your doctor about whether this is right for your specific situation, as this is one study and more research may be needed.

The Research Details

Researchers divided 102 postmenopausal women with thyroid cancer into two groups. One group received calcium and vitamin D supplements only, while the other group received the same supplements plus an additional bone-strengthening treatment called 99Tc-MDP. The researchers measured bone density using a special X-ray scan at the start and after 12 months. They also checked blood markers that show how quickly bones are breaking down and rebuilding throughout the year.

This type of study is called a prospective study, meaning researchers followed the same people forward in time and measured changes. It was open-label, meaning both the patients and doctors knew who was receiving which treatment. This design allows researchers to see real-world effects of the treatment over a full year.

This research approach is important because thyroid cancer patients on suppressive therapy face a real problem: their necessary cancer treatment weakens their bones. By comparing two groups with different treatments over a full year, researchers could see which approach actually works better. The blood markers they measured show not just bone density, but also how active bone breakdown and rebuilding are happening—giving a complete picture of bone health.

The study included a reasonable number of participants (102 women) and followed them for a full year, which is long enough to see meaningful changes. No serious side effects were reported in either group, suggesting the treatment is safe. However, this was an open-label study, meaning both patients and doctors knew who got which treatment, which could potentially influence results. The study was conducted in one location, so results may not apply equally to all populations.

What the Results Show

The main finding was clear: women who received the bone-strengthening treatment (99Tc-MDP) plus calcium and vitamin D maintained their bone density in the spine over 12 months. In contrast, women who received only calcium and vitamin D experienced a measurable decrease in bone density—their bone density dropped from 0.9148 to 0.8726, which was statistically significant.

The researchers also measured bone turnover markers—special proteins in the blood that show how quickly bones are breaking down and being rebuilt. In the treatment group, a marker called P1NP (which shows new bone formation) increased at both 6 and 12 months compared to the calcium-only group. Another marker called β-CTX (which shows bone breakdown) decreased significantly at 12 months in the treatment group.

These blood markers suggest that the 99Tc-MDP treatment not only maintained bone density but also shifted the balance toward more bone building and less bone breakdown. This is important because it shows the treatment is working at a biological level, not just maintaining numbers on a scan.

The study found that calcium and vitamin D supplementation alone was not sufficient to prevent bone loss in this specific population of thyroid cancer patients on suppressive therapy. This is an important finding because it shows that standard bone health recommendations may not be enough for these patients. The safety profile was excellent—no serious adverse events were reported in either group, suggesting the treatment is well-tolerated.

Previous research on bone health in thyroid cancer patients has been limited. This study adds important evidence that bisphosphonate treatments (the class of drugs that includes 99Tc-MDP) may be beneficial for this specific group. The finding that calcium and vitamin D alone don’t work well aligns with other research showing that thyroid-suppressive therapy causes significant bone loss that requires more aggressive treatment.

This study has several limitations to consider. First, it was open-label, meaning both patients and doctors knew who was getting which treatment, which could influence how they reported results. Second, the study only lasted one year—longer follow-up would show whether benefits continue. Third, the study was conducted in one location, so results may not apply equally to all populations or ethnic groups. Fourth, the study didn’t compare 99Tc-MDP to other bone-strengthening treatments, so we don’t know how it compares to alternatives. Finally, the study didn’t track whether the bone density improvements actually reduced fracture risk, which is the ultimate goal of bone treatment.

The Bottom Line

For postmenopausal women with differentiated thyroid cancer on thyroid-suppressive therapy who have osteopenia (early bone loss), adding 99Tc-MDP to calcium and vitamin D supplementation appears to be a safe and effective option to maintain bone density. This recommendation has moderate confidence based on this one-year study. Women in this situation should discuss this treatment option with their endocrinologist or oncologist to determine if it’s appropriate for their individual case.

This research is most relevant to postmenopausal women with thyroid cancer who are taking thyroid-suppressive medications and have early bone loss (osteopenia). It may also be relevant to women approaching or in menopause with thyroid cancer who want to prevent bone loss. This research is less relevant to men with thyroid cancer, premenopausal women, or people with normal bone density. Anyone considering this treatment should consult with their cancer care team.

Based on this study, you could expect to see stabilization of bone density within 12 months of starting treatment. The blood markers showed changes as early as 6 months. However, preventing fractures (the real-world benefit) may take longer to demonstrate, and individual results will vary based on age, overall health, and other factors.

Want to Apply This Research?

  • Track bone health appointments and medication adherence monthly. Specifically, log: (1) whether you took your calcium/vitamin D and 99Tc-MDP as prescribed, (2) any bone or joint symptoms, and (3) appointment dates for bone density scans and blood work. This creates a clear record to discuss with your doctor.
  • Set daily reminders to take calcium and vitamin D supplements at the same time each day. If prescribed 99Tc-MDP, follow the specific dosing schedule (typically given as injections). Also track dietary calcium intake and weight-bearing exercise, as these support bone health alongside medication.
  • Schedule bone density scans annually and blood work every 6 months to monitor bone turnover markers. Use the app to set reminders for these appointments and to track results over time. Compare results year-to-year to see if bone density is stable or improving. Share this tracking data with your healthcare provider at each visit.

This research summary is for educational purposes only and should not replace professional medical advice. The findings apply specifically to postmenopausal women with differentiated thyroid cancer on thyroid-suppressive therapy with osteopenia. If you have thyroid cancer or bone health concerns, consult with your oncologist or endocrinologist before starting any new treatment. Individual results may vary, and this one-year study should be considered alongside other available evidence and your personal health situation. Do not stop or change any cancer medications without medical guidance.