The Association of Rural Residence With Surgery and Adjuvant Radiation in Medicare Beneficiaries With Rectal Cancer

Abstract

Purpose: Radiation therapy and surgery are fundamental site-directed therapies for nonmetastatic rectal cancer. To understand the relationship between rurality and access to specialized care, we characterized the association of rural patient residence with receipt of surgery and radiation therapy among Medicare beneficiaries with rectal cancer.

Methods and materials: We identified fee-for-service Medicare beneficiaries aged 65 years or older diagnosed with nonmetastatic rectal cancer from 2016 to 2018. Beneficiary place of residence was assigned to one of 3 geographic categories (metropolitan, micropolitan, or small town/rural) based on census tract and corresponding rural urban commuting area codes. Multivariable regression models were used to determine associations between levels of rurality and receipt of both radiation and proctectomy within 180 days of diagnosis. In addition, we explored associations between patient rurality and characteristics of surgery and radiation such as minimally invasive surgery (MIS) or intensity modulated radiation therapy (IMRT).

Results: Among 13,454 Medicare beneficiaries with nonmetastatic rectal cancer, 3926 (29.2%) underwent proctectomy within 180 days of being diagnosed with rectal cancer, and 1792 (13.3%) received both radiation and proctectomy. Small town/rural residence was associated with an increased likelihood of receiving both radiation and proctectomy within 180 days of diagnosis (adjusted subhazard ratio, 1.15; 95% CI, 1.02-1.30). Furthermore, small town/rural radiation patients were significantly less likely to receive IMRT (adjusted odds ratio, 0.62; 95% CI, 0.48-0.80) or MIS (adjusted odds ratio, 0.80; 95% CI, 0.66-0.97) than metropolitan patients.

Conclusions: Although small town/rural Medicare beneficiaries were overall more likely to receive both radiation and proctectomy for their rectal cancer, they were less likely to receive preoperative IMRT or MIS as part of their treatment regimen. Together, these findings clarify that among Medicare beneficiaries, there appeared to be a similar utilization of radiation resources and time to radiation treatment regardless of rural/urban status.

Figure 1

Cohort build to identify incident of nonmetastatic patients with rectal cancer. *Includes all United-States-residing fee-for-service Medicare beneficiaries with continuous enrollment in Medicare Parts A and B between October 1, 2015 and December 31, 2018 (or until death).

Figure 2

Treatment patterns for proctectomy patients by geographic location on univariate analysis χ² test. For the preoperative radiation, preoperative chemotherapy, and MIS groups, the denominator was 3926. Denominator for the IMRT group was 1792. For the specialist surgeon group, defined as either colorectal surgeons or surgical oncologists, the denominator was 3913. Error bars represent standard errors. *P ≤ .05. Abbreviations: IMRT = intensity-modulated radiation therapy; MIS = minimally invasive surgery; pre-op = preoperative.