Yes, the lungs function quite adeptly at clearing out deposits (otherwise, they wouldn't work to well in environments with fine dust or wood fire based cooking). However, this doesn't really mitigate the damage of repeated exposure to carcinogens. In fact, lung cells divide very rapidly to facilitate such resilience, exacerbating carcinogenesis.
ebola
This.
Also, some Petroleum related hydrocarbons are cancerous in the same way Asbestos is cancerous. After reading about hydrocarbons with one certain molecular shape (don't remember what it was called, I have it book market on PC tho) are actually "too big" for blood cells to move, and therefore they can't be filtered out through the liver.
Normally, a foreign object is engulfed by a white blood cell, then take to the liver to be disposed of. When it's too big, the white blood cells, and certain antibodies will break the substance apart. This turns it into smaller pieces, which the white blood cells can move into liver to under go further metabolism or to be excreted.
The two I was reading about had a molecular structure that was too big to move, and couldn't be broken down by white blood cells, or antibodies. Therefore it just sits in the lungs. They also described the molecule being like a piece of glass in your lung tissue. Because it just sits there, as the tissue is moving, it actually tears and cuts the tissue apart - causing internal bleeding and scar tissue build up.
The lungs are able to expel some of these through exhalation, but the ones that don't (those certain hydrocarbon) can sit in your lungs for years without the body being able to do a thing about it.
These are the ones that are particularly cancerous. But as Ebola said, constant exposure causes irreparable damage overtime.
Don't fool yourself into believing that Hydrocarbons aren't as dangerous or cancerous, just because the body "removes them easily." It doesn't really matter what the smoke is made of. It's been retested, and reconfirmed everytime in every study over the past 120 years. Inhaling smoke can cause cancer. Period. No ifs, ands or buts. If you're inhaling smoke, eventually you're going to get cancer.
@ebola Even the studies provided stated that CB agonism isn't going to stop cancer in a moderate to heavy user. It merely states the users that only use once in a while (light users) have no increased risk if cancer.
From what I've read, the same thing goes for smoking cigarettes. Light users have a very decreased likelihood of developing cancer.
TL;DR - Smoke is cancerous. Period. Doesn't matter what "kind" of smoke it is. If it's been burned, and you're inhaling it - it's going to cause cancer. Science has proved that, again and again. If you don't believe, or can't accept that, then that's your problem, not science's.
