HIGH-PRECISION CONFORMAL FRACTIONATED RADIOTHERAPY IS EFFECTIVE IN ACHIEVING REMISSION IN PATIENTS WITH ACROMEGALY AFTER FAILED TRANSSPHENOIDAL SURGERY

Promising Outcomes in Acromegaly Patients Receiving CyberKnife Stereotactic Hypofractionated Radiotherapy

BACKGROUND

The primary treatment for patients with acromegaly has traditionally been transsphenoidal surgery, with decreasing reliance on radiotherapy (RT) due to advancements in pharmacotherapy (PT). Despite these advancements, a substantial portion of patients still face persistent acromegaly, necessitating novel treatment approaches. This study investigates the role of CyberKnife Stereotactic Hypofractionated Radiotherapy (CK-HFRT) in persistent acromegaly.

OBJECTIVE

The primary objective was to assess the impact of CK-HFRT on endocrine remission (ER) rates while maintaining acceptable toxicity levels.

METHODS

The study retrospectively analyzed 31 consecutive patients with acromegaly who received CK-HFRT following multiple unsuccessful surgeries and prolonged PT without ER. Various CK-HFRT dose fractionation regimes were administered, and dose volume histograms were evaluated. Tumor control, cured disease (CD), endocrine remission (ER) rates, and overall survival were estimated at a median follow-up of 62 months. Acute and late toxicity, including pituitary insufficiency and radiation-induced optic neuropathy (RION), were also assessed.

RESULTS

At 62 months of follow-up, the study group demonstrated excellent tumor control with 100% nonprogressive adenomas. Endocrine remission was achieved in 86.7% of patients, with a 22.4% CD rate at five years. Pituitary insufficiency occurred in 32.3% of patients, and no cases of RION were reported. The study observed three deaths related to cardiovascular diseases, all in patients receiving PT. Overall survival at five years was 79.2%.

CONCLUSION

CyberKnife stereotactic hypofractionated radiotherapy, as an adjunct to PT, provides a viable treatment option for patients with persistent acromegaly following unsuccessful surgeries. The therapy results in substantial ER rates and tumor control while minimizing the risk of permanent radiation-induced optic neuropathy. However, the decision to administer CK-HFRT should be individualized, considering the patient's overall condition and treatment history.

Current and Future Advances in Surgical Therapy for Pituitary Adenoma

The vital physiological role of the pituitary gland, alongside its proximity to critical neurovascular structures, means that pituitary adenomas can cause significant morbidity or mortality. While enormous advancements have been made in the surgical care of pituitary adenomas, numerous challenges remain, such as treatment failure and recurrence. To meet these clinical challenges, there has been an enormous expansion of novel medical technologies (eg, endoscopy, advanced imaging, artificial intelligence). These innovations have the potential to benefit each step of the patient's journey, and ultimately, drive improved outcomes. Earlier and more accurate diagnosis addresses this in part. Analysis of novel patient data sets, such as automated facial analysis or natural language processing of medical records holds potential in achieving an earlier diagnosis. After diagnosis, treatment decision-making and planning will benefit from radiomics and multimodal machine learning models. Surgical safety and effectiveness will be transformed by smart simulation methods for trainees. Next-generation imaging techniques and augmented reality will enhance surgical planning and intraoperative navigation. Similarly, surgical abilities will be augmented by the future operative armamentarium, including advanced optical devices, smart instruments, and surgical robotics. Intraoperative support to surgical team members will benefit from a data science approach, utilizing machine learning analysis of operative videos to improve patient safety and orientate team members to a common workflow. Postoperatively, neural networks leveraging multimodal datasets will allow early detection of individuals at risk of complications and assist in the prediction of treatment failure, thus supporting patient-specific discharge and monitoring protocols. While these advancements in pituitary surgery hold promise to enhance the quality of care, clinicians must be the gatekeepers of the translation of such technologies, ensuring systematic assessment of risk and benefit prior to clinical implementation. In doing so, the synergy between these innovations can be leveraged to drive improved outcomes for patients of the future.

Intensity-modulated Radiotherapy for Pituitary Somatotroph Adenomas

OBJECTIVE

To summarize our experience in the treatment of pituitary somatotroph adenomas by fractionated intensity-modulated radiotherapy (IMRT), describe the treatment outcomes, and determine predictors.

METHODS AND MATERIALS

Patients with pituitary somatotroph adenoma treated by IMRT in our institution from August 2009 to January 2019 were reviewed. A total of 113 patients (37 male) were included in this study. The median age was 33 years (range 12-67 years). A total of 112 patients had not achieved complete remission after surgery, and 1 patient was treated by radiotherapy (RT) alone because she refused to surgery. The median growth hormone level was 8.6 ng/mL (range 2-186 ng/mL) and the median insulin-like growth factor (IGF)-1 level was 732 ng/mL (range 314-1485 ng/mL) pre-RT. The radiation doses to clinical target volume were usually 50-56 Gy in 25 to 30 fractions and to gross tumor volume were 60.2 Gy in 28 fractions while simultaneous integrated boost-IMRT used. After RT, the patients were followed up with endocrine testing every 6 to 12 months and magnetic resonance imaging annually. Endocrine complete remission was defined as a normal sex- and age-adjusted IGF-1 level without any pituitary suppressive medications. The outcomes including endocrine remission and new hypopituitarism after RT were recorded. The median follow-up time was 36 months (range 6-105.5 months).

RESULTS

The endocrine complete remission rates of IGF-1 at 1, 2, 3, and 5 years were 6%, 22.8%, 48.6%, and 74.3%, respectively. The median time to complete remission was 36.2 ± 3.8 months. The tumor control rate was 99% during the follow-up. The overall incidence of RT-induced hypopituitarism was 28.3% at the last follow-up. Univariate and multivariate analysis demonstrated that tumor sizes before RT, pre-RT IGF-1 level, and age significant predicted the endocrine remission.

CONCLUSIONS

IMRT is a highly effective treatment for pituitary somatotroph adenoma. Endocrine remission rate, tumor control rate, the median time to remission and hypopituitarism incidence are similar to stereotactic radiosurgery. Age and IGF-1 level before RT were significant predictive factors in endocrine remission.

Efficacy and safety of fractionated conformal radiation therapy in acromegaly: a long-term follow-up study

BACKGROUND AND PURPOSE

Conformal, fractionated radiation therapy (XRT) is variably used as a treatment alternative for active acromegaly patients, usually, after failed pituitary surgery. Our objective was to evaluate the long-term efficacy and safety of XRT using strict criteria of biochemical control.

SETTING, DESIGN, PATIENTS, AND METHODS

Retrospective cohort study of 94 patients (73 women, mean age at radiation 53.16 ± 12.9 years) attending a specialized multidisciplinary clinic between 1998 and 2014 with a mean duration of follow-up of 12.9 ± 7.3 years.

RESULTS

A basal growth hormone < 1 ng/mL and an IGF-1 < 1.2 × the upper limit of normal was achieved by 41% and 50.8%, respectively, at 5 years of follow-up, and by 44% and 66%, respectively, 10 years after XRT. Median tumor volume decreased significantly from 904 mm³ at baseline to 424 mm³ upon last follow-up (p = 0.01). The prevalence of central hypogonadism, central hypocortisolism, and central hypothyroidism increased from 18%, 35%, and 35% at baseline, to 38%, 53%, and 64%, respectively, after 10 years of follow-up. One patient was diagnosed with a meningioma and another one developed optic neuritis. No cerebrovascular events were recorded, and all patients are currently alive.

CONCLUSION

XRT is an effective and reasonably safe means of controlling acromegalic activity. Its main disadvantages are the time required to achieve biochemical control and the development of anterior pituitary hormone deficiencies.

Demographic profile, clinicopathological spectrum, and treatment outcomes of primary central nervous system tumors: Retrospective audit from an academic neuro-oncology unit

Primary tumors of the central nervous system are relatively uncommon, comprising only 1%-2% of all neoplasms. However, they constitute the second most common type of malignancy in children (after leukemia) and the leading cause of cancer-related morbidity and mortality in children and young adults worldwide. Globally, there is substantial variability with nearly five-fold difference in incidence between various parts of the world. Brain tumors are quite heterogeneous with regard to histology, biological behavior, and prognosis mandating multidisciplinary therapeutic decision-making. This retrospective audit of all consecutive patients registered in a single calendar year (2013) in the neuro-oncology disease management group at Tata Memorial Centre is reflective of the ground reality and fair representation of outcomes in routine neuro-oncologic practice.

Updates in Diagnosis and Treatment of Acromegaly

Acromegaly is a rare disease, caused largely by a growth hormone (GH) pituitary adenoma. Incidence is higher than previously thought. Due to increased morbidity and mortality, if not appropriately treated, early diagnosis efforts are essential. Screening is recommended for all patients with clinical features of GH excess. There is increased knowledge that classical diagnostic criteria no longer apply to all, and some patients can have GH excess with normal GH response to glucose. Treatment is multifactorial and personalised therapy is advised.

Prolonged preoperative treatment of acromegaly with Somatostatin analogs may improve surgical outcome in patients with invasive pituitary macroadenoma (Knosp grades 1-3): a retrospective cohort study conducted at a single center

BACKGROUND

This study aimed to investigate preoperative somatostatin analogs (SSAs) treatment on the surgical outcome in patients with acromegaly.

METHODS

An analysis of 358 patients with acromegaly was conducted. The preoperative medical therapy group (81 patients) received SSA treatment for at least 3 months prior to surgery, while the primary surgery group (277 patients) underwent transsphenoidal surgery directly. Follow-up duration was ≥3 months. Tumor invasion was evaluated by magnetic resonance imaging (MRI) and classified according to the Knosp grading system.

RESULTS

Most patients were diagnosed with macroadenoma. Among all patients (Knosp grades 0-4), preoperative SSA therapy did not significantly improve the curative effect of surgery, according to the levels of growth hormone (GH) and/or insulin-like growth factor 1 (IGF-1) markers. In patients with macroadenoma (Knosp grades 1-3), the remission rates were significantly higher in the SSA group compared to the surgery group when considering GH (56.4% vs. 37.3%, P = 0.048) and IGF-1 (43.2% vs. 17.6%, P = 0.004). In the preoperative medical therapy group, long-term use of SSAs (>6 months) led to higher remission rates (GH, 72.2% vs. 51.0%; and IGF-1, 61.1% vs. 29.8%; P = 0.12 and 0.02, respectively].

CONCLUSIONS

The long-term preoperative SSAs treatment may improve the surgical curative rate in acromegalic patients with invasive macroadenomas (Knosp grades 1-3).

Long-term outcomes of acromegaly treated with fractionated stereotactic radiation: case series and literature review

Background

Growth hormone (GH)-secreting pituitary adenomas represent an uncommon subset of pituitary neoplasms. Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) have been used as primary or adjuvant treatment. The purpose of this study is to report the long-term tumor control and toxicity from our institution and to perform a systematic literature review of acromegaly patients treated with FSRT.

Methods

We retrospectively reviewed all patients treated with FSRT (median dose 50.4 Gray [Gy], range 50.4-54 Gy) between 2005 and 2012 who had: 1) GH-secreting adenoma with persistently elevated insulin growth factor-1 (IGF-1) despite medical therapy and 2) clinical follow up >3 years after FSRT. Patients were treated with modern FSRT planning techniques. Biochemical control was defined as IGF-1 normalization. Systematic review of the literature was performed for FSRT in acromegaly.

Results

With a median follow-up of 80 months, radiographic control was achieved in all 11 patients and overall survival was 100%. Long-term biochemical control was achieved in 10 patients (90.9%) with either FSRT alone (36.4%) or FSRT with continued medical management (45.5%). No patient experienced new hypopituitarism, cranial nerve dysfunctions, or visual deficits. Our systematic review found published rates of biochemical control and hypopituitarism vary, with uniformly good radiographic control and low incidence of visual changes.

Conclusions

Adjuvant FSRT offered effective long-term biochemical control and radiographic control, and there was a lower rate of complications in this current series. Review of the literature shows variations in published rates of biochemical control after FSRT for acromegaly, but low incidence of serious toxicities.

Updates in outcomes of stereotactic radiation therapy in acromegaly

Purpose Treatment of acromegaly has undergone important progress in the last 20 years mainly due to the development of new medical options and advances in surgical techniques. Pituitary surgery is usually first-line therapy, and medical treatment is indicated for persistent disease, while radiation (RT) is often used as third-line therapy. The benefits of RT (tumor volume control and decreased hormonal secretion) are hampered by the long latency of the effect and the high risk of adverse effects. Stereotactic RT methods have been developed with the aim to provide more precise targeting of the tumor with better control of the radiation dose received by the adjacent brain structures. The purpose of this review is to present the updates in the efficacy and safety of pituitary RT in acromegalic patients, with an emphasis on the new stereotactic radiation techniques. Methods A systematic review was performed using PubMed and articles/abstracts and reviews detailing RT in acromegaly from 2000 to 2016 were included. Results Stereotactic radiosurgery and fractionated stereotactic RT (FSRT) for patients with persistent active acromegaly after surgery and/or during medical therapy provide comparable high rates of tumor control, i.e. stable or decrease in size of the tumor in 93-100% of patients at 5-10 years and endocrinological remission in 40-60% of patients at 5 years. Hypofractionated RT is an optimal option for tumors located near the optic structures, due to its lower toxicity for the optic nerves compared to single-dose radiosurgery. The rate of new hypopituitarism varies from 10 to 50% at 5 years and increases with the duration of follow-up. The risk for other radiation-induced complications is usually low (0-5% for new visual deficits, cranial nerves damage or brain radionecrosis and 0-1% for secondary brain tumors) and risk of stroke may be higher in FSRT. Conclusion Although the use of radiotherapy in patients with acromegaly has decreased with advances in medical treatments, it remains an effective treatment option after unsuccessful surgery and/or resistance or unavailability of medical therapy. Long-term studies evaluating secondary morbidity and mortality rate after the new stereotactic techniques are needed, in order to evaluate their potential brain-sparing effect.