Prospective phase II study of tomotherapy based chemoradiation treatment for locally advanced anal cancer

Radiotherapy and Oncology 117 (2015) 234–239

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Phase II trial

Prospective phase II study of tomotherapy based chemoradiation treatment for locally advanced anal cancer Kurian Joseph a,⇑, Yugmel Nijjar a, Heather Warkentin b, Dan Schiller c, Keith Tankel a, Nawaid Usmani a, Diane Severin a, Sunita Ghosh d, Alasdair Syme b,1, Tirath Nijjar a, Karen Mulder d, Corinne Doll e, Clarence Wong f, Colin Field b a Division of Radiation Oncology; b Division of Medical Physics, Department of Oncology, University of Alberta & Cross Cancer Institute; c Department of Surgical Oncology, University of Alberta & Alberta Health Services, Edmonton; d Division of Medical Oncology, Department of Oncology, University of Alberta & Cross Cancer Institute, Edmonton; e Division of Radiation Oncology, Department of Oncology, University of Calgary & Tom Baker Cancer Centre; and f Department of Internal Gastroenterology, Royal Alexandra Hospital, Edmonton, Canada

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Article history: Received 24 April 2015 Received in revised form 28 July 2015 Accepted 8 August 2015 Available online 22 August 2015 Keywords: Anal cancer Helical tomotherapy Intensity-modulated radiation therapy (IMRT) Acute toxicity Late toxicity

a b s t r a c t Background and purpose: To evaluate toxicity, local control, and survival of anal cancer patients treated with helical tomotherapy (HT) and concurrent 5-fluorouracil and mitomycin-C (5FU/MMC). Materials and methods: Fifty-seven patients were treated with HT and concurrent 5FU/MMC. The planning objectives were to deliver 54 Gy to the tumor (PTV54) and 45 Gy to the nodes at risk (PTV45) in 30 fractions. Patients were reviewed for toxicity weekly during HT, every 6 weeks for 3 months, and then every 3–4 months for 5 years. Results: The median follow-up was 40 months. The median age was 58 years (range: 37–83). Stage distribution: stage II-48%, IIIA-18%, IIIB-34%. The majority of patients developed 6grade 2 acute toxicity scores. The most common Pgrade 3 acute toxicity was neutropenia (40%). Common late toxicities were grade 2 anal incontinence (16%) and telangiectasia (12%). The 3 year colostomy-free survival rate was 77% (95% CI: 61–87%), 3 year disease-free survival rate was 80% (CI: 66–89%), and 3 year overall survival was 91% (CI: 77–96%). Conclusions: Incorporation of HT with concurrent 5FU/MMC had low treatment-related acute and late morbidity with few treatment breaks. However, the expected dosimetric benefit for hematological toxicity was not experienced clinically. Ó 2015 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 117 (2015) 234–239

Radiotherapy combined with concurrent 5-fluorouracil and mitomycin-C (5FU/MMC) is the standard treatment for nonmetastatic squamous cell carcinoma (SCC) of the anal canal [1–6]. Chemoradiotherapy (CRT) has a 5 year disease-free survival (DFS) rate of 60–70%, but not without substantial treatmentrelated toxicities [2,7]. Two prospective phase II studies have reported improvements in both disease outcome and treatmentrelated acute toxicities with Linac-based intensity-modulated radiation therapy (IMRT) and concurrent chemotherapy [8,9]. The RTOG 0529 study has also reported shorter treatment breaks with IMRT [9]. Helical tomotherapy (HT) is an innovative means of delivering IMRT using a helical 360° radiation delivery system. A dosimetric study from our center has demonstrated superior target ⇑ Corresponding author at: Department of Radiation Oncology, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada. E-mail address: [email protected] (K. Joseph). 1 Current address: Medical Physics Unit, Department of Oncology, McGill University, Montreal, Quebec, Canada. http://dx.doi.org/10.1016/j.radonc.2015.08.008 0167-8140/Ó 2015 Elsevier Ireland Ltd. All rights reserved.

dose conformality and significant sparing of the OARs when using helical tomotherapy (HT) in the treatment of SCC of the anal canal [10]. Based on this evidence, we conducted a single institution, prospective phase II study to evaluate the potential benefit of tomotherapy-based CRT in limiting treatment related acute and late toxicities without compromising locoregional control. The primary study endpoint was the minimization of acute toxicity. Secondary endpoints were late toxicity, overall survival (OS), colostomy-free survival (CFS), and DFS. Materials and methods Patient selection and treatment specifics Newly diagnosed, biopsy-confirmed non-metastatic (stage T2– T4; N0–N3; M0) anal canal SCC patients were treated with HT and concurrent 5FU/MMC as part of an in-house prospective phase II study. The study was approved by the Regional Ethics board and written informed consent was obtained for enrollment into the

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study. The trial was registered (ClinicalTrials.gov Identifier: NCT00754078). Exclusion criteria were: T1N0 or M1 disease, HIV, previous history of pelvic malignancy, or pelvic radiation. Patient evaluation included computerized tomography (CT) scans of the chest/abdomen/pelvis, magnetic resonance imaging (MRI) scan of the pelvis, and a positron emission tomography (PET) scan. Any patient with suspicious groin node(s) clinically or on PET underwent biopsy for confirmation of nodal involvement. Chemotherapy consisted of 5-FU 1000 mg/m2/day continuous infusion over 96 h on days 1–4 and 29–32, and MMC 10 mg/m2 intravenous bolus on days 1 and 29.

Target volume definition and treatment planning CT simulation (Brilliance Big Bore, Philips Medical Systems, MA) with 3 mm axial slices was performed in supine position with a full bladder. A radio-opaque marker was placed over the anus or at the lower-most extent of the tumor, whichever was most inferior. The gross tumor volume (GTV), clinical target volume (CTV), planning target volume (PTV) and OAR were contoured using an Eclipse workstation (Eclipse v10.0, Varian Medical Systems, Palo Alto, CA). The GTV included the primary tumor and any involved lymph nodes >1.0 cm. Two CTVs were defined: CTV54 included GTV, the entire anal canal, plus a 1.0–1.5 cm isotropic margin excluding bone, muscles, genitourinary structures or air. CTV45 consisted of the regional lymph nodes at risk (the peri-rectal, internal iliac, external iliac, obturator, presacral, and inguinal lymph nodes), ischiorectal fossae and mesorectum with 7–10 mm expansion, excluding bone, genitourinary structures, muscles, or bowel [11]. PTV54 and PTV45 were generated by adding a uniform 1.0 cm margin around CTV54 and CTV45, respectively. In cases with uninvolved groin nodes, CTV45 and PTV45 volumes were limited to 3–5 mm from the skin surface. Bolus was used for 4 patients with perianal extension. OARs included bladder, femoral heads, external genitalia, bone marrow, skin and peritoneal cavity (in lieu of small bowel) [10]. Following contouring, patient datasets were transferred to the TomoTherapy Hi-Art system (version 3.1.5, Accuray Inc., Sunnyvale, CA) and a single-phase treatment plan was generated for each

patient. The planning objectives and the dose–volume constraints for the OARs were based on the preceding in-house dosimetric study and are given in Table 1 [10]. The radiotherapy (RT) dose prescription was 54 Gy to 95% of the PTV54 volume and simultaneous delivery of 45 Gy to 95% of the PTV45 volume in 30 fractions over six weeks at 1.8 Gy and 1.5 Gy per fraction respectively. The highest importance was assigned to sparing of the bone marrow followed by the external genitalia, peritoneal cavity, femoral heads, bladder, and skin. The plans were reviewed by all five of the gastrointestinal (GI) Radiation Oncologists as part of RT quality assurance. Megavoltage CT was used for positioning verification. Patient position was adjusted with initial automatic bone alignments, followed by a soft tissue alignment using symphysis pubis and anorectal soft tissue.

Patient review and toxicity assessment Patients were reviewed in clinic weekly during radiotherapy, followed by assessments every 6 weeks for 3 months, and then every 3–4 months for a total period of 5 years. Review included routine blood work and toxicity data based on Common Terminology Criteria for Adverse Events v3.0 (CTCAE). Acute toxicity was defined as toxicity experienced during treatment or within 3 months of completing treatment. Late toxicity was from 3 months post treatment to 5 years of follow-up. Unplanned treatment breaks were allowed for patients with Pgrade 3 acute toxicities. All patients underwent re-staging CT and PET imaging at 3 months and 6 months after completion of radiotherapy.

Statistical analysis Correlation between dosimetric parameters and acute toxicity was done with Student’s t-test (unpaired, 2-tailed). DFS was calculated from the date of diagnosis to disease progression and OS from the date of diagnosis to the last date of follow-up or death. CFS was calculated from the date of diagnosis to colostomy surgery. We used the date of diagnosis to the last date of follow-up to calculate the median time of follow-up. The study end points were

Table 1 Planning Objectives & Dose–volume constraints for organs at risk. Planning Objectives

Treatment Plan

Constraints

PTV54 volume

54 Gy to 95% in 30 fractions over six weeks

No more than 1% of the PTV54 will receive > 110% of 54 Gy No more than 1% of PTV54 will receive < 90% of 54 Gy

PTV45 volume

45 Gy to 95% in 30 fractions over six weeks

No more than 1% of the PTV45 will receive > 115% of 45 Gy No more than 1% of the PTV45 will receive < 80% of 45 Gy

Organs at risk

Dose–volume constraints

Not accepted

Peritoneal cavity

V30 6 50% V50 6 5% Dmax 6 52 Gy

Abs. Vol. receiving > 45 Gy Dmax > 52 Gy

Bone marrow

V10 6 65% V20 6 55% Minor Violation: V10 = 65–70% V20 = 55–60% Major Violation: V10 = 70–75% V20 = 60–65%

External genitalia

V25 6 50% V30 6 35% V40 6 5%

Femur

Dmax 6 52 Gy Median dose 6 45 Gy

Bladder

Median Dose 6 50 Gy

V10 > 75% V20 > 65%

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Tomotherapy based chemo-RT for anal cancer: K Joseph et al.

calculated by the Kaplan–Meier method. SAS (version 9.3, SAS Institute Inc., Cary, NC) was used for all statistical analysis. Results Fifty-eight patients (20 males and 38 females) were accrued for the study. The median age was 58 years (range: 37–83). One patient had undergone excision of primary tumor before enrollment. The stage distribution consisted of: stage II-48%, IIIA-18%, IIIB-34%. One enrolled patient was a screen fail and did not receive CRT due to comorbidity issues and was not included in toxicity or outcome analyses. Table 2 describes patient and disease characteristics and Supplementary Table 1 describes the dosimetry. Three patients were not able to complete the full course of radiation treatment for the following reasons: 1 declined treatment after 21 fractions; 1 developed acute paralytic ileus after 26 fractions; and 1 patient passed away after 8 fractions due to pulmonary embolism. Five patients had treatment breaks for more than 5 days due to hematological toxicity, skin reaction, and noncompliance (Supplementary Fig. 1); two of these patients had treatment delayed by 2 weeks. One patient declined any chemotherapy and five patients did not receive the 2nd cycle of chemotherapy for the following reasons: neutropenia, infection, myocardial infarction, noncompliance, and deceased. One patient received only partial 5FU in each cycle, as it was discontinued for development of chest discomfort while on 5FU. Twelve patients had physician recommended chemotherapy dose reduction for the 2nd cycle (Supplementary Fig. 1). Acute toxicity was defined as any toxicity that occurred during or within 3 months of CRT (Table 3). The majority of patients developed 6grade 2 scores during treatment that were resolved fully at 6 weeks of follow-up. In the 57 evaluable patients the rate of acute GI toxicity was: no toxicity in 1 (2%), grade 1 in 16 (28%), grade 2 in 30 (53%), and grade 3 or higher in 10 (18%) patients. Nine (16%) patients did not experience any genitourinary (GU) toxicity. Forty-six patients (81%) developed grade 1 or 2 toxicity and 2 (4%) developed grade 3 GU toxicity. Six patients (11%) experienced grade 3 dermatologic toxicity and 34 patients (60%) developed grade 2 dermatologic toxicity. Twelve patients (21%) developed grade 4 and 14 patients (25%) developed grade 3 hematologic toxicity. Peak hematological toxicity occurred between days 8–17 following MMC chemotherapy for all but one patient (day 22). For all

Table 2 Patient and tumor characteristics. Characteristics

Number of patients

Total number of patients Gender: male, female Median age in years (range) Location Histology AJCC stage grouping: II

57 20, 37 57 (37–83) Anal-55; perianal-2 Squamous cell carcinoma

T2N0M0 T3N0M0 IIIA T2N1M0 T3N1M0 IIIB T2N2M0 T2N3M0 T3N2M0 T3N3M0 T4N1M0 T4N2M0 TxN3M0

28 15 13 10 1 8 20 4 1 9 2 2 1 1

but two patients, blood counts recovered and the 2nd cycle of chemotherapy was not delayed due to hematological toxicity. One patient had a 2 week delay in chemotherapy and the other did not receive the 2nd cycle of chemotherapy. One patient received platelet transfusion and 3 had packed red blood cell transfusion. Three patients received granulocyte-colony stimulating factor (G-CSF) during treatment. Twenty-six patients were hospitalized during treatment, of which six patients were admitted more than once. Causes for hospital admission were symptom complex consisting of fatigue/ dehydration/pain, febrile neutropenia, skin reaction Pgrade 3, acute paralytic ileus, chest discomfort following 5FU infusion, and bacterial infection (Supplementary Fig. 1). Late toxicity was defined as any toxicity that occurred more than 3 months following completion of CRT (Table 4). Skin toxicity of grade 1 or 2 was seen in 30 patients (60%) and no patients had Pgrade 3. The most common grade 2 skin toxicity was telangiectasia (6 patients). Late GU and GI toxicity was negligible with only 1 (2%) patient having grade 3 GU toxicity and 3 patients with grade 3 or higher GI toxicity. In female patients (n = 33) the late gynecologic toxicity scores were: no toxicity in 10 (30%), grade 1 in 12 (36%), grade 2 in 8 (24%) and grade 3 in 3 (9%). No grade 4 gynecologic toxicity was reported. Other late events reported were interstitial pneumonia related to mitomycin (2 patients) and sacral insufficiency fracture (2 patients). Two patients underwent colostomy prior to CRT due to obstructive symptoms; one patient had colostomy reversal following CRT. Ten patients underwent abdominoperineal resection following CRT due to local recurrence (6 patients), fecal incontinence/rectal pain (2 patients), and planned surgery (2 patients). All recurrences were within the anal canal. Six patients developed metastatic disease; sites were paraaortic region (1 patient), liver (4 patients), and lung (1 patient). Nine patients have died to date: 5 of metastatic disease, 1 after developing mesothelioma, 1 from pulmonary embolism, and 2 from non-oncological causes without disease recurrence. The median follow-up time for all patients was 40 months. The 3 year CFS rate was 77% (95% confidence interval (CI): 61–87%), 3 year DFS rate was 80% (CI: 66–89%), and 3 year OS was 91% (CI: 77–96%) (Fig. 1).

Discussion Several non-randomized IMRT-based CRT studies have reported a significant reduction in acute GU, GI, and dermatologic toxicity compared to conventional radiotherapy [8,9,12,13]. Based on these acute data, many institutions are routinely using IMRT in the management of anal cancer. However, there are minimal prospective data available on toxicity. The work reported here is intended to provide more insight into the benefit of this therapeutic approach. Selecting appropriate dose-fraction for elective nodal irradiation (ENI) is significant when using IMRT, since nodal dose is delivered simultaneously (simultaneous integrated boost). In RTOG 9811, patients with uninvolved nodal region below the lower sacroiliac joints received 36 Gy over 4 weeks [2]. We used a dose of 45 Gy in 1.5 Gy per fraction for ENI and the equivalent standard dose was 43.1 Gy (EQD1.8). We adopted this dose regimen, since ENI is delivered over a period of six weeks. None of our patients failed regionally. The doses used for ENI in RTOG 0529 trial were based on tumor stage and nodal status, and were 42 Gy (1.5 Gy/ fx) or 45 Gy (1.68 Gy/fx) [9]. Our results compare favorably with acute toxicity data established in published chemoradiation trials [2,8,9] (Supplementary Table 1). Our data showed lower rates of grade 3 or higher acute non-hematological toxicities compared to the conventional series and comparable to published IMRT-based series. The RTOG 0529

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K. Joseph et al. / Radiotherapy and Oncology 117 (2015) 234–239 Table 3 Acute toxicity during treatment or within 12 weeks of treatment completion (n = 57). Acute toxicity site

Variable

Patients with acute toxicity, n (%) Grade 0

Grade 1

Grade 2

Grade 3

Grade 4

Gastrointestinal (GI)

Nausea Vomiting Anorexia Bloating/distention Diarrhea Rectal bleeding/discharge Proctitis Worst GI toxicity grade

16 (28.1%) 42 (73.7%) 17 (29.8%) 23 (40.4%) 7 (12.3%) 8 (14.0%) 7 (12.3%) 1 (1.8%)

32 14 30 29 28 37 25 16

(56.1%) (24.6%) (52.6%) (50.9%) (49.1%) (64.9%) (43.9%) (28.1%)

6 (10.5%) 0 (0%) 7 (12.3%) 3 (5.3%) 17 (29.8%) 12 (21.1%) 24 (42.1%) 30 (52.6%)

2 1 2 2 5 0 1 9

1 0 1 0 0 0 0 1

Hematologic (Hem)

Neutrophils Hemoglobin Platelets Worst Hem toxicity grade

15 (26.3%) 17 (29.8%) 18 (31.6%) 7 (12.3%)

5 (8.8%) 32 (56.1%) 23 (40.4%) 9 (15.8%)

14 (24.6%) 8 (14.0%) 11 (19.3%) 15 (26.3%)

11 (19.3%) 0 (0%) 5 (8.8%) 14 (24.6%)

12 (21.1%) 0 (0%) 0 (0%) 12 (21.1%)

Genitourinary (GU)

Urinary frequency/urgency Urinary retention Urinary Incontinence Dysuria Worst GU toxicity grade

20 (35.1%) 36 (63.2%) 48 (84.2%) 22 (38.6%) 9 (15.8%)

32 (56.1%) 19 (33.3%) 7 (12.3%) 31 (54.4%) 38 (66.7%)

4 2 2 3 8

1 0 0 1 2

0 0 0 0 0

Dermatologic

Radiation dermatitis

3 (5.3%)

14 (24.6%)

34 (59.6%)

6 (10.5%)

0 (0%)

General

Fatigue

1 (1.8%)

30 (52.6%)

20 (35.1%)

5 (8.8%)

1 (1.8%)

(7.0%) (3.5%) (3.5%) (5.3%) (14.0%)

(3.5%) (1.8%) (3.5%) (3.5%) (8.8%) (0%) (1.8%) (15.8%)

(1.8%) (0%) (0%) (1.8%) (3.5%)

(1.8%) (0%) (1.8%) (0%) (0%) (0%) (0%) (1.8%)

(0%) (0%) (0%) (0%) (0%)

Table 4 Late toxicity assessment after 3 months post treatment through 5 years. Late toxicity site

Variable

Percent of patients with late toxicity Grade 0

Grade 1

Grade 2

Grade 3

Grade 4

Dermatologic (Derm)

Skin induration/Fibrosis Skin atrophy Telangiectasia Radiation dermatitis Worst Derm toxicity grade

31 43 27 43 20

(62.0%) (86.0%) (54.0%) (86.0%) (40.0%)

14 (28.0%) 7 (14.0%) 17 (34.0%) 6 (12.0%) 19 (38.0%)

4 (8.0%) 0 (0%) 6 (12.0%) 1 (2.0%) 11 (22.0%)

0 0 0 0 0

(0%) (0%) (0%) (0%) (0%)

0 0 0 0 0

(0%) (0%) (0%) (0%) (0%)

Gastrointestinal (GI)

Incontinence Anal stricture/stenosis Pain Radiation Proctitis Worst GI toxicity grade

25 39 28 34 11

(50.0%) (78.0%) (56.0%) (68.0%) (22.0%)

15 (30.0%) 4 (8.0%) 15 (30.0%) 13 (26.0%) 24 (48.0%)

8 (16.0%) 5 (10.0%) 5 (10.0%) 2 (4.0%) 13 (26.0%)

0 0 2 0 2

(0%) (0%) (4.0%) (0%) (4.0%)

1 0 0 0 1

(2.0%) (0%) (0%) (0%) (2.0%)

Genitourinary (GU)

Urinary frequency/urgency Urinary retention Urinary Incontinence Worst GU toxicity grade

32 47 41 30

(64.0%) (94.0%) (82.0%) (60.0%)

17 (34.0%) 3 (6.0%) 7 (14.0%) 18 (36.0%)

1 0 1 1

0 0 1 1

(0%) (0%) (2.0%) (2.0%)

0 0 0 0

(0%) (0%) (0%) (0%)

General

Fatigue

20 (40.0%)

27 (54.0%)

2 (4.0%)

2 (2.0%)

0 (0%)

Gynecologic (Gyn) (n = 33)

Vaginal stenosis Dyspareunia Bleeding Dryness Worst Gyn toxicity grade

22 18 29 20 10

5 (15.2%) 6 (18.2%) 3 (9.1%) 10 (30.3%) 12 (36.4%)

4 5 1 3 8

1 2 0 0 3

0 0 0 0 0

(66.7%) (54.5%) (87.9%) (60.6%) (30.3%)

Survival proportions

Percent survival

100

CFS DFS OS

50

0

0

2

4

6

Time (years) Fig. 1. Kaplan–Meier Survival Curves Colostomy-free survival (CFS), disease-free survival (DFS), and overall survival (OS) were examined from time of diagnosis to the time of event or last follow-up.

(2.0%) (0%) (2.0%) (2.0%)

(12.1%) (15.2%) (3.0%) (9.1%) (24.2%)

(3.0%) (6.1%) (0%) (0%) (9.1%)

(0%) (0%) (0%) (0%) (0%)

study reported 23% of patients developed Pgrade 3 skin toxicity when treated with dose-painted IMRT in combination with 5FU/ MMC [9]. A single-institutional phase 2 study using IMRT by Han et al. reported that 47% of patients developed Pgrade 3 skin toxicity [8]. The series from Milano et al. reported no Pgrade 3 nonhematological toxicity using IMRT and concurrent 5FU/MMC [12]. In our study, 6 (11%) patients developed grade 3 skin toxicity and 34 (60%) experienced acute grade 2 skin toxicity. We did not find a correlation between radiation dose to the skin and toxicity although the total volume of skin was statistically correlated with toxicity (p = 0.035) (Supplementary Table 3). Of the 6 patients who developed grade 3 acute skin toxicity, 4 had been treated with bolus in the anal region. RTOG 0529 demonstrated nonrequirement of skin bolus when using IMRT as the oblique incidence of radiation beams increases superficial dose [9]. Similarly, with HT, skin bolus may not be required due to multiple beam projections, high beam modulation, and the dose contribution of the

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entrance and exit doses, all of which increase the average skin dose [14]. Reduction in severe skin toxicity in the treatment of anal cancer is important for patient quality of life and has significant clinical implications, since treatment related toxicity often leads to treatment interruptions that may have a negative impact on local tumor control [15–18]. We did not observe this as 2 patients had a treatment delay of 2 weeks for neutropenia and skin toxicity and neither had disease recurrence. Acute gastrointestinal toxicity was comparable to other IMRTbased series. The majority of patients (82.5%) experienced 6grade 2 GI toxicities. The lower incidence of GI toxicity could be multifactorial. Maintenance of a comfortably full bladder during radiotherapy and verification of bladder filling by MVCT could play a significant role. In addition, a lower dose per fraction (1.5 Gy) to the upper pelvis would also result in a decrease in bowel toxicity. Although dose–volume relationship with acute small bowel toxicity from CRT for rectal cancer has been previously reported we did not find a correlation between radiation dose and GI toxicity (Supplementary Table 3). This may be the result of differences in chemotherapy regime, RT dose, and RT technique. Incidence of GU toxicity was also low, with only two patients developing Pgrade 3 toxicity. A significant association between acute hematological toxicity and the iliac crest/bone marrow volume receiving >10 Gy and >20 Gy has been reported by Mell et al. [19]. Our dosimetric data have shown that the bone marrow V10 and V20 were significantly lower for the HT plans compared to IMRT [10]. We used stricter bone marrow dose–volume constraints compared to other IMRT studies and the toxicity scores were improved compared to RTOG studies; however the acute morbidity from hematological toxicity was higher. Nine patients were hospitalized due to febrile neutropenia, which presented during the final week of RT or within a week of completing RT for 7 of the 9 patients. Two patients had RT treatment breaks due to febrile neutropenia in combination with skin toxicity. No statistical correlation was seen between hematological toxicity and dose or volume of bone marrow irradiated (Supplementary Table 3). We believe hematological toxicity may be dominantly related to MCC chemotherapy as the blood counts dropped 1–2 weeks following chemotherapy and then recovered. Also, patients who did not have the 2nd cycle of chemotherapy only experienced 6grade 1 hematological toxicity during weeks 5 and 6 of RT. Studies have been done with MMC replaced by cisplatin, with and without adding cetuximab to CRT, but without improved clinical outcome [2,20,21]. We recommend limiting the bone marrow V10 and V20 to 665% and 675% of the bone marrow volume respectively, to reduce the RT contribution to hematological toxicity when using HT. Twenty-six patients were hospitalized during CRT. We are unable to compare this with other studies as they did not report SAE data. Ten patients were hospitalized with a symptom complex consisting of fatigue, dehydration, and perianal pain. These events occurred after the second course of chemotherapy and were treated with supportive care. Similarly the incidence of febrile neutropenia was common after the second course of chemotherapy, and resulted in treatment interruption for 2 patients. The data available on late toxicity provide more insight into the safety and benefit of modulated treatment deliveries, such as HT, for the treatment of anal cancer. To date there has been one grade 4 GI late toxicity score reported and the incidence of late Pgrade 3 toxicity was 0% for dermatologic toxicity and <5% each for GI and GU toxicity. The median follow-up time for all patients was 40 months. The 3 year CFS, DFS, and OS data are similar to other prospective phase 2 studies. Six of our patients had local recurrence and 6 had metastatic disease; five of the six metastatic patients died. Heterogeneity of clinical response has been linked to deferential tumor

biomarkers. Two highly studied biomarkers are p53 and p21; overexpression of these proteins has been associated with worse clinical outcomes by some groups while others have found no prognostic significance [22–27]. Recent studies have reported the influence of tumor HPV-DNA and p16 status on outcome of patients with anal canal cancer following CRT. While some studies found no significance [28,29], others found that high HPV-DNA load and p16 expression is correlated with improved CFS and OS [30,31]. Research on biomarkers in anal canal was in preliminary stages when we initiated this trial and we did not examine biomarkers for our patient cohort. At present studies have been with relatively small patient populations and there is no biomarker consensus but additional work may lead to biomarkers that would inform treatment of anal canal cancer. This study provides the first prospective report on treatment related late toxicity and safety of using dynamic helical IMRT for the treatment of anal cancer. However, this study has limitations in that it is a single arm study from a single institutional. The low incidence of anal cancer precluded a direct comparison arm so we have compared our data with RTOG 9811 and prospective phase 2 IMRT studies, even though these studies have used different doses and target definition criteria. In addition, our toxicity data were physician-reported and may be subject to bias. The clinical implications of this study include avoiding regular use of bolus and support for a simultaneous integrated boost. This study confirmed our previous findings [10] and supports integration of HT for the treatment of anal cancer as non-hematological toxicity scores were favorable to those reported with conventional RT. However, the expected dosimetric benefit for hematological toxicity was not experienced clinically and this may reflect that RT has a lower contributing role than chemotherapy to hematological toxicity from CRT. Future studies investigating newer treatment regimens should integrate IMRT as well as biomarker profiles of the patient. Conflicts of interest The authors have no conflicts of interest to declare. Funding This study was funded by the Alberta Cancer Board seed funding Grant and Alberta Innovates Health Solutions Grant: 2011RES0008619. The funding agencies had no role in study design, data analysis, or manuscript preparation. Acknowledgments The authors thank Larissa Vos, PhD, Scientific Publication Coordinator with the Clinical Trials Unit at the Cross Cancer Institute and John Hanson, MSc, statistician for their help in the preparation of the manuscript. Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.radonc.2015.08. 008. References [1] Epidermoid anal cancer: results from the UKCCCR randomised trial of radiotherapy alone versus radiotherapy, 5-fluorouracil, and mitomycin. UKCCCR Anal Cancer Trial Working Party. UK Co-ordinating Committee on Cancer Research. Lancet 1996;348:1049–54.

K. Joseph et al. / Radiotherapy and Oncology 117 (2015) 234–239 [2] Ajani JA, Winter KA, Gunderson LL, et al. Fluorouracil, mitomycin, and radiotherapy vs fluorouracil, cisplatin, and radiotherapy for carcinoma of the anal canal: a randomized controlled trial. JAMA 2008;299:1914–21. [3] Bartelink H, Roelofsen F, Eschwege F, et al. Concomitant radiotherapy and chemotherapy is superior to radiotherapy alone in the treatment of locally advanced anal cancer: results of a phase III randomized trial of the European Organization for Research and Treatment of Cancer Radiotherapy and Gastrointestinal Cooperative Groups. J Clin Oncol 1997;15:2040–9. [4] Flam M, John M, Pajak TF, et al. Role of mitomycin in combination with fluorouracil and radiotherapy, and of salvage chemoradiation in the definitive nonsurgical treatment of epidermoid carcinoma of the anal canal: results of a phase III randomized intergroup study. J Clin Oncol 1996;14:2527–39. [5] Glynne-Jones R, Nilsson PJ, Aschele C, et al. Anal cancer: ESMO-ESSO-ESTRO clinical practice guidelines for diagnosis, treatment and follow-up. Radiother Oncol 2014;111:330–9. [6] Leon O, Guren M, Hagberg O, et al. Anal carcinoma – survival and recurrence in a large cohort of patients treated according to Nordic guidelines. Radiother Oncol 2014;113:352–8. [7] Gunderson LL, Winter KA, Ajani JA, et al. Long-term update of US GI intergroup RTOG 98–11 phase III trial for anal carcinoma: survival, relapse, and colostomy failure with concurrent chemoradiation involving fluorouracil/mitomycin versus fluorouracil/cisplatin. J Clin Oncol 2012;30:4344–51. [8] Han K, Cummings BJ, Lindsay P, et al. Prospective evaluation of acute toxicity and quality of life after IMRT and concurrent chemotherapy for anal canal and perianal cancer. Int J Radiat Oncol Biol Phys 2014;90:587–94. [9] Kachnic LA, Winter K, Myerson RJ, et al. RTOG 0529: a phase 2 evaluation of dose-painted intensity modulated radiation therapy in combination with 5fluorouracil and mitomycin-C for the reduction of acute morbidity in carcinoma of the anal canal. Int J Radiat Oncol Biol Phys 2013;86:27–33. [10] Joseph KJ, Syme A, Small C, et al. A treatment planning study comparing helical tomotherapy with intensity-modulated radiotherapy for the treatment of anal cancer. Radiother Oncol 2010;94:60–6. [11] Taylor A, Rockall AG, Reznek RH, Powell ME. Mapping pelvic lymph nodes: guidelines for delineation in intensity-modulated radiotherapy. Int J Radiat Oncol Biol Phys 2005;63:1604–12. [12] Milano MT, Jani AB, Farrey KJ, et al. Intensity-modulated radiation therapy (IMRT) in the treatment of anal cancer: toxicity and clinical outcome. Int J Radiat Oncol Biol Phys 2005;63:354–61. [13] Salama JK, Mell LK, Schomas DA, et al. Concurrent chemotherapy and intensity-modulated radiation therapy for anal canal cancer patients: a multicenter experience. J Clin Oncol 2007;25:4581–6. [14] Lee N, Chuang C, Quivey JM, et al. Skin toxicity due to intensity-modulated radiotherapy for head-and-neck carcinoma. Int J Radiat Oncol Biol Phys 2002;53:630–7. [15] John M, Pajak T, Flam M, et al. Dose escalation in chemoradiation for anal cancer: preliminary results of RTOG 92–08. Cancer J Sci Am 1996;2:205–11. [16] Chakravarthy AB, Catalano PJ, Martenson JA, et al. Long-term follow-up of a Phase II trial of high-dose radiation with concurrent 5-fluorouracil and

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