Cancer therapy associated bone loss in the majority of cases is preventable and an aggressive approach to preserve bone health should be mandatory. Every cancer patient should be treated preventively for bone loss, prior to the occurrence of severe osteoporosis.
The following all cause bone loss: chemotherapy, radiation, arimidex, GnRh antagonists and proton pump inhibitors. It makes no sense to save a patient’s life by curing them of cancer unless bone loss is prevented. These patients have faced death and should not face deformity and loss of independence.
If a person with cancer already has one or more risk factors for osteoporosis, they may have undiagnosed osteoporosis prior to cancer treatment. Every cancer patient should be sent for a DXA scan of their spine and hips, not an ultrasound of their calcaneus or tibia. If the DXA scan is normal, they still need to be treated preventively.
More women die from complications of osteoporotic fractures, than from all cancers of the ovary, uterus and cervix combined. Lung cancer is the only cancer that supersedes Osteoporosis in death.
Ovarian failure usually develops within one year of chemotherapy, in a very high percentage of premenopausal women with breast cancer, who receive postoperative adjuvant chemotherapy. Chemotherapy induced ovarian dysfunction accelerates the onset of menopause by approximately 10 years. More men die from the complications of Osteoporotic fractures than prostate cancer.
NOTE: Premenopausal women with breast cancer treated with GnRH analog treatment, within the first six months, will experience amenorrhea, which results in loss of trabecular and cortical bone.
Aromatase inhibitors are replacing tamoxifen as the first choice of treatment for postmenopausal patients, with early and advanced oestrogen dependent breast cancer. Aromatase inhibitors cause bone loss by lowering the levels of endogenous oestrogen.
TIP:Tamoxifen causes bone loss in premenopausal patients, but not in postmenopausal, because it has a weaker effect than endogenous oestrogens.
Options for androgen deprivation therapy (ADT) include bilateral orchidectomy, administration of a gonadotropin releasing hormone (GnRH) analogue, or complete androgen blockade with a GnRH agonist and an antiandrogen.
NOTE: Bone loss that occurs with ADT is generally more rapid and severe than that associated with normal age related bone loss and comparable to the rate associated with menopause.
Who is going to monitor/treat these patients?
Every Physician should be checking to ensure, that every cancer patient is being monitored and treated. Please do not forget those who were treated for cancer in the past.
ONJ – Osteonecrosis of the Jaw
ONJ can be a dramatic complication of bisphosphonate therapy in cancer patients. Particularly if they have poor dental hygiene. The median duration of drug use in affected cancer patients ranges from 22 to 39 months. Besides other factors, such as local trauma and corticosteroids, bisphosphonate-associated ONJ appears to be linked with a marked suppression of bone turnover leading to accumulation of physiologic microdamage in the jawbones.
The prevalence of ONJ in cancer patients might reach 6-10% after prolonged therapy but, even if a few cases have been reported, its incidence is significantly lower compared to the amount of patients with multiple fractures, deformity, loss of independence and premature death due to osteoporosis.
The most relevant concerns with bisphosphonates are deterioration of renal function. Most cases of renal function deterioration are mild and reversible and can be avoided if creatinine clearance is monitored before each dose of zoledronic acid, and the dose adjusted to the level of renal insufficiency.
Who to Treat?
If the patient is negative prior to treatment, they still need to be treated preventively,
Patients with existing osteopenia and osteoporosis should be evaluated for conditions which further deteriorate bone health, such as low vitamin D (80nmol/L is desired result), hyperthyroidism, hyperparathyroidism and hypercalciuria.
Treat Mild or Moderate Osteopenia, as main bone loss occurs in the first six months with Aromatase inhibitors
It is essential to find and treat all other risk factors, particularly: low sex hormones, low oestrogen in women and low testosterone in men, high cortisol, low vitamin D, high PTH, low caloric intake, excess intake of fibre, high caffeine, excessive alcohol, smoking, gluten and wheat sensitivity and lack of weight bearing exercise. Calcium and vitamin D are recommended; however, they are not sufficient to prevent androgen deprivation therapy induced bone loss.
TIP: Low levels of vitamin D linked with Osteoporosis, multiple forms of cancer, TB, MS, Osteoarthritis, diabetes and mimics symptoms of fibromyalgia.
TIP: Gluten and wheat sensitivity is a major cause of low vitamin D levels, most are negative on Coeliac test.
Symptoms – people can have one or more: Bloating of stomach after food (clothes feel tight, think they have eaten too fast or too much), loose stools (lighter color, bad odour), constipation, flatulence, mouth ulcers and stomach upset.
Oral Bisphosphonate: if no upper GI problems, especially gluten and wheat sensitivity.
Zoledronic acid: Intravenous infusion (Bisphosphonate) must have normal vitamin D and Calcium levels and normal Renal function. It is recommended for the patient to take paracetamol before the infusion to prevent flu like symptoms.
SERMS: Tamoxifen protects bone but not in premenopausal women
Denosumab: Must have normal vitamin D, Calcium and renal function. Contraindicated if they are lactose intolerant.
Forsteo: For Vertebral fracture pain or severe Osteoporosis: Must have normal vitamin D, Calcium and renal function. Contraindicated if they have received Radiation. Forsteo can significantly decrease fracture pain – Morphine will not decrease osteoporotic fracture pain but will increases the risk of falls. You need to refer these patients.
Who is going to monitor/treat these patients?
Every physician should be checking to ensure cancer patients are being monitored and treated. PLEASE DO NOT ASSUME THEY ARE! Remember 280,000 people have undiagnosed Osteoporosis.
Professor Moira O’Brien, FRCPI, FFSEM, FFSEM (UK) FTCD, Osteoporosis and Sports Medicine Consultant, Affidea Dundrum, Dublin