Guidelines: Treating Basal, Squamous Cell Carcinoma

Rates of nonmelanoma skin cancer (NMSC), the most common type of skin cancer in the United States, have grown substantially in recent decades.^1,2 The incidence of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) increased by 145% and 263%, respectively, between 1976-1984 and 2000-2010.³ Combined, these and the less common types of NMSC affect more than 3.3 million Americans annually.^4,5

In January 2018, the American Academy of Dermatology (AAD) published evidence-based guidelines for the treatment of BCC and SCC.^6,7

The recommendations were developed by board-certified dermatologists and other relevant experts based on the best available evidence to date.

“Although many recommendations in these guidelines reaffirm common knowledge and current practice, other recommendations may remind clinicians of alternative therapeutic or preventive options when insufficient evidence is available to support new therapies or previously dogmatic practice patterns,” the guideline authors noted. Key points of the guidelines are highlighted below.

Surgical Treatment

With few exceptions, surgical therapy is the most effective approach for the treatment of BCC and SCC. The most commonly used surgical techniques for both conditions are standard excision, Mohs micrographic surgery (MMS), and curettage and electrodessication (C&E). “A treatment plan that considers recurrence rate, preservation of function, patient expectations, and potential adverse effects is recommended,” as stated in the guidelines.

In low-risk primary BCC and SCC, surgical excision (with 4 mm clinical margins for BCC, and 4 to 6 mm margins for SCC) and histologic margin assessment is recommended. C&E may be appropriate for the treatment of low-risk BCC or SCC in non-terminal hair-bearing locations. Although “standard excision may be considered for select high-risk tumors…. strong caution is advised when selecting a treatment modality for high-risk tumors without a complete margin assessment.” MMS is recommended in high-risk BCC and SCC.

Non-surgical Treatment

When more effective treatments are contraindicated or impractical, cryosurgery may be considered in BCC and SCC. For low-risk BCC, considerations may include topical therapy with imiquimod or 5-FU (with dose adjustments based on adverse effect tolerance), photodynamic therapy (PDT), or radiation therapy, although cure rates may be lower with these techniques compared with surgical options. In low-risk SCC, radiation therapy or cryosurgery may be considered, while PDT and topical therapies are not recommended. Data is inadequate to support a recommendation of laser or electronic surface brachytherapy in the treatment of BCC or SCC.

Management of Locally Advanced or Metastatic BCC or SCC

Multidisciplinary consultation is recommended in patients with metastatic BCC, along with treatment with smoothened inhibitors. If such treatment is not feasible, recommendations include platinum-based chemotherapy or supportive care. A smoothened inhibitor should also be considered for the treatment of locally advanced BCC when surgery and radiation therapy are not suitable.

In SCC with regional lymph node metastases, the recommended approach is surgical resection, possibly with adjuvant radiation therapy and systemic therapy. For inoperable metastases, combination chemoradiation should be considered. Limited data support the efficacy of epidermal growth factor inhibitors and cisplatin, singularly or in combination, in metastatic disease. Multidisciplinary consultation is recommended in patients with SCC with locoregional or distant metastases, and in some cases of locally advanced disease without known metastases.

Patients with advanced BCC or SCC “should be provided with or referred for best supportive and palliative care to optimize symptom management and maximize quality of life,” the guideline authors wrote.

Follow-Up and Reducing Future Risk

After the first diagnosis of BCC or SCC, skin cancer screening should be performed at least once a year, and patients should be counseled on the need for such screenings, as well as the benefits of self-screening and the importance of sun protection. Topical and oral retinoids are not recommended for the reduction of recurrent keratinocyte cancers, except in patients with SCC who are solid organ transplant recipients (SOTRs). In those cases, acitretin is the only agent that may be beneficial. Dietary supplementation with selenium and beta-carotene is not recommended to reduce future risk in patients with a history of BCC or SCC, and there is insufficient data regarding the use of oral nicotinamide, α-difluoromethylornithine (DFMO), or celecoxib in the chemoprevention of either disease.

For additional insight regarding the new recommendations, Dermatology Advisor spoke with the co-chair of the guidelines work group, Murad Alam, MD, chief of cutaneous and aesthetic surgery in the department of dermatology at Northwestern University Feinberg School of Medicine in Chicago, Illinois.

Dermatology Advisor: Why was there a need for these guidelines?

Dr Alam: While the first-line treatment of basal cell carcinoma and cutaneous squamous cell carcinoma has been some form of surgery for many years, new research has given rise to new information, and new medicines and treatment techniques have been developed. These guidelines are an efficient way for dermatologists and other physicians to understand the latest evidence and recommendations without having to do a lot of research on their own. Some guidelines rely on flowcharts and footnotes, which can be helpful, but we felt there was a need for simple, clear writing that would be easier for the reader to digest, and that is what we have tried to present in the guidelines. 

Dermatology Advisor: What are the top takeaway messages for clinicians?

Dr Alam: Surgery, whether by cutting out a cancer or destroying it in situ, is still the best way to treat most BCC and SCC. And the best way to find and prevent skin cancer is still via skin checks at a dermatologist’s office at least once a year. 

Dermatology Advisor: What should be the focus of future research in this area? 

Dr Alam: We would all like to work towards a cure to eliminate skin cancer completely. There is now a pill that helps control advanced and life-threatening cases of BCC, but it has adverse events that make it inappropriate in individuals with just one or a few small basal cells. It would be nice to have a drug that works as well or better with fewer adverse events, and to have a similar drug for SCC.

Finally, we could all benefit from a sunscreen that is more effective in filtering out the harmful rays of the sun. At present, sunscreen or sunblock is really “sun-slow,” meaning ultraviolet light gets through, just much more slowly. But if we could find something that was easy to apply, didn’t interfere with activities, and truly blocked out ultraviolet light, BCC and SCC may become a thing of the past.

References

1. Guy GP, Thomas CC, Thompson T, Watson M, Massetti GM, Richardson LC; Centers for Disease Control and Prevention (CDC). Vital signs: Melanoma incidence and mortality trends and projections—United States, 1982–2030. MMWR Morb Mortal Wkly Rep. 2015;64(21):591-596. 
2. Guy GP, Machlin S, Ekwueme DU, Yabroff KR. Prevalence and costs of skin cancer treatment in the US, 2002–2006 and 2007–2011. Am J Prev Med. 2015;48(2):183-187.
3. Muzic JG, Schmitt AR, Wright AC, et al. Incidence and trends of basal cell carcinoma and cutaneous squamous cell carcinoma: a population-based study in Olmstead County, Minnnesota, 2000-2010. Mayo Clin Proc. 2017;92(6):890-898.
4. American Academy of Dermatology. Burden of skin disease. www.aad.org/about/burden-of-skin-disease. Accessed February 8, 2018. 
5. Rogers HW, Weinstock MA, Feldman SR, Coldiron BM. Incidence estimate of nonmelanoma skin cancer (keratinocyte carcinomas) in the US population. JAMA Dermatol. 2015;151(10):1081-1086.
6. Baum C, Bordeaux JS, Brown M, et al. Guidelines of care for the management of basal cell carcinoma [published online January 10, 2018]. J Am Acad Dermatol. doi:10.1016/j.jaad.2017.10.006
7. Alam M, Armstrong A, Baum C, et al. Guidelines of care for the management of cutaneous squamous cell carcinoma [published online January 10, 2018]. J Am Acad Dermatol. doi:10.1016/j.jaad.2017.10.007