The role of preoperative radiotherapy rectal cancer, preoperative radiotherapy in rectal cancer treatment has been unanimously affirmed the role, for resectable rectal cancer with preoperative radiotherapy have multiple benefits, including biological aspects (reduction of tumor cells during surgery Preoperative seeding and oxygen due to increased cellular radiosensitivity more), physical (there is a small adhesions after surgery in the pelvic fixation) and functions (which may improve the security of embryo, make changes in abdominal perineal resection is reserved the status of embryos before the door sphincter or colon resection anastomosis in January BBA). Another advantage is unresectable locally advanced or preoperative radiotherapy in patients with resection rate can be increased.
20th century, early 90s, when the North American progress in the postoperative radiotherapy, Europe to begin to assess preoperative radiotherapy. Randomized controlled study in which eight groups, the total number of nearly 4,700 patients, sub preoperative radiotherapy and surgery alone. 7 groups of which confirmed a significant reduction in local recurrence rate, and that there are 3 groups confirmed improved survival. The difference in efficacy may be related to different methods of radiotherapy, and some short-term high-dose, rectal cancer radiotherapy immediately after surgery; some are taking time dose routine program, the interval 2-4 weeks after surgery.
Observed that when the expansion of the pelvic area or beyond the target volume set when only two field before and after pelvic irradiation on the wear will increase the short-term postoperative mortality. Clinical observation and biological predicts that high doses of each field programs and early and late toxicity of radiotherapy, such as intestinal perforation, venous thrombosis and changes in retained sphincter. The conventional external beam radiation therapy program using appropriate technology, 5 days a week, every day 180-200cGy, total 4500-5000cGy/5-6 week preoperative radiotherapy can get better treatment than. Animal model studies and clinical practice show that high-dose conventional radiation therapy before surgery, radiotherapy and long-term side effects of the recent general acceptable and will not increase the difficulty of surgery, and no significant increase in the incidence of postoperative mortality and complications . The main disadvantage of preoperative radiotherapy is the treatment of patients over the early part of. However, the correct preoperative evaluation can be used as the basis for treatment choice. Now preoperative pathological diagnosis can not meet the clinical needs, we need to check with the judge:
Zhichang Zi refers to the examination: an experienced doctor can local infiltration of the tumor and preliminary understanding.
Transrectal endoscopic ultrasound B-scan or rectal examination: Transrectal B-is to determine the depth of tumor invasion rectal examination of the most valuable tool, the correct rate of 90% or more; Zhejiang Cancer Hospital, ultrasound miniature probe preoperative examination of rectal cancer, T1, T2, T3 .. T4 compliance rates were 75%, 80%, 88%, 67% of the total compliance rate was 84%; the regional lymph nodes (N) with a sensitivity of 79 %, a specificity of 91%, 92% positive predictive value, negative predictive value of 77% of the total compliance rate of 84%.
Role in cancer radiotherapy before surgery, pelvic CT scan: its characteristics is advanced rectal cancer to determine depth of invasion of the bowel wall thick, while the scope and extent of violations compared parenteral fine, and the cavity has a complementary role of B-. According to preoperative clinical staging of rectal cancer (in particular, the following 6cm from the edge of the tumor anus) T3 or T4, NO dirty surgery scheduled for protection; rectum 1 / 3 of the tumor and lymph node metastasis, tumor or tumor next to the perforation persons; any location on the N2 ~ N3 rectal cancer, preoperative radiotherapy options have a positive meaning.