Abstract
This cohort study uses data from the Surveillance, Epidemiology, and End Results–Medicare Linked Database to assess the attribution of patients with newly diagnosed lung, breast, colorectal, or prostate cancer to care from multidisciplinary specialists—medical oncologists, surgeons, or radiation oncologists—within 6 months after diagnosis.
Introduction
As payers implement value-based payments for oncology care, assignment of patients to physician practices is increasingly important to accurately assess quality and reimburse clinicians accordingly. Yet, patient attribution remains a challenge.1 Most claims-based attribution algorithms assign patients to practices based on the plurality of primary care visits. However, clinician attribution for specialty care is complex. The challenges of attribution are particularly salient in oncology because cancer care is often multidisciplinary—involving medical oncologists, surgeons, and radiation oncologists—rendering it difficult to discern which practice should be held accountable.2 We sought to identify practices treating Medicare beneficiaries with a new diagnosis of cancer to inform potential attribution algorithms based on care received in the 6 months after diagnosis.
Methods
We used data from the Surveillance, Epidemiology, and End Results (SEER)–Medicare Linked Database (2010-2016) for analyses. The SEER program collects data from population-based cancer registries3; these data are linked with Medicare administrative data.4 We identified traditional (fee-for-service) Medicare beneficiaries 65 years or older who had received a new diagnosis of invasive breast, colorectal, lung, or prostate cancer between January 1, 2011, and December 31, 2015 (eTable 1 in eAppendix 1 in the Supplement), and examined claims through 6 months after diagnosis. The Harvard Medical School Committee on Human Studies approved the study. A waiver of patient informed consent was obtained because patient identifiers are not included in the SEER-Medicare data. We followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline for cohort studies.
We attributed patients to practices based on outpatient evaluation and management (E&M) claims with a cancer diagnosis in the 6 months after diagnosis (eTables 2 through 7 in eAppendixes 2 through 5 in the Supplement). We attributed patients to the practice with the most E&M visits and to medical oncology, surgery, or radiation oncology practices. We also assessed whether inclusion of inpatient E&M claims improved attribution rates. Finally, we described the proportion of patients who visited more than 1 practice of each type. This analysis was performed between August 1, 2019, and November 30, 2020. No statistical testing was conducted for this descriptive study.
Results
The 301 327 patients with newly diagnosed lung, breast, colorectal, or prostate cancer had a mean (SD) age of 75.1 (7.3) years, 149 485 (49.6%) were male, and 241 232 (80.0%) were White patients (Table 1). Only 77.9% of patients with colorectal cancer and 74.1% of patients with lung cancer were attributed to a practice based on outpatient E&M visits (Table 2). These numbers increased to 90.4% and 87.6%, respectively, when inpatient E&M claims were included. Most patients with breast cancer (73.2%), colorectal cancer (61.6%), and lung cancer (65.3%) had visits with a medical oncologist, but only 11.3% of patients with prostate cancer did.
Table 1. Characteristics of the Study Population of 301 327 Patients.
| Characteristic | No. (%)a |
|---|---|
| Age, mean (SD), y | 75.1 (7.3) |
| Cancer type | |
| Breast | 78 736 (26.1) |
| Colorectal | 51 385 (17.0) |
| Lung | 95 635 (31.9) |
| Prostate | 75 571 (25.0) |
| Sex | |
| Male | 149 485 (49.6) |
| Female | 151 842 (50.4) |
| Race/ethnicity | |
| White | 241 232 (80.0) |
| Black | 26 650 (8.8) |
| Hispanic | 15 991 (5.3) |
| Asian/Pacific Islander | 13 537 (4.5) |
| Otherb | 3917 (1.3) |
| Marital status | |
| Married | 155 337 (52.0) |
| Single/divorced/separated/widowed | 122 485 (40.6) |
| Unknown | 23 505 (7.8) |
| Year of diagnosis | |
| 2011 | 64 185 (21.3) |
| 2012 | 61 478 (20.4) |
| 2013 | 59 317 (19.7) |
| 2014 | 57 960 (19.2) |
| 2015 | 58 387 (19.4) |
| Charlson Comorbidity Index | |
| 0 | 116 382 (38.6) |
| 1 | 73 049 (24.4) |
| 2 | 43 857 (14.2) |
| ≥3 | 68 039 (22.6) |
| SEER registry sites | |
| San Francisco-Oakland/San Jose-Monterey | 17 804 (5.9) |
| Connecticut | 16 249 (5.4) |
| Detroit | 18 429 (6.1) |
| Hawaii | 3181 (1.0) |
| Iowa | 17 778 (5.9) |
| New Mexico | 5877 (2.0) |
| Seattle-Puget Sound | 18 135 (6.0) |
| Utah | 5710 (1.9 |
| Los Angeles | 17 340 (5.8) |
| Greater California | 55 755 (18.5) |
| Kentucky | 23 668 (7.9) |
| Louisiana | 19 974 (6.7) |
| New Jersey | 45 134 (15.0) |
| Georgia | 36 293 (12.0) |
| Cancer-directed surgery within 6 mo | |
| No | 165 129 (54.8) |
| Yes | 136 198 (45.2) |
| Chemotherapy within 6 mo | |
| No | 180 885 (60.0) |
| Yes | 120 442 (40.0) |
| Radiation within 6 mo | |
| No | 222 558 (73.8) |
| Yes | 78 769 (26.2) |
Percentages may not total 100 because of rounding.
Other racial/ethnic groups include 1119 American Indian/Alaska Native patients and 2798 patients with unknown race/ethnicity.
Table 2. Attribution of Patients With Newly Diagnosed Cancer to Medical Oncology, Surgery, and Radiation Oncology Practices.
| Practice assignment | Type of cancer, No. (%) or No./total No. (%)a | |||
|---|---|---|---|---|
| Breast (n = 78 736) | Colorectal (n = 51 385) | Lung (n = 95 635) | Prostate (n = 75 571) | |
| Proportion of patients attributed to practices based on visits in the 6 mo after diagnosis | ||||
| Assigned to any practice type | ||||
| Based on outpatient visits | 72 291 (91.8) | 40 054 (77.9) | 70 854 (74.1) | 67 390 (89.2) |
| Based on outpatient and inpatient visits | 73 258 (93.0) | 46 439 (90.4) | 83 797 (87.6) | 68 201 (90.2) |
| Based on outpatient visits, stratified by cancer stage | ||||
| Stage I | 33 036/33 942 (97.3) | 9384/12 225 (76.8) | 19 129/23 132 (82.7) | 399/681 (58.6) |
| Stage II | 19 684/20 440 (96.3) | 11 734/14 316 (82.0) | 3478/3996 (87.0) | 51 946/57 896 (89.7) |
| Stage III | 5448/5698 (95.6) | 11 011/12 810 (86.0) | 17 128/22 326 (76.7) | 4840/5122 (94.5) |
| Stage IV | 3304/4138 (79.8) | 7212/10 482 (68.8) | 29 033/42 541 (68.2) | 6975/8288 (84.2) |
| Assigned to any medical oncology practiceb | ||||
| Based on outpatient visits | 56 884 (72.2) | 27 857 (54.2) | 53 635 (56.1) | 8010 (10.6) |
| Based on outpatient and inpatient visits | 57 631 (73.2) | 31 647 (61.6) | 62 458 (65.3) | 8548 (11.3) |
| Based on outpatient visits by cancer stage | ||||
| Stage I | 27 453/33 942 (80.9) | 4163/12 225 (34.1) | 10 468/23 132 (45.3) | 8/681 (1.2) |
| Stage II | 16 888/20 440 (82.6) | 7969/14 316 (55.7) | 2870/3996 (71.8) | 3658/57 896 (6.3) |
| Stage III | 4817/5698 (84.5) | 9238/12 810 (72.1) | 14 361/22 326 (64.3) | 491/5122 (9.6) |
| Stage IV | 2939/4138 (71.0) | 6114/10 482 (58.3) | 24 651/42 541 (57.9) | 3640/8288 (43.9) |
| Assigned to any surgical practice | ||||
| Based on surgery claim | 65 849 (83.6) | 36 733 (71.5) | 16 939 (17.7) | 13 974 (18.5) |
| Based on surgery claim or visit to a surgeon | 73 599 (93.5) | 42 993 (83.7) | 35 527 (37.1) | 67 722 (89.6) |
| Stratified by cancer stage | ||||
| Stage I | 23 928/33 942 (97.0) | 10 375/12 225 (84.9) | 15 296/23 132 (66.1) | 552/681 (81.1) |
| Stage II | 19 482/20 440 (95.3) | 13 497/14 316 (94.3) | 2550/3996 (63.8) | 52 803/57 896 (91.2) |
| Stage III | 5301/5698 (93.0) | 12 051/12 810 (94.1) | 7818/22 326 (35.0) | 4846/5122 (94.6) |
| Stage IV | 2208/4138 (53.4) | 6166/10 482 (58.8) | 8506/42 541 (20.0) | 6200/8288 (74.8) |
| Assigned to any radiation oncology practice | ||||
| Based on radiation claim | 9432 (12.0) | 1647 (3.2) | 8404 (8.8) | 11 503 (15.2) |
| Based on radiation claim or visit to a radiation oncologist | 42 221 (53.6) | 6083 (11.8) | 34 086 (35.6) | 34 208 (45.3) |
| Stratified by cancer stage | ||||
| Stage I | 21 647/33 942 (63.8) | 1108/12 225 (9.1) | 7998/23 132 (34.6) | 32/681 (4.7) |
| Stage II | 9769/20 440 (47.8) | 1823/14 316 (12.7) | 1680/3996 (42.0) | 28 480/57 896 (49.2) |
| Stage III | 2250/5698 (39.5) | 2053/12 810 (16.0) | 9771/22 326 (43.8) | 2002/5122 (39.1) |
| Stage IV | 1011/4138 (24.4) | 936/10 482 (8.9) | 13 799/42 541 (32.4) | 2240/8288 (27.0) |
| Proportion of patients with cancer-related visits to >1 practice in the 6 mo after diagnosis | ||||
| Outpatients with visits to >1 practice of any type | 56 223/78 736 (71.4) | 26 084/51 385 (50.8) | 47 774/95 635 (50.0) | 42 812/75 571 (56.7) |
| Outpatients with any visits to medical oncology practiceb | ||||
| Outpatients with visits to >1 medical oncology practice | 4489/56 684 (7.9) | 2285/27 857 (8.2) | 5492/53 635 (10.2) | 599/8010 (7.5) |
| Outpatients with only 1 visit to medical oncology practice | 12 443/56 684 (21.9) | 6467/27 857 (23.2) | 11 181/53 635 (20.8) | 3218/8010 (40.2) |
| Outpatients with surgery visits or surgery | ||||
| Outpatients with surgical visits or surgical procedures from >1 surgery practice | 15 184/73 599 (20.6) | 9540/42 993 (22.2) | 5522/35 527 (15.5) | 15 338/67 722 (22.6) |
| Outpatients with ≥1 radiation oncology visit or radiation | ||||
| Outpatients with visits to or radiation therapy from > l radiation oncology practice | 2313/42 221 (5.5) | 268/6083 (4.4) | 1925/34 086 (5.6) | 3593/34 208 (10.5) |
Percentages may not total 100 because of rounding.
A visit to a medical oncology practice was defined as a claim with a specialty code of medical oncology, hematology/oncology, hematology, or gynecologic oncology.
Attribution based on all cancer-related visits and medical oncology visits varied by cancer type and stage (Table 2). For example, only 34.1% of patients with stage I colorectal cancer had a medical oncology visit within 6 months of diagnosis vs 72.1% of those with stage III cancers. Most patients had cancer-related outpatient visits to multiple practices. For example, 71.4% of patients with breast cancer, 50.8% with colorectal cancer, 50.0% with lung cancer, and 56.7% with prostate cancer had visits to multiple practices (Table 2). Across cancer types, 7.5% to 10.2% of patients had outpatient visits with more than 1 medical oncology practice.
Discussion
Our analysis reveals the challenges of attribution of patients with newly diagnosed cancer that should be addressed for accurate quality measurement and emerging value-based payments in oncology.5,6 First, many patients with newly diagnosed lung or colorectal cancer were not attributed to a practice based on outpatient E&M claims alone. Efforts seeking to characterize practice-level quality for patients who may receive only inpatient care (eg, early-stage colon cancer, metastatic lung cancer) should include inpatient E&M or procedure claims.
Second, attribution varied substantially by cancer type and stage, underscoring the importance of considering the clinical context of the care being delivered. For instance, approximately a quarter to a third of patients with breast, colorectal, and lung cancers and 88% of patients with prostate cancer had no medical oncologist visits. These patterns are consistent with medical indications (ie, many patients with early-stage disease do not require chemotherapy) and clinical norms (eg, patients with prostate cancer are primarily treated by urologists). Attribution algorithms ideally would consider cancer stage and tumor characteristics. Unfortunately, such variables are not available in claims data, creating a need to leverage other data sources to collect inputs to attribution algorithms.
Third, many patients have cancer-related visits to multiple practices. The payment methodology and application of quality metrics should be tailored to the type of clinician and type of care delivered by a practice (eg, surgery, systemic therapy, radiation). Some patients have multiple visits to the same type of clinician at different practices (8% to 11% of those who saw a medical oncologist had visits to >1 practice). In such cases, it is challenging to determine the practice accountable for care.
Our study is limited by its focus on traditional Medicare beneficiaries living in SEER areas. The generalizability of our findings to commercially insured populations or individuals in other areas requires further study.
eAppendix 1. Study Population
eTable 1. CONSORT Diagram for Study Population
eAppendix 2. Methods for Identifying Outpatient and Inpatient Visits With Physicians and Attribution to Practices
eTable 2. Diagnosis Codes for Breast, Colorectal, Lung, and Prostate Cancer
eAppendix 3. Attribution to Medical Oncology Practices
eAppendix 4. Attribution to Surgery Practices
eTable 3. Lung Cancer Surgery Codes
eTable 4. Colorectal Cancer Surgery Codes
eTable 5. Breast Cancer Surgery Codes
eTable 6. Prostate Cancer Surgery Codes
eAppendix 5. Attribution to Radiation Oncology Practices
eTable 7. Radiation Delivery Codes
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Associated Data
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Supplementary Materials
eAppendix 1. Study Population
eTable 1. CONSORT Diagram for Study Population
eAppendix 2. Methods for Identifying Outpatient and Inpatient Visits With Physicians and Attribution to Practices
eTable 2. Diagnosis Codes for Breast, Colorectal, Lung, and Prostate Cancer
eAppendix 3. Attribution to Medical Oncology Practices
eAppendix 4. Attribution to Surgery Practices
eTable 3. Lung Cancer Surgery Codes
eTable 4. Colorectal Cancer Surgery Codes
eTable 5. Breast Cancer Surgery Codes
eTable 6. Prostate Cancer Surgery Codes
eAppendix 5. Attribution to Radiation Oncology Practices
eTable 7. Radiation Delivery Codes