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New guideline provides recommendations for radiation therapy of basal cell, squamous cell cancers



Radiation therapy should be the primary treatment for patients with basal cell carcinoma and cutaneous squamous cell carcinoma who are not candidates for surgery, according to a new guideline from an American Society for Radiation Oncology task force.

“We hope that the dermatology community will find this guideline helpful, especially when it comes to defining clinical and pathological characteristics that may necessitate a discussion about the merits of postoperative radiation therapy,” said lead author Anna Likhacheva, MD, of the Sutter Medical Center in Sacramento, Calif., in an email. The guideline was published in Practical Radiation Oncology.

To address five key questions in regard to radiation therapy (RT) for the two most common skin cancers, the American Society for Radiation Oncology convened a task force of radiation, medical, and surgical oncologists; dermatopathologists; a radiation oncology resident; a medical physicist; and a dermatologist. They reviewed studies of adults with nonmetastatic, invasive basal cell carcinoma (BCC) or cutaneous squamous cell carcinoma (cSCC) that were published between May 1998 and June 2018, with the caveat that “there are limited, well-conducted modern randomized trials” in this area. As such, the majority of the recommendations have low to moderate quality of evidence designations.

“The conspicuous lack of prospective and randomized data should serve as a reminder to open clinical trials and collect outcomes data in a prospective fashion,” added Dr. Likhacheva, noting that “improving the quality of data on this topic will ultimately serve our common goal of improving patient outcomes.”

Their first recommendation was to strongly consider definitive RT as an alternative to surgery for BCC and cSCC, especially in areas where a surgical procedure would potentially compromise function or cosmesis. However, they did discourage its use in patients with genetic conditions associated with increased radiosensitivity.

Their second recommendation was to strongly consider postoperative radiation therapy for clinically or radiologically apparent gross perineural spread. They also strongly recommended PORT for cSCC patients with close or positive margins, with T3 or T4 tumors, or with desmoplastic or infiltrative tumors.

Their third recommendation was to strongly consider therapeutic lymphadenectomy followed by adjuvant RT in patients with cSCC or BCC that has metastasized to the regional lymph nodes. They also recommended definitive RT in medically inoperable patients with the same metastasized cSCC or BCC. In addition, patients with BCC or cSCC undergoing adjuvant RT after therapeutic lymphadenectomy were recommended a dose of 6,000-6,600 cGy, while patients with cSCC undergoing elective RT without a lymphadenectomy were recommended a dose of 5,000-5,400 cGy.

Their fourth recommendation focused on techniques and dose-fractionation schedules for RT in the definitive or postoperative setting. For patients with BCC and cSCC receiving definitive RT, the biologically effective dose (BED10) range for conventional fractionation – defined as 180-200 cGy/fraction – should be 70-93.5 and the BED10 range for hypofractionation – defined as 210-500 cGy/fraction – should be 56-88. For patients with BCC and cSCC receiving postoperative RT, the BED10 range for conventional fractionation should be 59.5-79.2 and the BED10 range for hypofractionation should be 56-70.2.

Finally, their fifth recommendation was to not add concurrent carboplatin to adjuvant RT in patients with resected, locally advanced cSCC. They also conditionally recommended adding concurrent drug therapies to definitive RT in patients with unresected, locally advanced cSCC.

Several of the authors reported receiving honoraria and travel expenses from medical and pharmaceutical companies, along with serving on their advisory boards. The others reported no conflicts of interest.

SOURCE: Likhacheva A et al. Pract Radiat Oncol. 2019 Dec 9. doi: 10.1016/j.prro.2019.10.014.

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