Colorectal cancer (CRC) is one of the most common malignant tumors, with more than 1.8 million new cases and more than 900000 fatal cases every year, and its morbidity and mortality rank third and second in the world respectively[5, 6]. COVID-19 pandemic poses a potential risk to cancer patients, that is, delayed diagnosis and treatment may lead to disease progression and survival shortening[7]. As the epidemic situation has been effectively controlled in most parts of China, the normal diagnosis and treatment order of colorectal cancer is gradually restored. It is very important to sum up the experience during the epidemic and to better carry out clinical work in the situation of regular epidemic prevention and control.
During the severe epidemic of COVID-19, the number of non-local patients coming to the hospital decreased due to the adoption of traffic restrictions and the strategy of reducing personnel mobility. On behalf of Group of Colorectal Surgery, Society of Surgery, Chinese Medical association, our team drafted and published a Chinese expert consensus on surgical diagnosis and treatment strategies for CRC patients during COVID-19 epidemic[8]. The flow chart of diagnosis and treatment of CRC during COVID-19 is shown in Fig. 1.
We emphasize the importance of multidisciplinary team (MDT) meetings in the formulation of diagnosis and treatment strategies for colorectal cancer patients (screening for COVID-19 infection was negative) during the epidemic. MDT can effectively integrate the advantages of multiple disciplines, more reasonable pre-treatment evaluation of patients, and strive to ensure that patients get effective treatment[9, 10], under the premise of minimizing the risk of COVID-19 infection during treatment.
During the COVID-19 epidemic, CRC patients inevitably have difficulties in hospitalization and delayed operation[11, 12]. We suggest that Neo-CRT should be given priority according to patients’ condition, and radical surgery should be performed when epidemic remission. Both National Comprehensive Cancer Network (NCCN) and European Society for Medical Oncology (ESMO) guidelines recommend Neo-CRT, surgery and adjuvant chemotherapy as the gold standard treatment for locally advanced rectal cancer[13, 14]. The implementation of Neo-CRT can significantly benefit patients with locally advanced rectal cancer in reducing the local recurrence rate and improving the rate of sphincter preservation[15, 16]. 15% of rectal cancer patients who underwent radical surgery after Neo-CRT could achieve complete remission of tumor pathology, that is, there was no tumor residue in the surgical specimens, and this part of the patients had a good prognosis[17]. According to Consensus on the Watch and Wait policy in rectal cancer patients after neoadjuvant treatment in China (2020 version), patients who are judged to be clinically complete remission or near clinical complete remission after Neo-CRT can directly enter the follow-up process of waiting and watch (W&W)[18]. According to the actual situation during the epidemic period of COVID-19, patients can choose to adopt the non-operative treatment strategy of W&W. Although neoadjuvant chemotherapy for patients with colon cancer is still in the exploratory stage, it is considered to have the advantages of reducing the primary tumor, killing micrometastases as soon as possible, reducing iatrogenic dissemination, increasing local drug concentration, and being conducive to the choice of postoperative chemotherapeutic drugs. the early results of previous studies have shown that the effective rate of neoadjuvant chemotherapy for colon cancer is good, the clinical remission rate and pathological remission rate are 68%, and no patient has disease progression[19].
A multicenter cross-sectional study in China showed that 7.2%(83/1 147)of CRC patients’ surgery were affected by COVID-19 outbreak, and 3.4% of patients underwent emergency surgery because of colorectal cancer complications[20]. In order to deal with the influence of COVID-19, China[8], Italy[21] and France[22] have all made some changes to the surgical treatment strategies of CRC. The principle of endoscopic treatment or radical surgery for patients with early CRC (cT1N0) and some locally advanced CRC (cT2-3N0) remains basically unchanged, but can be appropriately delayed; for patients with locally advanced CRC (cT 4) and patients with distant metastasis who can be resected by radical resection, elective surgery is performed after Neo-CRT; short-term neoadjuvant radiotherapy is recommended for rectal cancer (cT3-4N+). Emergency surgery should be considered for CRC patients with primary tumor bleeding (endoscopic or interventional therapy is ineffective), perforation and obstruction.
Based on the above treatment strategies for CRC, in our study, we can found that patients who received surgical treatment during the severe epidemic period are mainly in stage Ⅰ and Ⅱ. More stage Ⅲ patients underwent surgery in the period of remission. But for these stage Ⅲ patients who choose to postpone surgical treatment, their long-term survival still needs follow-up observation. In our study, we found a special phenomenon that a higher proportion of patients had vascular and perineural invasion in SEG, this may be related to a higher proportion of patients in ECG had received preoperative Neo-CRT. In some CRC patients Neo-CRT can delay local tumor progression or even local regression[23, 24]. At the same time, in our study, the proportion of postoperative complications in SEG was higher, and most of these patients received preoperative Neo-CRT (5/6). Previous studies had suggested that preoperative Neo-CRT may lead to the incidence of postoperative complications increasing[25, 26]. Therefore, when considering the benefits of Neo-CRT during COVID-19 epidemic, attention should also be paid to the increased risk of postoperative complications.
This study only included patients undergoing CRC surgery in a single center in Beijing, China. In view of the current epidemic of COVID-19 in the world, the public health resources, populace obedience and some aspects vary in different regions, for which some of our recommendations might be impractical to imitate. In addition, the sample size is limited, so the results of this study still need to be verified by multicenter and larger sample size studies. Furthermore, the data analysis of this study is lack of subgroup analysis, and the related results may have potential confounding factors.