</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span><span class="st">"age.factor"</span>, <span class="st">"sex.factor"</span>, <span class="st">"obstruct.factor"</span>, <span class="st">"perfor.factor"</span><span class="op">)</span></span></span>
<span class="r-in"><span><span class="va">dependent</span> <span class="op">=</span> <span class="st">"Surv(time, status)"</span></span></span>
<span class="r-in"><span></span></span>
<span 