Incidence of primary cancers and intracranial tumour recurrences in GH-treated and untreated adult hypopituitary patients: analyses from the Hypopituitary Control and Complications Study.

OBJECTIVE

Speculation remains that GH treatment is associated with increased neoplasia risk. Studies in GH-treated childhood cancer survivors suggested higher rates of second neoplasms, while cancer risk data for GH-treated and untreated hypopituitary adults have been variable. We present primary cancer risk data from the Hypopituitary Control and Complications Study (HypoCCS) with a focus on specific cancers, and assessment of recurrence rates for pituitary adenomas (PA) and craniopharyngiomas (CP).

DESIGN

Incident neoplasms during HypoCCS were evaluated in 8418 GH-treated vs 1268 untreated patients for primary malignancies, 3668 GH-treated vs 720 untreated patients with PA history, and 956 GH-treated vs 102 untreated patients with CP history.

METHODS

Using population cancer rates, standardised incidence ratios (SIRs) were calculated for all primary cancers, breast, prostate, and colorectal cancers. Neoplasm rates in GH-treated vs untreated patients were analysed after propensity score adjustment of baseline treatment group imbalances.

RESULTS

During mean follow-up of 4.8 years, 225 primary cancers were identified in GH-treated patients, with SIR of 0.82 (95% CI 0.71-0.93). SIRs (95% CI) for GH-treated patients were 0.59 (0.36-0.90) for breast, 0.80 (0.57-1.10) for prostate, and 0.62 (0.38-0.96) for colorectal cancers. Cancer risk was not statistically different between GH-treated and untreated patients (relative risk (RR)=1.00 (95% CI 0.70-1.41), P=0.98). Adjusted RR for recurrence was 0.91 (0.68-1.22), P=0.53 for PA and 1.32 (0.53-3.31), P=0.55 for CP.

CONCLUSIONS

There was no increased risk for all-site cancers: breast, prostate or colorectal primary cancers in GH-treated patients during HypoCCS. GH treatment did not increase the risk of PA and CP recurrences.