Cancer

A radiological image of breast carcinoma (note whitish nodule in lower left).

Signs and Symptoms: Cancer is a multisymptom, multisystem disorder. The range of signs and symptoms is far too broad to discuss within this context, and indeed the clinical presentations will vary considerably depending upon the type and location of the malignancy.

Cancer may afflict patients of all ages, although elderly patients are predisposed to the vast majority of malignancies. With retinoblastoma, a malignant tumor of the sensory retina, the mean age of diagnosis is 18 months. Hodgkin's lymphoma typically affects adults between ages 20 and 40. Lung carcinoma, basal cell carcinoma and malignant melanoma are usually seen in those over age 50 who have risk factors such as smoking and chronic sun exposure.

Despite the wide variety of cancers known to the medical community, one feature that unifies all of them is the great potential for mortality. Despite all the advances in diagnosis and treatment, cancer is the second leading cause of death for American adults.

Pathophysiology: Cancer is not a single disease entity, but a group of related disorders that share common features and elements. The cancerous cells grow abnormally and excessively, many times accumulating into a very large mass within a short period of time. This large mass of growing cells competes with normal tissue for the intrinsic blood supply and vital nutrients, compresses the normal cells and kills them. The malignant cells are unable to execute vital metabolic functions, leading to more rapid organ system failure.

Cancerous cells are also defined by their ability to metastasize. As cancer cells divide and the mass expands, invasion occurs at the level of the capillary beds and lymph tissue. Metastasis occurs when the malignant tumor cells, unbound by normal regulatory mechanisms and unencapsulated, break off from the main tumor mass and act as "tumor seeds," traveling through the body via vascular and lymphatic networks.

Management: The nature and location of the malignancy dictates the level and type of intervention. In general, skin cancers are most often managed surgically with the Mohs micrographic technique. Local excision of the tumor mass (often with radiation or chemotherapy) is usually indicated in breast cancer. Deeper tumors that are surgically inaccessible are often irradiated. In the eye, episcleral plaque radiotherapy is the treatment of choice for most uveal melanomas. Many tumors of the brain are treated with gamma knife surgery, which employs more than 200 finely focused beams of gamma radiation.

Other non-invasive forms of treatment include chemotherapy. Some common chemotherapy drugs include Nolvadex (tamoxifen, AstraZeneca), Doxil (doxorubicin, Alza), Mutamycin (mitomycin, Bristol Myers Squibb), Oncovin (vincristine, Eli Lilly) and Efudex (fluorouracil or 5-FU, ICN pharmaceuticals).

Clinical Pearls:

• Beware of new and unusual skin lesions on the lids and adnexa. Red flags for skin malignancies may include rapid changes in size or coloration, asymmetry of shape and irregular borders, bleeding with minimal manipulation, and persistency or regrowth despite seemingly appropriate treatment.
• Intraocular tumors noted on routine dilation are often asymptomatic. Lesions affecting the macula may present with reduced vision, metamorphopsia or other visual field defect; malignancies of the optic nerve may present with the same signs as well as a loss of color vision and an afferent pupillary defect.
• Suspect cancer until proven otherwise in patients with any history of cancer who manifest optic neuropathy, or retinal or choroidal hemorrhages or lesions. This is especially true in cases of blood-cell related cancers, such as lymphoma or leukemia.
• Cancer may have a widely variable course and prognosis, depending upon the tissue involved and other factors. Some cancers have a very favorable cure rate, while others are almost always lethal.
• Patients with any metastatic disease in the eye or elsewhere have an extremely poor prognosis. In cases of metastatic choroidal carcinoma, for example, mean survival from the time of detection is approximately nine months.¹
• Like most diseases, early detection and treatment of cancer carries the best prognosis for successful management.

1. Ferry AP, Font RL. Carcinoma metastatic to the eye and orbit. Part I. A clinicopathologic study of 227 cases. Arch Ophthalmol 1974;92:276-86.