The professional seniority affects the clinical application of total neoadjuvant therapy for locally advanced rectal cancer

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Background: Total neoadjuvant therapy (TNT) integrates whole planned systemic chemotherapy within standard neoadjuvant protocols either before or after radiotherapy for locally advanced rectal cancer (LARC). Preference of neoadjuvant treatment type may vary among the medical oncologists. This study aimed to evaluate impact of professional seniority on TNT approach for LARC. Methods: A 20-item questionnaire was presented to medical oncologists as a cross-sectional survey during a national oncology congress via tablets. The evaluation was stratified by position; early-career oncologists (ECOs) and seniors. 2 questions were about experience regarding rectal cancer treatment. 5 questions were about physicians’ choice of screening and treatment in LARC and the factors affecting their treatment choices. 13 questions were about TNT approach (the sequencing of treatment, denominators of sequencing, chemotherapy choice, treatment response evaluation, operation preferences, adjuvant treatment and its denominators). Results: 189 medical oncologists were included (62.4% (n = 118) ECOs). An endorectal ultrasound was significantly preferred by the seniors (p = 0.039) in addition to conventional staging tools. 65.6% (n = 124) of the participants preferred long-course chemoradiation as their favorite neoadjuvant treatment approach. External sphincter invasion, threatened circumferential resection margin (CRM) and clinical stage were the most common denominators of TNT regardless of experience. ECOs favored short-course RT (p = 0.009) while the seniors chose long-course chemoradiotherapy (p = 0.041) as the index step of TNT. 57% (n = 108) of the physicians preferred to monitor treatment response for TNT at 8-weeks periods. Almost half of the participants (47.1%) reported pathological complete response (pCR) rates between 25-50% with TNT in their clinical practice. The physicians who prefer to give adjuvant treatment after completion of TNT make individualized decisions when surgical pathology reveals non-pCR, CRM and lymph node involvement. There was a significant difference between the ECOs and seniors (63.6 vs 45.1%, p = 0.013) in terms of choosing the adjuvant chemotherapy based on CRM positivity. Majority of the senior medical oncologists (88%) and ECOs (76.3%) agree that TNT should be the standardized neoadjuvant treatment approach for LARC. The preferred adjuvant chemotherapy after TNT was capecitabine-oxaliplatin (51.1%) or capecitabine alone (46%). Conclusions: TNT for LARC is well accepted among the medical oncologists and the professional seniority seems to affect its clinical application.

The prognostic impact of intramural invasion in patients undergoing surgery for non-metastatic colon cancer

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Background: The invasion of extramural veins is an independent predictor of poor outcome in colorectal cancer whereas the significance of intramural component of venous as well as lymphatic and perineural invasion is less clear. We aimed to search the prognostic impact of these invasion patterns and their association with various clinicopathological variables. Methods: All patients undergone surgery for colon cancer between December 2014 and December 2020 were analyzed retrospectively and patients with stage II and III disease were enrolled. The patients were divided into four categories as no invasion, intramural invasion only, extramural invasion only or both (intramural and extramural) for vascular invasion (VI), lymphatic invasion (LI) and perineural invasion (PNI). 5-year disease-free (DFS) and overall-survival (OS) were the primary outcomes. Results: 626 patients were included (47.1% stage II patients). There was no significant difference between the presence of ‘intramural only’ venous (DFS, 87.2 vs 88.4% p = 0.84; OS, 88.3 vs 90.7% p = 0.90), lymphatic (DFS, 89.5 vs 85.1%, p = 0.13; OS, 89.5 vs 89.4%, p = 0.9) and perineural invasion (DFS, 89.1 vs 80.9%, p = 0.26; OS, 90.6 vs 84.8%, p = 0.12) compared to ‘no invasion’ in terms of DFS and OS. Invasion of both intramural and extramural compartments for each of these parameters demonstrated poor survival. Presence of exclusively extramural venous and perineural invasion without intramural invasion had adverse effect on DFS (87.2 vs 78.7%, p = 0.036, 89.1 vs 80.9%, p = 0.044, respectively) but not OS (88.3 vs 89.3%, p = 0.78, 90.6 vs 83.8%, p = 0.215, respectively). Tumor sidedness did not have impact on the depth and rate of lymphatic invasion however right-sided and dMMR tumors exhibited less venous and perineural invasion (24.7 vs 33.9% p = 0.007; 34.5 vs 41.5% p = 0.034 and 13.5 vs 33.5% p < 0.001; 25 vs 41.4% p = 0.004, respectively). The ratio of stage III patients with venous, lymphatic and perineural invasion was consistently higher when compared with stage II patients (for LI 69.8 vs 39.7% vs p < 0.001; for VI 36.9 vs 22.7% p < 0.001; for PNI 51.4 vs 24.4% p < 0.001). Low grade tumors exhibited less LI and PNI when compared with high grade tumors (for LI 53.2 vs. 71.3% p = 0.004, for PNI 37.1 vs. 48.3% p = 0.031) however there was no significant difference for venous invasion rates among two groups. Conclusions: Presence of merely intramural component of invasion may not be considered a synonym for lymphovascular invasion which is supposed to be a high-risk factor for systemic recurrence.

Efficacy of regorafenib and 5-fluorouracil-based rechallenge treatment in the third-line treatment of metastatic colorectal cancer: A Turkish oncology group study

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Background: The optimal treatment for metastatic colorectal cancer (mCRC) after the second line is still controversial. Regorafenib (Reg) revealed promising results by improving overall survival compared to best supportive care. However, in real-world practice rechallenge chemotherapy (CTr) is often preferred even though supporting evidence is not enough. We aim to compare the efficacy of regorafenib and 5-fluorouracil-based (5-FU) rechallenge treatment in the third line setting of mCRC. Methods: In this retrospective multi-institutional trial, mCRC patients from 21 centers in Turkey progressing after 2 lines of chemotherapy between 2012-2020 were analyzed. Patients who were treated with Reg or rechallenge therapy in the third-line setting were eligible. Rechallenge chemotherapy was identified as the re-use of the 5-FU based regimen which was administered in one of the previous treatment lines. Overall survival (OS), objective response rate (ORR), progression free survival (PFS) and toxicity were analyzed. Chi-square, Kaplan-Meier method and Cox regression analysis were used for analysis. Results: The clinical data of 441 mCRC patients were analyzed. Of these, 284 received regorafenib while 156 received rechallenge chemotherapy. The mean age was 57 and 56% was male. Median OS since the diagnosis was better with CTr than with Reg (48 months (95% CI, 43.4–52.6) vs. 39 months (95% CI, 35.4–42.5), p<0.001). Median OS after the third-line treatment was 12.0 (95% CI, 9.9–14) and 9.0 months (95% CI, 7.5–10.4) for CTr and Reg groups, respectively (p<0.001). PFS was 6 months for patients receiving CTr and 4 months for those treated with Reg (p = 0.139). ORR was significantly higher in CTr group than Reg (p<0.001). BRAF status, MSI status and treatment type (CTr vs. Reg) are factors found associated with OS in Cox regression analysis (p<0.001, p=0.021 and p<0.001, respectively). Adverse effects were seen in 82% and 68.2% of patients receiving Reg and CTr, respectively. Discontinuation of treatment due to adverse effects was higher in patients treated with Reg (10% vs. 2.5%). Conclusions: Our analysis revealed that rechallenge is an appreciated option, in both efficacy and toxicity, when the limited treatment options for mCRC is considered. Although regorafenib treatment contributes to survival, CTr shows better disease control. Our study has the highest number of patients in the literature. Still, prospective studies are mandatory for validation of CTr in the third-line treatment of mCRC.