The etiology of pituitary adenoma growth rate is multifactorial and may be influenced by patient age and gender, as well as adenoma subtype, hormonal activity, immunohistological profile and the direction of growth relative to the pituitary fossa, according to results of a retrospective study.
- Researchers evaluated pre- and postoperative pituitary adenoma (PA) traits in relation to patient demographics, MRI specifications and histopathological factors. They examined 153 patients who underwent surgery for removal of a histologically-proven PA at Toronto Western Hospital between 1999 and 2011.
All patients had at least two preoperative and two postoperative MRIs to measure tumor volume doubling time. Both scans were completed a minimum of 3 months apart.
Patients all underwent a sella/pituitary imaging protocol, and volume was determined using partitioning and target volume software. Each patient was also reviewed by two endocrine pathologists, and standardized diagnostic synoptic pathology reports provided information on MIB-1 labeling index, p27 and N-terminally truncated fibroblast growth factor receptor 4 (FGFR4). Growth direction patterns were classified as superior, anterior, posterior and lateral in relation to the sellar fossa.
The researchers found a relationship between preoperative growth rate and age (P=.0001), as well as suprasellar growth (P=.003), existence of a cyst or hemorrhage (P= .004), the MIB-1 (P=.005), FGFR4 positivity (P=.047) and p27 negativity (P=.007).
Postoperatively, 34.6% of patients demonstrated residual volumes, while the remaining 100 patients did not. Residual volume was found to be associated with older patient age (57 vs. 51, P=.038), as well as growth patterns, including anterior, posterior, suprasellar and cavernous sinus extension (P=.001). There was a correlation between pre-and postoperative growth rates (r=0.497, P=.026). The rates of postoperative growth were linked with age (P=.015) and gender (P= .017).
“Due to the heterogeneity of PA, no single predictor of PA growth behavior can be taken in isolation as a means to predict its outcome,” the researchers wrote. “These predictors must be combined in order to formulate the most accurate estimation of PA growth, which in turn will inform sound clinical management.”