Stereotactic Body Radiotherapy Effective in Non-Small Cell Lung Cancer

AuntMinnie | Stereotactic body radiotherapy (SBRT) provides good local control and overall survival in patients with stage I non-small cell lung cancer (NSCLC), according to a report from Japan.

The authors consider SBRT a good alternative to surgery for these patients. The lead author, Dr. Yuta Shibamoto from Nagoya City University Graduate School of Medical Sciences, told Reuters Health by email, “Physicians must be aware of the new treatment, and they must explain to operable stage I NSCLC patients that there are two treatment options. Choice of either treatment is definitely at the discretion of each patient.”

The most common SBRT regimen for stage I NSCLC in Japan involves 48 Gy delivered in four fractions over four days, the authors reported online August 25 in Cancer.

But, the paper says, “radiobiologically, higher doses are necessary to control larger tumors, and interaction intervals should be greater than 24 hours to take advantage of reoxygenation.”

To take advantage of the benefits of reoxygenation in tumors, Dr. Shibamoto and colleagues delivered their four fractions with interfraction intervals of at least three days.

Patients received a total of 44 Gy for tumors less than 1.5 cm, 48 Gy for tumors 1.5 to 3.0 cm, and 52 Gy for tumors larger than 3.0 cm.

The median follow-up was 36 months for all 180 patients in the study and 42 months for the patients who remained alive.

The overall survival rate was 69% at three years and 52% at five years. The local control rate was 83% at three years and thereafter. Control rates at three years were 85% for regional metastasis and 80% for distant metastasis.

There were no local recurrences for patients who received 44 Gy. The local control rate at three years and thereafter was 86% for patients who received 48 Gy and 73% for patients who received 52 Gy. All local recurrences in these patients developed within three years after SBRT.

Overall survival rates were higher for the 60 operable patients (74% at three years; projected at 70% at five years) than for the 120 inoperable patients (59% at three years; projected at 44% at five years). Three-year overall survival rates were also higher for 45 operable patients with T1 tumors (80%) than for 15 operable patients with T2 tumors (58%).

“The standard treatment for medically operable patients with stage I NSCLC has been surgery,” Dr. Shibamoto explained. “The overall survival rate in our series is 70% at five years for medically operable patients. This rate is similar to most published results of surgery. The local control rate may be slightly inferior to that obtained by surgery, but some of the local recurrences can be salvaged, so overall survival results are comparable.”

“The standard treatment for medically inoperable patients with stage I NSCLC has been conventional radiation therapy,” Dr. Shibamoto continued. “Our results are definitely superior to those obtained by conventional radiation (five-year survival: usually 15-20%). Conventional radiation seems to have no role any longer.”

Grade 2 or greater toxicities included radiation pneumonitis (24 patients, 13.3%), esophagitis and rib fracture (three patients each, 1.7%), dermatitis (seven patients, 3.9%), and pleural effusion and cardiac effusion (one patient each, 0.6%).

“We are not completely satisfied with the results,” Dr. Shibamoto said. “To further improve the results (especially local control), we are now conducting the next study using higher radiation doses or combination chemotherapy with TS-1. To obtain mature results, we still need another three years.”

By Will Boggs, MD


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