1. Combination of radiotherapy and chemotherapy for cervical cancer: In the United States, five prospective studies have shown that the efficacy of radiotherapy in combination with chemotherapy for cervical cancer is better than that of radiotherapy alone. When chemotherapy was added, the five-year survival rate could reach 73%, so they concluded that the addition of chemotherapy to radiotherapy for locally advanced cervical cancer significantly improved the prognosis. The same results were also obtained in three other studies.
A total of 118 patients were treated with concurrent radiotherapy from 1998 to 2003. These patients were all between stage IB-IIIB and were treated weekly with cisplatin 40 mg to 60 mg per week. The overall survival rate in five years was 75.6%, then the disease-free survival rate was 62.3%, and the local control rate could reach 85.6%.
2.Post-operative radiotherapy for cervical cancer: Patients with the following high-risk factors need post-operative radiotherapy for cervical cancer.
(1) Positive pelvic lymph nodes;
(2)The edge of the severed end is less than 3mm from the lesion;
(3) deep muscle infiltration;
(4) Vascular lymphoma embolism;
(5) poor tissue differentiation.
In the GOG study, the mortality and recurrence rates of postoperative patients treated with radiotherapy were significantly lower than those of postoperative patients who did not receive any radiotherapy. This led to the following conclusions: for stage 1b-2a cervical cancer post-radical surgery pelvic radiotherapy significantly reduces the risk of recurrence, and for adenocarcinoma and adenosquamous carcinoma patients can enjoy the benefits of radiotherapy more significantly.
Postoperative radiotherapy for cervical cancer requires special attention to.
(1) Avoid excessive doses of radiation to the small intestine, bladder and sigmoid colon locations;
(2) General external pelvic irradiation of 50Gy, when adding internal irradiation, pay attention to the protection of the rectum;
(3) Internal irradiation with separate vaginal applicator, 5-7Gy at 5-10mm, 2-3 times in total
3. External irradiation for cervical cancer.
The effects of external irradiation.
(1)shrink cervical tumor and reduce bleeding and other symptoms;
(2) Improving the anatomical changes in the cervical area caused by tumor infiltration, so that internal irradiation can be easily performed;
(3) enable the high dose area of internal irradiation to include the tumor volume;
(4) External irradiation gives a higher dose to the parametrium and lymphatic drainage area.
4. Intensity-modulated radiation therapy for cervical cancer
Intensity-modulated radiation therapy is the most advanced technology in radiation therapy, which can better protect normal tissues, improve the quality of life, and reduce the incidence of radiation cystitis and proctitis. Intensification radiation therapy is currently used a lot in China and abroad, especially in the United States; why should cervical cancer be treated with intensity modulation? The target area of radiation therapy for cervical cancer includes the uterus (vaginal stump after surgery) and part of the vagina; it also includes the regional lymph nodes: paracervical, parametrial, internal and external iliac, and sometimes presacral, and the lower group of para-aortic.
With routine irradiation up to 45-50 Gy, patients experience grade III-IV complications with an incidence of 4-15%. Long-term chronic diarrhea develops in 40% of patients after radiation therapy. Another 2%-8% of patients will have serious bladder complications about one year after radiation therapy, such as blood in urine, urinary frequency, urinary urgency, etc.
Intensity-modulated radiation therapy, which has the following advantages.
(1) Reduce the volume of irradiation to the small intestine, rectum and bladder, and reduce acute reactions Mondt et al. reported 32 patients with gynecologic tumors treated with pelvic intensity-modulated radiotherapy (IM-WPRT), 97.9% of PTV were given 45 Gy of irradiation, and 80% of acute reactions required medication or interruption of radiation under conventional irradiation, while only 32% of patients with IM-WPRT had acute reactions requiring medication. (2) It can reduce the bone and bone loss.
(2) It can reduce the irradiated volume and dose of bone marrow, which can reduce the acute reaction of hematopoietic system Lujan et al. reported the results of IM-WPRT in 10 patients, 10 patients had both conventional radiotherapy and intensity-modulated radiotherapy plans, and compared the irradiated volume of bone marrow at different dose levels of 45Gy, 40.5Gy, 31.5Gy and 22.5Gy. The results showed that the irradiated volume of bone marrow was 33%, 42.5%, 52.8%, and 87% for conventional radiotherapy and 4.5%, 12.1%, 25.9%, and 43.7% for intensity-modulated radiotherapy, respectively. This shows that intensity-modulated radiotherapy can significantly reduce the irradiated volume of bone marrow, which plays a pivotal role in maintaining stable blood picture in combination with radiotherapy and chemotherapy for cervical cancer.
(3) Giving local top-up dose simultaneously with intensity-modulated radiotherapy can bring good biological dose ratio Guerrero et al. applied IMRT top-up dose simultaneously with conventional external irradiation for locally advanced cervical cancer, and the tumor dose of SIB plan 25X3.1Gy (77.5Gy) of IMRT was equivalent to conventional pelvic 45Gy external irradiation plus 30Gy/5F brachytherapy with normal The low tissue dose indicates that SIB with IMRT has a better treatment ratio and a shorter treatment time (5 weeks).
5.Intracavitary radiotherapy for cervical cancer
Intracavitary radiotherapy is the application of post-mounting technology to implant the source device into the tumor site in the cavity and use radiation to kill the tumor cells directly. It is a practical and effective treatment for patients who are unwilling or unable to undergo surgery. For gynecologic tumors, especially cervical cancer, intracavitary radiation therapy is one of the main radiation treatment methods.