Oral therapy for nonmelanoma skin cancer in patients with advanced disease and large tumor burden: a review of the literature with focus on a new generation of targeted therapies

Nonmelanoma skin cancer (NMSC) is the most common cancer in patients and includes basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Treatments useful for SCC and BCC include surgical, topical, and in advanced cases systemic chemo-radiation. This review of the literature aims to describe previous and current treatment options for oral therapy in locally advanced and metastatic NMSC otherwise unamenable to standard treatment. Oral Smoothened (Smo) inhibitors Vismodegib, Sonidegib, and Taladegib have shown to be effective in several trials. Oral tyrosine kinase inhibitors Erlotinib and Gefitinib, which target epidermal growth factor receptor (EGFR), have early supporting data and are currently undergoing large multicenter trials. Other less studied oral therapies which have shown at least partial efficacy include 5-Fluorouracil, capecitabine, and picropodophyllin. In vitro studies have elucidated new targets for dual combination oral therapy targeting both EGFR and insulin-like growth factor 1 receptor (IGF-1R). It is important to stratify treatment options based on patient risk of advanced disease, failure of conservative treatment, and ill-tolerated intravenous chemotherapy adverse events. Oral therapy in NMSC is useful in high risk patients with recurrent and aggressive disease who may not tolerate other systemic therapies.

Developments in the treatment of locally advanced and metastatic squamous cell carcinoma of the skin: a rising unmet need

Squamous cell carcinoma of the skin (SCCS) is a common malignancy with potentially devastating consequences in patients with locally advanced or metastatic disease. Its rising incidence, primarily a result of an aging population and increased ultraviolet (UV) radiation exposure, characterize an emerging unmet need. A firm understanding of the biology of this disease, likely distinct from that of other squamous malignancies because of the influence of UV radiation, is necessary in the evaluation of treatment paradigms. Careful recognition of high-risk features pertaining to tumor and host characteristics is paramount to proper management. However, a lack of standardization in guidelines in this regard creates a challenge for physicians. Questions persist regarding additional evaluation and treatment for advanced disease such as the roles for sentinel lymph node biopsy and the adjuvant use of radiation and chemotherapy. With respect to advanced disease, multiple combinations of chemotherapy have been tested with variable success, but no rigorous randomized studies have been conducted. In addition, EGFR inhibitors such as cetuximab and erlotinib have displayed antitumor activity and as such, warrant further investigation. In sum, the treatment of locally advanced and metastatic SCCS is a ripe area for clinical investigation. This article summarizes the current understanding of disease biology and emerging questions in the management of this disease.

Phase II study of cetuximab as first-line single-drug therapy in patients with unresectable squamous cell carcinoma of the skin

PURPOSE

To evaluate the efficacy and safety of cetuximab, a monoclonal antibody that inhibits the epidermal growth factor receptor (EGFR), as a first-line monotherapy in patients with unresectable squamous cell carcinoma of the skin (SCCS).

PATIENTS AND METHODS

Thirty-six patients received cetuximab (initial dose of 400 mg/m(2) followed by subsequent weekly doses of 250 mg/m(2)) for at least 6 weeks with a 48-week follow-up. The primary end point was the disease control rate (DCR) at 6 weeks (according to Response Evaluation Criteria in Solid Tumors [RECIST] criteria). Secondary end points included best response rate, overall survival, progression-free survival (PFS), and toxicity assessment. Association of treatment efficacy with RAS mutations or FcγR genotypes was investigated.

RESULTS

Median age of the study population was 79 years. DCR at 6 weeks was obtained in 25 of 36 patients (69%; 95% CI, 52% to 84%) of the intention-to-treat population. The best responses were eight partial responses and two complete responses. There were no cetuximab-related deaths. There were three related serious adverse events: two grade 4 infusion reactions and one grade 3 interstitial pneumopathy. Grade 1 to 2 acne-like rash occurred in 78% of patients and was associated with prolonged PFS. One HRAS mutation was identified. Combined FcγRIIa-131H/H and/or FcγRIIIa-158V/V polymorphisms were not associated with the clinical outcomes.

CONCLUSION

As a first-line treatment in patients with unresectable SCCS, cetuximab achieved 69% DCR. A randomized phase III trial is warranted to confirm that cetuximab may be considered as a therapeutic option especially in elderly patients. The low frequency of RAS mutations in SCCS makes SCCS tumors attractive for EGFR inhibition.