Evaluation of the outcomes of treating pituitary tumor by rotating gamma knife at the Nuclear Medicine and Oncology Center, Bachmai hospital

Objectives: To evaluate treatment outcomes of rotating Gamma knife radiosurgery (RGKR) for pituitary adenomas at the Nuclear Medicine and Oncology Center, Bachmai Hospital. Subjects and methods: A prospective interventional study was conducted on 48 patients, whowere treated with rotating Gamma knife for pituitary tumor. All patients had size of tumor < 5 cmon MRI and recruited in between April, 2008 and April, 2016.

EVALUATION OF THE OUTCOMES OF TREATING PITUITARY TUMOR

BY ROTATING GAMMA KNIFE AT THE NUCLEAR MEDICINE AND

ONCOLOGY CENTER, BACHMAI HOSPITAL

Nguyen Thi Minh Phuong*; Mai Trong Khoa**

Doan Van De***; Tran Quoc Hung*

Summary

Objectives: To evaluate treatment outcomes of rotating Gamma knife radiosurgery (RGKR) for pituitary adenomas at the Nuclear Medicine and Oncology Center, Bachmai Hospital Subjects and methods: A prospective interventional study was conducted on 48 patients, who were treated with rotating Gamma knife for pituitary tumor All patients had size of tumor < 5 cm

on MRI and recruited in between April, 2008 and April, 2016 Results: Male/female ratio was 1/2, patient age ranged from 21 - 78 years old with median of 44.58 ± 12.84 years old Clinical symptoms were reduced gradually after radiosurgery: the percentage of patients with headache symptom at baseline after the time of 6 months, 12 months, 24 months and 36 months accounted for 70.8%, 50%, 36.4%, 20.5% and 8.6%, respectively Abnormal hormone level had been improved after radiosurgery Size of the tumor was reduced Severe side effects or death were not reported in the follow-up period Conclusion: Radiosurgery with rotating Gamma knife

is an effective and safe treatment method for pituitary tumor

* Keywords: Pituitary tumor; Rotating Gamma knife; Outcomes

INTRODUCTION

The pituitary gland tumors are tumors

that occur in the anterior pituitary, which

account for 10 - 15% of the intracranial

tumors, more than 99% of the pituitary

tumors are benign tumors and grow

slowly Pituitary tumors are mainly seen in

adults, very rarely seen before puberty,

and the incidence rate of men compared

to women is 1/2 Different methods for

treatment of pituitary tumors are available such as surgery, medicine, radiation therapy, and radiotherapy by rotating Gamma knife The main purpose of these methods

is to remove or inhibit tumor growth, to maintain the endocrine function of the pituitary gland, to suppress or reduce the secretion of hormones caused by tumors, and with minimum of invasion to the surrounding areas In previous decades,

* 198 Hospital

** Bachmai Hospital

*** 103 Hospital

Conresponding author: Nguyen Thi Minh Phuong (drminhphuong198@gmail.com)

Date received: 20/04/2017 Date accepted: 25/07/2017

treatment of pituitary tumors was mainly

with medications When medical treatment

fails, surgery may be performed to open

the cranium but it was done only in some

major hospitals with high rate of postoperative

complications and the mortality rate over

10% In recent decades, surgical removal

of the tumor by endoscopy through the

sinus fracture has partially reduced the

mortality rate [1, 2] but the rate of

recurrence after surgery is still high

Globally, the application of rotating Gamma

knife for treatment is widely accepted in

the United States, Japan, Singapore, France,

Hungary [3, 4, 5, 6] Since 2007, the

American rotating Gamma knife system

has been introduced at the Center for

Nuclear Medicine and Oncology, Bachmai

Hospital for the treatment of brain tumors

and some cranial diseases including pituitary

tumors This treatment method is less

invasive, requires no anesthesia, with less

complication rate and short hospital stay

In Vietnam, there has been no studies

evaluating the role of rotating Gamma

knife for the treatment of pituitary tumors

Therefore, this study aims to: Evaluate

the treatment results of pituitary tumors by

rotating Gamma knife at the Center of

Nuclear Medicine and Oncology, Bachmai

Hospital

SUBJECTS AND METHODS

1 Subjects

* Inclusion criteria:

The study enrolled 48 patients aged

≥ 18 years diagnosed with pituitary tumor

based on cranial MRI and treated with

rotating Gamma knife at the Center for

Nuclear Medicine and Oncology, Bachmai

Hospital from April, 2008 to April, 2016

* Exclusion criteria:

- Patients with other endocrine diseases such as Basedow disease, adrenal tumors

- Patients taking prolonged steroids, pregnant women, breast-feeding women

- Patients < 18 years old

2 Research methods

Interventional study with

repeated-measures analysis

* Study procedures:

- Baseline evaluations:

+ Record clinical and laboratory information

in study case report forms

+ Clinical: functional and physical symptoms

+ Para-clinical tests: hormone levels, size and nature of tumors on brain MRI

- Steps for conducting the operation:

+ Step 1: prepare the patient

+ Step 2: fix the patient's head using the Fraim frame

+ Step 3: MRI simulation

+ Step 4: plan the radiosurgery

+ Step 5: proceed with radiotherapy

- Post-treatment evaluation: based on clinical and paraclinical symptoms of the patient being examined, compared before and after treatment

+ Clinical characteristics: age, sex, history

of treatment, clinical symptoms before treatment and 6 months, 12 months, 24 months and 36 months after treatment

+ Clinical features:

Evaluation of size, nature and extent

of invasive on MRI before treatment,

6 months, 12 months, 24 months, 36 months

after treatment

Hormonal tests: PRL, GH, ACTH, LH,

TSH, FSH before treatment, 6 months,

12 months, 24 months, 36 months after

treatment

+ Patients underwent pituitary hormone

quantification using morning venous blood

(fasting condition)

+ Investigation of TSH, FSH, PRL, ACTH,

LH, GH by electrochemistry immunoassay

on Elecsys 2010 with Roche reagent at

Biochemistry Department, Bachmai Hospital

* Data analysis and processing:

The collected information is encrypted

and processed on SPSS 16.0 software

RESULTS AND DISCUSSIONS

1 Patient disposition by age group

18 - 30 years old: 4 patients (8.3%);

31 - 45 years old: 21 patients (43.8%);

46 - 60 years old : 16 patients (33.3%);

> 60 years old: 7 patients (14,6%)

The study on 48 patients with pituitary tumors using rotating Gamma radiography

at the Center for Nuclear Medicine and Oncology, Bachmai Hospital showed that: The majority of patients in the age group

of 31 - 45 years old, the lowest age was

21, the highest age was 78, the average was 44.58 ± 12.84 years old The percentage

of male accounted for 33.3%; females accounted for 66.7%

2 Distribution of patients by gender

Figure 1: Patient distribution

In the study group, the proportion of

male patients was 33.3% male, female

was 66.7% Heng Wan's study (2007) [3]

reported that the average age of patients

with pituitary tumors was 44.58 ± 12.84

years old and the proportion of women

was higher than men

3 Medical history before surgery

No interventions: 6 patients (12.5%);

medication interventions: 30 patients

(62.5%); surgical interventions: 12 patients (25.0%)

Most patients have received medication

or surgical treatment for recurrence 12.5%

of the patients who received no treatment were indicated to use radiotherapy According to Faglia G, 92% of patients with pituitary gland tumors who had been treated with Gamma irradiation had failed

to response to prior medication treatments

4 Irradiation dosages

Table 1:

Dose (Gy)

Standard deviation

Clinically non-functioning

> 0.05

The mean surgical irradiation dose of 13.6 ± 2.2 Gy The dose was used in the hormonally active group was higher than that in the hormonally non-active group, but the difference was not statistically significant (p > 0.05)

5 Time to follow-up after surgery

Table 2:

The mean postoperative follow-up time was 38.9 ± 10.9 months (from 12 months to

63 months) after radiosurgery We found that all of the clinical signs of postoperative irradiation were significantly improved

6 Clinical symptoms before and after the radiosurgery

Table 3:

Baseline (n = 48)

6 months (n = 46)

12 months (n = 44)

24 months (n = 39)

36 months (n = 35) Symptoms

(n = 48)

Clinical symptoms decreased over time Headache was one of the most common symptoms before treatment (70.8% of patients) and this had decreasead to 50%, 36.4%, 20.5%, and 8.6% after 6, 12, 24, and 36 months, respectively The study on

over 270 patients of Sheehan J.P (2011) [5] showed that rotating Gamma kife treatment improved functional symptoms in 90% of patients and 55% of them improved their physical symptoms

7 Tumor size (on MRI) before and after the radiosurgery

Table 4:

Time-points Baseline

(n = 48)

6 months (n = 46)

12 months (n = 44)

24 months (n = 39)

36 months (n = 35)

Mean tumor size (mm) 20.9 ± 10.3 19.5 ± 11.5 15.6 ± 12.3 12.9 ± 12.7 12.9 ± 12.4

Mean tumor size decreased after treatment, significantly decreased after 12 months compared with pretreatment, difference was statistically significant (p < 0,05) Heng Wan et al (2002) [3] showed that the percentage of patients with tumor size decreased

or remained constant after tumor resection was 89.7%

8 Hormone level before and after treatment

Table 5:

Baseline 36 months after treatment Hormon level

The post-treatment hormone levels decreased, especially PRL and GH, these levels significantly decreased and difference was statistically significant (p < 0.01) LH, ACTH, THS and FSH levels were not significantly reduced (p > 0.05) This was probably due

to the fact that the number of patients with ACTH, TSH, LH and FSH hypersecretion was not significant Shota Tanaka et al (2010) [6] reported that after the radiotherapy, the PRL concentration decreased from 88.4 ng/mL to 28.4 ng/mL The difference was statistically significant (p = 0.001) There was no cases of death after treatment

CONCLUSION

The study on 48 patients with pituitary

tumors using rotating Gamma radiosurgery

at the Center for Nuclear Medicine and

Oncology, Bachmai Hospital:

- Patient age ranged from 21 - 78 years

old with average of 44.58 ± 12.84 years old

- Male/female ratio was 1/2

- Clinical symptoms were reduced

gradually after radiosurgery: the percentage

of patients with headache symptom at the

time point of baseline, after 6 months, 12

months, 24 months, 36 months accounted

for70.8%, 50%, 36.4%, 20.5% and 8.6%,

respectively

- Abnormal hormone level GH, PRL

had been improved after radiosurgery

- Size of the tumor was reduced

- Severe side effects or death were not

reported in the follow-up period

- Radiosurgery with rotating Gamma

knife has been shown as an effective and

safe treatment method for pituitary tumor

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