The histologic spectrum of epithelial neoplasms induced by sorafenib

Penile and scrotal infundibular cysts in an adolescent treated with sorafenib

Sorafenib is a multikinase inhibitor increasingly used for the treatment of several solid tumors. Different types of keratotic lesions, such as squamous cell carcinoma, actinic keratosis, or infundibular cyst, have been reported in association with this therapy. We present a 15-year-old male diagnosed with desmoid fibromatosis who developed multiple penile and scrotal infundibular cysts while receiving treatment with sorafenib.

BRAF inhibitor-associated cutaneous squamous cell carcinoma: new mechanistic insight, emerging evidence for viral involvement and perspectives on clinical management

Mutations in the BRAF proto-oncogene occur in the majority of cutaneous melanomas. The commonly detected valine (V) to glutamate (E) mutation (V600E) is known to drive melanomagenesis and has thus been the target of two highly selective chemotherapeutic agents: vemurafenib and dabrafenib. While BRAF inhibitor therapy has revolutionized the treatment of metastatic melanoma, unanticipated cutaneous toxicities, including the development of cutaneous squamous cell carcinomas (cSCCs), are frequently reported and hinder therapeutic durability. However, the mechanisms by which BRAF inhibitors induce cutaneous neoplasms are poorly understood, thus posing a challenge for specific therapies. In this review, we summarize the clinical and molecular profiles of BRAF inhibitor-associated cSCCs, with a focus on factors that may contribute to disease pathogenesis. In particular, we discuss the emerging evidence pointing towards viral involvement in BRAF inhibitor-induced cutaneous neoplasms and offer new perspectives on future therapeutic interventions. Continued clinical and mechanistic studies along this line will not only allow for better understanding of the pathogenic progression of BRAF inhibitor-induced cSCCs, but will also lead to development of new therapeutic and preventative options for patients receiving targeted cancer therapy.

Keratoacanthoma of the Nasal Septum Secondary to Ranibizumab Use

Keratoacanthoma (KA) is a benign epithelial tumor that typically presents as a firm, cone-shaped, flesh-colored nodule with a central horn-filled crater. KA is considered to be a low-grade variant of squamous cell carcinoma (SCC). We report a rare case of a 72-year-old male who presented with a KA involving the nasal septum, possibly related to ranibizumab use. A flesh-colored lesion on the right anterior nasal septum lesion was visualized on examination. Histologic examination revealed a well-circumscribed, dome-shaped central crater filled with keratin, well-differentiated squamous epithelium with ground-glass cytoplasm with pushing margins, and intraepithelial microabscesses establishing the diagnosis of KA. KA of the nasal septum has only been reported once in the literature. This case is unusual because it normally presents on sun-exposed areas. Additionally, this patient was taking ranibizumab, a vascular endothelial growth factor (VEGF) inhibitor for macular degeneration. Despite ranibizumab not being directly linked to precancerous and cancerous skin lesions, agents in this medication class have been. Although it is difficult to prove associations in this isolated case, the role of ranibizumab causing cutaneous lesions should be further investigated.

Cutaneous adverse effects of targeted therapies: Part I: Inhibitors of the cellular membrane

There has been a rapid emergence of numerous targeted agents in the oncology community in the last decade. This exciting paradigm shift in drug development lends promise for the future of individualized medicine. Given the pace of development and clinical deployment of targeted agents with novel mechanisms of action, dermatology providers may not be familiar with the full spectrum of associated skin-related toxicities. Cutaneous adverse effects are among the most frequently observed toxicities with many targeted agents, and their intensity can be dose-limiting or lead to therapy discontinuation. In light of the often life-saving nature of emerging oncotherapeutics, it is critical that dermatologists both understand the mechanisms and recognize clinical signs and symptoms of such toxicities in order to provide effective clinical management. Part I of this continuing medical education article will review in detail the potential skin-related adverse sequelae, the frequency of occurrence, and the implications associated with on- and off-target cutaneous toxicities of inhibitors acting at the cell membrane level, chiefly inhibitors of epidermal growth factor receptor, KIT, and BCR-ABL, angiogenesis, and multikinase inhibitors.

BRAF inhibitors: experience in thyroid cancer and general review of toxicity

The US Food and Drug Administration-approved BRAF inhibitors, vemurafenib and dabrafenib, have demonstrated superior efficacy in patients with BRAF-mutant melanomas but have limited efficacy in BRAF-mutant colorectal cancer. Little is known at this time regarding BRAF inhibitors in thyroid cancer. Initial reports in patients with progressive, radioactive iodine-refractory BRAF-mutant papillary thyroid cancer suggest response rates of approximately 30-40%. In this review, we discuss BRAF inhibitors in the context of thyroid cancer, the toxicities associated with BRAF inhibitors, and the suggested management of those toxicities. The management of vemurafenib and dabrafenib toxicities is applicable across all tumor types and may serve as a practical guide to their use.

Histopathologic characteristics of therapy-associated cutaneous neoplasms with vemurafenib, a selective BRAF kinase inhibitor, used in the treatment of melanoma

BACKGROUND

Activating mutations in BRAF have been observed in up to 60% of melanomas, indicating a pivotal role for kinase deregulation in tumor progression. Vemurafenib is a specific inhibitor of BRAF for treatment of melanomas with activating BRAF V600E mutations and has been a major advancement in melanoma treatment. Treatment with vemurafenib, and to a lesser extent, sorafenib, a relatively non-specific inhibitor of BRAF, has been associated with cutaneous squamous cell carcinoma (SCC).

METHODS

Clinical and microscopic characteristics of cutaneous neoplasms were evaluated following vemurafenib administration.

RESULTS

Twenty-four of 47 (51%) patients receiving vemurafenib at our institution developed 146 total cutaneous neoplasms, with 75% developing multiple lesions. The median number of lesions in affected patients was three. Body distribution included head/neck (29%), chest/back (21%), upper (23%) and lower extremities (27%). Lesions were biopsied and pathologically showed multiple types of epidermal tumors including, but not limited to, verrucous keratoses with/without partial thickness dysplasia, actinic keratoses and well-differentiated and invasive SCCs with/without keratoacanthomatous features.

CONCLUSIONS

We describe the histopathologic findings of skin lesions potentially associated with vemurafenib. Additional investigation is necessary to further elucidate cutaneous neoplasms associated with vemurafenib; however, frequent dermatologic evaluation is warranted in all patients receiving BRAF inhibitors.

Dermatological adverse events from BRAF inhibitors: a growing problem

The development of targeted therapies has ushered in a new era in the management of melanoma. Inhibitors of the RAS-RAF-MEK-ERK pathway have taken the center stage with development at a rapid pace. Vemurafenib was recently approved by regulatory agencies, and other agents (e.g. dabrafenib) are in various stages of clinical testing. These agents are producing remarkable results for patients, but are also presenting new challenges. Clinical toxicities and drug resistance are topmost issues. Some of the most common and vivid representations of adverse events to these agents are the dermatologic manifestations. Published trials and initial observations reflect a toxicity profile (e.g. squamous cell carcinomas/keratoacanthomas, maculopapular rashes, hyperkeratosis) that is distinct from cutaneous toxicities from EGFR and mTOR inhibitors (acneiform rash, paronychia, xerosis). Their management extends beyond conservative treatment and includes specific physical and surgical treatment modalities, skill sets unique to dermatologists. All these pose significant challenges to clinicians, and sound knowledge of such toxicities and their management will likely result in improved patient outcomes and quality of life. In this manuscript, we provide an overview of the emerging scientific literature on dermatological adverse events arising out of BRAF inhibition.

Skin toxicity of targeted cancer agents: mechanisms and intervention

In recent years, targeted agents have rapidly evolved as effective tools in the clinical management of a broad range of malignant diseases. These agents disrupt molecular mechanisms and signaling modules that drive the malignant phenotype in defined subsets of malignancies. Beyond the intended cellular targets crucial to tumor growth and progression, these agents also affect signal transduction in normal cells and tissues. The resulting adverse events and their clinical management continue to change, as newer agents with an ever-increasing target spectrum are developed. We provide a succinct overview of dermatologic toxicities arising from the targeting of receptor tyrosine kinases and downstream effectors. Emergent insights into the pathomechanisms involved and the use of this knowledge base to alleviate cutaneous adverse events are discussed.

Dermatologic toxicities to targeted cancer therapy: shared clinical and histologic adverse skin reactions

BACKGROUND

Dermatologic toxicities (DT) to targeted cancer therapy may present as inflammatory dermatoses, keratoses, and as benign and malignant squamous proliferations.

METHODS

Published reports of DT with cancer therapy with epidermal growth factor receptor (EGFR), tyrosine kinase (TK), MEK, PI3K, AKT, and BRAF inhibitors were reviewed.

RESULTS

DT associated with targeted cancer therapy demonstrated similar reactions and may be grouped as (i) DT as cutaneous inflammation, and (ii) DT as cutaneous epithelial proliferation. EGFR inhibitor, cetuximab, and MEK inhibitors, selumetinib and trametinib, demonstrated papulopustular rash with a suppurative folliculitis in 83%, 93%, and 80% of the patients on therapy, respectively. Common DT with EGFR inhibitors erlotinib and tyrosine kinase inhibitor sorafenib were hand-foot skin reactions in 30-60% of patients on therapy. PI3K inhibitor BKM-120 and AKT inhibitor MK2206 produced maculopapular eruptions seen as dermal hypersensitivity reaction on the skin biopsy. RAF inhibitors vemurafenib and sorafenib were associated with a variety of cutaneous epithelial proliferations (keratosis pilaris, seborrheic keratosis, verruca vulgaris, actinic keratosis, keratoacanthoma, and squamous cell carcinoma.

CONCLUSION

Various anticancer agents may target similar cellular compounds and/or cell signaling pathways thus share similar clinical and histologic features of DT. The knowledge of the overlap of DT with different types of targeted cancer therapy will assist in evaluation of cutaneous reactions.

Cutaneous effects of BRAF inhibitor therapy: a case series

BACKGROUND

The cutaneous effects of rapidly accelerated fibrosarcoma kinase B (BRAF) inhibitors are not well understood. Squamous cell carcinoma (SCC), keratoacanthoma, and photosensitivity have been described in patients taking BRAF inhibitors.

PATIENTS AND METHODS

To characterize the timing and frequency of skin lesions in patients receiving BRAF inhibitor therapy, we utilized a retrospective case review of 53 patients undergoing treatment with BRAF inhibitors for 4-92 weeks of therapy. Patients were evaluated at baseline, and then followed at 4- to 12-week intervals. Charts were retrospectively reviewed, and the morphology and timing of cutaneous events were recorded.

RESULTS

Thirty-three of the 53 charts met exclusion/inclusion criteria, 15 were treated with vemurafenib, and 18 were treated with GSK 2118436/GSK 1120212. Of 33 patients treated with BRAF inhibitor, 13 developed photosensitivity (39.4%), 10 developed actinic keratoses (30.3%), 10 developed warts (30.3%), and 6 developed SCC (18.2%).

CONCLUSIONS

Multiple cutaneous findings were observed in the 33 patients taking BRAF inhibitors. The previously described association with SCC and photosensitivity was observed in these patients as well. Over half of the observed SCCs were invasive in nature. Photosensitivity continues to be frequent with BRAF inhibitors. Patients taking BRAF inhibitors should have regular full body skin exams. Further studies are necessary to better elucidate the rates of these adverse cutaneous effects.

Diverse cutaneous side effects associated with BRAF inhibitor therapy: a clinicopathologic study

BACKGROUND

Vemurafenib, a novel selective small molecule inhibitor of BRAF, has recently been shown to be effective in the treatment of melanomas harboring the BRAF V600E mutation. Similar to the broad-spectrum RAF inhibitor sorafenib, vemurafenib induces development of squamous cell carcinomas and keratoacanthomas as a side effect of therapy.

OBJECTIVE

We sought to detail additional cutaneous adverse effects of vemurafenib and a similar BRAF inhibitor, dabrafenib.

METHODS

We evaluated the clinical and histologic feature of skin side effects developing on vemurafenib or dabrafenib therapy in 14 patients.

RESULTS

Eight patients developed one or more squamous cell carcinomas, and 11 patients formed benign verrucous keratoses. Eight patients developed single lesions and/or widespread eruptions with histopathologic findings of acantholytic dyskeratosis, consistent with warty dyskeratomas and Darier- or Grover-like rashes, respectively. One patient developed palmoplantar hyperkeratosis, and darkening of existing nevi and new nevi within 2 months of starting vemurafenib. Side effects presented as early as 1 week after beginning therapy, with a mean time of onset of 12.6 weeks in our cohort.

LIMITATIONS

This study was limited by the small number of cases, all from a single institution.

CONCLUSION

Selective BRAF inhibitor therapy is associated with the development of malignant and benign growths, including keratoacanthoma-like squamous cell carcinomas, warty dyskeratomas, and verrucous keratoses, along with widespread eruptions with histologic features of acantholytic dyskeratosis. Given the potential for malignant lesions to develop on treatment, awareness of potential adverse effects of these agents is necessary, and a low threshold for biopsy of new growths is recommended.

[Skin manifestations of new targeted treatments]

Many cutaneous adverse events have been identified with recently developed targeted treatments. Some of them are common and specific, like paradoxical psoriasiform eruptions with anti-TNFα, papulopustular eruptions and paronychias with EGFR inhibitors and peculiar hand-foot skin reactions with multitargeted kinase inhibitors sorefenib and sunitinib. Patients treated with these recently available biologics need a careful monitoring.

Chemotherapy-induced iatrogenic injury of skin: new drugs and new concepts

Chemotherapy and its cutaneous side effects are an increasingly common source of iatrogenic injury to the skin, hair, and nails. Cutaneous changes are among the most common side effects from treatment with particular targeted chemotherapeutic agents, especially those that target the epidermal growth factor receptor and small molecule multikinase inhibitors. Less common, but growing in recognition, are the development of secondary cutaneous neoplasms and subacute cutaneous lupus erythematosus as a result of chemotherapy. There is considerable overlap of the multiple entities described as a side effect from conventional chemotherapeutic agents; therefore, the term "toxic erythema of chemotherapy" can be used as an easily understood name.

RAS mutations are associated with the development of cutaneous squamous cell tumors in patients treated with RAF inhibitors

PURPOSE

RAF inhibitors are effective against melanomas with BRAF V600E mutations but may induce keratoacanthomas (KAs) and cutaneous squamous cell carcinomas (cSCCs). The potential of these agents to promote secondary malignancies is concerning. We analyzed cSCC and KA lesions for genetic mutations in an attempt to identify an underlying mechanism for their formation.

METHODS

Four international centers contributed 237 KA or cSCC tumor samples from patients receiving an RAF inhibitor (either vemurafenib or sorafenib; n = 19) or immunosuppression therapy (n = 53) or tumors that developed spontaneously (n = 165). Each sample was profiled for 396 known somatic mutations across 33 cancer-related genes by using a mass spectrometric-based genotyping platform.

RESULTS

Mutations were detected in 16% of tumors (38 of 237), with five tumors harboring two mutations. Mutations in TP53, CDKN2A, HRAS, KRAS, and PIK3CA were previously described in squamous cell tumors. Mutations in MYC, FGFR3, and VHL were identified for the first time. A higher frequency of activating RAS mutations was found in tumors from patients treated with an RAF inhibitor versus populations treated with a non-RAF inhibitor (21.1% v 3.2%; P < .01), although overall mutation rates between treatment groups were similar (RAF inhibitor, 21.1%; immunosuppression, 18.9%; and spontaneous, 17.6%; P = not significant). Tumor histology (KA v cSCC), tumor site (head and neck v other), patient age (≤ 70 v > 70 years), and sex had no significant impact on mutation rate or type.

CONCLUSION

Squamous cell tumors from patients treated with an RAF inhibitor have a distinct mutational profile that supports a mechanism of therapy-induced tumorigenesis in RAS-primed cells. Conceivably, cotargeting of MEK together with RAF may reduce or prevent formation of these tumors.

Update on the molecular signature of differentiated thyroid cancer: clinical implications and potential opportunities

With the development and maturation of new technologies, there has been a steady incorporation of powerful new tools into the evaluation and management of thyroid nodules and thyroid cancer. An increasing number of reports on oncogene testing and molecular screening in fine-needle aspiration biopsy samples have been published. However, there remains a paucity of data and consensus on combining both conventional and molecular technologies to determine the diagnosis and/or prognosis of disease. All patients with differentiated thyroid cancer stand to benefit from the identification and incorporation of reliable molecular markers into clinical practice. Identification of reliable markers would allow for stratification of treatment, affording the medical and surgical teams an ability to individually tailor evaluation and treatment, applying aggressive therapy and monitoring only when clinically warranted. For the majority of patients with thyroid cancer, the incorporation of a validated, multifaceted molecular profiling system may not improve survival; however, there is great opportunity for these efforts to decrease the morbidity associated with our current approach.

Sorafenib-induced premalignant and malignant skin lesions

PURPOSE

To review characteristics of patients who develop premalignant and malignant skin lesions while on sorafenib therapy and discuss implications for subsequent treatment of their primary malignancies.

BACKGROUND

Sorafenib is a newly developed multitargeted protein kinase inhibitor reported to induce a variety of adverse cutaneous effects, rarely including actinic keratoses, keratocanthomas, and squamous cell carcinomas (SCCs).

METHODS

Published reports of individuals who have developed cutaneous lesions demonstrating atypia of the epidermis are reviewed. In addition, a 77-year-old man who developed not only an SCC but also verrucas within one month of taking sorafenib monotherapy for metastatic adenocarcinoma of the lung is described.

RESULTS

Cutaneous lesions develop most commonly in Caucasian men older than 40 years without previous histories of skin cancer, within two weeks to three years of starting sorafenib therapy. Currently there is no definitive explanation for the relationship between sorafenib and cutaneous neoplasms. Management typically involves treatment of skin lesions with cryotherapy or excision with at least a brief discontinuation of sorafenib. In patients whose primary malignancies were responding well, sorafenib therapy was continued with close follow-up.

CONCLUSIONS

The possibility of rapidly developing actinic keratoses, keratocanthomas, verrucas, and SCC during treatment with sorafenib, warrants close dermatologic follow-up and a lower threshold for biopsy and treatment of suspicious cutaneous lesions. Development of a sorafenib-induced SCC is not an absolute contraindication for continued use of sorafenib therapy; however, the drug should be briefly discontinued until lesions are treated.

Improved survival with vemurafenib in melanoma with BRAF V600E mutation

BACKGROUND

Phase 1 and 2 clinical trials of the BRAF kinase inhibitor vemurafenib (PLX4032) have shown response rates of more than 50% in patients with metastatic melanoma with the BRAF V600E mutation.

METHODS

We conducted a phase 3 randomized clinical trial comparing vemurafenib with dacarbazine in 675 patients with previously untreated, metastatic melanoma with the BRAF V600E mutation. Patients were randomly assigned to receive either vemurafenib (960 mg orally twice daily) or dacarbazine (1000 mg per square meter of body-surface area intravenously every 3 weeks). Coprimary end points were rates of overall and progression-free survival. Secondary end points included the response rate, response duration, and safety. A final analysis was planned after 196 deaths and an interim analysis after 98 deaths.

RESULTS

At 6 months, overall survival was 84% (95% confidence interval [CI], 78 to 89) in the vemurafenib group and 64% (95% CI, 56 to 73) in the dacarbazine group. In the interim analysis for overall survival and final analysis for progression-free survival, vemurafenib was associated with a relative reduction of 63% in the risk of death and of 74% in the risk of either death or disease progression, as compared with dacarbazine (P<0.001 for both comparisons). After review of the interim analysis by an independent data and safety monitoring board, crossover from dacarbazine to vemurafenib was recommended. Response rates were 48% for vemurafenib and 5% for dacarbazine. Common adverse events associated with vemurafenib were arthralgia, rash, fatigue, alopecia, keratoacanthoma or squamous-cell carcinoma, photosensitivity, nausea, and diarrhea; 38% of patients required dose modification because of toxic effects.

CONCLUSIONS

Vemurafenib produced improved rates of overall and progression-free survival in patients with previously untreated melanoma with the BRAF V600E mutation. (Funded by Hoffmann-La Roche; BRIM-3 ClinicalTrials.gov number, NCT01006980.).

[Squamous cell carcinoma in a patient receiving sorafenib]

BACKGROUND

Sorafenib is a multikinase inhibitor approved for the treatment of renal cell carcinoma and hepatocellular carcinoma. Associated short-term cutaneous adverse events are well known. Regarding long-term adverse events, keratoacanthoma has been reported more recently and, more rarely, invasive squamous cell carcinoma.

PATIENTS AND METHODS

A 56-year-old man was treated with sorafenib in December 2008 for renal cell carcinoma with cutaneous metastases. The patient had a skin phototype IV and no history of intense sun exposure. Within five months of starting sorafenib, he developed deeply invasive well-differentiated retroauricular squamous cell carcinoma.

DISCUSSION

Sorafenib modifies the immunostimulatory capacity of dendritic cells by reducing cytokine secretion and CD1a expression. Blockade of autocrine vascular endothelial growth factor (VEGF) signalling in keratinocytes can also select tumoural clones with increased oncogenic Ras mutation, increased activation of phospholipase D and modulation of the Ras/Raf/MAP kinase signalling pathway involved in cutaneous squamous cell carcinogenesis.

CONCLUSION

Cases of keratoacanthomas and deeply invasive squamous cell carcinomas reported in patients on sorafenib emphasise the need for multidisciplinary follow-up of this population and the important role of dermatologists in managing the short and long-term adverse effects of multitarget tyrosine inhibitors.