Top Line: Radiation dose-escalation during total neoadjuvant therapy for locally-advanced rectal cancer is an intriguing concept to increase the success rate of organ preservation.
The Study: The OPERA trial—not to be confused with the OPRA trial—was a large French multicenter phase 3 trial where 141 patients with operable T2-T3bN0-N1 rectal cancers <5 cm receiving neoadjuvant chemoradiation to the pelvis 45 Gy in 25 fractions with concurrent Xeloda were randomized to an external beam versus contact x-ray brachytherapy tumor boost. In the external beam arm, the target was gross tumor with a 2 cm margin prescribed an additional 9 Gy in 5 fractions. Now to contact x-ray brachy. Apparently it’s been done in France for roughly 70 years and uses endoscopy to visualize the tumor and deliver an endoluminal superficial radiation of sorts of around 50 kV energy. Here the boost dose was 90 Gy in 3 fractions delivered over 4 weeks. Of note, the contact x-ray brachy boost preceded pelvic radiation when the tumor was <3 cm and followed it when ≥3 cm. In both arms, surgery was performed roughly 14 weeks from the start of radiation in the case of a partial response per endoscopy and/or MRI. A watch and wait approach was used for complete responders with some “near” complete responders getting away with a TEM alone (still considered organ preservation). The primary outcome of organ preservation at 3 years was 59% with the standard approach versus a whopping 81% with contact x-ray brachy. For tumors <3 cm those rates were 63% versus an impressive 97%, and for tumors ≥3 cm it was 55% versus 68%. What’s more, this was all achieved without adjuvant chemotherapy, which was discouraged and received only by six enrollees following resection per physician preference. The biggest discrepancy in toxicity was late grade 1-2 bleeding telangiectasias experienced by 63% of patients following contact x-ray brachy for tumors >3 cm.
TBL: In this randomized trial, endoluminal contact x-ray brachytherapy boost for rectal cancers <3 cm significantly improved organ preservation for rectal cancer compared to external beam boost. | Gerard, Lancet Gastroenterol Hepatol 2023
The Study: The OPERA trial—not to be confused with the OPRA trial—was a large French multicenter phase 3 trial where 141 patients with operable T2-T3bN0-N1 rectal cancers <5 cm receiving neoadjuvant chemoradiation to the pelvis 45 Gy in 25 fractions with concurrent Xeloda were randomized to an external beam versus contact x-ray brachytherapy tumor boost. In the external beam arm, the target was gross tumor with a 2 cm margin prescribed an additional 9 Gy in 5 fractions. Now to contact x-ray brachy. Apparently it’s been done in France for roughly 70 years and uses endoscopy to visualize the tumor and deliver an endoluminal superficial radiation of sorts of around 50 kV energy. Here the boost dose was 90 Gy in 3 fractions delivered over 4 weeks. Of note, the contact x-ray brachy boost preceded pelvic radiation when the tumor was <3 cm and followed it when ≥3 cm. In both arms, surgery was performed roughly 14 weeks from the start of radiation in the case of a partial response per endoscopy and/or MRI. A watch and wait approach was used for complete responders with some “near” complete responders getting away with a TEM alone (still considered organ preservation). The primary outcome of organ preservation at 3 years was 59% with the standard approach versus a whopping 81% with contact x-ray brachy. For tumors <3 cm those rates were 63% versus an impressive 97%, and for tumors ≥3 cm it was 55% versus 68%. What’s more, this was all achieved without adjuvant chemotherapy, which was discouraged and received only by six enrollees following resection per physician preference. The biggest discrepancy in toxicity was late grade 1-2 bleeding telangiectasias experienced by 63% of patients following contact x-ray brachy for tumors >3 cm.
TBL: In this randomized trial, endoluminal contact x-ray brachytherapy boost for rectal cancers <3 cm significantly improved organ preservation for rectal cancer compared to external beam boost. | Gerard, Lancet Gastroenterol Hepatol 2023