International Journal of Radiation Oncology*Biology*Physics
Clinical InvestigationTotal Gross Tumor Volume Is an Independent Prognostic Factor in Patients Treated With Selective Nodal Irradiation for Stage I to III Small Cell Lung Cancer
Introduction
Classic prognostic factors for survival in small cell lung cancer (SCLC) include stage, age, level of lactate dehydrogenase (LDH), time between start of any treatment to the end of radiation therapy (SER), male sex, N3 nodal status, and WHO performance score (WHO-PS) (1).
Clinicians intuitively accept that larger tumors are less likely to remain controlled. Gross tumor volume (GTV) is a fairly recent concept, which could not be investigated in the pre-computed tomography (CT) era. Indeed, in the International Union Against Cancer (UICC) TNM classification, only the T-stage may include the 2-dimensional (2D) diameter of the primary tumor, but size of nodes or total GTV are not present (2).
In prognostic models concerning non-small cell lung cancer (NSCLC), GTV, together with the number of nodal stations, outweigh TNM stage 3, 4 Therefore we investigated the value of total GTV, defined as the volume of the primary tumor and the involved lymph nodes on a planning positron emission tomography (PET)-CT as a potential stratification factor in SCLC. Furthermore, we updated our results of selective nodal irradiation (SNI) based on PET-CT (5).
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Patient population
Since 2003, patients treated at Maastro Clinic are collected in a prospective database.
We analyzed all patients with stage I to III SCLC referred for concurrent chemoradiation therapy from May 2004 until June 2009.
Patients had pathologically proven SCLC stage I to III according to UICC TNM classification version 6, excluding T4 disease due to malignant pleural or pericardial effusion (6). WHO-PS of 0 to 2 and adequate pulmonary function (forced expiratory volume at 1 second [FEV1], carbonic
Patient characteristics
From April 2004 until June 2009, 119 patients with stage I to III SCLC were referred to Maastro Clinic for concurrent chemoradiation therapy.
Patient characteristics are summarized in Table 1.
Patients were 41 to 85 years of age, with a median age of 66 ± 8.8 years. All but 2 patients received carboplatin-etoposide. Both of these patients received carboplatin-paclitaxel instead: 1 patient because of synchronous ovarian cancer, and the other because of intolerance to etoposide.
Two patients (1.6%)
Discussion
In the past years, the interest of researchers in selective nodal irradiation in SCLC has grown. Already starting from the late 1980s, smaller radiation ports were used in trials to decrease the acute toxicity of emerging combined modality treatments (10). However, omission of elective nodal irradiation was pioneered by De Ruysscher et al, whose first attempt of CT-based SNI yielded an elective nodal failure rate of 11%, probably due to the low sensitivity and specificity of CT in mediastinal
References (18)
- et al.
Small-cell lung cancer
Lancet
(2011) - et al.
Development and validation of a prognostic model using blood biomarker information for prediction of survival of non-small-cell lung cancer patients treated with combined chemotherapy and radiation or radiotherapy alone (NCT00181519, NCT00573040, and NCT00572325)
Int J Radiat Oncol Biol Phys
(2011) - et al.
Development and external validation of prognostic model for 2-year survival of non-small-cell lung cancer patients treated with chemoradiotherapy
Int J Radiat Oncol Biol Phys
(2009) - et al.
Selective nodal irradiation on basis of (18)FDG-PET scans in limited-disease small-cell lung cancer: a prospective study
Int J Radiat Oncol Biol Phys
(2010) - et al.
Routine individualised patient dosimetry using electronic portal imaging devices
Radiother Oncol
(2007) - et al.
Report from the International Atomic Energy Agency (IAEA) consultants' meeting on elective nodal irradiation in lung cancer: small-cell lung cancer (SCLC)
Int J Radiat Oncol Biol Phys
(2008) - et al.
Omission of elective node irradiation on basis of CT-scans in patients with limited disease small cell lung cancer: a phase II trial
Radiother Oncol
(2006) - et al.
Final results of a phase I/II dose escalation trial in non-small-cell lung cancer using three-dimensional conformal radiotherapy
Int J Radiat Oncol Biol Phys
(2006) - et al.
Positron emission tomography/computed tomography-guided intensity-modulated radiotherapy for limited-stage small-cell lung cancer
Int J Radiat Oncol Biol Phys
(2012)
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Conflict of interest: none.