Does delay in breast irradiation following conservative breast surgery in node-negative breast cancer patients have an impact on risk of recurrence?

Does delay in starting treatment affect the outcomes of radiotherapy? A systematic review

PURPOSE

The objective of this study was to synthesize what is known about the relationship between delay in radiotherapy (RT) and the outcomes of RT.

METHODS

A systematic review of the world literature was conducted to identify studies that described the association between delay in RT and the probability of local control, metastasis, and/or survival. Studies were classified by clinical and methodologic criteria and their results were combined using a random-effects model.

RESULTS

A total of 46 relevant studies involving 15,782 patients met our minimum methodologic criteria of validity; most (42) were retrospective observational studies. Thirty-nine studies described rates of local recurrence, 21 studies described rates of distant metastasis, and 19 studies described survival. The relationship between delay and the outcomes of RT had been studied in diverse situations, but most frequently in breast cancer (21 studies) and head and neck cancer (12 studies). Combined analysis showed that the 5-year local recurrence rate (LRR) was significantly higher in patients treated with adjuvant RT for breast cancer more than 8 weeks after surgery than in those treated within 8 weeks of surgery (odds ratio [OR] = 1.62, 95% confidence interval [CI], 1.21 to 2.16). Combined analysis also showed that the LRR was significantly higher among patients who received postoperative RT for head and neck cancer more than 6 weeks after surgery than among those treated within 6 weeks of surgery (OR = 2.89; 95% CI, 1.60 to 5.21). There was little evidence about the impact of delay in RT on the risk of metastases or the probability of long-term survival in any situation.

CONCLUSION

Delay in the initiation of RT is associated with an increase [corrected] in LRR in breast cancer and head and neck cancer. Delays in starting RT should be as short as reasonably achievable.

Delay in adjuvant radiation treatment and outcomes of breast cancer--a review

Recent meta-analyses have shown the importance of locoregional control as a long-term determinant of breast cancer survival. Whether factors related to the delivery of radiotherapy, such as delay, dose, fractionation or irradiated volume, are associated with outcome remains unclear. We performed a critical review of the literature on delay to radiation using a computerized search of papers published between 1985 and 2000. Periods of accrual, details of radiotherapy, surgical and systemic treatment, and information on prognostic factors were noted. Studies on sequencing of adjuvant therapy were compared to studies on delay to radiation, classified according to whether or not patients also received chemotherapy. Comparisons of patients receiving systemic therapy to individuals spared this option were considered uninformative since the impact of delaying radiation is then highly confounded by systemic treatment received. The single published experimental study on sequencing suggests that delay to radiation may compromise local control, and this is consistent with a few retrospective reports on delay to radiotherapy among patients receiving chemotherapy. However, indirect evidence from two randomized clinical trials of chemotherapy, and the majority of observational studies on delay to radiotherapy, suggest that it has no impact on either local, distant control or survival. Factors, methodological, and others, that could explain these inconsistencies are discussed. No study restricted to patients at low risk of recurrence suggested an impact of delaying radiation. Short chemotherapy regimens are likely to represent a safe option with respect to outcome of radiation treatment.

The role of radiotherapy in rectal cancer

In Europe, short-term radiotherapy is increasingly used in the primary management of rectal cancer. In the United States, postoperative chemoradiotherapy is the standard treatment of choice. The rationale and indications for radiotherapy and possible combinations with chemotherapy are discussed and an overview of all of the randomised trials containing radiotherapy as one randomisation arm is given. Three major indications for radiotherapy can be identified: the reduction of local recurrences in mobile rectal cancer, downstaging of the tumour in primary irresectable tumours and downsizing of low-lying tumours in attempts to more frequently perform a sphincter-saving procedure. For reduction of local recurrences, radiotherapy can be given either pre- or postoperatively, although preoperative therapy is more dose-efficient. Short-term preoperative radiotherapy reduces the number of recurrences and improves survival. Improved survival is also reported after postoperative radiotherapy in combination with chemotherapy, however, the relevance of the radiotherapy component is discussed. Although the debate about radiotherapy is still ongoing, we strongly believe that the results demonstrate that short-term preoperative radiotherapy is the treatment of choice for resectable rectal cancer.

Timing of radiotherapy in breast cancer conserving treatment

The optimal timing and sequencing of adjuvant radiotherapy and chemotherapy after breast-conserving surgery for early invasive breast cancer is controversial. Several studies demonstrated that postoperative radiation therapy significantly reduces the incidence of breast recurrences. For patients who do not need systemic treatment, the interval between surgery and the start of radiotherapy should not exceed eight weeks. For node-positive and high-risk patients receiving breast-conserving treatment, adjuvant chemotherapy should be administered prior to radiotherapy, but the delay of radiation should not exceed 20-24 weeks. Side effects and complications of radiotherapy can be expected to increase when chemotherapy is administered concurrently. In particular, antracycline-based chemotherapy regimens increase the damage to heart muscle and coronary arteries: to avoid the risk of ischemic cardiovascular disease, radiotherapy must be performed after the end of systemic treatment.

Impact of chemotherapy dose-density on radiotherapy dose-intensity after breast conserving surgery

PURPOSE

To evaluate if chemotherapy (CT) dose-intensification jeopardizes radiotherapy (RT) dose-intensity (DI).

PATIENTS AND METHODS

From 1992 to 1997, 247 stage I-II breast cancer patients, treated with conserving surgery, were treated at the National Cancer Institute of Genoa in a randomized study comparing the same CEF regimen delivered every two weeks (CEF14) or three weeks (CEF21). RT was applied to the residual breast at a total dose of 50 Gy in five weeks. Allowance was made for treatment at 2.3 Gy per fraction in order to compensate for gaps (hypofractionation). Radiotherapy DI was expressed as the average total dose received each week, i.e., 'weekly dose-rate' (WDR). The effect of various tumour, treatment and patient-related factors on the endpoint (a delivered WDR of RT < 9.5 Gy) was investigated by univariate analysis. Factors found to have P-value < or = 0.20 were entered in multivariate analysis.

RESULTS

All but three patients (244 of 247, 98.8%) received a cumulative total dose of RT within +/- 10% of that planned. Moreover, most of them (197 of 247, 79.8%) received an average WDR of > or = 9.5 Gy/wk. With univariate analysis the probability of WDR < 9.5 Gy/wk significantly correlated with age, menopausal status, concomitant administration of RT and CT, and white blood cell toxicity. Moreover, a positive effect on WDR was found in patients treated at 2.3 Gy per fraction. The type of treatment (CEF14 vs. CEF21) did not affect the probability of WDR < 9.5 Gy/wk. With multivariate analysis, age (< or = 55 vs. > 55 years, RR = 3.99, 95% CI: 1.89-8.42, P = 0.0003), RT fractionation (conventional vs. hypofractionation, RR = 0.32, 95% CI: 0.15-0.68, P = 0.017) and WBC toxicity (none vs. some, RR = 1.54, 95% CI: 1.06-2.22, P = 0.027) were independent predictors of WDR < 9.5 Gy. Regarding the CT-RT overlap, patients receiving more than two cycles of chemotherapy during radiotherapy had an increased risk of RT delay compared to other patients (RR = 3.74, 95% CI: 1.44-9.48, P = 0.0063).

CONCLUSIONS

There is no evidence of a direct effect of CT dose-density on dose-intensity of RT. However, the concomitant use of CT and RT reduces the possibility of giving a full dose-intensity of RT.

Concurrent radiation therapy and paclitaxel or docetaxel chemotherapy in high-risk breast cancer

PURPOSE

Evidence supports the inclusion of the taxanes in the treatment of breast cancer. A recent randomized trial has shown a survival advantage to the addition of paclitaxel in the adjuvant treatment of node-positive patients. Several studies have suggested diminished local control if adjuvant radiation is delayed, while in vitro and in vivo studies have demonstrated a benefit of concurrent administration of taxanes with radiation. For these reasons, we began in 1995 to administer radiation therapy concurrently with the taxanes in advanced breast cancer. This retrospective review examines the feasibility of such treatment.

METHODS AND MATERIALS

Forty-four patients were treated with concurrent radiation and either paclitaxel (29 patients) or docetaxel (15 patients). One patient received both paclitaxel and docetaxel. Eighteen patients were treated for recurrent disease, 9 had received prior radiation. Toxicity was assessed by the RTOG scale for acute and late effects.

RESULTS

Concurrent radiation and taxane chemotherapy was well tolerated. Nine patients (20%) experienced Grade 3 acute skin toxicity. This was more likely with docetaxel than paclitaxel (p = 0. 04). Among patients undergoing breast conservation, there were no Grade 3 toxicities. With a median follow-up of 11 months, 1 patient has developed breast fibrosis.

CONCLUSION

Concurrent administration of both paclitaxel and docetaxel with radiation resulted in acceptable toxicity. Overall, the acute skin toxicity seen with docetaxel was more pronounced. However, among patients undergoing breast conservation the taxanes were both well tolerated. Further study is necessary to assess the impact of concurrent treatment on long-term outcome.

A shorter fractionation schedule for postlumpectomy breast cancer patients

PURPOSE

The purpose of this retrospective review was to determine the effectiveness of 40 Gy in 16 daily fractions in preventing local recurrence in postlumpectomy invasive breast cancer patients whose margins of resection were clear of tumor by at least 2 mm.

METHODS

Between September 1989 and December 1993, 294 breasts were treated with this regimen. The entire breast was treated, using a tangential parallel pair, with wedges as necessary, to a dose of 40 Gy in 16 daily fractions. No additional boost was given. The median duration of follow-up of surviving patients is 5.5 years. Recently, the patients' assessment of the cosmetic outcome of their treatment was obtained, using a mailed questionnaire.

RESULTS

The 5-year actuarial breast-relapse rate was 3.5%, with an overall 5-year survival and disease-specific survival of 87.8% and 92.1%, respectively. In response to the cosmesis questionnaire, 77% of patients stated they were either extremely or very satisfied with the overall appearance of the breast, 19.5% moderately satisfied, and 3.5% either slightly or not at all satisfied. The corresponding responses for overall level of comfort of the breast were 79%, 16.5%, and 4.5% respectively.

CONCLUSION

This regimen is very effective at preventing recurrent breast cancer in this group of patients, and it provides a high level of patient satisfaction with cosmetic outcome. Its short duration offers the added advantage of a more efficient use of resources and greater patient convenience.

Effect of time interval between breast-conserving surgery and radiation therapy on ipsilateral breast recurrence

PURPOSE

To examine the effect of the time interval (interval) between breast-conserving surgery (BCS) and the start of radiation therapy (RT) on the subsequent risk of ipsilateral breast cancer recurrence (IBR).

METHODS AND MATERIALS

We reviewed interval and a number of prognostic and treatment factors among 1,962 women treated with BCS and RT for invasive breast cancer diagnosed between January 1, 1989 and December 31, 1993 in British Columbia, Canada. Subjects were female, less than 90 years old at diagnosis, not treated with chemotherapy, not stage T4 or M1, and had survived more than 30 days from diagnosis. The cumulative incidence of IBR was estimated in four interval groups: 0-5, 6-8, 9-12, and 13+ weeks. Only 23 women had an interval of greater than 20 weeks between BCS and start of RT. To assess whether an imbalance of prognostic and treatment factors could be obscuring real differences between the interval groups, Cox proportional hazards regression analyses were conducted.

RESULTS

Median follow-up was 71 months. The crude incidence of IBR for the entire sample was 3.9%. The cumulative incidence of IBR in the 6-8, 9-12, and 13+ week groups was not statistically significantly different from the cumulative incidence of IBR in the 0-5 week group. Multivariate analyses demonstrated that patients not using tamoxifen p = 0.027) and those with grade 3 histology (p = 0.003) were more likely to recur in the breast. Interval between BCS and RT was not a statistically significant predictor of breast recurrence when entered into a model incorporating tamoxifen use and tumor grade (0-5 vs. 6-8 weeks, p = 0.872; 0-5 vs. 9-12 weeks, p = 0.665; 0-5 vs. 13+ weeks, p = 0.573).

CONCLUSIONS

We found no univariate or multivariate difference in ipsilateral breast cancer recurrence between intervals of 0 to 20 weeks from breast conserving surgery to start of radiation therapy, in a population-based, low risk group of women not receiving adjuvant chemotherapy, after controlling for other factors important in predicting ipsilateral breast cancer recurrence.