Androgen deprivation therapy (ADT) is the most common first therapy for men diagnosed with metastatic prostate cancer as well as many men with non-metastatic prostate cancer. ADT brings with it many side effects including significant weight gain. Weight gain, which may contribute to cardiovascular comorbidities as well as diabetes, is among the many adverse metabolic changes associated with ADT.
We need a better understanding of the risk factors for weight gain on ADT to allow optimal management of this ADT-associated morbidity.
Researchers performed a retrospective review that assessed weight change among 118 men with non-metastatic prostate cancer who were treated with ADT. Their primary endpoint was weight change at one year from the date of beginning ADT, with the secondary aim of stratifying the risk of weight gain by baseline patient characteristics. They performed a statistical analysis using two-tailed t-tests and linear regression.
They found that in their sample a significant increase in weight gain in the subjects (p=0.0005) in one year following ADT initiation. They also found three risk factors for weight gain on ADT:
1- Younger than age 65 (5.98 pounds gained, p=0.001 vs. 1.63 pounds, p= 0.09 for age 65+)
2- Body mass index (BMI) less than 30 (4.36 pounds gained, p=0.00002 vs. 0.22 pounds, p=0.87 for BMI 30+) and
3- Non-diabetic status (3.43 pounds gained, p=0.0003 vs. 0.57 pounds, p=0.74 for diabetics).
To further their analysis the researchers developed an aggregate risk scoring system to allow for weight change prediction by total number of risk factors present: scores of 0, 1, 2, and 3 risk factors corresponded to weight changes of -2.42 (p=0.43), +0.9 (p=0.56), +2.9 (p=0.01) and +8.3 pounds (p= 0.0001) respectively.
Weight gain increased significantly with increasing risk score (p-trend= 0.0005), decreasing baseline age (p-trend= 0.004) and decreasing baseline BMI (p-trend= 0.01).
In summary, they found that men at age 65, BMI less than 30, and non-diabetic status were each significantly associated with weight gain one year after starting ADT. Increasing weight gain was strongly associated with increasing number of these three baseline risk factors.
Metabolic consequences were previously considered most significant for men with preexisting comorbidity; these data suggest younger, slimmer, and non-diabetic men may be at higher risk for gaining weight on ADT. The assumption is that these three categories; younger, slimmer and not diabetic, have higher endogenous testosterone (T) levels prior to ADT compared to older, obese, and diabetic men. The magnitude of the T decline following the onset of ADT might explain these findings.
Knowing your risk factors could help you have a better conversation with your doctor about how to manage possible side effects for wright gain as you begin ADT.
J Clin Oncol 32, 2014 (suppl 4; abstr 80); Daniel Martin Seible, Xiangmei Gu, Andrew Hyatt, Clair Beard, Jason Alexander Efstathiou, David Tomoaki Miyamoto, Timur Mitin, Neil E. Martin, Joshua Beckman, Shehzad Basaria, Paul Linh Nguyen.
Joel T. Nowak, M.A., M.S.W.