An estimated 1,399,790 cancer diagnoses were made in 2006.[1] Of these, the majority will require interventions with radiation and/or chemotherapy, which, in turn, will contribute to 65% of individuals surviving 5 years after their initial diagnosis. Consequently, the number of cancer survivors has reached considerable numbers—about 9.8 million (or 3.5% of the total population) in the United States.[2,3] This longer survival has underscored the importance of emotional, social, and medical problems as integral components of continued cancer care. Notably, dermatologic issues occur frequently in individuals affected by cancer, leading to significant physical and psychosocial discomfort along with dose modification and/or interruption of important antineoplastic therapy.[4-6]
Despite their high frequency and negative impact on quality of life and clinical outcome in some cases, the majority of these untoward events are underrecognized and undertreated. This may be attributed, at least in part, to the recent approval of novel agents with unexpected toxicities, the aforementioned longer survival times, and lack of timely access to dermatology-oncology clinical programs. The importance of this field is underscored by an increasing number of published reports in recent years (Figure 1), as well as the establishment of interdisciplinary clinical programs dedicated to the management of untoward events to cancer therapies.[5] This review describes common and clinically significant dermatologic problems in those whose lives have been affected by cancer.
Skin and the Cancer Patient
With dramatic increases in survival rates associated with most cancers[3] and greater use of radiation and novel anticancer agents causing acute and chronic adverse reactions involving the skin,[6] attention has increasingly focused on the dermatologic components of the cancer experience. The skin and its appendages are high-turnover tissues with epithelial, connective tissue, vascular, and neural components—all of which may explain the high frequency of pathobiologic events from drugs directed against rapidly dividing malignant cells. Whereas disorders preceding the diagnosis are of importance, as they may be the first indicators of an underlying neoplasm, and therapy-related events may affect survival, late events can have a significant emotional and physical impact.[4,7,8]
Importantly, conditions affecting dermatologic structures (ie, skin, hair, and nails) may present before the diagnosis of cancer, during therapy, or months to years afterwards. The categorization of such events based on chronology (in relation to the initial cancer diagnosis) allows for a better understanding of (1) malignancy-associated dermatoses, which tend to occur prior to or during the initial diagnosis; (2) therapy-related toxicities, which occur during treatment, and; (3) late events, which are usually chronic or persistent sequelae of therapeutic regimens or indicative of recurrence (Figure 2). Knowledge and management of these various manifestations by oncologists would represent a considerable step toward maximizing clinical outcomes and enhancing patients' well-being. This review describes the clinical presentation of common entities and their etiologies in each of these categories, with a greater emphasis on treatment-related events.
Malignancy-Associated Dermatoses
Dermatologic findings prior to or during the diagnosis of cancer may reflect a cancer syndrome that is inherited,[9] caused by environmental carcinogens,[10] or paraneoplastic (Table 1).[11] Whereas the first two entities have well established causal genetic and external culprits, paraneoplastic syndromes are poorly understood, as they represent dermatoses that are distant to an underlying cancer yet believed to be causally and biologically related to it.[11] Overall, the identification of malignancy-associated dermatoses is important, as they may represent the first signs of and allow for earlier diagnosis and treatment of solid or hematologic tumors.[9]
