E384: Contemporary Trends in Utilization of Metastasectomy Across Common Malignancies

Metastasectomy is a useful adjunct in the management of metastatic cancer. Widespread adoption of novel targeted and immunotherapies has improved the survival profiles of multiple malignancies, potentially altering utilization of metastasectomy. In this study, we aim to characterize trends in metastasectomy across five primary cancers eligible for these therapies.

Methods:

We utilized the National Inpatient Sample to identify patients who underwent metastasectomy in the United States (2016 – 2019). Patients with procedure codes for resection of the lung, liver, adrenal gland, brain or small bowel and concurrent diagnosis codes for secondary malignant neoplasm of that site were included. Subjects were subcategorized by primary malignancy: colorectal (CRC), lung, breast, melanoma, or renal cancer. Sample weights were used to produce national estimates, which were incidence-adjusted by primary malignancy. Trends in utilization were calculated using average annual percent change (AAPC) and linear regression.

Results:

Over the study period, 94,430 patients underwent metastasectomy for the five included primary malignancies (CRC: n=39,370; lung cancer: n=38,605; breast cancer: n=7,650; renal cancer: n=5,360; melanoma: n=3,445). The mean age was 63.4 ± 27.7 years. 48.4% were female, 71.0% were White, and 12.4% were Black. Most patients were insured by Medicare (48.2%) or private insurance (32.8%). 80.4% of metastasectomies were performed at urban teaching hospitals.

Resection of liver metastases was the most common procedure (n=55,230), of which 59.0% were performed for primary CRC. For all primary malignancies, metastasectomy utilization trended upward over the study period, though this was only statistically significant in breast cancer: CRC (AAPC 2.7%; 95% CI -0.3 to +5.6%, p=0.06), lung cancer (AAPC 1.2%; 95% CI -8.6 to +11.1%; p=0.65), breast cancer (AAPC 19.9%; 95% CI  +12.9 to +27.0%; p< 0.01), melanoma (AAPC 9.9%; 95% CI -7.7 to +27.5%; p=0.14), renal cancer (AAPC 5.5%; 95% CI -10.9 to +21.9%; p=0.28).

Across all primary malignancies, inpatient mortality was highest for primary lung cancer (6.4%) and lowest for melanoma (2.9%). Median inpatient length of stay was 7 days (IQR 4 – 10). Median total charges increased from $80,233 to $93,265 during the study period.

Conclusions: Between 2016 and 2019, utilization of metastasectomy increased significantly for breast cancer. The role for metastasectomy will likely continue to develop as new systemic therapies are introduced and as the population of patients living with metastatic disease continues to grow.