In 1982, Heald et al. [7] proposed that TME reduces the local recurrence rate of rectal cancer to approximately 10%. However, this idea was not accepted by most surgical professionals worldwide until the end of the 20th century, when it became the gold standard for the treatment of middle and lower rectal cancer. Subsequent studies such as CAO/ARO/AIO-94 [8, 9]CKVO9504 [10]and MRCCR07 [11]showed that preoperative neoadjuvant radiotherapy and chemotherapy further reduced the local recurrence rate in LARC after radical resection to approximately 5%. Since then, preoperative neoadjuvant radiotherapy combined with TME has become the standard treatment regimen for intermediate- and low-grade LARC. Although local recurrence rates are reduced by approximately 5%, preoperative radiotherapy does not improve overall survival (OS).Given the fact that long-term adverse reactions caused by radiotherapy severely impact the patient’s quality of life by impairing anal, urinary, and sexual functions, the damage increases over time. and potentially increase the risk of developing secondary tumors [12, 13]some scholars have attempted to exclude radiation therapy from the perioperative treatment of LARC.
Chinese FOWARC study [14] was the first phase III clinical randomized controlled trial to introduce preoperative neoadjuvant chemotherapy into the neoadjuvant regimen for the treatment of rectal cancer. Results show no significant difference in disease-free survival (DFS) and local recurrence rates between radiotherapy-free perioperative mFOLFOX6 chemotherapy regimens and standard fluorouracil-based neoadjuvant radiotherapy and chemotherapy showed. His 3-year local recurrence rates in the two groups were 8.3% and 8.0%, respectively. The aforementioned study speculated that mFOLFOX6 chemotherapy could be used as an initial regimen for neoadjuvant therapy in his LARC, and radiation therapy could be used as an selective supplement based on chemotherapy efficacy. increase.US PROSPECT study [15] Since this was a controlled study aimed at comparing neoadjuvant therapy using a simple mFOLFOX6 regimen with standard neoadjuvant radiotherapy and chemotherapy, it is the most promising candidate for neoadjuvant chemotherapy for rectal cancer. It was research. The results of the aforementioned studies will have a decisive impact on the status of radiotherapy in the perioperative treatment of LARC and whether comprehensive treatment of LARC enters the era of neoadjuvant chemotherapy. The results of the FOWARC study pose significant challenges to the use of perioperative radiotherapy for LARC.
In a retrospective study, the 10-year local control and recurrence-free survival rates for pT3N0M0 rectal cancer with favorable prognostic pathologic features were 95% and 87%, respectively, whereas the prognostic pathologic features were The 10-year local control and recurrence-free survival rates were found to be 71% and 55% for patients without %, Each.This study suggests that adjuvant therapy offers little benefit for favorable prognosis pT3N0M0 rectal cancer [16]Based on the aforementioned studies, the NCCN Guidelines recommend observation of patients with pT3N0M0 rectal cancer with a favorable prognosis, but not for patients with postoperative pathology confirmed as pT3-4 or N1-2 tumors. , routine postoperative adjuvant radiotherapy and chemotherapy are recommended.
Our results suggest that, in the era of relatively well-established TME treatment (2004–2016), adjuvant chemotherapy efficacy-based radiotherapy provides tumor-specific shown to not improve survival). The same results were obtained after matching baseline clinical data through propensity score balancing to eliminate bias. In a real study, these results suggest that postoperative adjuvant radiotherapy in combination with TME, an effective treatment for patients with pT1/pT2, pT3, and pN1 rectal cancer, improves prognosis in pT1-3N1M0 rectal cancer. suggesting no significant improvement. As recommended by the European Society for Medical Oncology (ESMO), postoperative chemoradiation is ineffective and unnecessary if a good, smooth, intact mid-rectum is present after TME. [17].
However, not all patients with pT1-3N1M0 rectal cancer benefit from postoperative radiotherapy. A subgroup analysis of the present study showed that there were 3 positive lymph nodes and a tumor size >50 mm, which, when combined with adjuvant chemotherapy, may improve tumor-specific survival, whereas other patients It was shown that they may not benefit from postoperative radiotherapy. Therefore, postoperative chemoradiotherapy (CRT) is suitable only for some of her LARC patients with poor selective prognosis, and screening these patients is key. As an international pioneer in personalized treatment for rectal cancer, the 2017 edition of his ESMO guidelines for rectal cancer states that preoperatively untreated LARC should have his You point out that daily use of a CRT is not necessary. Postoperative CRT may be selectively used in patients with poor histopathological features after primary surgery.
ESMO guidelines specify four recommendations for adjuvant radiotherapy and chemotherapy. ① Sufficient and Necessary – Circumferential resection margin (CRM) ≤ 1 mm, pT4b or pN2, extracapsular extension (MRF) near mesorectal fascia (MRF), extranodular deposition (N1c), or mesorectal quality /pN2 if the defect is bad. ② Adequate- pN2 tumor reduction within 4 cm of the anal verge (risk of lateral pelvic lymph node involvement) or extensive extramural vascular or perineural invasion close to MRF. ③ Adequate borderline—pN2 in the middle or upper rectum, CRM 1–2 mm, or surrounding obstructive tumor with good mesorectal tissue quality.and ④ Inadequate and unnecessary — if pT1/pT2, pT3, CRM > 2 mm, pT4a outweighs reflex, or pN1 with good, smooth, intact mesorectal ligament.
Recommendations based on ESMO guidelines are largely based on the MERCURY study. In this study, a patient with a favorable prognosis based on high-resolution magnetic resonance imaging (MRI) was treated with her TME alone and no adjuvant radiotherapy before or after surgery. A total of 374 patients were enrolled in the study, of whom 122 (33%) had a 5-year local recurrence rate of 3% his.In subgroup analyses, MRI (mesorectal invasion, regardless of N stage) < 5 mm) によって評価された、予後良好なステージ T3 直腸癌の局所再発率はわずか 1.7% であることが示されました。 [5]. MERCURY 研究の結果は、放射線療法は T3a または T3bN 直腸癌には価値がない可能性が高いことを示唆しています。 テイラー等。 [6] は、MERCURY研究に含まれるすべての症例の5年間の追跡結果を次のように報告しました。高解像度MRIに基づいて、すべての症例はMRIクリアCRMグループとMRI関連CRMグループに分けられました。 予測された明らかな mrCRM は、腫瘍から MRF までの距離 > was defined as 1 mm, but for third tumors in the lower rectum, mrCRM involvement was defined as tumors ≤1 mm from the levator muscle. If the tumor was present at or below the level of the puborectal sling, involvement of mrCRM was predicted if there was invasion at or beyond the sphincteric interface. A total of 205 patients in the MRI clear CRM group received TME without postoperative radiotherapy, and 58% of patients were treated with adjuvant chemotherapy. Of these patients, pathologic peripheral resection margins (pCRM) were negative in 190, and local recurrence occurred in 11 during the follow-up period. pCRM was positive in 15 of his cases, and local recurrence occurred in 3 of these his cases during follow-up. The overall local recurrence rate was 6.8%, while the 190 CRM-negative patients had a local recurrence rate of only 5.8%. In the MERCURY study, TME quality was tightly controlled, and his recommendations based on the aforementioned ESMO guidelines depend heavily on surgical quality. Therefore, surgical quality is an important factor in deciding whether to use radiation therapy. For her LARC patient not receiving preoperative neoadjuvant therapy, routine postoperative CRT is only selected for patients with poor histopathologic features after initial surgery if her TME of high quality can be guaranteed. should be used effectively. In the ESMO guidelines, adverse histopathologic features include CRM ≤ 1 mm, pT4b, pN2, extracapsular extension near the MRF, extranodal deposits (N1c), mesorectal quality/defect when It has been shown to contain pN2, and extensive extramural vascular or perineural infiltration close to the MRF. Based on the results of this study, the presence of 3 positive lymph nodes and a tumor size >50 mm should be considered poor histopathological features and a sufficient condition for the use of postoperative radiotherapy. is showing. The results of this study are applicable to patients whose preoperative staging was underestimated and who did not receive preoperative neoadjuvant radiotherapy or chemotherapy. Preoperative neoadjuvant radiotherapy and chemotherapy are the first treatment options for his newly diagnosed LARC, including complete neoadjuvant therapy (TNT).
This study has some limitations. This study has a selection bias as some patients may not have received neoadjuvant treatment or postoperative adjuvant radiotherapy due to comorbidities. As this study was retrospective in nature, the details of surgery and the quality of postoperative rectal specimens are unknown. Although this study reflects real-world data, it spanned 12 years, during which surgical techniques and adjuvant chemotherapy regimens may have changed. Therefore, potential offsets may exist. In the post-TME era, a multicenter phase III clinical trial of adjuvant radiotherapy for rectal cancer is still needed to confirm our findings.
