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SURGEON-LEVEL VARIATION IN UTILIZATION OF NEOADJUVANT THERAPY FOR LOCALLY ADVANCED RECTAL ADENOCARCINOMA
Douglas S. Swords*2,1, David E. Skarda2,1, William T. Sause3, Ute Gawlick2, George M. Cannon3, Mark A. Lewis3, Jesse Gygi3, H T. Kim2
1Surgery, University of Utah, Salt Lake City, UT; 2Surgical Services Clinical Program, Intermountain Healthcare, Salt Lake City, UT; 3Oncology Services Clinical Program, Intermountain Healthcare, Salt Lake City, UT
Background: Neoadjuvant therapy for clinical stage II-III rectal adenocarcinoma has been standard of care for over a decade, and delivery of preoperative chemoradiation to such patients is a Commission on Cancer quality metric. National Cancer Database studies have shown that only 75% of appropriate patients receive neoadjuvant therapy, but the determinants of this failure to deliver evidence-based therapy remain largely unknown. We aimed to determine the underlying reasons for omission of neoadjuvant therapy using granular clinical data from a 22-hospital system.
Methods: This is a retrospective study of patients with clinical or pathologic stage II-III rectal adenocarcinoma treated with initial curative intent from 2010-2016 in an Intermountain Healthcare hospital. Patients who were stage I by endoscopic ultrasound or MRI who were upstaged to pathologic stage II-III at surgery were excluded (N=12). Covariates with a univariate P<0.2 were included in a multivariable logistic regression model for predictors of omission of neoadjuvant therapy. Risk ratios and adjusted risk differences were obtained using marginal standardization. Risk- and reliability-adjusted rates of neoadjuvant therapy were calculated for surgeons who treated ≥3 patients. Rates of positive margins (positive proximal/distal margin or circumferential radial margin ≤ 1 mm) and long-term outcomes were examined after excluding patients who were not resected(N=4) or who underwent local excision(N=6).
Results: There were 240 patients with clinical stage II-III or undocumented clinical stage/pathologic stage II-III rectal cancer who were treated by 36 surgeons at 9 hospitals. Three surgeons treated 122/240 patients (50.8%). Neoadjuvant therapy was omitted in 41/240 (17.1%). Processes of care in which neoadjuvant therapy was omitted and independent predictors of omission of neoadjuvant therapy are shown in the Table. Among 21 surgeons who treated ≥ 3 cases, adjusted rates of neoadjuvant therapy varied 3.5-fold (28% to 97%, Figure A). Rates of positive margins were higher in patients who did not receive neoadjuvant therapy: 8/40 (20.0%) vs. 16/190 (8.4%) (P=0.03, chi-square). Neoadjuvant therapy was associated with lower rates of local recurrences (P=0.0175, log-rank, Figure B) but no differences in rates of distant metastases, disease-specific survival, or overall survival (P>0.26 for all, log-rank, not shown).
Conclusions: The dominant risk factors for omission of neoadjuvant therapy are tumor location in the upper rectum and treatment by a low volume surgeon. Surgeon rates of neoadjuvant therapy varied 3.5-fold, and low volume surgeons utilized neoadjuvant therapy less often. Neoadjuvant therapy was associated with lower rates of positive margins and local recurrences. Initiatives that give low-utilizing surgeons feedback about appropriate utilization of neoadjuvant therapy are warranted.
Processes of Care and Factors Associated with Omission of Neoadjuvant Therapy
|Processes of Care in Patients Where Neoadjuvant Therapy was Omitted (N=41)|
|Process of Care||N (%)|
|Taken directly to surgery without EUS or MRI||19(46.3%)|
|Thought to be sigmoid cancer preoperatively||11 (26.8%)|
|"Urgent" presentation (obstruction, substantial bleeding, or perforation)||4 (9.8%)|
|Upfront surgery even though cT3-T4 and/or cN1 on EUS or MRI||3 (7.3%)|
|Concerns about functional status||2 (4.9%)|
|Synchronous colon cancer||1 (2.4%)|
|Tumor not thought to be an invasive cancer preoperatively||1 (2.4%)|
|Multivariable Analysis of Factors Associated with Omission of Neoadjuvant Therapy|
| ||Risk Ratio|
|Adjusted Absolute Risk Difference |
|Female sex (vs. male)||1.78 (1.11, 2.87)||9.4 (3.1, 15.7)||0.003|
|Cancer history (vs. none)||2.31 (1.26, 4.22)||19.9 (1.7, 38.1)||0.03|
|Location (vs. ≤ 6 cm from anal verge)|| || || |
|6.01-12 cm||1.70 (0.75, 3.86)||6.7 (-4.9, 18.3||0.26|
|> 12 cm||4.35 (2.67, 7.09)||32.1 (20.8, 43.3)||<0.001|
|Urgent presentation||1.86 (0.90, 3.84)||13.9 (-8.6, 36.4)||0.22|
|Colorectal surgeon||0.91 (0.49, 1.66)||-1.6 (-11.6, 8.3)||0.75|
|Surgeon volume (vs. > 3 cases/year)|| || || |
|≤ 3 cases/year||9.45 (2.78, 32.06)||25.1 (14.0, 36.2)||<0.001|
Risk- and reliability adjusted rates of neoadjuvant therapy among surgeons that treated ≥ 3 patients (A) and cummulative probability of local recurrences (B)
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