3.2. Concurrent Chemotherapy vs Sequential Radiotherapy
In these studies, according to the advances in novel drugs discovery at the end of 90’ years, schedules containing mitoxantrone, taxanes, anthracyclines and the most used CMF have been delivered concurrently or sequentially with standard fractionated RT, indicating the advantages of the concomitant arm in terms of local control with several differences in toxicity.
A first study on concurrent treatment was proposed by
Serin et al using an anthracenedione agent like mitoxantrone to reduce cardiac toxicity [
20]. In this study 154 patients affected by stage I or II BC received conventional RT of 50 Gy in 25 fractions concurrently to chemotherapy. Chemotherapy consisted of 5-fluorouracil, mitoxantrone, and cyclophosphamide every 21days for 4 to 6 cycles. As toxicity, G 1 cutaneous toxicity occurred in 62.3% of the cases, and severe G 3 radiation dermatitis requiring temporary interruptions of therapy was found in 4.5% of patients. Only one case of G 3 acute cardiac toxicity was recorded.
Bellon et al presented a retrospective study on 45 high risk breast cancer patients treated with RT concurrently with taxanes (paclitaxel or docetaxel) [
21]. Radiation was delivered to the chest wall or breast with doses ranging from 4680 cGy to 5040 cGy. A boost dose of radiation was provided to almost of them while nodal RT was delivered when indicated. Grade 3 acute
skin toxicity was 20% in the docetaxel arm vs the paclitaxel arm (
p= 0.04). With a median follow-up of 11 months, only one patient developed
breast fibrosis. The use of taxanes concurrent to A-RT was officialized by Burnstein in a randomized trial on 40 BC patients [
22]. Paclitaxel was delivered according to two schedules: 60 mg/m
2 weekly x12 weeks or 135-175 mg/m
2every 3 weeks x4 cycles. As a first result, weekly paclitaxel treatment at 60 mg/m
2 per week with concurrent radiation was the dose-limiting toxicity in 4 of 16 patients (25%) with one case of severe pneumonitis requiring steroids. On the contrary, dose-limiting toxicity was not recorded among patients receiving concurrent radiation with paclitaxel given every 3 weeks at 135-175 mg/m
2. However, G 2 radiation pneumonitis not requiring steroid therapy was seen in 2 of 24 patients (8%). No severe radiation dermatitis was observed in both paclitaxel schedules. Authors concluded that while concurrent treatment with weekly paclitaxel and radiation therapy was not adviceble, the concurrent arm with less frequent paclitaxel dosing schedule was defined less toxic although the possibility of pulmonary injury as side effect.
In the set of antracycline,
a dose-dense intensification study with standard fractionated RT given sequentially or concomitantly was assessed by Sanguineti et al [
23]. This study provided a mild RT dose-intensity (DI) to compensate gaps with 2.3 Gy per fraction in case of RT interruptions for toxicity. Forty-seven stage I-II breast cancer patients, after conserving surgery, were randomized to receive the CEF regimen delivered every two weeks (CEF14) or three weeks (CEF21). RT was applied to the residual breast to a total dose of 50 Gy in five weeks. Radiotherapy DI was expressed as the average total dose received each week defined as ‘weekly dose-rate’ (WDR). As a result, 98.8% of patients received a cumulative total dose of RT within ±10% of that planned. The type of treatment (CEF14 vs. CEF21) did not affect the probability of WDR < 9.5 Gy/wk. 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).
Rouëssè J et al enrolled 638 BC patients in randomized trial providing two chemotherapy arms concurrent or sequential to standard fractionated radiotherapy. [
24]. A arm consisted of 5-fluorouracil 500 mg/m
2, mitoxantrone 12 mg/m
2, and cyclophosphamide 500 mg/m
2 and concurrent RT. In B arm adjuvant CT with FEC regime and sequential standard RT were provided. Chemotherapy was administered on day 1 every 21 days for 4 cycles.
The median treatment duration times were 64 days in A arm and 126 days in B arm , respectively. No significant difference in overall or disease-free survival were observed but a 5-year locoregional relapse-free survival in Arm A of 3% vs 9%; in Arm B (p = 0.01) was recorded. The increased risk of locoregional recurrence in B arm was 2.8-fold increased by multivariate analysis (p = 0.027). In A arm the most frequent acute toxic effect was febrile neutropenia with Grade 3-4 leukopenia. At 1 year , cardiac side effects like subclinical left ventricular ejection fraction events at 1 year were reported due to concomitant radiotherapy (p = 0.02).
In the
ARCOSEIN trial 716 patients were randomized to receive CT and sequential RT versus concurrent RT using a CT regimen with mitoxantrone 12 mg/m
2, 5 fluorouraci500 mg/m
2, cyclophosphamide 500 mg/m
2 every 21 days for six cycles and standard fractionated RT. Adjuvant treatment started within 6 weeks after surgery. As a result, the 5-year DFS was 80% in both groups ( p = .83). Moreover no statistically significant difference in locoregional recurrence-free survival and OS were observed (p =.76 respectively). However, in the node-positive subgroup, the 5-year LRFS was improved in the concurrent arm (p= .02), corresponding to a risk of locoregional recurrence decreased by 39% (HR, 0.61; 95% CI, 0.38 to 0.93). Moderate acute locoregional toxicities were found in the two arms [
25].
Two concomitant AC based regimes with standard RT study was conducted by
Livi et al on 60 BC patients. Four cycles of AC (doxorubicin plus cyclophosphamide) vs four cycles of epirubicin (EPI) followed by four courses of iv CMF every 28 days were adopted. RT was appplied to the breast and nodal areas with 50 Gy mean delivered dose ( range 46–52 Gy). The boost dose was 10 Gy for patients with tumour-free surgical margins and 20 Gy for patients with positive margins. As a result, the concomitant treatment yelded 8.9% of acute skin G3 toxicity with one case of G4 toxicity (1.7%). RT was stopped in 21.3% of patients with a temporary RT delay of 5 mean 5 days. CT interruption of ≤7 days. was applied in 57.1% of patients because of haematological toxicity. An asymptomatic reduction of left ventricular ejection fraction >10% and <20% of the baseline value was recorded in both groups [
26].
See Table 1
3.3. CMF or AC (Concurrent vs Sequential RT )
The CMF combination has been the most used treatment delivered concurrently to RT over AC schedule.
Faul et al tested the efficacy of concurrent “standard” CMF vs iv CMF regimes in 116 BC patients with stage I-II BC treated with CMF and A-RT [
27]. The standard CMF regime consisted of cyclophosphamide 100 mg/ m
2 os days 1–14, methotrexate 40 mg/m
2 i.v. days 1 and 8 and 5-fluorouracil 600 mg/m
2 days 1 and 8 repeated every 28 days for six cycles. The i.v. CMF regimen consisted of cyclophosphamide 600 mg/m2 i.v., methotrexate 40 mg/m2 i.v. and 5-fluorouracil 600 mg/m2 i.v. given every 21 days for 6 to 8 cycles. Radiotherapy was delivered according standard fractionation. In this study 73 patients were treated prospectively with concurrent therapy and were retrospectively compared with a matched group of 40 patients treated with sequential or sandwich therapy. Concurrent sequencing didn’t influence the scheduled delivered RT and CT doses. No significant difference in acute skin reactions or complications between the two groups were recorded with a small and significant delay in RT delivery : 1.32 days (0-15) vs 0.36 (0-7 ) in the concurrent group (p=0.03). Sequencing had no significant impact on haematological toxicity. ‘Standard’ CMF impacted on treatment delivery more than i.v. CMF . In fact the RT delay was 2.2 days versus 0.26 (p=0.002), the percent of delivered chemotherapy was 93% versus 99% (P=0.000004). This study showed that iv CMF was safe when delivered concurrently with standard RT.
To confirm the safety of concurrent administration of CMF vs antracycline based regimen,
Fiets et al reported on a prospective, non-randomized, comparative study on the acute toxicity of RT alone vs RT given concurrently (RCT) to doxorubicin-cyclophosphamide (AC/RT) or CMF (CMF/RT). Standard fractionated RT on breast, chest wall and nodal areas was applied [
28]. Totally 112 patients received CT/RT as follows: 61 patients were treated with AC/RT and 51 with CMF/RT; 42 patients were treated with RT only as controls. As a result, patients treated with AC/RT and CMF/RT had significant higher incidences of high-grade toxiciy compared with those treated with RT only. The AC/RT scheme was associated with significant high-grade skin toxicity than CMF/RT. A less than 85% of the planned chemotherapy reduction dose was applied to 11% of patients and 17% of patients treated with RCT had an admission to hospital. Authors concluded that RCT administration yielded an unacceptably high level of acute toxicity mainly with AC regimen.
At the same time,
Arcangeli et al published results of a randomized trial on RT concomitant vs sequential iv CMFfor 6 cycles conducted on 206 elegible patients [
29]. A-RT was applied only to the whole breast to a dose of 50 Gy in 20 fractions followed by an electron boost of 10-15 Gy to the tumor bed. Patients in the concurrent treatment group generally received one cycle of CMF before the RT starting course. Radiation therapy started within 2 months from the day of definitive surgery and concomitantly with the second CMF course in the concurrent treatment group. In the sequential treatment group, RT started 7 months after surgery, mainly at the conclusion of the last CMF course. All patients in the two groups received 100% of the planned dose. There were no RT breaks during the radiation time for skin or hematologic toxicity. All patients completed the planned radiotherapy and chemotherapy. No differences in 5-year breast recurrence-free survival ( (p 0.97), metastasis-free survival (p 0.44), disease-free (p 0.99) and overall (p 0.56) survivals were observed in the two treatment groups. Neither , no increased risk of toxicity was observed between the two arms. Authors concluded that iv CMF concurrent to RT , due to its advantage in shortening the overall treatment time could had been more useful to patients with high risk of recurrence, like those R1 surgical margins and with large tumor size.
In the prospective study of
Han et al, 238 patients with stages I and II breast cancers were prospectively enrolled in a study with iv CMF concurrent vs sequential RT [
30]. After BCS, all patients underwent iv CMF every 3 weeks for 6 cycles. RT on breast and nodal areas was delivered with standard fractionation with a 56 Gy median dose. In the sequential group, RT was started after the completion of 3 cycles of CT ; then additional 3 cycles of CT were delivered after RT. There was no significant difference in G3 or G4 hematologic toxicities during CT between the two groups. Neither a difference in RT related adverse effects was observed. During the median follow-up of 42 months, systemic recurrences occurred in 18 patients (13.5%) of the concurrent group and in 20 patients (19.1%) of the sequential group.
Livi et al in the same year showed a retrospective 3 arms study comparing 485 patients treated with conservative breast surgery, 6 courses of CMF and postoperative whole-breast RT vs 300 patients who received postoperative CMF only vs 509 patients treated with postoperative whole-breast RT only [
31]. As a result, a G2 acute skin toxicity occurred in the concurrent group (21.2% vs. 11.2% of the RT only group, p < 0.0001). Local recurrence rate was 7.6% in CT/RT group and 9.8% in RT group; this difference was not statistically significant at univariate analysis (log-rank test p = 0.98). However, at multivariate analysis adjusted also for pathological tumor, pathological nodes, and age, the CT/RT group showed a statistically lower rate of local recurrence (p = 0.04).
A retrospective study on 244 BC patients treated by radical surgery or breast conservative surgery [
32] was conducted by
Ismaili et al. In this study two adjuvant schedules of chemotherapy concurrently given to radiotherapy were compared. In A group 110 BC patients received anthracycline based chemotherapy according several regimens. All cyclces were delivered every 21 days for 6 courses: AC 60 (doxorubicin 60 mg/m
2 and cyclophosphamide 600 mg/m
2); FEC75 (5-fluorouracile 500 mg/m
2, epirubicin 75 mg/m
2, and cyclophosphamide 500 mg/m
2); iv FAC50 (5-fluorouracile 500 mg/m
2, doxorubicin 50 mg/ m
2, and cyclophosphamide 500 mg/m
2). The B group consisted of 134 BC patients receiving iv CMF every 21 days for 6 couses. .Conventional fractionated radiotherapy 50 Gy on the whole breast (or on the external wall) and/or on the nodal areas was provided. .As a result, after 76.4 months median follow-up , locoregional relapse occurred in 1 patient in the antacycline treated group and in 8 patients in the iv CMF treated group. The disease free survival and oveall survival after 5 years were not statical significant between the two groups (p = 0.136 and p = 0.428 respectively), However, the loco-regional free survival at 5 years was better in A group than the B group (98.6% vs 94% p = 0,033). The rate of G2 and G3 anaemia was 13.9% and 6.7% in anthracycline group and CMF group respectively (p = 0.009). Grade 2-3 skin toxicity in the was 4.5% in A group vs 0% in the B group B (p = 0.013). Thus antacycline treatment concurrent to RT was more effective and toxic. See
Table 2