54 Chapter 4 Table 2. Frequency distribution of the clinicopathological characteristics for the Four Major pT3N0 Subtypes (continued) pT3N0 >7 cm 2nd/multiple nodule(s) Parietal pleural invasion Mixed Total p-value Characteristic n % n % n % n % n (%) Chemotherapy 0.51 No 153 61.0 114 65.9 90 58.4 62 59.0 Yes 98 39.0 59 34.1 64 41.6 43 41.0 Radiotherapy <0.001 No 241 96.0 167 96.5 119 77.3 83 79.0 Yes 10 4.0 6 3.5 35 22.7 22 21.0 Chemoradiation <0.001 No 148 59.0 112 64.7 68 44.2 48 45.7 Only CT 93 37.1 55 31.8 51 33.1 35 33.3 Only RT 5 2.0 2 1.2 22 14.3 14 13.3 Yes 5 4 13 8 Note: the four major subtypes are as follows: larger than 7 cm; with second / multiple nodules; with pleural invasion and mixed. AdC, adenocarcinoma; SqCC, squamous cell carcinoma; NOS, NSCLC not otherwise specified; Rx, microscopic resection margin unknown; R0, microscopic negative resection margin; R1, microscopic positive resection margin; CT, chemotherapy; RT, radiotherapy. Tumors with a diameter larger than 7 cm were more often found in the lower lobes, whereas at least two-thirds of the other subtypes were found in the upper lobes (p<0.001). However, no differences in OS were noted for tumors ‘larger than 7 cm’ found in the lower lobes, compared to those in the upper lobes (p=0.16, log-rank test). A total of 264 of the 683 (38.7%) were treated with adjuvant chemotherapy, irrespective of the pT3N0 subtype. Post-operative radiotherapy was administered in 73 patients (10.7%), but rarely to patients with pT3N0 subtypes tumor diameter larger than 7 cm and two or more nodules. However, nearly 20% of patients in the group with the pleural invasion and mixed subtypes received radiotherapy (p<0.001). Survival The 3-and 5-year overall survival rates for the entire study population was 57.0% and 47.9%, respectively (Fig. 2). The four pT3N0 subtypes showed significant differences in OS (p<0.001) with the best prognosis for the subtype with two or more nodules in the same lobe (5-years OS 62.8%), and the worst for the mixed subtype (5-years OS 28.7%) (Fig. 3).
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