Original Oncology News
The choice of surgical option for patients with early-stage breast cancer is influenced by many factors, and several studies have concluded that breast-conserving treatment (mastectomy + radiotherapy) is preferable to total mastectomy.
For patients with stage I or II breast cancer, the choice of surgical option is influenced by many factors. At this year’s SABCS, a large retrospective study showed that breast-conserving treatment may be a better option than total mastectomy.
The study included more than 37,000 women diagnosed between 2000-2004 with 10 years of follow-up, 58.4% of whom were treated with breast-conserving therapy. The results showed that the relative risk of death during follow-up was approximately 20%, with a lower relative risk in the breast-conserving treatment group (HR 0.81, p<0.001). The 10-year overall survival rate was higher in the breast-conserving group than in the total mastectomy group (76.8% vs. 59.7%).
The study further analyzed data from a subgroup of 7552 patients diagnosed in 2003 and similar to overall at baseline to assess 10-year disease-free survival. The results showed that the 10-year disease-free survival rate was better in the breast-conserving treatment group than in the total mastectomy group (83.6% vs. 81.5%). Although the difference was not significant and did not meet the statistical criteria, the data still indicated to some extent that patients in the breast-conserving treatment group had fewer local recurrences and distant metastases. Further analysis revealed that the 10-year distant metastasis-free survival rate of breast-conserving treatment was significantly higher than that of total mastectomy in T1N0 breast cancer patients.
In fact, breast-conserving treatment was recommended by the National Institutes of Health for patients with stage I or II breast cancer as early as 1990, based on several large randomized controlled trials showing similar survival rates after breast-conserving treatment and total mastectomy. However, these trials are 40 years old and need to be confirmed by additional studies.
In January 2013, Cancer reported on a large observational study showing that breast-conserving treatment may be superior to total mastectomy.
The study included 122,000 patients with stage I or II breast cancer. During an average of 9 years of follow-up, 31,416 patients died, 39 percent of them from breast cancer, with a 5-year overall survival rate of 89.3 percent and a 5-year disease-related survival rate of 94.4 percent. Overall survival and disease-related survival rates were better in the breast-conserving treatment group than in the total breast excision group.
The researchers divided the patients into four groups according to their age and hormone receptor levels: the HR- group over 50 years of age, the HR+ group over 50 years of age, the HR- group under 50 years of age, and the HR+ group under 50 years of age. After correcting for many variables (type of surgery, tumor grade, tumor size, lymph node positivity, socioeconomic status, race, etc.), the researchers compared the survival rates of patients in the four groups by Cox multifactorial analysis, which showed that patients in the HR+ group over 50 years of age had the most significant disease-related survival benefit from breast-conserving treatment, with a 14% reduction in breast cancer mortality in this group (HR 0.86, 95% CI 0.82-0.91).
In January 2014, a large observational study was also reported in JAMA, which concluded that patients with early invasive breast cancer had higher disease-related survival rates with breast-conserving treatment than with total mastectomy.
The study included 132,149 patients with early-stage breast cancer (tumor size ≤4 cm and ≤3 positive lymph nodes) from the SEER database between 1998 and 2008. Of these patients, 70% were treated with breast-conserving therapy, 27% received total breast excision alone, and 3% received total breast excision + radiotherapy. The results showed that the 10-year breast cancer-related survival rate was 94% in the breast-conserving treatment group, 90% in the total breast excision alone group, and 83% in the total breast excision + radiotherapy group (P < 0.001). After correcting for many variables (number of positive lymph nodes, tumor size, hormone receptor levels, tumor grade, etc.), it was shown that breast-conserving treatment had a higher survival rate than total mastectomy alone (HR 1.31, P < 0.001) and total mastectomy + radiotherapy (HR 1.47, P < 0.001).
Many patients have misconceptions about breast-conserving treatment, believing that total breast excision has a higher survival rate than breast-conserving treatment, but the results of the study showed the opposite, which brings confidence to patients with feasible breast-conserving treatment and may reduce the number of patients who do not accept breast-conserving treatment due to psychological factors.
However, the above-mentioned studies still have a number of limitations, such as.
1. no matching or correction for systemic adjuvant therapy, patient HER2 levels, and other comorbidities.
2. women receiving breast-conserving treatment were younger and tended to have smaller well-differentiated ductal carcinomas and unifocal tumors; whereas patients with multifocal or more complex breast cancer were more likely to opt for total breast excision.
3. Socioeconomic status has a greater influence on patient selection. It has been shown that patients with higher education and income tend to choose breast-conserving treatment, and are better equipped for regular systemic adjuvant therapy and regular review; on the contrary, patients with lower socioeconomic status tend to choose total mastectomy, and their survival rate is indeed lower than the former group.
4. The number of patients undergoing total mastectomy has decreased over the years, and guidelines for systemic therapy have changed from being used only for patients with positive lymph nodes to a routine regimen regardless of lymph node positivity.
Although the evidence from these studies is of average quality and has many limitations, a retrospective study of this magnitude can at least show that breast-conserving treatment is at least as effective, if not more effective, than total mastectomy.
Dr. Siesling said at the conference that the differences in endpoints such as survival between the two groups may be due to the important role that radiation therapy plays in treatment. Although the data from these studies do not directly demonstrate the benefit of radiation therapy in this context, it is possible to speculate that patients in the breast-conserving group had improved survival rates due to radiation therapy, while patients in the total breast excision group may have had their survival rates affected by the absence of radiation therapy.
In the discussion that followed, Dr. Arteaga concluded that these findings do not change current treatment guidelines. In making clinical decisions, physicians and patients weigh a variety of factors, and with so many factors at play, it is difficult to shake the current guidelines because of a few retrospective studies with limitations, especially for patients with multicentric lesions and early-stage breast cancer whose breast size is not suitable for breast-conserving treatment, and the guidelines still recommend total breast excision.
Reference.
Ten-Year Data: Lumpectomy and Radiotherapy Trump Mastectomy. San Antonio Breast Cancer Symposium (SABCS) 2015: Abstract S3-05. Presented December 10 , 2015.
Survival after lumpectomy and mastectomy for early stage invasive breast cancer. cancer. published online January 28,2013.
Effect of Breast Conservation Therapy vs Mastectomy on Disease-Specific Survival for Early-Stage Breast Cancer FREE. jAMA Surg. Published online January 15, 2014.
Are Mastectomies on the Rise? A 13-Year Trend Analysis of the Selection of Mastectomy Versus Breast Conservation Therapy in 5865 Patients.Ann Surg Oncol. Ann Surg Oncol. 2009;16:2682-2690
(This article is originally published by [Good Medical Practice – Oncology Information], welcome to forward, reprint with authorization and attribution)