Dose escalation using dose-painted IMRT in locally advanced rectal cancer.

582 Background: After preoperative chemo-radiation, clinical response and tumor pathologic downstaging showed a close correlation with improved outcomes. We report our initial experience in dose escalation using dose-painted intensity-modulated radiation therapy (DP-IMRT) in patients with locally advanced rectal cancer. Methods: Fifteen patients with locally advanced rectal cancer (T3-4,N0-1) were prospectively identified. Tumors were staged using the cTNM classification by PET/CT, EUS & MRI. All received preoperative 5-FU and DP-IMRT. Doses were prescribed as follows:56 Gy/2.0 Gy fractions (fxn) to the planning target volume (PTV) and 47.6Gy/1.7Gyfxn to elective nodal PTV. Surgery was performed 6-8 weeks after chemo-radiation. The surgical procedure was tailored to tumor downstaging. The choice of sphincter-preserving surgery was based on the distance between the lower tumor pole and the anorectal ring “ after” chemoradiation. All were reevaluated for tumor response, preoperatively by imaging studies (ycTNM) and by pathological staging (ypTN) following surgery. Acute and late toxicities were monitored by the treating physician. Results: All patients completed therapy. Tumors were in the lower 1/3 in 3 patients, middle 1/3 in 7, and upper 1/3 in 5. With preoperative endorectal US, PET/CT and MRI, the clinical staging of the tumors was: 13 (T3N0) and 2 (T4N0). Acute toxicity was limited to a moderate proctitis (RTOG acute toxicity scoring system, G1 ) in all patients, with two patients with tumors extending into the anal canal having G 3 dermatitis. Complete clinical response was obtained in 10 of 15 patients.All 15 underwent surgery; 6 had pathological pT0N0, 4 had residual micro foci of carcinoma (pT1N0), and 5 had residual disease limited to the muscularis propria (pT2N0). No difference in perioperative complications was seen. Conclusions: Preoperative dose-escalation using dose-painted radiation therapy (DP-IMRT) seems to be safe. Moderate local acute toxicity was seen with very low-lying tumors. This modality provides a high rate of tumor downsizing especially for patients with lesions in the lower 2/3 of the rectum with a possible potential for an increased ability to perform sphincter-preserving surgery.

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Radiation Therapy Dose Escalation to Clinically Involved Pelvic Sidewall Lymph Nodes in Locally Advanced Rectal Cancer

Advances in Radiation Oncology ◽

10.1016/j.adro.2019.03.007 ◽

2019 ◽

Vol 4 (3) ◽

pp. 478-486 ◽

Cited By ~ 1

Author(s):

Pehr E. Hartvigson ◽

Smith Apisarnthanarax ◽

Stephanie Schaub ◽

Stacey Cohen ◽

Greta Bernier ◽

...

Keyword(s):

Rectal Cancer ◽

Radiation Therapy ◽

Lymph Nodes ◽

Dose Escalation ◽

Locally Advanced ◽

Advanced Rectal Cancer ◽

Locally Advanced Rectal Cancer

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Deferral of rectal surgery following a continued response to preoperative chemoradiotherapy (Watch and Wait) study: A phase II multicenter study in the United Kingdom.

Journal of Clinical Oncology ◽

10.1200/jco.2011.29.4_suppl.489 ◽

2011 ◽

Vol 29 (4_suppl) ◽

pp. 489-489 ◽

Cited By ~ 11

Author(s):

S. K. Yu ◽

G. Brown ◽

R. J. Heald ◽

S. Chua ◽

G. Cook ◽

...

Keyword(s):

Rectal Cancer ◽

Surgical Resection ◽

Locally Advanced ◽

Neoadjuvant Treatment ◽

Neoadjuvant Chemoradiotherapy ◽

Complete Response ◽

Advanced Rectal Cancer ◽

Locally Advanced Rectal Cancer ◽

Clinical Staging ◽

Pet Ct

489 Background: Neoadjuvant chemoradiotherapy (CRT) and surgical resection are standard components of therapy for patients locally advanced rectal cancer (T3,T4 or N+) in UK. In 15%-30% of patients treated pre-operatively with CRT will develop pathological complete response (CR). The time from completion of CRT to maximal tumour response is as yet unknown. This study is the first prospective study to attempt to identify the percentage of patients who can safely omit surgery and the safety of deferred surgery in patients who achieve clinical complete response post CRT. Of the 59 patients required for the study, this provides an update on 19 patients entered. Methods: Patients with locally advanced rectal cancer requiring neoadjuvant treatment are identified in the multidisciplinary meet (MDT). Patients undergo CRT using a minimum of 50.4Gy in 28 # daily conformal CT planned CRT with concomitant Capecitabine at 825mg/m2 BD. MRI pelvis and body CT are repeated 4 weeks post CRT and rediscussed at MDT. If there is a good partial response or CR, patients are considered for Deferral of Surgery Study. Based on the pre treatment clinical staging, patients are considered for adjuvant chemotherapy as per NICE guidance. At any point of the study, if there is histology proven tumour regrowth or progression, patient undergo surgery. Results: 10 (53%) patients remain in CR. 6 (32%) patients underwent surgical resection with clear margin after detection of tumour regrowth at from 2-23 months post CRT. 5 out of 6 of the patients with tumour regrowth underwent PET CT as per protocol, and all tumour regrowth in those 5 patients were detected by PET CT, i.e. FDG avid disease. The pathological stages on these 6 patients were ypT2N0 CRM negative in 5 and ypT3N0 CRM negative in 1. 3 (15%) patients with tumour regrowth refused surgery. Conclusions: In the 19 recruited patients, all the patients with tumour regrowth underwent surgical resection with clear margins. PET CT appears a useful tool for detecting tumour regrowth. The median time for tumour regrowth is 17.5 months post CRT. The trial will be successful if at least 11/59 patients are able to safely omit surgery. Accrual of patients continues. No significant financial relationships to disclose.

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