Lung Cancer.pdf

148 R. Komaki
Around 1998, by using 3-dimensional conformal radiation therapy and
respiratory gating, we started to use a much tighter margin. We usually set
the CTV at 5 to 8 mm beyond the GTV and set the PTV at 10 to 15 mm beyond
the CTV when respiratory gating is done. When patients have atelectasis,
magnetic resonance imaging and PET help to distinguish tumor
from atelectasis. However, if the patient has a totally collapsed lung and
the tumor is endobronchial, we usually do endobronchial brachytherapy
to open up the main bronchial obstruction. Endobronchial techniques are
described later in this chapter. After expansion of the lung, we usually
give 60 Gy of external-beam radiation over 6 weeks.
Combined Chemotherapy and Radiation Therapy
Because of the poor outcomes in patients with stage II or III NSCLC treated
with radiation therapy alone, the Cancer and Leukemia Group B conducted
a trial designed to determine the value of adding chemotherapy to
this treatment. In this trial, 155 patients with stage III NSCLC with good
performance status and weight loss of less than 5% were randomly assigned
to treatment with 2 cycles of vinblastine and cisplatin followed by
radiation therapy (60 Gy in 6 weeks) or radiation therapy alone (60 Gy in 6
weeks) (Dillman et al, 1990) (Table 8–3). Patients who were treated with induction
chemotherapy followed by radiation therapy had a median survival
of 13.8 months, compared to 9.7 months for patients treated with radiation
therapy alone (P .04). The 2-year survival rate was significantly
better among the patients who received induction chemotherapy (26% vs
13%; P .006). A reanalysis of the results of this study after a longer followup
time (Dillman et al, 1996) showed a 5-year survival rate of 19% for patients
treated with induction chemotherapy, compared to 7% for those who
received radiation therapy alone.
In RTOG trial 88–08 (Sause et al, 1995), 452 patients with stage III
NSCLC with good performance status and weight loss of less than 5%
Table 8–3. Outcomes in Cancer and Leukemia Group B Trial Comparing
Induction Chemotherapy plus High-Dose Radiation Therapy
versus Radiation Therapy Alone in Patients with Stage III
NSCLC
Chemotherapy Radiation
and Radiation Therapy
Therapy Alone
Outcome
Survival rate
(N 78) (N 77)
1-Year 55% 44%
2-Year 26% 13%
5-Year 19% 7%
Median survival time 13.8 months 9.7 months
Source: Dillman et al, 1990 and 1996.