## 4 Search Method and Results  
Literature searches for the putative lung LPO-derived aldehydes were performed using the SciFinder\({}^{\text{n}}\) and PubMed\({}^{\text{\textregistered}}\) databases, last searched 25 May 2022, with no restrictions on date of publication. The searches used combinations of the keywords and phrases: lung cancer, breath, and marker. The PubMed\({}^{\text{\textregistered}}\) searches had no exclusions, while SciFinder\({}^{\text{n}}\) marked 70,178 reports to be ineligible using an automation tool due to a low relevance to the searched terms. Titles and abstracts were screened for reports of exhaled breath related to lung cancer. Those that passed the initial screening process and reported aldehydes were collected for this review. Table 3 is a summary of the results. Specifically, 16,378 records were screened by the author [PERSON], 114 were assessed for eligibility, and 44 studies spanning 34 years, from 1988-2022, were selected. Tabulated data from these 44 reports was reviewed by the authors [PERSON] and [PERSON]. Given the timespan of the reports in our study and differences in patient details reported, our analysis of the data does not include patient age, sex, or race. Smoking history, reported by some studies but not all, is also not tabulated in our analysis and is another limitation of this review.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Year**} & \multirow{2}{*}{**Study b**} & \multirow{2}{*}{**Patients c**c**} & \multicolumn{3}{c}{**Breath Collection**} & \multicolumn{1}{c}{**Preconcentration Method**} & \multicolumn{1}{c}{**Analytical Instrument**} & \multirow{2}{*}{**Saturated Aldehydes**} & \multirow{2}{*}{
\begin{tabular}{c} **Unsaturated Aldehydes** \\ **Aldehydes** \\ \end{tabular} } \\ \cline{5-5}  & & & & & & & \\ \hline
1988 & O’Neill [59] & 8 & NR & Teflon bag & Tenax TA & GC-MS &
\begin{tabular}{c} proposal, octanal, \\ nonanal \\ \end{tabular} & \\
1999 & Phillips [60] & 108 & I–IV & \
\begin{tabular}{c} 10 L \\ collection \\ apparatus \\ \end{tabular} &
\begin{tabular}{c} activated \\ carbon \\ \end{tabular} & GC-MS & **hexanal, heptanal** \\
2004 & Deng [61] & 10 & I & \
\begin{tabular}{c} sampling \\ bulb \\ \end{tabular} &
\begin{tabular}{c} CAR/PDMS \\ SPME \\ (unspecified) \\ \end{tabular} & GC-SAW & **hexanal, heptanal** \\
2005 & [PERSON] [62] & 24 & NR & Tedlar bag & \
\begin{tabular}{c} SPME \\ (unspecified) \\ \end{tabular} &
\begin{tabular}{c} GC-SAW \\ sensor \\ \end{tabular} & **hexanal, heptanal** \\
2007 & [PERSON] [63] & 29 & NR & [PERSON] bag & PDMS & GC-FID & **hexanal, heptanal** \\
2009 & [PERSON] [64] & 285 \({}^{\text{c}}\) & NR & [PERSON] bag & CAR/PDMS &
\begin{tabular}{c} PTR-MS/ \\ GC-MS \\ \end{tabular} & **pentanal** \\
2009 & [PERSON] [65] & 18 & IV & [PERSON] bag & PDMS & GC-MS & hexanal, heptanal \\ \hline \hline \end{tabular}
\end{table}
Table 3: Study details and exhaled aldehydes reported in breath analysis articles reviewed \({}^{\text{a}}\).  
\begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline
**Year** & **Study b** & **Patients c** & **Stage d** & **Breath** & **Preconcentration** & **Analytical** & **Saturated Aldehydes** & **Unsaturated Aldehydes** \\ \hline
2009 & [PERSON] [(66)] & 65 & NR & Tedlar bag & CAR/PDMS & GC-MS & pentanal & \\  & & & & PDMS/DVB & & & & \\
2010 & [PERSON] [(67)] & 12 & III-IV & Tedlar bag & (PFB