From the Guidelines
Megace (megestrol acetate) should be used at a dose of 400-800 mg daily to stimulate appetite and promote weight gain in patients with cancer cachexia, despite potential side effects, as it has been shown to improve appetite, weight, and quality of life in these patients 1.
Mechanism of Action and Effects
Megace works by affecting the hypothalamus to increase appetite and alter metabolism, promoting fat accumulation rather than lean body mass. The evidence from a 2020 study published in the Journal of Clinical Oncology suggests that megestrol acetate is effective in improving appetite, weight, and quality of life in patients with cancer cachexia 1.
Dosage and Administration
The typical dosage of Megace ranges from 400-800 mg daily for adults, taken orally as a tablet or suspension. Treatment duration varies based on clinical response but is generally continued as long as benefits outweigh side effects.
Side Effects and Precautions
Common side effects of Megace include fluid retention, blood clots, menstrual irregularities in women, impotence in men, and potential adrenal suppression with long-term use. Blood glucose should be monitored as it may worsen diabetes control. Megace is contraindicated in pregnancy and should be used cautiously in patients with a history of thromboembolism.
Comparison with Other Agents
A study comparing megestrol acetate to other active agents or combination regimens found that megestrol acetate was more effective than fluoxymesterone for appetite improvement, and produced similar appetite results to dexamethasone, but with different toxicities 1. Another study found that megestrol acetate was more effective than dronabinol in improving appetite and weight gain in patients with cancer cachexia 1.
Quality of Life and Mortality
While Megace has been shown to improve appetite, weight, and quality of life in patients with cancer cachexia, it is also associated with increased risks of death, thromboembolic events, and edema 1. However, the benefits of Megace in improving quality of life and promoting weight gain may outweigh the risks in some patients.
Clinical Guidelines
The ESPEN guidelines on nutrition in cancer patients recommend the use of progestins, such as megestrol acetate, to stimulate appetite and promote weight gain in patients with cancer cachexia 1. The guidelines also note that the optimal dose of megestrol acetate is between 480 and 800 mg per day, and that the influence of megestrol acetate on quality of life is minimal.
From the FDA Drug Label
Megestrol acetate tablets are indicated for the palliative treatment of advanced carcinoma of the breast or endometrium (ie, recurrent, inoperable, or metastatic disease). The main use of Megace (megestrol acetate) is for the palliative treatment of advanced carcinoma of the breast or endometrium 2.
- Key indications:
- Advanced carcinoma of the breast
- Advanced carcinoma of the endometrium
- Important note: It should not be used in lieu of currently accepted procedures such as surgery, radiation, or chemotherapy.
From the Research
Megestrol Acetate Studies
- Megestrol acetate has been studied for its potential to stimulate appetite and improve weight gain in patients with cancer-associated anorexia and cachexia 3, 4, 5, 6.
- A randomized, double-blind, placebo-controlled trial found that patients assigned to megestrol acetate reported improved appetite and food intake, and experienced significant weight gain compared to those receiving a placebo 3.
- Another study found that megestrol acetate can stimulate appetite and food intake in patients with anorexia and cachexia associated with cancer, leading to significant weight gain in a proportion of patients 3.
- The effect of megestrol acetate on weight gain and quality of life aspects, such as appetite, nausea, body image, and mood, has been reported in cancer patients treated with 160 mg to 1,600 mg daily 4.
- Maximal weight gain is normally achieved within 8 weeks, but the weight gain is mainly due to an increase in fat mass and partly due to edema 4.
Megestrol Acetate in HIV Patients
- Megestrol acetate has been used to treat anorexia and cachexia associated with human immunodeficiency virus (HIV) infection 7.
- A study found that 21 of 22 HIV-positive patients gained weight, with an average weight gain of 7.3 kg, when treated with oral megestrol acetate 7.
- The median time to peak weight during megestrol acetate treatment was 14 weeks, and seven patients returned to within 1 kg of their normal body weight 7.
Meta-Analysis and Clinical Use
- A systematic review and meta-analysis of the clinical use of megestrol acetate for cancer-related anorexia/cachexia found that the overall pooled mean change in weight among cancer patients treated with megestrol acetate was 0.75 kg 6.
- The studies were divided into high-dose treatment (>320 mg/day) and low-dose treatment (≤320 mg/day), and patients who received high-dose megestrol acetate tended to have weight loss rather than weight gain 6.
- Megestrol acetate was generally well-tolerated, except for a clear thromboembolic risk, especially with higher doses 6.