Cryotherapy is a medical procedure which involves using very low temperatures to kill retinoblastoma cells. A small probe is cooled below freezing and placed onto the eye closest to where the tumors are present. Cryotherapy is usually only used to treat retinoblastoma tumors that are small and located towards the front of the eye.

Retinoblastoma Cryotherapy Procedure

When a patient is admitted for cryotherapy, the patient is placed under general anesthesia before the procedure begins. While the child is under anesthesia, physicians often perform a more thorough examination called a EUA to check for cancers in other parts of the body. Doing this eliminates the need for two separate procedures.

To begin the cryotherapy, a metal probe is placed on the sclera of the eye nearest to the retinoblastoma cells. The probe is frozen to the point where it begins to kill the cells. The eye is then allowed to thaw, and the procedure is repeated. This is typically done a few times in each session. Physicians usually recommend two or three sessions of cryotherapy, depending upon results after each session.

Effectiveness of Retinoblastoma Cryotherapy

In data taken from 113 cases in which cryotherapy was used for treatment, approximately 70 percent of the cases were cured using cryotherapy alone. In cases where cryotherapy was utilized subsequent to radiation therapy, however, cryotherapy was often not as effective. The cases in which cryotherapy was not entirely successful were often cured using other treatment, and about 93 percent of the patients survived. The size and location of the tumor have a great deal to do with the overall success of cryotherapy in curing pediatric retinoblastoma.

Retinoblastoma Cryotherapy Side Effects

After undergoing retinoblastoma cryotherapy, there will be a visible scar on the eye. The eye and the lid will often swell immediately following the procedure, and remain swollen for several days. Swelling may be severe in some cases, and the eye may not close. While this can be frightening for patients, it will usually subside quickly. The treating physician may prescribe or recommend drops or ointment to help with swelling and discomfort.

In some cases, cryotherapy can cause damage to the retina. This may result in blind spots in the patient’s field of vision and sometimes causes the retina to become temporarily unattached from the eyeball. Overall, however, cryotherapy is considered to be one of the treatment methods for pediatric retinoblastoma that carries the lowest risk of harmful and lasting side effects.


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“Retinoblastoma.” Memorial Sloan-Kettering Cancer Center. Memorial Sloan-Kettering Cancer Center, n.d. Web. 5 Dec 2013. <>.