Breaking News: Increased Risk of Breast Cancer in FD/MAS Patients

Researchers from Leiden University Medical Center (LUMC) in the Netherlands and the National Institutes of Health (NIH) in the US have recently concluded a study researching the link between breast cancer and fibrous dysplasia and McCune-Albright syndrome(FD/MAS). Findings suggest that FD/MAS patients are more likely to develop breast cancer, and at a younger age, than general population.

“We found that FD patients are about 3 times more likely to develop breast cancer than the general population.” said the lead researcher of the study, Natasha Appelman-Dijkstra, MD, PhD. “We also found that FD patients tended to develop breast cancer at a younger age. The general population is diagnosed at the median age of 62 in the US and 61 in the Netherlands, whereas FD patients were diagnosed at a median age of 36 in the US cohort and 46 in the Dutch cohort.”

The study analyzed the medical histories of 255 female patients, 15 of whom ultimately developed breast cancer. All of the FD/MAS patients in the study who were diagnosed with breast cancer had polyostotic FD, or MAS with polyostotic FD. None of the patients with monostotic FD in this study developed breast cancer.

Polyostotic FD and MAS patients with FD lesions in the thoracic region (ribs, sternum, thoracic vertebrae) should especially take note.

Of the 15 patients who developed breast cancer, 13 had thoracic FD. The researchers estimate that patients with FD lesions in the thoracic region are somewhere between 6 to 13 times more likely to get breast cancer than the general population. History of precocious puberty or growth hormone excess might also be an additional risk factor.

Thankfully, while FD/MAS patients appear to be at higher risk for breast cancer, preliminary analysis suggests that FD-related breast cancer is not extremely aggressive. Of the 15 patients diagnosed with breast cancer, 10 had ductal carcinoma in situ, which is considered a non-invasive, early-stage breast cancer. Only 5 of the 15 diagnoses were invasive adenocarcinoma. So far, the prognoses for the breast cancer patients have been very good. Two to fifteen years after diagnosis, all of the 15 breast cancer patients survived the breast cancer. None of the 15 breast cancer patients have experienced recurrence or distant metastases.

These findings may change the way patients and clinicians approach their care and treatment plans. “In the Netherlands we will start screening FD/MAS patients for breast cancer at age 40, ten years earlier than the general population.” said Dr. Appelman-Dijkstra.

The US researchers also think that the study’s findings should impact screening guidelines. “We recommend women with FD/MAS begin regular screening mammography starting at age 40 years.” said Alison Boyce, MD of the NIH, “This is 5 years earlier than the general American population. These recommendations apply to women with polyostotic FD, thoracic FD, a history of precocious puberty, or growth hormone excess.”

“Screening programs should be individually tailored with the treating physician.” said Dr. Appelman-Dijkstra. “Our plan is to screen all Dutch patients with polyostotic FD/MAS or FD in their thoracic region.” NIH clinicians suggest patients with  a history of precocious puberty and growth hormone excess take extra precaution, as these may be drivers of the increased risk.

These important findings would not have come to light without charitable donations to support FD research. “My PhD student and I noticed that lots of the FD/MAS patients in our database had breast cancer, and that triggered our interest in studying this link,” said Dr. Appelman-Dijkstra. “We knew that the GNAS mutation could result in Mazabraud’s syndrome, which meant it could affect other soft tissues as well. We did not know the exact connection between this gene mutation and differentiated FD/MAS diagnosis.” explained  Dr. Appelman-Dijkstra. The PhD student who noticed the link, Bas Majoor, is supported by a grant from the Bontius Foundation in Leiden for research into fibrous dysplasia. Dutch FD/MAS patients have been instrumental in Bontius Foundation fundraising efforts.

After Drs. Appelman-Dijkstra and Majoor noticed the link, they knew that they needed to collaborate with another research group in order to validate their findings and show that the increased risk of breast cancer could be seen in patients outside of the Netherlands. Thankfully, the International Consortium on FD has been meeting more and more frequently, including a recent scientific meeting in Lyon, and a Fibrous Dysplasia Foundation-supported gathering at last year’s ASBMR annual meeting. During these interactions, LUMC and NIH researchers decided to team up to study the link between FD/MAS and breast cancer with more patient data.

The study will be published after peer-review and the Fibrous Dysplasia Foundation will share the full article as soon as it is available. **AVAILABLE NOW HERE***

There is still more to be understood regarding the link between FD/MAS and cancer. LUMC and NIH researchers are determined to pursue continued funding in support of future research. The FDF is especially grateful to Dr. Natasha Appelman-Dijkstra, Dr. Neveen Hamdy, Dr. Alison Boyce, and Dr. Michael Collins for sharing this news with the FD/MAS patient community as soon as they could, in advance of the study’s formal publication.