Assessment of the 2020 NICE criteria for preoperative radiotherapy in patients with rectal cancer treated by surgery alone in comparison with proven MRI prognostic factors: a retrospective cohort study.

BACKGROUND: Selection of patients for preoperative treatment in rectal cancer is controversial. The new 2020 National Institute for Health and Care Excellence (NICE) guidelines, consistent with the National Comprehensive Cancer Network guidelines, recommend preoperative radiotherapy for all patients except for those with radiologically staged T1-T2, N0 tumours. We aimed to assess outcomes in non-irradiated patients with rectal cancer and to stratify results on the basis of NICE criteria, compared with known MRI prognostic factors now omitted by NICE. METHODS: For this retrospective cohort study, we identified patients undergoing primary resectional surgery for rectal cancer, without preoperative radiotherapy, at Basingstoke Hospital (Basingstoke, UK) between Jan 1, 2011, and Dec 31, 2016, and at St Marks Hospital (London, UK) between Jan 1, 2007, and Dec 31, 2017. Patients with MRI-detected extramural venous invasion, MRI-detected tumour deposits, and MRI-detected circumferential resection margin involvement were categorised as MRI high-risk for recurrence (local or distant), and their outcomes (disease-free survival, overall survival, and recurrence) were compared with patients defined as high-risk according to NICE criteria (MRI-detected T3+ or MRI-detected N+ status). Kaplan-Meier and Cox proportional hazards analyses were used to compare the groups. FINDINGS: 378 patients were evaluated, with a median of 66 months (IQR 44-95) of follow up. 22 (6%) of 378 patients had local recurrence and 68 (18%) of 378 patients had distant recurrence. 248 (66%) of 378 were classified as high-risk according to NICE criteria, compared with 121 (32%) of 378 according to MRI criteria. On Kaplan-Meier analysis, NICE high-risk patients had poorer 5-year disease-free survival compared with NICE low-risk patients (76% [95% CI 70-81] vs 87% [80-92]; hazard ratio [HR] 1·91 [95% CI 1·20-3·03]; p=0·0051) but not 5-year overall survival (80% [74-84] vs 88% [81-92]; 1·55 [0·94-2·53]; p=0·077). MRI criteria separated patients into high-risk versus low-risk groups that predicted 5-year disease-free survival (66% [95% CI 57-74] vs 88% [83-91]; HR 3·01 [95% CI 2·02-4·47]; p<0·0001) and 5-year overall survival (71% [62-78] vs 89% [84-92]; 2·59 [1·62-3·88]; p<0·0001). On multivariable analysis, NICE risk assessment was not associated with either disease-free survival or overall survival, whereas MRI criteria predicted disease-free survival (HR 2·74 [95% CI 1·80-4·17]; p<0·0001) and overall survival (HR 2·44 [95% CI 1·51-3·95]; p=0·00027). 139 NICE high-risk patients who were defined as low-risk based on MRI criteria had similar disease-free survival as 118 NICE low-risk patients; therefore, 37% (139 of 378) of patients in this study cohort would have been overtreated with NICE 2020 guidelines. Of the 130 patients defined as low-risk by NICE guidelines, 12 were defined as high-risk on MRI risk stratification and would have potentially been missed for treatment. INTERPRETATION: Compared to previous guidelines, implementation of the 2020 NICE guidelines will result in significantly more patients receiving preoperative radiotherapy. High-quality MRI selects patients with good outcomes (particularly low local recurrence) without radiotherapy, with little margin for improvement. Overuse of radiotherapy could occur with this unselective approach. The high-risk group, with the most chance of benefiting from preoperative radiotherapy, is not well selected on the basis of NICE 2020 criteria and is better identified with proven MRI prognostic factors (extramural venous invasion, tumour deposits, and circumferential resection margin). FUNDING: None.

Advanced Pseudomyxoma Peritonei Requiring Gastrectomy to Achieve Complete Cytoreduction Results in Good Long-Term Oncologic Outcomes.

BACKGROUND: Optimal outcomes in pseudomyxoma peritonei (PMP) require complete macroscopic tumor removal by cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC). Partial or complete gastrectomy may be required with ongoing debate as to the risks and benefits of gastrectomy in what is often a low-grade malignancy. METHODS: Retrospective single-center analysis of 1014 patients undergoing CRS and HIPEC for PMP of appendiceal origin. Complications and survival were compared in patients who had gastrectomy versus the nongastrectomy cohort. RESULTS: Of 1014 patients, 747 (74 %) had CRS and HIPEC with complete cytoreduction. Overall, 86 (12 %) of 747 had partial (n = 80) or total (n = 6) gastrectomy. Median age was 55 years for gastrectomy patients and 56 for nongastrectomy patients (p = 0.591). Preoperative tumor markers [carcinoembryonic antigen, carbohydrate antigen (CA) 125 and CA19-9] were elevated more frequently in the gastrectomy group compared to the nongastrectomy group [81, 61 and 81 % compared to 41 % (p = 0.001), 20 % (p = 0.001) and 39 % (p = 0.001), respectively]. The proportion of high-grade histology was similar in the two groups (gastrectomy 19 % vs. nongastrectomy 18 %, p = 0.882). Postoperative complications (Clavien-Dindo III-IV) were 31 % for the gastrectomy group and 13 % for the nongastrectomy group (p = 0.001). The 30-day postoperative mortality was 3 (0.5 %) of 661 for the nongastrectomy group and 1 (1.2 %) of 86 for the gastrectomy group (p = 0.387). Three- and 5-year overall survival were 96 and 88 % in the nongastrectomy group and 87 and 77 % in the gastrectomy group (p = 0.018). Three- and 5-year disease-free survival were 89 and 77 % in the nongastrectomy group versus 66 and 48 % in the gastrectomy group (p = 0.001). CONCLUSIONS: Gastrectomy is an essential component of complete cytoreduction in advanced PMP and was required in 12 % of patients with good long-term survival.