Type of Lymph Node Involvement Influences Survival Rates in T1N1M0 Non-small Cell Lung Carcinoma (Results)

In: Lung Carcinoma

22 Dec 2013

Type of Lymph Node Involvement Influences Survival Rates in T1N1M0 Non-small Cell Lung Carcinoma (Results)One patient died within 30 days of the operation, accounting for a hospital mortality of 1.7%. Only survival of hospital survivors was analyzed (n=57). The cumulative post-operative survival at 5 years was 45.7% (Fig 1).

Direct Extension Compared With Hilar and Lobar Metastases

The 5-year survival of patients with nodal involvement by direct extension was significantly better than those with nodal metastases (68.6% vs 31.2%; p=0.0038) (Fig 2). When patients with nodal metastases were divided into patients with hilar or lobar metastases, and subsequently compared to patients with nodal involvement by direct extension, survival of patients with direct extension was significantly better than those with hilar metastases (68.6% vs 23.3% at 5 years; p=0.0006). The survival was also superior to those with lobar metastases, but not significantly (68.6% vs 55.6% at 5 years; p=0.34) (Fig 3).

Direct Extension Into Hilar or Lobar Lymph Nodes Compared With Hilar and Lobar Lymph Node Metastases

No significant difference was found in survival between patients with hilar vs lobar direct extension (57.1% vs 72.9%; p=0.91) or between these subgroups and hilar or lobar metastases (hilar by direct extension vs hilar metastases, p=0.068; lobar by direct extension vs lobar metastases, p=0.33; and hilar by direct extension vs lobar metastases, p=0.67) except for lobar by direct extension vs hilar metastases, p=0.019 (Table 2). Survival of patients with lobar metastatic disease was better than of patients with hilar metastatic disease (55.6% vs 23.3% at 5 years; p=0.09).

Prognostic Factors

The influence of various factors related to postoperative survival was examined by univariate analysis (Table 3). Besides type of nodal involvement, the site of nodal involvement influenced the prognosis significantly. When the total study population was divided in hilar (n=32) and lobar (n=25) disease, a significantly better survival was seen in the lobar-disease group (p=0.016). All other variables did not show significant differences in survival.

Also, multivariate analysis using Cox’s proportional hazards model showed a significant difference for site of lymph node involvement (relative risk [RR] of 2.28; confidence interval [Cl], 1.14 to 4.56; p=0.019 for “hilar disease”)- When the variable .“type’ of lymph node involvement” (direct extension vs nodal metastases) was added to Cox’s model, “site of lymph node involvement” showed no significance anymore, but type of N1 disease was observed as a prognostic factor for survival (RR of 0.31; Cl, 0.15 to 0.66; p=0.0024 for “direct extension”). Age, too, was observed as a prognostic factor for survival (RR of 0.48; Cl, 0.24 to 0.97; p=0.042 for age ^60 years).

Patterns of Recurrence

Recurrent disease was seen in 50.9% of the cases. Local recurrence of malignancy was found in 7 patients, distant metastases in 11, and both local recurrence and metastases in 11 (Table 4). Two patients with local recurrence are still alive. The pattern for local and distant recurrence in both lobar and hilar metastatic disease is similar, but recurrence is less frequent in the direct extension group. When taking both distant and combined recurrences together, relapses are more frequently seen in patients with hilar than in patients with lobar metastases or in patients with involvement by direct extension (56% vs 33% vs 22%). As already mentioned, one patient was unavailable for follow-up; he had nodal involvement by direct extension and died 2 years after a combined operation (resection of right upper lobe and coronary bypass grafting). Table 5 gives the cause of death and the clinical status at the end of the study period.

Death rates as a result of the primary tumor seem to be lowest in the direct extension group (0.26 vs 0.44 for lobar and 0.64 for hilar), although the cause of death in 1 patient is not known. All patients who died as a result of their primary tumor had recurrent disease. Total survival rate at the end of the study period is best in the direct extension group, worse in the lobar metastases group, and worst in the hilar metastases group; 52.1%, 44.4%, and 16.0%, respectively.

Table 2—Estimated Mean 5-Year Survival for Different Types of Lymph Node Involvement

Type of Involvement No. of Patients Mean 5-yr Survival, %
By metastases 34 31.2
Hilar metastases 25 23.3
Lobar metastases 9 55.6
By direct extension 23 68.6
Direct extension hilar 7 57.1
Direct extension lobar 16 72.9

Table 3—Univariate Analysis of Factors Influencing Postoperative Survival

Variable Categories No. of Patients Mean 5-yr Survival, % p Value (Log-Rank)
Age, yr
<60 24 49.6 0.11
>60 33 42.6
Sex
Male 51 44.6 0.78
Female 6 50.0
Histology
Squamous 45 45.2 0.77
Nonsquamous* 12 46.1
Type of node involvement
By direct extension 23 68.6 0.0038
Metastases 34 31.2
Site of node involvement
Lobar* 25 67.3 0.016
Hilar^ 32 29.9
Type of resection
Lobectomy 37 37.6
Sleeve lobectomy 6 83.3 0.28
Bilobectomy 8 60.0
Pneumonectomy 6 50.0

Table 4—Patterns of Recurrence 

Direct Extension,No. (%) Hilar, No. (%) Lobar, No. (%)
Local 2 (8.7) 3 2 (22.2)
Distant 1 (4.3) 8 2 (22.2)
Combined 4 (17.4) 6 1(11.1)

Table 5—Death and Survival Patterns

Direct Extension Hilar Lobar
Cause of death
Primary tumor 6 (0.26) 16 (0.64) 4 (0.44)
Other 4 5 1
Unknown 1
Survivors
Local recurrence/ 1 1
metastases
No evidence of 11 4 3
recurrence
Unknown

figure-1

Figure 1. Overall survival at 5 years after complete resection of TIN 1 MO non-small cell lung carcinoma. Vertical notches=censored cases.

figure-2

Figure 2. Five-year survival curves: nodal involvement by direct extension (solid line) vs nodal metastases (dotted line). Vertical notches=censored cases.

figure-3

Figure 3. Five-year survival curves for direct extension (solid line), lobar node metastases (dash-dot line), and hilar node metastases (dotted line). Vertical notches=censored cases./td


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