Second Primary Malignancies of Eye and Ocular Adnexa
Cancer found in the eye is a significant cause of death and disability around the world. Tumors of the eye and ocular adnexa are some of the most challenging cases that can lead to blindness or death. The eye and its ocular adnexa (EOA) are often linked with a broad spectrum of malignant tumors. As medical technology advances, opportunities to detect second ocular and adnexal primary cancers have become available. This helps doctors create better diagnostic techniques and provide treatments that result in better-prolonged survival for cancer patients. However, much complexity must be interpreted when it comes to establishing distinct epidemiological patterns.
Tumors are abnormal growths that occur when cells expand. They are either benign or malignant. Both orbital and adnexal tumors are tumors that develop from the tissue. Orbital tumors are those that grow in the tissues surrounding the eyeball. Adnexal tumors involve the structures that are found in tear glands or eyelids.
Second primary malignant tumors (SPMTs) are those primary malignant tumors that are encountered after another primary one. SPMTs are challenging to diagnose and their symptoms are often overlooked. They are also often thought of as primary tumors. All eye malignancies have the chance to send metastases to the eye and its adnexa. The most common sites to metastasize are the lung and breasts. In almost all situations, metastatic tumors at the EOA present first and incite the search for a primary site. SPMTs in the ocular and adnexal regions currently don’t have established epidemiological patterns. This is because they are seldom reported as a distinct entity with calculated risks as with other regions.
The Study
The eye and its adnexal structures experience either consecutive primary malignancies or metastases as initial findings. This study was done to examine the characteristics of second primary neoplasms affecting the eye and its adnexa. The researchers also analyzed the risk modifying factors for the malignancies found in the body. They explored major themes of SPMTs in the ocular and adnexal region using the date from SEER. The researchers also examined how other factors such as age, gender, and race impacted the risk of SPMTs.
Methods
The researchers used data from the Surveillance, Epidemiology, and End-Results “SEER”-0 program of the National Cancer Institute for the eye malignancies and its adnexa. The timeline was extensive, ranging from 1973 to 2015. Malignancies were classified chronologically according to their incidence: first or second primary malignancies. While the tumors were classified using the ICD-O-3 classification. The standardized incidence ratios (SIR) and survival probabilities were then calculated for each group. The study used records of patients that are diagnosed with second primary cancer in the EOA after being diagnosed with at least one primary cancer elsewhere in the body. They defined cancers of interest as malignancies occurring in the cornea, eyelid, conjunctiva, retina, lacrimal glands, ciliary body, choroid, overlapping lesions of the eye, adnexa, and optic nerve.
Results
There were a total of 3,578,950 cancer patients with 1222 primary malignancies of the EA in 1203 patients after malignancy elsewhere. Of those patients, 93.4% were white, 67% were married, 58% were 50-69 years old and diagnosed with first malignancy. The male to female ratio was 1.22 and the males represent 54.9% of the patients. The median time to develop second primary ocular and ocular adnexal malignancies was 9.7 years after the first cancer diagnosis. The most common site was the prostate and the genitourinary tract. The age-adjusted rate showed a steady increase over 5 years since 1976.
In the 3,578,950 cancer patients, only 1203 experienced second malignancies of the eye and its adnexa. First malignancies were diagnosed in patients aging between 50 and 69 years old. The eyelid showed 280 events while 50 in the lacrimal gland, 181 in the orbit, and 21 in overlapping session, 15 in the optic nerve. There were also 148 in the conjunctiva, 6 in the retina, and 9 in the cornea. A total of 379 was found in the choroid and 93 were found in the ciliary body. The malignancies found in the eyeball are not far from the orbital ones and they share similar challenges. Since ocular metastasis is the most common intraocular malignancy, they are also the most studied. Lacrimal gland tumors are most common with the white race with an age-adjusted incident rate of 0.6 per 1,000,000. However, in the study, the lacrimal gland didn’t show a higher overall risk for SPMT. It also found that lacrimal gland secretion decreases upon the start of thyroid carcinoma therapy.
The relative risk of second malignancy after a non-Hodgkin lymphoma was 2.42. In the previous carcinomas, it was 3.02. For melanoma of the skin, it was 2.13 and for oral cavity or pharynx malignancies, the relative risk was 1.58. Second ocular and adnexal neoplasms increased in the span of five years contrary to the first primary neoplasms. Survival of patients affected with first ocular and adnexal neoplasms was higher than the second ocular and adnexal neoplasms. However, second primary ocular and adnexal tumors showed a better survival rate than second primary malignancies elsewhere.
Limitations of the Study
The researchers believe that their study has superior reliability compared to other case studies when it comes to the primary sites reported and the histological type of malignancies. However, the study has a risk of bias because of misreporting of primary malignancy for SMPT. Other limitations include the coding of cancer registries in which some anatomical regions are not represented in topographical classifications.
Conclusion
Epidemiological differences between the first and second ocular adnexal primaries have different underlying mechanisms. Seemingly benign symptoms such as vison changes or allergies could be a malignancy, or even a metastasis. The researchers believe that for every primary malignancy found there should be a suspicion for screening for metastasis or SPMT. A careful ocular examination should also be done in the long-term follow-up plan of the cancer patients. Special attention should also be given to patients that have underlying non-Hodgkin lymphoma and melanoma.
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