Breast cancer-related death is usually a result of disease recurrence, which occurs even in early breast cancer patients with small tumors and a negative lymph node status after long-term follow-up [1, 2]. Previous studies indicated that 70% of recurrences occur ≤3 years postsurgery, and the recurrence risk reaches a peak at 1–2 years after surgery [3, 4]. In 1997, the American Society of Clinical Oncology (ASCO) published breast cancer surveillance guidelines for the first time , in which the expert panel recommended that all women have a careful history and physical examination every 3–6 months for the first 3 years after primary therapy, then every 6–12 months for the next 2 years, then annually. The rationale for such an approach is that, because 60%–80% of all breast cancer recurrences are detected ≤3 years postsurgery, scheduling of surveillance visits should be more frequent during that time period . Of note, the recurrence data that the guidelines were based on were derived from early clinical studies in which most patients underwent mastectomy rather than well-performed breast-conserving surgery (BCS). ASCO subsequently updated these guidelines several times, but the above-mentioned schedule of surveillance visits never changed despite the fact that the target population could have received either mastectomy or lumpectomy [6, 7].
Thus far, there are few prospective trials investigating whether or not early detection of breast cancer recurrence results in a better outcome. It seems that surveillance aimed at early detection of “distant metastases” does not improve survival ; however, the effect on survival of early detection of “breast recurrences” is debatable [17–19]. Greater monitoring of the breast after BCS would identify more signs of early recurrence, whereas early detection of second breast cancers (either IBTR or contralateral breast cancer [CBC]) in the asymptomatic phase could improve relative survival by 27%–47%, as Houssami et al.  suggested. Perrone et al.  also reported that early detection of local recurrence might have a favorable impact on the prognosis of patients followed after primary treatment for breast cancer because a difference in survival was recorded in favor of cases detected in the asymptomatic state (p < .001). Another meta-analysis  found that recurrences assessed in patients without symptoms were related to a higher probability of survival than when symptoms were present (hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.36–1.79). The authors thus concluded that detection of isolated locoregional or CBC recurrences in patients without symptoms has a beneficial impact on the survival of breast cancer patients, when compared with late symptomatic detection. Besides the potential benefits in terms of survival, a few patients who refuse salvage mastectomy at locoregional relapse after BCS could be treated with a second lumpectomy, albeit the treatment choice for locoregional relapse historically has been salvage mastectomy . We believe that early detection of breast cancer allows for a higher proportion of reconservation. Of course, the safety and effectiveness of reconservation should be further evaluated.
In most studies, the risk for recurrence is generally described by survival curves rather than annual hazard rates. In recent years, some investigators have scrutinized patterns of recurrence and the annual recurrence rate (ARR) is used to assess dynamic changes in recurrence risk by year. Thus far, we have little information on the difference in the recurrence pattern between lumpectomy and mastectomy patients. The aim of the present study was to show the differential recurrence pattern between these two surgical modalities using our single-institution data, as well as to review relevant literature-based data to confirm our observations. A better understanding of the recurrence pattern with each type of surgery would be helpful in clinical surveillance and monitoring.