Malignant eye tumors are the most common and life-threatening diseases in ophthalmology, and radiation therapy is a commonly used clinical method for treating malignant eye tumors.

Surgery is a commonly used method for treating eye tumors, but after treatment, in addition to common surgical complications, patients with enucleated eyeballs may also lose vision.

With the increasing emphasis on quality of life, patients' expectations for preserving their eyeballs are increasing.

Proton therapy for ocular tumors

Uveal melanoma is a common primary malignant tumor in the eyes of adults.

As early as 1975, Gragoudas et al. began experimenting with proton therapy for uveal melanoma. Afterwards, he used this technique to treat 130 patients with eye tumors.

Among them, Bob Pierson, 63 years old from Ohio, has a malignant tumor the size of a kidney bean in his right eye.

He has only two options, either to have his right eye removed or to go to the cyclotron laboratory at Harvard University for proton beam radiation therapy.

In order to save his right eye, he chose proton therapy.

Bob Pierson began proton therapy in August 1981, and by December, the tumor had shrunk by 26% [3]。

It has been over 40 years since proton therapy successfully treated eye tumors in 1975, and multiple proton therapy centers around the world have accumulated rich treatment experience.

Due to the Bragg peak characteristic of proton radiation therapy, the proton beam, after receiving energy through an accelerator, is precisely controlled to enter the human body and concentrate the energy to release to the affected area. At the same time, the energy rapidly decays and stops, forming a Bragg peak.

Therefore, proton therapy has less damage to surrounding tissues and better targeting.

In recent years, proton therapy has been widely applied in the treatment of systemic tumors.

The Paul Scherrer Institute (PSI) is the largest national research institute in Switzerland, and its proton therapy center is second to none in the world.

According to PSI data, as of the end of 2022, they have treated 7900 patients with eye tumors.质子治疗眼部肿瘤的预后很好，超过98%的患者肿瘤

Disappearance or permanent cessation of growth, over 90% of patients can retain their eyes.

The Paul Schell Institute in Switzerland released a study on proton therapy for ocular tumors in 2014.

The study compared 43 patients (under 21 years old) who received proton therapy for uveal melanoma with 129 matched adult control groups.

The results showed that the 10-year metastasis rate of 43 eye tumor patients receiving proton therapy was significantly lower than the control group (11% vs 34%), and their 10-year survival rate was as high as 93% [6].

The two groups of patients had similar eye retention rates and maintained useful visual acuity levels.

Of course, the reason why PSI has such good proton therapy effects is closely related to its world-class equipment and technology.

The ophthalmic team of the Eye, Ear, Nose and Throat Hospital affiliated with Fudan University in China reviewed literature on proton therapy in recent years and found that most treatment centers have an eye retention rate of over 85%, or even better!

As for survival rate, although the survival rates reported by various proton therapy centers are not entirely consistent, it is estimated that the 5-year survival rate is above 80%, and the 10-year survival rate is approximately above 65%.

图源：参考文献[2]

In 2022, the ophthalmic team of the Eye, Ear, Nose and Throat Hospital affiliated with Fudan University in China published a study on proton therapy for ocular tumors.

A total of 11 patients were included, with an average age of 47.5 years.

The average maximum basal diameter of the patient's tumor is 10.8 millimeters, with an average thickness of 6.6 millimeters.

Treatment plan: The general treatment dose is 60Gy, completed in 4 sessions, once a day [2].

After treatment, regularly return to the hospital for further examination of vision, intraocular pressure, tumor body, and overall condition. The average follow-up time was 30.3 months.

The results showed that after proton therapy, the tumor thickness decreased by an average of 22.4% compared to before treatment, and the diameter decreased by an average of 17.3%.

Compared with before treatment, the visual acuity of 3 patients (27.3%) improved or remained unchanged. Only one case underwent enucleation surgery due to persistent high intraocular pressure and visual loss.

Overall, proton therapy for eye tumors not only has a high eye preservation rate, but also saves some effective vision.