BACKGROUND
Once a cancer is diagnosed and surgery is an option, patients usually proceed with surgery quickly after diagnosis. Waiting a long time from diagnosis to surgery is known to worsen survival in several cancers, such as lung, colorectal, and breast cancer. An exception to this is papillary thyroid cancer. Papillary thyroid carcinoma, the most common type of thyroid cancer, represents a less aggressive type of cancer with an overall good prognosis. Over the last two decades, treatment guidelines for papillary thyroid cancer have changed from total thyroidectomy followed by radioactive iodine therapy recommended for the majority of patients, to total thyroidectomy or lobectomy only for low-risk patients, and to a more recent option of watching without surgery for cancer growth using ultrasound (active surveillance) for very low risk patients with papillary thyroid cancer. The impact of delayed surgery during active surveillance in patients with papillary thyroid cancer has not yet been fully investigated. The aim of this study was to evaluate whether a delay in surgery affects survival in patients older than age 65 diagnosed with papillary thyroid cancer.

THE FULL ARTICLE TITLE
Chaves N et al 2023 Delay in surgery and papillary thyroid cancer survival in the United States: A SEERMedicare analysis. J Clin Endocrinol Metab. Epub 2023 Mar 29. PMID: 36987566.

SUMMARY OF THE STUDY
The authors used the U.S. Surveillance, Epidemiology, and End Results (SEER)–Medicare linked data files to identify 8170 Medicare beneficiaries who were diagnosed with papillary thyroid cancer and underwent thyroid surgery between 1999 and 2018. These patients were divided into three groups based on the time to surgery, defined as the time from diagnosis to the date of surgery in days: within the first 90 days (0-90 days), 91 to 180 days (91-180 days), and more than 180 days (>180 days) after diagnosis. Overall survival (OS) and disease-specific survival (DSS) were defined as the time from the date of diagnosis to the time of all-cause mortality and disease-specific mortality, respectively. Age, gender, race and ethnicity, marital status, urban/rural setting, comorbidities, year of diagnosis, cancer stage, number of positive lymph nodes, primary surgery type, radioactive therapy use, and length of follow-up were included in the analysis.

Given their eligibility to receive Medicare, according to the study design, all patients were 65 or older, with an average age of 69 years; 70% of the patients were females, 86% were White and 90% were non-Hispanic. Almost half of the patients had no other significant medical conditions. The patients were followed for an average time of 99 months. The majority of patients (90%) had surgery within the first 90 days after the initial diagnosis, 8% had surgery within 91 to 180 days, and 2% after 180 days. Cancer staging was similar across the three time to surgery groups: 64% of patients had localized disease, 28% had regional disease, and 8% had distant disease.

The estimated overall survival at 1, 5, and 10 years was 95.2%, 81.8%, and 63.2% in the 0-90 days group; 95.7%, 78.6%, and 55.3% in the 91-180 days group; and 98.0%, 67.4%, and 48.9% in the >180 days group. The estimated thyroid cancer-specific survival at 1, 5, and 10 years was 97.8%, 94.4%, and 90.9% in the 0-90 days group; 98.1%, 94.6%, and 87.4% in the 91-180 days group; and 99.5%, 88.1%, and 80.8% in >180 days group.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
This study suggests that delayed surgery may decrease the overall survival and thyroid cancer-specific survival in older patients with papillary thyroid cancer. Surprisingly, spread of the cancer outside of the neck, which would usually prompt more aggressive treatment, were more common in patients with surgery delayed more than 90 and 180 days. However, survival was not affected by the delay in surgery in patients with more advanced papillary thyroid cancers. Additional research is needed to understand the significance and clinical implications of these findings.

— Alina Gavrila, MD, MMSC

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