1

Introduction

The mainstay of treatment for patients with cutaneous melanoma is surgery. Although relatively radioresistant, adjuvant radiotherapy (RT) has been shown to reduce the risk of local–regional recurrence in patients who are thought to be at high risk of failure after surgery alone . The purpose of this paper is to report our experience with adjuvant RT for patients treated with curative intent for high risk cutaneous melanoma.

2

Materials and Methods

Between August 1981 and December 2009, 82 patients with cutaneous melanoma thought to be at high risk for a local–regional recurrence were treated with adjuvant RT at the University of Florida. The median age was 62 years (range, 21 to > 89 years). Sixty-two patients (76%) were male and the remainder were female. Eighty-one patients (99%) were white. Risk factors included recurrence after prior surgery, positive regional nodes, close or positive margins, gross residual disease, extracapsular extension, metastatic lymph node ≥ 3 cm, incomplete or absent node dissection with a high risk of occult regional metastases, and in-transit metastases. Thirty-one patients (38%) were treated after the initial operation and the remainder for recurrent disease after prior surgery. Sixty-four patients (78%) had primary sites in the head and neck and 18 had sites below the clavicles.

Margins following surgery were: negative, 62 patients (76%); microscopically positive, 14 patients (17%), and gross residual disease, 2 patients (2%). Elective nodal RT was administered to 4 patients (5%) thought to be at high risk for occult regional metastases and who were not candidates for a regional node dissection or sentinel lymph node biopsy. The number of risk factors was: 1, 22 patients (27%); 2, 26 patients (32%); 3, 24 patients (29%); and 4, 10 patients (12%). In-transit metastases were present in 5 patients (6.1%).

Patients were treated with electrons and/or photons depending on the site. Intensity modulated RT (IMRT) has been used on occasion in recent years, particularly to treat the ilio-inguinal nodes to reduce the RT dose to the adjacent bowel. The most common dose fractionation schedule was 30 Gy in 5 fractions administered 2 fractions per week as described by investigators at the M. D. Anderson Cancer Center . Depending on the site and volume of tissue irradiated, some patients were treated with conventional fractionation to improve the cosmetic and/or functional outcome. Hypofractionation was employed to treat 42 patients (51%) and the remainder were treated with conventional fractionation.

Statistical analyses were performed using SAS and JMP software (SAS Institute, Cary, NC). The Kaplan–Meier product limit method was used to estimate time dependent outcomes including overall survival, cause-specific survival, local–regional control, in-field local–regional control, and distant metastasis-free survival . The level of statistical significance between strata of selected prognostic factors was tested with the log-rank test statistic. Complications were coded as severe if they required hospitalization, required surgical intervention, or resulted in death .

2

Materials and Methods

Between August 1981 and December 2009, 82 patients with cutaneous melanoma thought to be at high risk for a local–regional recurrence were treated with adjuvant RT at the University of Florida. The median age was 62 years (range, 21 to > 89 years). Sixty-two patients (76%) were male and the remainder were female. Eighty-one patients (99%) were white. Risk factors included recurrence after prior surgery, positive regional nodes, close or positive margins, gross residual disease, extracapsular extension, metastatic lymph node ≥ 3 cm, incomplete or absent node dissection with a high risk of occult regional metastases, and in-transit metastases. Thirty-one patients (38%) were treated after the initial operation and the remainder for recurrent disease after prior surgery. Sixty-four patients (78%) had primary sites in the head and neck and 18 had sites below the clavicles.

Margins following surgery were: negative, 62 patients (76%); microscopically positive, 14 patients (17%), and gross residual disease, 2 patients (2%). Elective nodal RT was administered to 4 patients (5%) thought to be at high risk for occult regional metastases and who were not candidates for a regional node dissection or sentinel lymph node biopsy. The number of risk factors was: 1, 22 patients (27%); 2, 26 patients (32%); 3, 24 patients (29%); and 4, 10 patients (12%). In-transit metastases were present in 5 patients (6.1%).

Patients were treated with electrons and/or photons depending on the site. Intensity modulated RT (IMRT) has been used on occasion in recent years, particularly to treat the ilio-inguinal nodes to reduce the RT dose to the adjacent bowel. The most common dose fractionation schedule was 30 Gy in 5 fractions administered 2 fractions per week as described by investigators at the M. D. Anderson Cancer Center . Depending on the site and volume of tissue irradiated, some patients were treated with conventional fractionation to improve the cosmetic and/or functional outcome. Hypofractionation was employed to treat 42 patients (51%) and the remainder were treated with conventional fractionation.

Statistical analyses were performed using SAS and JMP software (SAS Institute, Cary, NC). The Kaplan–Meier product limit method was used to estimate time dependent outcomes including overall survival, cause-specific survival, local–regional control, in-field local–regional control, and distant metastasis-free survival . The level of statistical significance between strata of selected prognostic factors was tested with the log-rank test statistic. Complications were coded as severe if they required hospitalization, required surgical intervention, or resulted in death .