Highest grade adverse event per subject were counted. Adverse events were graded using CTCAE v3.0. Grade refers to the severity of the AE. The CTCAE v3.0 assigns Grades 1 through 5 with unique clinical descriptions of severity for each AE based on this general guideline: Grade 1 Mild AE, Grade 2 Moderate AE, Grade 3 Severe AE, Grade 4 Life-threatening or disabling AE, Grade 5 Death related to AE. Acute toxicities occur within 90 days of the start of treatment.

Eligible patients with adverse event information.

Deviations in intensity-modulated radiation therapy technique (IMRT) planning were determined by central review by the radiation oncology co-chairs of the study.

All eligible patients who started IMRT

Highest grade adverse event per subject were counted. Adverse events were graded using CTCAE v3.0. Grade refers to the severity of the AE. The CTCAE v3.0 assigns Grades 1 through 5 with unique clinical descriptions of severity for each AE based on this general guideline: Grade 1 Mild AE, Grade 2 Moderate AE, Grade 3 Severe AE, Grade 4 Life-threatening or disabling AE, Grade 5 Death related to AE. Acute toxicities occur within 90 days of the start of treatment.

Eligible patients who started protocol treatment

Highest grade adverse event per subject were counted. Adverse events were graded using CTCAE v3.0. Grade refers to the severity of the AE. The CTCAE v3.0 assigns Grades 1 through 5 with unique clinical descriptions of severity for each AE based on this general guideline: Grade 1 Mild AE, Grade 2 Moderate AE, Grade 3 Severe AE, Grade 4 Life-threatening or disabling AE, Grade 5 Death related to AE. Late toxicities occur greater than 90 days from the start of treatment.

Eligible patients who started IMRT and were on-study > 90 days from the start of treatment (or did not withdraw consent until after 90 days).

A complete clinical response was defined as complete resolution of all palpable tumor determined by digital rectal exam and proctosigmoidoscopy supplemented with pelvic axial imaging.

Eligible patients who started study treatment

Number of days from radiotherapy treatment start to radiotherapy treatment end

Eligible patients who started IMRT

Overall survival time is defined as time from registration/randomization to the date of death from any cause. Overall survival rates are estimated by the Kaplan-Meier method. Patients last known to be alive are censored at the date of last contact.

Eligible patients who started study treatment

Disease-free survival time is defined as time from registration to the date of local-regional failure, the appearance of distant metastases, the appearance of a second primary failure, or date of death from any cause and is estimated by the Kaplan-Meier method. Patients last known to be alive without failure are censored at the date of last contact. Local failure is defined as any measurable disease after 12 weeks from the completion of chemoradiation therapy. Local failure is defined as: a) For patients with no disease in pelvic and/or groin nodes, the appearance of disease in pelvic or groin nodes; b) For patients with disease in pelvic and/or groin nodes at study entry, nodal recurrence following clearance or persistent nodal disease for more than 12 weeks after completion of treatment.

Eligible patients who started study treatment

Local-regional failure time is defined as time from registration to date of failure and is estimated by the cumulative incidence method. Patients last known to be alive without failure are censored at the date of last contact. Local-regional failure is defined as a local or regional failure. Local failure is defined as any measurable disease after 12 weeks from the completion of chemoradiation therapy. Regional failure is defined as: a) For patients with no disease in pelvic and/or groin nodes, the appearance of disease in pelvic or groin nodes; b) For patients with disease in pelvic and/or groin nodes at study entry, nodal recurrence following clearance or persistent nodal disease for more than 12 weeks after completion of treatment.

Eligible patients who started study treatment

Distant failure time is defined as time from registration to the appearance of distant metastases and is estimated by the cumulative incidence method. Patients last known to be alive without failure are censored at the date of last contact.

Eligible patients who started study treatment

Colostomy failure time is defined as time from registration to the date of colostomy or abdominoperineal (A-P) resection and is estimated by the cumulative incidence method. Patients last known to be alive without failure are censored at the date of last contact.

Eligible patients who started study treatment

Colostomy-free survival time is defined as time from registration to date of colostomy or abdominoperineal (A-P) resection, or date of death from any cause and is estimated by the Kaplan-Meier method. Patients last known to be alive without failure are censored at the date of last contact.

Eligible patients who started study treatment