 |
|
Collaborative Ocular Melanoma Study Group
Choroidal melanoma (Figure 1), while an uncommon cancer, is still the most common primary eye cancer that occurs in adults. (The most common eye cancer is a metastatic tumor.) Since choroidal melanoma are so rare (frequency rate, 7 per 1 million), most general ophthalmologists see only a few cases during a lifetime practice. Correspondingly, family physicians rarely make the diagnosis although they may provide care for patients who have melanoma and systemic metastases. Patients with primary choroidal melanoma may be asymptomatic or may complain of blurred vision or occasionally eye pain. Since mortality is related to tumor size at the time of diagnosis and treatment, early recognition and treatment will improve the prognosis. As with all cases of vision loss, prompt evaluation by an ophthalmologist is recommended.
In June 1998, the Collaborative Ocular Melanoma Study Group (COMS) reported initial survival data for patients with large choroidal melanoma who were enrolled in a randomized clinical trial.1 With the 5-year outcomes known for 80% of the patients, the COMS investigators reported that 60% of the patients were alive 5 years after enrollment and treatment; no difference in survival was observed between the group treated with enucleation only vs the group treated with enucleation following external beam radiotherapy.
The COMS group also reported that histologically confirmed melanoma metastasis was present in 60% of the patients who died. In another 21% of deaths, malignancy was present but histopathologic confirmation that the malignancy was melanoma was unavailable. The liver was the most common site of metastasis, while metastases to the lung, bone, and skin were diagnosed less frequently. There is no effective treatment for metastatic choroidal melanoma. Ophthalmologists, radiotherapists, and medical oncologists are continuing to look for chemotherapy or immunotherapy that might be administered as an adjunctive therapy at the time of primary enucleation in an effort to reduce the risk of death from metastatic choroidal melanoma.
The COMS investigators also are conducting a randomized clinical trial for patients with medium-sized choroidal melanoma. In this trial, patients are randomized to enucleation or to local radiotherapy administered via a plaque containing radioactive iodine I 125 seeds. The plaque is sutured to the sclera for a calculated number of hours, depending on tumor size and activity of the 125I seeds. Patient accrual ended on July 31, 1998, with 1316 patients enrolled. All patients enrolled, in both the large eye tumor trial and the medium eye tumor trial, will be followed up for a minimum of 10 years.
Patients with small choroidal melanoma, those less than 2.5 mm in height, are being managed with observation by most ocular oncologists. To reduce mortality from metastatic choroidal melanoma, the primary cause of death for patients with larger choroidal melanoma, the COMS investigators are proposing a trial for patients with small melanoma that have ophthalmoscopically visible risk factors that predict tumor growth. Patients will be assigned randomly to immediate radiation therapy or to deferral of treatment until growth of the tumor occurs. Patients assigned to the deferred treatment group will be observed at specified intervals. If there is documented evidence of tumor growth, in any dimension, those patients will be eligible for treatment.
For patients with a large choroidal melanoma, most ophthalmologists agree that enucleation is the treatment of choice. Longer follow up of patients enrolled in the COMS trial for large choroidal melanoma will determine whether there is any advantage to pre-enucleation radiotherapy. For patients with a medium choroidal melanoma, the COMS trial of 125I brachytherapy will determine whether standard enucleation or plaque radiotherapy is preferable from the perspective of survival. Either treatment is acceptable. For patients with small tumors, the investigators expect to launch a prospective trial to evaluate the benefit of early intervention.
The COMS is conducted at more than 50 centers, including medical schools and physicians' offices, throughout the United States and Canada. The study is supported by the National Eye Institute and the National Cancer Institute. The National Eye Institute and the National Cancer Institute will continue to support the COMS during the follow-up phase of these trials.
Stuart L. Fine, MD
Philadelphia, Pa
1. COMS Study Group. Collaborative Ocular Melanoma Study randomized trial of pre-enucleation radiation of large choroidal melanoma, II: initial mortality findings COMs report No. 10. Am J Ophthalmol. 1998;125:779-796.
FULL TEXT
|
ISI
| PUBMED
Arch Fam Med. 1999;8:11-12.
|
