Abstract 4768: Characteristics of patients diagnosed de novo with AJCC7 stage III or regionally advanced cutaneous melanoma and trends in adjuvant therapy: An analysis of the SEER cancer registry in the United States
Authors: Tarhini Ahmad , Ghate Sameer , Nakasato Antonio , Ionescu-Ittu Raluca , Shi Sherry , Ndife Briana , Burne Rebecca , Laliberté François , Duh Mei S. 
Published: August 2018

Background: The v1.2018 National Comprehensive Cancer Network guidelines adopted nivolumab and dabrafenib/trametinib as potential adjuvant therapies for selected patients (pts) with AJCC7 stage III/regionally advanced melanoma. There is a need to understand which patient characteristics may affect adjuvant treatment choices and what lessons can be learned from the era of adjuvant interferon-alfa and ipilimumab. This study aimed to describe characteristics and use of adjuvant therapy in pts with stage III/regional melanoma.

Methods: Pts newly diagnosed with invasive melanoma were identified in the US Surveillance, Epidemiology, and End Results (SEER) cancer registry (most recent 5 years: 2010 -2014; n = 106,195). Stage III melanoma was defined based on the AJCC7 classification (n = 7,669); pts classified as AJCC7 stages I/II but with reported lymphatic metastasis were considered regionally advanced and included (n =169). Pt characteristics measured at the time of the diagnosis are reported by treatments (systemic and radiation) initiated as the main course of treatment in the 4 months post-diagnosis.

Results: Of 7,838 pts with stage III/regional disease at diagnosis from 2010-2014, 1,414 (18.0%) received radiation therapy (± systemic), 1,001 (12.8%) received systemic therapy (± radiation), 443 (5.7%) received radiation + systemic therapy, and 5,866 (74.8%) were not treated with either radiation or systemic therapy. Table 1 reports selected patient characteristics by treatment received.

Conclusions: The results of this study indicate that many pts with stage III/regional melanoma, even those not treated, have risk factors known to be associated with worse prognosis. Use of radiation therapy or adjuvant systemic therapy was rare during the study period (2010-2014). It remains to be determined how the new treatment landscape will change the use of adjuvant therapy.

Table 1.Stage III1/regionally advanced melanomaRadiation (± systemic)(n =1,414 )Systemic (± radiation) (n = 1,001)Systemic + radiation (n = 443)Neither2 (n =5,866 )Age at diagnosis, median (Q1-Q3)65 (55 - 76)58 (48 - 68)61 (51 - 71)62 (51 - 73)Males, %57.351.174.337.6LN classification (from TNM), %N145.347.545.461.9N2 (includes N2c)35.334.139.726.7N319.118.114.011.4Ulceration, %Yes20.325.29.339.0No22.824.38.846.3Unknown56.950.581.914.7Number mitoses per square mm, %None1.62.70.94.71 - 514.818.84.539.3≥ 615.018.27.924.3Unknown68.660.386.731.7LN involvement (any), %91.494.091.693.91 LN33.637.431.857.72 - 3 LNs25.326.323.922.5&gt; 3 LNs19.216.818.57.5Unknown number of LNs13.313.617.46.2Microscopic nodal metastasis3 (regardless of the number of LNs)20.231.28.861.7Satellite / in-transit without LN involvement (N2c), %5.32.62.55.2LN, lymph node; TNM, tumor/node/metastasis (TNM) classification of malignant tumors. [1] Stage III melanoma was defined based on the American Joint Committee on Cancer (AJCC) 7 edition classification; [2] Radiation therapy and chemotherapy are reported in the SEER with moderate sensitivity (80% and 68%, respectively) and high specificity. This implies the "Neither" category may include some false -negative (i.e., treated) pts.[3] Includes pts identified with clinically occult (microscopic) LN metastases only, pts with isolated tumor cells only in LN, and/or pts who underwent sentinel LN biopsy and were found to have LN metastasis.

Citation Format: Ahmad Tarhini, Sameer Ghate, Antonio Nakasato, Raluca Ionescu-Ittu, Sherry Shi, Briana Ndife, Rebecca Burne, François Laliberté, Mei S. Duh. Characteristics of patients diagnosed de novo with AJCC7 stage III or regionally advanced cutaneous melanoma and trends in adjuvant therapy: An analysis of the SEER cancer registry in the United States [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4768.