Abstract
BackgroundCranial radiotherapy (cRT) can induce hormonal deficiencies as a consequence of significant doses to the hypothalamic-pituitary (HP) axis. In contrast to profound endocrinological follow-up data from survivors of childhood cancer treated with cRT, little knowledge exists for adult cancer patients.MethodsA systematic search of the literature was conducted using the PubMed database and the Cochrane library offering the basis for our debate of the relevance of HP axis impairment after cRT in adult cancer patients. Against the background of potential relevance for patients receiving whole brain radiotherapy (WBRT), a particular focus was set on the temporal onset of hypopituitarism and the radiation dose to the HP axis.ResultsTwenty-eight original papers with a total of 1728 patients met the inclusion criteria. Radiation doses to the HP area ranged from 4 to 97 Gray (Gy). Hypopituitarism incidences ranged from 20 to 93% for adult patients with nasopharyngeal cancer or non-pituitary brain tumors. No study focused particularly on hypopituitarism after WBRT. The onset of hypopituitarism occurred as early as within the first year following cRT (range: 3 months to 25.6 years). However, since most studies started follow-up evaluation only several years after cRT, early onset of hypopituitarism might have gone unnoticed.ConclusionHypopituitarism occurs frequently after cRT in adult cancer patients. Despite the general conception that it develops only after several years, onset of endocrine sequelae can occur within the first year after cRT without a clear threshold. This finding is worth debating particularly in respect of treatment options for patients with brain metastases and favorable survival prognoses.
Highlights
Cranial radiotherapy can induce hormonal deficiencies as a consequence of significant doses to the hypothalamic-pituitary (HP) axis
Mehta et al BMC Cancer (2019) 19:1213 a total of 813 adult cancer patients treated with Cranial radiotherapy (cRT) in 2011, Appelman-Dijkstra et al were able to show that the prevalence of cRT-induced hypopituitarism was of clinical relevance and argued for a structured periodical endocrine follow-up of these adults [11]
We were able to gather more detailed information on the course of HP axis impairment after whole brain radiotherapy (WBRT) in adults, enabling the discussion of the following clinical questions in particular: i) What is the current evidence on HP axis dysfunction after WBRT in literature? ii) Are WBRT doses within the range of potential harm? iii) Can we neglect the impact of cRT-related hormonal deficiency in patients with brain metastases and limited life expectancy as a typically late manifesting side effect?
Summary
Cranial radiotherapy (cRT) can induce hormonal deficiencies as a consequence of significant doses to the hypothalamic-pituitary (HP) axis. In contrast to profound endocrinological follow-up data from survivors of childhood cancer treated with cRT, little knowledge exists for adult cancer patients. In contrast to comprehensive data on childhood cancer patients, information on hormonal impairment after cRT in adults is scarce. Mehta et al BMC Cancer (2019) 19:1213 a total of 813 adult cancer patients treated with cRT (nasopharyngeal cancer and non-pituitary brain tumors) in 2011, Appelman-Dijkstra et al were able to show that the prevalence of cRT-induced hypopituitarism was of clinical relevance and argued for a structured periodical endocrine follow-up of these adults [11]. We aimed to update the existing knowledge database on HP axis dysfunction after cRT in adult cancer patients (non-pituitary brain tumors and nasopharyngeal cancer) by including current literature for further debate. We were able to gather more detailed information on the course of HP axis impairment after WBRT in adults, enabling the discussion of the following clinical questions in particular: i) What is the current evidence on HP axis dysfunction after WBRT in literature? ii) Are WBRT doses within the range of potential harm? iii) Can we neglect the impact of cRT-related hormonal deficiency in patients with brain metastases and limited life expectancy as a typically late manifesting side effect?
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