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Osteoporosis Case of the Month
by Harvey
S. Marchbein, M.D.
The patient is a very pleasant 76 year old white female gravida 2 para 2002. Her last menstrual period was in 1974. In 1986, she had a right lumpectomy and radiation therapy for breast cancer. She was also treated with Tamoxifen from 1986 until 1996. She was first seen in our office in 1990. She sees an oncologist for followup examinations as well as her breast surgeon. She was initially seen in our office for symptoms of urinary incontinence. She underwent urodynamic studies and was treated with bladder training, biofeedback and Urispas for uninhibited contractions and urgency incontinence. Due to mild hypertension, she is on Dyazide.
On a yearly basis, she has received mammograms which have been read as normal, status post lumpectomy. Yearly physical examinations were also carried out by her primary care physician, oncologist, breast surgeon and gynecologist. Her gynecologic examination was normal except for atrophic changes as anticipated. Her urinary symptoms continued and she was referred to a urologist for further evaluation. She was then treated with Levsinex.
In September 1995, a letter was received from her oncologist. It stated the following - "Enclosed is a sonogram on one of our patients, who has been treated for breast cancer and now has been maintained on Tamoxifen for 9 years. I asked her to contact your office for an appointment and an evaluation to assess whether the hyperplasia is related to Tamoxifen and whether this requires definitive biopsy and treatment".
The sonogram was done transabdominally and endovaginally. "The uterus measures approximately 7.2 cm in length x 4.6 cm AP x 7.1 cm transversely. The endometrial canal is markedly thickened measuring 3.2 cm with prominent cystic changes. No definite endometrial mass was visualized."
The final impression was "markedly thickened endometrial canal with prominent cystic changes which may be related to cystic hyperplasia due to Tamoxifen. No definite endometrial mass was visualized. The ovaries were unremarkable."
Her pap smears were consistently normal. An attempt was made to do an endometrial biopsy in the office but there was an inability to dilate the cervix to allow for the biopsy. A D&C was carried out and the pathology report was read as "endometrial polyp". (Teaching note - today, three years later, this may have been able to be diagnosed with a saline infusion sonohysterogram).
Tamoxifen was discontinued in January, 1996. In October, 1996, it was recommended that the patient obtain DEXA bone densitometry measurements. Her lumbar spine had a T score of (-1.94), femoral neck (-1.82) and radius of (-2.57). The spine and femur measurements were consistent with osteopenia and the radius was just over the cutoff for osteoporosis. The patient desired no therapy at that time and was not a Hormone Replacement Therapy (HRT) candidate secondary to her personal history of breast cancer. The patient had been on Tamoxifen for nearly 10 years and it was well known that Tamoxifen can be protective against osteoporosis. Not having any other measurements, it was not known as to whether or not these numbers represented a loss, gain or status quo from premenopausal levels in this patient. Also well known, is the variability between bone densitometry scans, both on differing machines and intrapatient variation. There can be a 2-3% variation from scan to scan. If bone loss or gain is 2-3% or less, a scan done too early may show no change when, in fact, change has occurred.
Therefore, a repeat DEXA was performed in May, 1998. The lumbar spine measurements are now being measured separately as cortical and trabecular bone. The combination "cortical and trabecular BMD (bone mineral density) to be compared to the older (1996) measurement had a T score of (-1.63) (still osteopenia but representing a 4.1% increase since 10/96). The trabecular BMD of the lumbar spine had a T score of (-3.33) representing osteoporosis and "moderate risk for fracture". The femoral neck, with a T score of (-2.24) still showed osteopenia but represented a 9.7% bone loss in 19 months. The radius had a T score of (-2.44), changing from a diagnosis of osteoporosis to that of osteopenia, with a 2.9% increase in bone density (not inconsistent with variations noted above).
The greatest concerns here are twofold and were not anticipated this rapidly after cessation of Tamoxifen. The 9.7% bone loss in the femoral neck (despite the fact that it is not diagnosable as osteoporosis yet) AND the trabecular BMD of the lumbar spine with a T score of (-3.33) (probably due to change in DEXA methodology).
Taking all of this into consideration, the patient was placed on Fosamax 10mg daily and 1000-1200 mg. of calcium. She is presently tolerating this well.
The take-away points are these:
- Order bone densities on appropriate patients regardless of their medical history (i.e. don't skip patients with cancers or other chronic/prolonged/severe diseases because you don't wish to burden them further).
- Follow up appropriately on DEXAs. (Repeat at correct intervals for patient-specific results or risk factors).
- Treat appropriately. (Anti-resorptive therapy can be used in most patients with adequate instructions and enthusiasm). Adequate therapy includes calcium supplementation, whether the adjuvant therapy is HRT, ERT or newer classes of bisphosphonates.
- Strongly consider urinary NTX measurements in patients either at the beginning of therapy and 3 months later as follow up (especially in patients being placed on HRT or ERT where the anti-resorptive response is approximately 82%), or in patients who have discontinued medication (e.g. Tamoxifen) and aren't due for another DEXA but in whom you wish objective information as to their bone metabolism.
