Treatment for less toxicity in locally advanced esophageal cancer

19 Oct 2015

For patients with locally advanced esophageal cancer that has spread to the lymph nodes, radiation therapy that targets only the involved lymph nodes regions results in less toxicity without causing a statistically significant difference in loco-regional lymph nodal recurrence, distant failure and overall survival rates. This is revealed in a new clinical research.

Chemo radiation (the combination of chemotherapy and radiation therapy) is a standard treatment for locally advanced esophageal cancer (cancer that has spread to the lymph nodes and surrounding tissue). Elective nodal irradiation (ENI) a radiation therapy to the tumor and lymph nodes, including uninvolved lymph nodes in the region around the cancerous tumor, is a common form of radiation therapy used to treat esophageal squamous cell carcinoma. However, the use of elective nodal irradiation has been controversial due to increased level of irradiation and possible toxicity.

Esophageal cancer is far more prevalent in China, with esophageal squamous cell carcinoma being the most common type of esophageal cancer in China.

Details of the clinical study

This study evaluated the feasibility of reducing the nodal irradiation volume of radiation therapy by comparing elective nodal irradiation to involved-field irradiation, meaning a radiation therapy that involves only the regions where the lymph nodes are located. The prospective, randomized controlled clinical trial included 110 patients with esophageal cancer enrolled from nine cancer centers across China between April 2012 and November 2014.

The patients had inoperable, newly diagnosed stage II-stage III thoracic esophageal squamous cell carcinoma. The patients were treated with concurrent chemo-radiotherapy and all of the patients received docetaxel and CDDP every 21 days for two to four cycles. The patients received image-guided radiation therapy in once-daily fractions of 1.8-2Gy to a total dose of 60-66 Gy to the gross tumor volume and 50-54 Gy to the clinical target volume.

The patients were randomly divided into two groups; 56 patients received elective nodal irradiation (the ENI group); and 54 patients received involved-field irradiation (the IFI group). The primary endpoints of the study were toxicities (side effects) and loco-regional lymph nodal recurrence (indicating the cancer had returned to the area and nearby lymph nodes). The secondary end points were distant failure and overall survival.

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Involved-field irradiation resulted in significantly decreased radiation pneumonitis

At a median follow-up of 20 months, data showed that:

  • Involved-field irradiation resulted in significantly decreased radiation pneumonitis (inflammation of the lungs) and radiation esophagitis (inflammation of the lining of the esophagus).
  • Grade ≥ 2 radiation pneumonitis in the ENI group was 26.8%, compared to 12.9% in the IFI  group.
  • The rate of radiation esophagitis was 37.5% in the ENI group compared to 20.4% in the IFI group.
  • No significant differences in the loco-regional lymph nodal recurrence rate were observed between the two groups.
  • The ENI group experienced a 17.9% loco-regional lymph nodal recurrence, compared to the IFI group, which experienced a 20.4% loco-regional lymph nodal recurrence.
  • Evaluation of distant failure rates (measurement of whether the cancer appeared in other areas other than the original tumor site), indicated a positive result with no difference between the two groups.
  • The ENI group had a 12.5% distant failure rate and the IFI group had a 13% distant failure rates.

Were there any differences in survival rates between the two groups?

With a reference to survival rates, the analysis of the results also showed that:

  • The two groups achieved similar one-year and two-year overall survival rates.
  • The one-year overall survival rate was 89.2% for the ENI group and 88.3% for the IFI group  and
  • The two-year overall survival rates was 64.2% for the ENI group, compared to 55.6% for the IFI group.

“A significant discovery for future esophageal cancer radiotherapy care”

“Elective nodal irradiation (ENI) is the most commonly used type of radiation therapy for treating esophageal cancer, but its side effects and toxicity have been criticized,” said Tao Li, MD, PhD, lead author of the study and vice chairman of the department of radiation oncology at Sichuan Cancer Hospital and Institute.

“Researchers have suggested decreasing the nodal irradiation volume with the use of involved-field irradiation, yet prior to this study its potential advantages had only been measured in smaller trials. We anticipated that involved-field irradiation could significantly decrease toxicity such as radiation pneumonitis and radiation esophagitis, but were initially uncertain if involved-field irradiation might increase the loco-regional lymph nodal recurrence rates, distant failure and overall survival. The mid-term results of our trial show that involved-field irradiation is an acceptable and toxicity-minimizing method of treatment for thoracic esophageal squamous cell carcinoma. This is a significant discovery for future esophageal cancer radiotherapy care.”

Source: eCancer News
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